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Procedure to Inspect and Repair the Center Section Frame on Certain 793F Off-Highway Trucks{0679, 7051} Caterpillar Usage: 793F AC EMD 793F CMD RBT 793F-XQ SND 793F SSP
Off-Highway Truck/Tractor: 793F AC (S/N: EMD76-77) 793F (S/N: SND1-UP; SSP1-UP; RBT1-UP)
Introduction ReferenceSpecial Reference Special Instruction, REHS4439, "High Voltage Isolation Procedure for Welding on a Large Off-Highway Electric Drive Truck" Ref erenceSpec erenceSpecial ial Instruction Instruction,, REHS1841 REHS1841,, "G "General eneral Welding Procedures" This special instruction contains the necessary instructions for inspection and repair of the center section of the frame for certain 793F Off-Highway Trucks. When you need to remove components in order to repair the chassis, refer to the appropriate Disassembly and Assembly Manual. Note: The body does not need to be removed for inspection or frame repair as long as retaining cables are in serviceable condition and used properly. Table 1 Disassembly and Assembly Manuals Sales Model
Machine Systems
Power Train
KENR8579
KENR8397
UENR1142
UENR1143
793F 793F XQ 793F CMD (Command For Hauling) Table 2
Required Tooling
Telescoping Mirror Bore Scope Magnetic Particle Test Kit Dye Penetrant Test Kit Table 3 Required Parts
(1 )
Qty
Part Number
Description
2
431-7565 431-7565
Plate (1)
24
441-3206
Plate (1)
4
441-3208 441-3208
Plate (1)
1
378-9104
Bracket As
1
295-3006
Bracket As
Serviceable part can be ordered or fabricated
The Power Train Electric Drive System will contain hazardous voltage levels during machine operation and for a short period of time after engine shutdown. Do not remove any covers that will expose energized high voltage electrical components while the engine is operating. Any type of maintenance on the following components can only be performed after the Power Train Electrical System Service Shutdown procedure has been followed: High voltage compartments in the inverter cabinet The rear axle housing that contains the electric drive traction motors The generator The retarding resistor grid, the grid blower motor and the grid system cabling The excitation field regulator The high voltage cables and connection enclosures Failure to follow these instructions could result in personal injury or death.
NOTICE In order to prevent damage to components. The power train high voltage system must be shorted to the cabinet ground before welding anywhere on the truck.
NOTICE Do not allow any dirt or foreign material to get into the hydraulic system during assembly, connection of lines, when components are filled with fluid, or during any maintenance operation.
NOTICE Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates.
Important Safety Information The following information is an explanation of various labels that are found in this document. Warnings The warning label informs the technician that an injury or death can occur as a result of a condition that may exist. Notices A notice informs the technician that component damage can occur as a result of a condition that exists. Notes
A note contains general information for the technician about the operation that is being performed. Proper repair is important to the safe operation and the reliable operation of this machine. This document outlines basic recommended procedures. Some of the procedures require special tools, devices, or work methods. Before you perform any repairs or before you perform any maintenance, read all safety information. Understand all safety information before you perform any repairs or before you perform any maintenance. Safety information is provided in this document and on the machine. If these hazard warnings are not heeded, bodily injury or death could occur to you or other persons. The "Safety Alert Symbol" that is followed by a "Signal Word" identifies a hazard. "DANGER", "WARNING", and "CAUTION" are "Signal Words".
Illustration 1
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The signal word "WARNING" has the following meanings: Pay Attention ! Become Alert ! Your Safety Is Involved ! The message that appears under the safety alert symbol explains the hazard. Operations or conditions that may cause product damage are identified by "NOTICE" labels on the machine and in the service information. The person that services the machine may be unfamiliar with many of the systems on the machine. Use caution when you perform service work. Special knowledge of the systems and of the components is important. Before you remove or disassemble any component, obtain knowledge of the system and knowledge of the component. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The safety information in this document and the safety information on the machine are not all inclusive. Determine that the tools, procedures, work methods, and operating techniques are safe. Determine that the operation, lubrication, maintenance, and repair procedures will not damage the machine. Determine that the operation, lubrication, maintenance, and repair procedures will not make the machine unsafe.
Basic Precautions
Improper operation, lubrication, maintenance or repair of this product can be dangerous and could result in injury or death. Do not operate or perform any lubrication, maintenance or repair on this product, until you have read and understood the operation, lubrication, maintenance and repair information.
Always observe the list of basic precautions that follows:
Safety Signs Safety signs include the items that follow: signs, information plates and decals. Read all "Safety" signs on the machine before operating, lubricating, or repairing the machine. Understand all "Safety" signs on the machine before operating, lubricating, or repairing the machine. Replace any safety signs that are in the conditions that follow: damage, unreadable and missing.
Protective Equipment When you work around the machine, always wear protective equipment that is required by the job conditions. Protective equipment includes the items that follow: hard hat, protective glasses and protective shoes. In particular, wear protective glasses when you use a hammer or when you use a sledge hammer. When you weld, use the appropriate protective equipment that is required by the job conditions. Protective equipment for welding includes the items that follow: gloves, welding hood, goggles and apron. Do not wear loose clothing or jewelry that can catch on parts of the machine.
Mounting and Dismounting Use steps and handholds when you mount a machine. Also, use steps and handholds when you dismount a machine. Before you mount the machine, clean any mud or debris from steps, walkways, or work platforms. Always face the machine when you use steps, handholds, and walkways. When you cannot use the accesses on the machine, use ladders, scaffolds, or work platforms to perform safe repair operations.
Specifications for Cables, Chains, and Lifting Devices
Use approved cables, chains, and lifting devices in order to lift components. Refer to the manufacturer's weights in order to determine the application when you select the following items: cable, chain and lifting devices. When you lift a component, the lift angle is critical. Refer to the Illustration that follows in order to see the effect of the lift angle on the working load limit. Note: The lifting devices that are shown in this publication are not Caterpillar parts. Note: Ensure that the hooks are equipped with a safety latch. Do not place a side load on the lifting eyes during a lifting operation.
Illustration 2 Lift angles for lifting slings. (A) The load capacity is 100% of the working load limit for the sling. (B) The load capacity is 86% of the working load limit for the sling. (C) The load capacity is 70% of the working load limit for the sling. (D) The load capacity is 50% of the working load limit for the sling.
Hot Fluids and Parts
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To avoid burns, be alert for hot parts on machines which have been stopped and hot fluids in lines, tubes and compartments. Be careful when you remove filler caps, breathers, and plugs on the machine. Hold a rag over the cap or plug in order to prevent being sprayed by pressurized liquids. When the machine has been stopped, the danger of hot fluids is greater.
Corrosion Inhibitor Corrosion inhibitor contains alkali. Avoid contact with the eyes. Do not allow corrosion inhibitor to contact the skin for extended periods of time. Avoid repeated contact with the skin. Do not drink corrosion inhibitor. In case of contact, immediately wash skin with soap and water. For contact with the eyes, flush the eyes with large amounts of water for at least 15 minutes. Seek medical attention.
Batteries Do not smoke when an inspection of the battery electrolyte level is made. Never disconnect any charging unit circuit or battery circuit cable from the battery when the charging unit is operating. A spark can cause an explosion from the flammable vapor mixture of hydrogen and oxygen that is released from the electrolyte through the battery outlets. Do not allow battery electrolyte to contact skin or eyes. Battery electrolyte is an acid. In case of contact with battery electrolyte, immediately wash the skin with soap and water. For contact with the eyes, flush the eyes with large amounts of water for at least 15 minutes. Seek medical attention.
Pressurized Items 1. Always use a board or a piece of cardboard when you check for a leak. Leaking fluid under pressure can penetrate body tissue. Fluid penetration can cause serious injury and possible death. A pin hole leak can cause severe injury. If fluid is injected into your skin, you must get treatment immediately. Seek treatment from a doctor that is familiar with this type of injury. 2. Relieve all pressure in air, oil, or water systems before any lines, fittings, or related items are disconnected or removed. Always make sure that all raised components are blocked correctly. Be alert for possible pressure when you disconnect any device from a system that utilizes pressure. 3. Fuel lines that are damaged and fuel lines that are loose can cause fires. Lubrication lines that are damaged and lubrication lines that are loose can cause fires. Hydraulic lines, tubes, and hoses that are damaged can cause fires. Loose hydraulic lines, loose tubes, and loose hoses can cause fires. Do not bend or strike high-pressure lines. Do not install lines which have been bent or damaged. Check lines, tubes, and hoses carefully. Do not use your bare hand to check for leaks. If fluids are injected into your skin, you must get treatment immediately. Seek treatment from a doctor that is familiar with this type of injury.
4. Pressure air or water can cause personal injury. When pressure air or water is used for cleaning, wear a protective face shield, protective clothing, and protective shoes. The maximum air pressure for cleaning purposes must be below 205 kPa (30 psi). When you use a pressure washer, keep in mind that the nozzle pressures are high. The nozzle pressures are frequently above 13790 kPa (2000 psi). Follow all of the recommended practices that are provided by the manufacturer of the pressure washer.
Approved Inspection Methods Visual inspection (VT), dye penetrant inspection (PT), magnetic particle inspection (MT) and ultrasonic inspection (UT) are required for this repair procedure. Each of these inspection methods should be conducted and reported by qualified personnel. Examples of qualified personnel are as follows: VT - AWS CWI (American Welding Society Certified Welding Inspector) or equivalent. MT/PT/ - ASNT (American Society of Nondestructive Testing) Level II (minimum) for each method used. Do not use the magnetic particle inspection process around components that will be affected by magnetism. Do not use the dye penetrant inspection process around components that will be affected by the dye penetrant solution.
Requirements for Ultrasonic (UT) Testing
Personnel Personnel performing the inspections will be at least Level II Certified Technicians in the Ultrasonic Testing method, as defined by ASNT SNT-TC-1A, ASNT CP-189, or other equivalent international standard. Personnel performing the inspections will be trained by a Level II or Level III, until the personnel show proficiency and understanding of procedures and rejection criteria.
Apparatus Ultrasonic (UT) Instrument The UT flaw detection instrument shall be capable of generating, receiving, and amplifying highfrequency electrical pulses at such frequencies and energy levels required to perform a meaningful examination and provide suitable readouts. Preferred functions/features include but not limited to: inspection program recording, signal gating system, measurement data display, DAC/TCG recording, and 0 Db Reference. UT instrument certification/qualification should be performed annually according to ASTM E317 or equivalent. Including the verification of key performance characteristics, such as horizontal limit and linearity, vertical limit and linearity, resolution - entry surface and far surface, sensitivity and noise, accuracy of calibration gain controls.
Angle Beam/Shear wave Search Unit
The ultrasonic transducer (probe, or search unit) shall be capable of transmitting and receiving ultrasound at the required frequencies and energy levels necessary for discontinuity detection in the material being examined. Frequencies of 2 MHz to 5 MHz shall be employed for anglebeam shear wave inspection. Transducer crystal can be round, square, or rectangular. Crystal size recommended for weld examination shall be in the range of 9 mm (0.35 inch) to 25 mm (1.0 inch). Selection of a transducer is determined by testing variables. Testing variables include weld thickness, testing surface, acceptable flaw size, flaw orientation, and the acoustic properties of the metal. In angle-beam inspection, the wedge/shoe is attached to the transducer to generate the desired incident beam angle and wave mode in the parts. The common beam angles used in weld inspection are 45°, 60°, and 70°. The refracted angle shall be no greater than ± 2° from normal. The edge distance shall not exceed 25 mm (1.0 inch). The wedge angles shall be selected according to information found in the ""Probe Selection" " section.
Couplant Couplant is required between the face of the search unit and the examination surface. Couplant permits the transmission of ultrasonic waves from the search unit into the material under examination. Typical couplants include cellulose gel, glycerin, and light machine oil. Corrosion inhibitors or wetting agents may be added. Couplants must be selected that are not detrimental to the product or the process. Special couplant and search unit may be required at elevated temperatures (above 52° C (125° F).
Distance Calibration Blocks Refer to ASTM E164 for two options of distance calibration blocks, other suitable blocks may be used.
Illustration 3
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Option 1: IIW Type 1 or Type two Block
Illustration 4
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Option 2: DSC Block
Sensitivity Calibration Blocks Three options for sensitivity calibration blocks are given but other blocks may be used. Minimum requirements shall meet the requirement determined in the ""Sensitivity Calibration" "
section. For other sensitivity blocks: 1.5 mm (0.06 inch) side-drilled- holes (SDH) parallel to the inspection surface and perpendicular to the sound path shall be used as the calibration target.
Illustration 5
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Option 1: Cat® DAC Block (A) 340 mm (13.40 inch) (B) 90 mm (3.55 inch) (C) 40 mm (1.60 inch) (D) 1.5 ± 0.05 mm (0.05 ± 0.001 inch) diameter SDH's (E) 10 ± 0.1 mm (0.40 ± 0.004 inch) (F) 20 ± 0.1 mm (0.80 ± 0.004 inch) (G) 30 ± 0.1 mm (1.20 ± 0.004inch) (H) 40 ± 0.1 mm (1.60 ± 0.004 inch) (J) 63 ± 0.1 mm (2.50 ± 0.004 inch) (K) 126 ± 0.1 mm (5.0 ± 0.004 inch) (L) 189 ± 0.1 mm (7.40 ± 0.004 inch) (M) 252 ± 0.1 mm (9.90 ± 0.004 inch)
Option 1: Cat® DAC Block 1.5 mm (0.06 inch) SDH's at 10 mm (0.40 inch) steps from the surface to include all depths over all thickness ranges to be used. Use the dimensions in Illustration 5 in order to fabricate Cat® DAC Block use ASTM A572 Grade 42/50 steel.
Illustration 6
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Option 2: Cat® t Blocks (N) 200 mm (8.0 inch) (P) 16 mm (0.60 inch) (R) 40 mm (1.60 inch) (S) 1.5 ± 0.05 mm (0.05 ± 0.001 inch) diameter SDH's (T) 4 ± 0.1 mm (0.16 ± 0.004 inch) (U) 8 ± 0.1 mm (0.30 ± 0.004 inch) (V) 20 ± 0.1 mm (0.80 ± 0.004 inch) (W) 160 ± 0.1 mm (6.30 ± 0.004 inch)
Illustration 7
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Option 2: Cat® t Blocks (X) 200 mm (8.0 inch) (Y) 50 mm (2.0 inch) (Z) 40 mm (1.60 inch) (AA) 1.5 ± 0.05 mm (0.05 ± 0.001 inch) diameter SDH's (BB) 12.5 ± 0.1 mm (0.50 ± 0.004 inch) (CC) 25 ± 0.1 mm (1.0 ± 0.004 inch) (DD) 20 ± 0.1 mm (0.80 ± 0.004 inch) (EE) 160 ± 0.1 mm (6.30 ± 0.004 inch)
Option 2: Cat® t Blocks: Blocks the same material and thickness as the parts to be tested. Machined 1.5 mm (0.06 inch) SDH's at 1/4t and 1/2t depths. Blocks must be long enough for full skip path and wide enough for the entire search unit to sit on the scanning surface. Use the dimensions in Illustration 6 and Illustration 7in order to fabricate Cat® t Blocks use ASTM A572 Grade 42/50 steel.
Illustration 8
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Option 3: IIW Type 1 or 2 Blocks
Option 3: Use 1.5 mm (0.06 inch) SDH position A refer to Illustration 8. An attenuation factor for indication interpretation will have to be used to compensate for attenuation of the sound-beam as the sound beam propagates through the material. Reference AWS D1.1 or equivalent code or standard for further instruction.
Sample Preparation Surface Preparation The surface must have contour allowing the close coupling between the search unit and scanning surface. The inspection surface shall be free of loose scale, loose paint, weld spatter, dirt, excessive roughness, or other foreign objects that would interfere with the transmission of sound energy from the search unit into the part. Cleaning and/or grinding may be needed.
Test Procedure Equipment Calibration In addition to the annual UT equipment certification/qualification, periodical calibration or standardization is required to verify that UT equipment is performing as intended for day-to-day usage. For angle beam applications, the following key parameters shall be checked: Distance Calibration: The distance and sensitivity calibration should be verified by the UT operator. Re-calibration shall be made a minimum of every 4 hours or process change, such as changing operator, search unit and/ cable, battery, testing weld, and re-couple search unit. Verify the Beam Index Point: (The following example is conducted on a IIW Type Block.) Position the UT probe toward the 100 mm (4.0 inch) radius on the IIW-type reference block. Set proper range in the instrument to ensure that the signal from the 100 mm (4.0 inch) radius is displayed. Scan the search unit back and forth to peak the 100 mm (4.0 inch) signal. The point on the search unit wedge aligning with the 0 reference line on the calibration block is the beam index/entry point (position D in Illustration 3). Verify the Beam Angle: Position the search unit toward the Lucite/open window on the IIWtype reference block. Set proper range in the instrument to ensure that the signal from the Lucite/open window is displayed. Scan the search unit back and forth to peak the signal. The angle marked on the reference block in line with the search unit index point is the actual beam angle. The beam angle tolerance shall be within ± 2°. Depending on the beam angle and the type of reference block, other techniques recognized by related industrial standards may be used (position B or C in Illustration 3). Distance Calibration: In order to ensure the accuracy of locating weld discontinuities, the distance shall be calibrated through the entire sound path used during the specific examination.
100 mm (4.0 inch) radius on the IIW-type reference block is commonly used for distance calibration in angle beam applications (position D in Illustration 3). Position the UT probe toward the 100 mm (4.0 inch) radius. Set the proper range in the instrument to ensure the second reflection from the 100 mm (4.0 inch) radius can be displayed. In order to obtain meaningful readings, other instrument settings, such as probe angle, gate and gain level shall be properly selected.
Sensitivity Calibration 1.5 mm (0.06 inch) side-drilled-holes (SDH) parallel to the inspection surface and perpendicular to the sound path shall be used as the calibration target. DAC/TCG - DAC (distance-amplitude-correction) or TCG (time corrected gain): The signal from the 1.5 mm (0.06 inch) SDH should be calibrated to be 80% FSH (full-screen height) for the first point of a DAC curve and all points for the TCG. DAC and TCG shall be used to ensure the same inspection sensitivity at different sound paths across the entire range. Minimum of three points shall be used to establish the DAC/TCG, over the entire range and a full skip distance for the material thickness being tested. Use Sensitivity Calibration Blocks Option 1 or Option 2 described in the ""Sensitivity Calibration Blocks" " section. Example for DAC/TCG set-up for a 16 mm (0.60 inch) thick weld joint using 70° wedge using the Cat® DAC Block use the 10 mm (0.40 inch), 20 mm (0.80 inch), and 30 mm (1.20 inch) holes. Example for DAC/TCG set-up for a 16 mm (0.60 inch) weld joint using 70° wedge using the Cat® t block. Use the 1/4t hole, 3/4t hole, and the 7/4t hole. Reference Reflector: When, a single 1.5 mm (0.06 inch) Reference Reflector (refer to AWS D1.1) is used to attain a horizontal reference-line height indication. The maximum Db level used to obtain an 80% FSH peak signal shall be recorded as the Reference Gain Level. An attenuation factor for indication interpretation will have to be used to compensate for attenuation of the sound beam as the sound beam propagates though the material. An Indication Rating should be calculated for the basis of Acceptance or Rejection. Use Sensitivity Calibration Block Option 3 position A in Illustration 8.
Scan Pattern, Scan Distance, and Scan Speed
Illustration 9
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(FF) Scan distance less than 150 mm (6.0 inch) per second (GG) First leg (HH) Second leg (JJ) Weld center line (KK) Scan pattern (LL) Scanning advance (not to exceed 75% of search unit width) (MM) Oscillating angle ± 15° (NN) Search unit
The entire volume of weld and HAZ (heat affected zone) shall be examined from each side of the weld wherever practical. Examination shall be made in first and second leg wherever possible. Scan speed shall be less than 150 mm (6.0 inch) per second unless the inspection procedure specifies differently. The typical inspection configuration for a butt weld is shown in Illustration 9 in the ""Sensitivity Calibration Blocks" " section. In order to detect longitudinal discontinuities. The search unit shall be oscillated to the left and right with an angle of approximately ± 15° while continuously scanning perpendicularly to the weld axis. The lateral movement advancing the search unit shall not exceed 75% of the search unit width. In order to ensure full volume coverage. The scan distance shall cover at least 1 full skip path (first and second leg) back from the weld center line. To detect transverse discontinuities, the sound beam shall be directed at approximately 15° parallel to the weld axis. The search unit shall be moved along the weld edge from both sides and from opposite directions.
Initial Surveillance Scanning For initial scanning, extra gain (6dB or 12dB) may be required in order to facilitate detection of potential discontinuities. The evaluation of the indication shall be performed back to the reference sensitivity.
793F UT Inspection Areas
Illustration 10 Joint detail around the window plate (PP) Weld seams around the window plate
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Illustration 11
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View of a crack which propagated through the bottom rail section
Refer to the repair procedures in this document for specific information for joint type and configuration.
Probe Selection Table 4 Weld Thickness
6 mm (0.25 inch) thru
Wedge Angle (1)
Range (2)
70
100
70
150
45
200
20 mm (0.80 inch)
20 mm (0.80 inch) thru 38 mm (1.50 inch)
38 mm (1.50 inch) thru 80 mm (3.15 inch) (1 )
Multiple wedge angles can be used for thicknesses outside guideline.
(2 )
Range setting should be adjusted accordingly to have a full skip path on the screen.
The window plates are 16 mm (0.65 inch) thick, a 70° wedge shall be used for locations (PP) as shown in Illustration 10. The 4 bar link casting to the main rail weld will need UT inspection after a repair or through wall crack in the bottom or top rail section. Refer to Illustration 11. The weld/plate is 50 mm (2.0 inch) thick and a 45° wedge shall be used. Table 4 shall be used for reference if needed. Alternate angles can be used for multiple thicknesses if warranted by joint design or joint preparation.
Accept/Reject Criteria and Sizing
Illustration 12 (AB) Search unit (AC) Search unit (AD) Search unit (AE) Distance between (L1) and (L2) (AF) Signal amplitude (AG) Amplitude profile (AH) Threshold (AJ) 50% threshold (AK) Search unit position (L) Length of indication over the threshold (LR) Length of indication over the 50% threshold (L1) Longer discontinuity (L2) Shorter discontinuity
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Note: Adjacent discontinuities: when (AE) is smaller than the designated minimum length ( (AE) < (L1) or a specific length), the two discontinuities shall be regarded as continuous and the overall length is (L1) + (AE) + (L2) . Subsurface internal weld quality will meet the requirements set forth by Table 10. In order to determine the rejectable lengths of indications that meet or exceed the 1.5 mm (0.06 inch) SDH reverence level: An indication that meets or exceeds the reference level (DAC, TCG, or 0 Reference Level) continuously for 25 mm (1.0 inch) or 10% of the weld length whichever is less is rejectable. Intermittent indications that do not meet the criteria but the aggregate length of the indications exceed 10% of total weld length is rejectable. Indications below 5 mm (0.20 inch) in length are not typically included in the aggregate indication length. In determining the ends of rejectable indications. The 6dB drop method shall be used, with the flaw detector sensitivity set to the reference level (0dB). Move the search unit parallel to the weld until the tip of the signal drops to 50% of the DAC height. Mark the weld even with the center of the search unit. Move the search unit parallel to the weld in the opposite direction until the signal drops to 50% of the DAC height. Mark the weld even with the center of the search unit. Acceptability of welds with multiple defective areas. If the space between two defective areas is less than the largest defect length, the area between the two defective areas shall also be considered rejectable and should be marked for repair. Refer to Illustration 12.
Mark for Weld Repair To repair the rejected weld, additional excavation length at each end of the rejectable discontinuity is normally required. A general guideline is to mark an additional 25 mm (1.0 inch) to 50 mm (2.0 inch) on both ends of the discontinuity in order to ensure proper removal of defective areas. This guideline shall be followed wherever practical.
Reporting After the ultrasonic (UT) inspection is completed, fill out the forms provided. Refer to Table 15 and Table 16 at the end of this document. A copy should be provided to the Customer, Dealer, and/or the appropriate Caterpillar product support representative.
Inspection Intervals Inspections of the frame assembly for cracks should be conducted during regular maintenance intervals. Areas to be inspected are blocked by one or more components. If the component that is blocking the frame is removed, an inspection of that area should be performed. Take advantage of the opportunity to inspect those parts of the frame assembly that are exposed whenever components are removed. As an example, if the hydraulic tank is ever removed, the area behind the hydraulic tank should be cleaned and inspected. Refer to Operation and
Maintenance Manual, SEBU8406, "793F Off-Highway Truck", "Frame - Clean/Inspect" for the proper inspection intervals.
Welding Specifications and Qualifications
Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can kill. Read and understand the manufacturer's instruction and your employer's safety practices. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing zone and the general area. Wear correct eye, ear and body protection. Do not touch live electric parts. Refer to the American National Standard Z49.1, "Safety in Welding and Cutting" published by the American Welding Society, 2501 N.W. 7th Street, Miami, Florida 33125: OSHA Safety and Health Standards, 29 CFR 1910, available from U.S. Dept. of Labor, Washington D.C. 20210.
Note: Personal breathing protection should be worn by the personnel that are welding. Personal breathing protection will prevent fumes from entering the lungs of the person that is welding. Use a 237-5181 Respirator for breathing protection.
Qualifications Welders must be qualified for the appropriate type of weld that is being performed. Welders must be qualified for the appropriate position of weld that is being performed. Welders must be qualified for the welding process that is being utilized: Shielded Metal Arc Welding (SMAW) and Flux Cored Arc Welding (FCAW). Refer to Specification ANSI/AWS D1.1 for information that regards qualification requirements. The welders must have used the process at some time within the last 6 months. The welders must complete the process of certification if the welders have not used the welding processes for 6 months.
Proper Welding Procedure on Machines and Engines with Electronic Controls Proper precautions are necessary to prevent damage to electronic controls. When you weld on a machine with electronic controls, use the steps that follow: 1. Turn off the engine. Put the key start switch in the OFF position.
2. If the machine has a battery disconnect switch, open the switch. If the machine does not have a battery disconnect switch, disconnect the negative battery cable at the battery. 3. Attach the clamp for the ground cable as close as possible to the area that is being welded. This process will reduce the likelihood of damage from the welding current to the following components: bearings, hydraulic components, and electrical components. DO NOT weld plates to the frame for grounding/clamping purposes. Use existing blocks, brackets, bosses, and so on, to attach the clamp. Note: Do NOT use electrical components as a ground point for the welder. Do NOT use ground points for electronic components as a ground point for the welder. 4. Protect the wiring harnesses and machine surfaces from sparks and welding spatter.
Area Preparation The area to be welded shall be clean, dry, and free of the following contaminants: Oil Grease Paint Dirt Rust Any fluids or moisture All welding shall be conducted on base material heated and maintained at a minimum temperature of 15.6° C (60° F). Note: Heating instructions (preheat, interpass, and postheat) for any specific repair shall override the minimum 15.6° C (60° F) requirement. Note: Heat distortion of the base metal is possible when you weld. Avoid excessive heating of the base metal.
Welding Electrodes and Parameters Flux Cored Welding Electrode for the FCAW Process Use the Flux Cored Arc Welding (FCAW) with E71T-1 H8 (ANSI/A5.20) welding electrode and the manufacturer's shielding gases that are specified (typically 75% argon and 25% carbon dioxide). The H8 implies that the electrode is designed to provide less than 8 ml/100 g of diffusible hydrogen in the weld deposit. The weld that is deposited by the flux cored welding electrode will have the following minimum mechanical properties: Table 5 Mechanical Properties from Flux Cored Welding Electrode That Is Classified as
"ANSI/AWS A5.20 E71T-1 H8" Tensile Strength
480 MPa (70000 psi)
Yield Strength
400 MPa (58000 psi)
Elongation
22%
Impact Toughness
27 J @ -18 °C (20 ft lb @ -0 °F)
The tables that follow show the recommended parameter ranges for out of position welding in the field for two different flux cored welding electrode diameters. Table 6 Welding Current for Flux Cored Welding Electrode that Is 1.2 mm (0.045 inch) Wire Feed Rate
7620 mm (300 inch) Per Minute to
Voltage
Amperage
24 to 28
190 to 240
10,160 mm (400 inch) Per Minute Table 7 Welding Current for Flux Cored Welding Electrode that Is 1.4 mm (0.052 inch) Wire Feed Rate
5080 mm (200 inch) Per Minute to
Voltage
Amperage
23 to 27
180 to 220
6350 mm (250 inch) Per Minute Note: The settings listed above are recommendations-based on experience from welding in the horizontal, vertical-up, and overhead positions. Slight changes in the voltage and amperage may be necessary due to welding position and various formulations by different electrode manufacturers. The use of higher parameters than specified for welding in the flat position is acceptable. Use a polarity setting of DC reverse polarity. Remove the slag after each welding pass. The fast freezing characteristics of flux cored welding electrode increases the possibility of evolving gas that is trapped in the weld. Control the size of the weld in order to reduce the possibility of evolving gas that is trapped in the weld. The maximum size weld per pass should be equivalent to that of a 8.0 mm (.32 inch) fillet weld.
Low Hydrogen Electrodes for the SMAW Process
As an alternative process or when wind conditions are a factor, use SMAW and low hydrogen electrodes that meet the following requirements. Table 8 Mechanical Properties of Welds from Low Hydrogen Electrodes That Are Classified as "ANSI/AWS A5.1 E7018H4R" Tensile Strength
480 MPa (70000 psi)
Yield Strength
400 MPa (58000 psi)
Elongation
22%
Impact Toughness
27 J @ -29 °C (20 ft lb @ -20 °F)
Low hydrogen electrodes must be stored in an electrode oven at 120 °C (250 °F) when not in use. If low hydrogen electrodes get damp, scrap the low hydrogen electrodes or recondition the low hydrogen electrodes to the manufacturer's specifications. The table that follows shows the settings for the welding current based on electrode diameter. Table 9 Welding Current for Low Hydrogen Electrodes Diameter
Amperage Rating
3.2 mm (1/8 inch)
105-155
4.0 mm (5/32 inch)
130-200
4.8 mm (3/16 inch)
200-275
Use a polarity setting of DC reverse polarity. Remove the slag after each pass of the welding electrode. The width of the weld should not exceed two times the electrode diameter.
Weld Inspection and Acceptance Criteria Table 10 ISO 6520 Defect Name
Defect Reference Number 1011, 1012,
Cracks -
1013, 1014,
Longitudinal,
1023, 1024,
Transverse,
1031, 1033,
Remarks
Defect Limit
Radiating,
1034, 1045,
Crater,
1046, 1047,
Disconnected,
1051, 1053,
Branching
1054, 1061,
--
Not Permitted
1021
Hard Surfacing Welds Only
Permitted
1021
Joining Welds
Not Permitted
1063, 1064 Crack Transverse Crack Transverse
Maximum Diameter for a Single Pore
Porosity
2011, 2012, 2014, 2017
Maximum Pores in Any 300 mm (11.81 inch) Length of Weld
1 mm (0.040 inch)
6
Maximum Number of Pores in Any 50 mm (2.0 inch) of Weld Length for Welds Less Than
1
300 mm (11.81 inch) in Length Clustered Porosity
2013
Maximum Length of Cluster in Any Weld
Maximum Height or Width Elongated Cavities
2015
Discontinuity
Maximum Dimension of Any Single Cavity
Cavities
3 mm (0.120 inch)
Maximum Length for Any Single
Maximum Length in Any Weld
Elongated
3 mm (0.120 inch)
2016
25 mm (1.00 inch) 10% of Weld Length
3 mm (0.120 inch)
10% of Weld Maximum Total Length of Affected
Length Not to
Area in Any Weld
Exceed 25 mm (1.00 inch)
Shrinkage
2021, 2024,
Maximum Diameter or Length
1 mm (0.040 inch)
Cavities
2025
Maximum Height or Width Slag or Flux Inclusions
1 mm (0.040 inch)
3011, 3012, 3014, 3021,
Maximum Length for Any Single
3022, 3024
Discontinuity Maximum Length in Any Weld
Maximum Height or Width Oxide
3031, 3032,
Inclusions
3033
25 mm (1.00 inch) 10% of Weld Length
1 mm (0.040 inch)
Maximum Length for Any Single Discontinuity Maximum Length in Any Weld
25 mm (1.00 inch) 10% of Weld Length
Puckering (Oxide Inclusion -
3034
--
Not Permitted
--
Not Permitted
Visual (Breaking the Surface)
Not Permitted
Aluminum) Metallic
3041, 3042,
Inclusion
3043
Subsurface Maximum Height or Width Lack of Fusion
1 mm (0.040 inch)
4011, 4012, 4013
Subsurface Maximum Length for Any Single Discontinuity Maximum Length in Any Weld
25 mm (1.00 inch) 10% of Weld Length 10% of Nominal Penetration Not to
Maximum Reduced Penetration Lack of Penetration
Exceed 1 mm (0.040 inch)
402, 4021 Maximum Allowed Total Length of
10% of Weld
Reduced Penetration
Length
5011, 5012, Undercut
5013, 5014, 5015
Maximum Depth Measured From Plate Surface - Any Length Any Length
0.5 mm (0.020 inch) --
Weld Face Width 5 mm (0.20 inch) or Less
1 mm (0.040 inch)
Weld Face Width Over Excess Weld
5 mm (0.20 inch) But Less Than
1.5 mm (0.060
10 mm (0.40 inch)
inch)
Metal Groove Weld
502
Weld Face Width Over (10 mm)
Reinforcement
(0.40 inch) But Less Than
(Convexity)
20 mm (0.80 inch)
2 mm (0.080 inch)
Weld Face Width Over 20 mm (0.80 inch) But Less Than 30 mm (1.20 inch)
3 mm (0.120 inch)
Weld Face Width 30 mm (1.20 inch) and Over Convexity Affects Weld Toe Angle, Reducing Fatigue Life
Excess Weld Metal - Fillet Weld
503
Convexity
Weld Toe Angles of 135 Degrees and More Are Better Defect Limits Expressed as Minimum Toe Angles Allowed
Without Drawing Limitation
4 mm (0.160 inch) 90 Degrees
--
--
2 mm (0.080 inch) (Any Length)
Excess
5041, 5042,
Penetration
5043
Incorrect Weld Toe Overlap
With "Melt - Thru" and "Flush" Weld Symbols
1 mm (0.040 inch) (Any Length)
With "Melt - Thru" and "Grind Flush"
Not Permitted
Symbols
(After Grinding)
When 1E2995 Applies (Expressed 505
5061, 5062
as a Toe Radius Rather Than a Toe
3 mm (0.120 inch)
Angle)
Minimum Radius
Expressed as Minimum Toe Angle
90 Degrees
Applies to Either Weld Leg Measured Independent of the Other
Maximum Undersize Fillet Weld Leg Size -
--
1 mm (0.040 inch) 10% of Total Weld
--
Length If At Least
Undersize
10% of Total Weld Length is at Least Maximum Length of Undersize Weld
1 mm (0.040 inch) Over Nominal Size, Otherwise, No Undersize Length is Permitted
Applies to Either Weld Leg Measured Independent of the Other
Maximum Oversize Fillet Weld Leg Size -
--
Oversize
--
+25% (max 3 mm (0.120 inch))
Conformance to Design - Fillet Weld Leg Sizes May be Oversized (Within Defect Limitations or Beyond) Without Correction Provided the Excess Does not Interfere with
--
Satisfactory End Use of the Component (i.e., Distortion, Fit-Up Interference, etc.) Fillet Weld -
Weld Size ≤
Linear Length
6.5 mm (0.256 inch)
when specified at less than the length of the joint
± 6.5 mm (0.256 inch)
-Weld Size ≥ 6.5 mm (0.256 inch)
± 12.5 mm (0.492 inch)
Nominal Size (0.7 x Leg Size) Not Inclusive of Penetration Beyond the
Not Permitted
Weld Root
2 mm (0.080 inch)
Fillet Weld Throat Size -
MAX - and Not to 5213
Undersize
Exceed 20% of Weld Crater Only - Maximum
Specified Throat,
Undersize
Not Inclusive of Penetration Beyond the Weld Root (0.7 x Leg Size)
Careful Consideration Needs to be Given When Plate Mismatch is
Incompletely Filled Groove
511
Weld
Not Permitted
Apparent Weld Depth Must be Maintained as a Minimum
--
Root Concavity on Open Root
Maximum Depth measured From 515, 5013
Groove Welds
Plate Surface or Tube Inner Surface
0.5 mm (0.020
- Any Length
inch)
Measured in Terms of Excess Weld Metal (Fillet Weld Convexity) or Overlap on Groove Welds, Lack of
--
Fusion, or Insufficient Throat Excess Weld Metal on Fillet Welds, Defect Limits Expressed as Poor Restart (Tie - In)
5171, 5172
90 Degrees
Minimum Toe Angles Allowed Overlap on Groove Welds, Defect Limits Expressed as Minimum Toe
90 Degrees
Angles Allowed Lack of Fusion - Visual Maximum
Stray Arc Strike
601
Length Per Restart
3 mm (0.120 inch)
Insufficient Weld Throat
Not Permitted
--
Not Permitted
SMAW, SAW, FCAW, GMAW
Not Permitted Silicon Residue
Slag Residue
615
Permitted Unless GTAW
Removal Specified by Drawing Note Total Maximum Combined Length of All Imperfections in a Weld, Expressed as a Percent of Total
Combined Discontinuities
--
15%
Weld Length (No Single Type of Imperfection Can Exceed the Limits for That Single
--
Type of Imperfection)
General Weld Repair 1. Remove any components that prevent access to the cracked weld. 2. Refer to ""Area Preparation" " Section in this Special Instruction. 3. Use dye penetrant (PT) or magnetic particle (MT) in order to identify the extent and/or length of the necessary repair. 4. Protect machined surfaces from sparks and weld debris. 5. Ensure that the base material is at a minimum temperature of 15.6° C (60° F) before welding. Ensure that a minimum temperature of 15.6° C (60° F) is maintained throughout the entire welding procedure. 6. The crack (and sound metal 50 mm (2.00 inch) beyond each end of the crack) shall be removed by gouging and/or grinding. Caution should be used to avoid excessive removal of the surrounding base material. Areas that are gouged by air carbon arc torch shall be later ground and cleaned prior to welding in order to remove all carbon absorption or contamination. Gouged areas requiring rewelding shall have a root radius of not less than 5 mm (0.20 inch) and a Single V - 60 degree included angle joint preparation to allow the welder reasonable access to reinstate the weld. 7. Use PT or MT to inspect the gouged and ground area in order to ensure that the crack has been removed before welding commences. 8. Repair the prepared groove utilizing the recommendations provided in the ""Welding Electrodes and Parameters" " Section in this Special Instruction. 9. Clean the weld area. Inspect the area that was welded. All weld quality shall conform to the criteria specified in the ""Weld Inspection and Acceptance Criteria" " section in this Special Instruction.
Proper Cleaning for Inspection
When it is necessary to work under the machine with the body (bed) raised, attach the body (bed) retaining cables to the rear tow points. Install the rear tow point pins through the ends of the retaining cables. Failure to properly secure the body (bed) may result in personal injury or death.
Personal injury can result from working with cleaning solvent. Because of the volatile nature of many cleaning solvents, extreme caution must be exercised when using them. If unsure about a particular cleaning fluid, refer to the manufacturer's instructions and directions. Always wear protective clothing and eye protection when working with cleaning solvents.
NOTICE Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates.
Illustration 13
g03361075
Top view of the frame assembly with center section highlighted
Clean the center section of the frame thoroughly, especially behind tanks, in order to ensure visible detection of any cracks. Refer to Illustration 13 for location of the center section. Ensure that the substances that follow are removed from the area that will be inspected. Oil Grease Dirt
Inspection Procedure
Inspect Center Section of the Frame
Illustration 14
g03361127
1. Visual inspection will require a combination of a telescoping mirror and/or a bore scope in order to view some of the areas listed. In most cases, visual inspection will be satisfactory: however any uncertainty should be verified via magnetic particle MT inspection.
Inspect 4 Bar Link Casting to Main Rail Connection
Illustration 15 Top view of the frame
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Illustration 16
g03361144
Bottom view of the frame
Illustration 17
g03361154
Example of corner crack at 4 bar link connection
1. Visually inspect the 4 bar link casting to main rail connection as shown in Illustration 15 and Illustration 16.
If cracking occurs, cracks will be most readily visible at the corners of the weld joint as shown in Illustration 17. Note: The weld reinforcement has been sanded flush with the parent material so the groove weld connection is not readily identifiable.
Inspect Fillet Welds Connecting Tube to Volcano Plate Interior
Illustration 18
g03361176
Interior view of tube assembly (A) Tube assembly (B) Plate (volcano)
1. Visually inspect the fillet welds connecting tube assembly (A) to volcano plate (B) on the interior side. 2. Inspect fillet weld 360 degrees on both interior sides of the truck. Refer to Illustration 18 for guidance.
Inspect Fillet Welds Connecting Tube Assembly to Outer Window Plate and Cover Plate - Exterior
Illustration 19
g03361203
Exterior view of tube assembly (A) Tube assembly (C) Outer window plate (D) Cover plate
Illustration 20 Example of a fillet weld crack in the tube assembly to the outside window plate location
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1. Visually inspect the fillet welds connecting tube assembly (A) to outer window plate (C) and cover plate (D) on the exterior side. Refer to Illustration 19. 2. Inspect fillet welds 360 degrees on both exterior sides of the truck. Refer to Illustration 20 for guidance.
Inspect Groove Weld Between Outer Window Plate and 4 Bar Link Casting - Exterior
Illustration 21 Exterior view of tube assembly (C) Outer window plate
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Illustration 22
g03361229
Example of groove weld crack between outer window plate and 4 bar link casting
1. Visually inspect the groove weld connecting outer window plate (C) to the 4 bar link casting on both exterior sides. Refer to Illustration 22 for guidance.
Inspect Vertical Groove Weld Between Adjacent Window Plates - Exterior
Illustration 23 View of the left-hand side (C) Outer window plate (E) Outer window plate
g03361246
Illustration 24
g03361252
Example of a crack in the groove weld connecting the adjacent outer window plates
1. Visually inspect the vertical groove weld connecting adjacent outer window plate (E) and outer window plate (C). Refer to Illustration 23 for guidance.
Inspect Fillet Welds Attaching Hardware to Outer Window Plates - Exterior
Illustration 25
g03361502
View of the right-hand side of the frame
1. Visually inspect the fillet welds attaching all hardware on the two outer window plates as shown in Illustration 25. Inspect both sides of the truck.
Illustration 26
g03361516
Example of fillet weld crack around hardware Illustration 26 shows a large bottom cooler mount. The large cooler mount can be found on earlier model trucks. Later model trucks will reflect the three small blocks on the bottom as shown in Illustration 25.
Illustration 27 View of the inside right-hand side of the frame (F) Pump box
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Illustration 28
g03361533
2. Visually inspect the fillet weld connecting pump box (F) to the inside window plate on the right-hand side of the frame as shown in Illustration 27. The main concern is the top right-hand corner of pump box (F). Refer to Illustration 28. 3. Once inspection of the frame is completed, refer to Illustration 29 in the following section in order to determine what course of repair is recommended. If no cracks are visually detected, then no repair is required.
Decision Tree
Illustration 29
g03361557
Repair Option A is the least invasive repair, but has exceptions attached: Exception 1: If the crack length in the weld is more than 150 mm (6.00 inch) in length or if the crack propagates out into the base material more than 12 mm (0.50 inch), call the 793F Product Group Service Engineer for guidance. Exception 2: If the crack goes through thickness of the plate or casting or if there is a loss of backing material, proceed to Repair Option B.
Repair Option A The following information pertains to visual inspection results that warrant weld repairs/modifications to the outside of the frame and post weld treatments to external attachments. This repair applies to both sides of the frame. This repair option is the least invasive repair and does not require access to the inside of the frame components. Pre-Heat: As a precaution for the thicker sections of material (t >= 50 mm (2.00 inch)), maintain a 100° C (212° F) preheat/interpass temperature for the top/bottom rail to casting connections. The thinner side sections can be welded at room temperature 20° C (68° F). When you need to remove components in order to repair the chassis, refer to the appropriate Disassembly and Assembly Manual. Table 11 Disassembly and Assembly Manuals Sales Model 793F 793F XQ 793F CMD (Command For Hauling)
Machine Systems
Power Train
KENR8579
KENR8397
UENR1142
UENR1143
Illustration 30 Section view (A) Inner curved plate 16 mm (0.60 inch) to 25 mm (1.00 inch) (B) Rolled rail plate 50 mm (2.00 inch) (C) Outer window 16 mm (0.60 inch)
g03361777
Illustration 31
g03361767
Internal view of weld joint with steel backing
1. For visual cracks detected at the 4 bar link casting to main rail connection, as shown in Illustration 17 proceed with the repair using the following information for guidance. 2. To assist with excavation and repair see Illustration 30 and Illustration 31 for reference information regarding material thickness, weld joint design, and geometrical perspective. Note: Rolled rail plate (B) is 50 mm (2.00 inch) in thickness. Care should be taken not to excavate beyond the steel backing strip. The crack should be no deeper than 50 mm (2.00 inch) for the bottom weld seam.
Illustration 32 Excavate crack by arc air gouging (D) Gouged profile
g03361816
(E) Section thickness
Illustration 33 Cross sectional view of anticipated grinding (E) Section thickness (F) Finish grind to achieve 70 degree included angle
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Illustration 34 Cross sectional view of prepared joint prior to welding (slight radius at root) (E) Section thickness (G) 70 degree angle (H) 35 degree angle
g03361830
Illustration 35
g03361835
Longitudinal view of prepared joint (E) Section thickness (J) 45 degree angle
3. Excavate and remove the crack and prepare the joint for welding. Illustrations 32, 33, 34, and 35 demonstrate the sequence of steps necessary to obtain the desired joint configuration prior to welding. The depth of excavation and grinding will depend on the depth of the crack. 4. Upon completion of excavation and preparation, refer to welding procedure guidelines and reinstate by welding.
Illustration 36
g03361861
View of cracks at corners on bottom rail before excavation
Illustration 37 View of cracks excavated and run on/off tabs attached (K) Run on/off tabs
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Illustration 38
g03361879
View of completed weld, tabs removed, and surface sanded flush
5. As an example Illustration 36, 37, and 38 demonstrate the proper sequence (before, during, and after) for cracks that did not propagate through the thickness of the plates. Note: For repairs made on plates with open ends, attach run on/off tabs (K) in order to place weld starts on tabs and outside of finished weld. Lack of fusion defects associated with starts will then be non-existent when run on/off tabs (K) are removed. 6. Perform visual inspection in order to ensure that all weld quality meets or exceeds the requirements shown in the ""Weld Inspection and Acceptance Criteria" " section. 7. After welding has been completed, sand flush to profile of surrounding parent material leaving the appearance that no weld repair has been conducted.
Illustration 39
g03361900
16 mm (0.60 inch) fillet weld both interior ends of tube assembly (L) Tube assembly (M) Plate (volcano)
8. For visual cracks detected in the fillet welds connecting tube assembly (L) to plate (volcano) (M) on the interior side, excavate completely, prepare joint by grinding and reinstate fillet weld to correct size. Refer to Illustration 39 for minimum weld size.
Illustration 40
g03361910
12 mm (0.50 inch) fillet weld both exterior sides 16 mm (0.60 inch) fillet weld over a 10 mm (0.40 inch) bevel groove weld both exterior sides (L) Tube assembly (N) Outer window plate (P) Cover plate
9. For visual cracks detected in the fillet welds connecting tube assembly (L) to outer window plate (N) and to cover plate (P) on the exterior side, excavate completely, prepare joint by grinding and reinstate fillet weld to correct size. Refer to Illustration 40 for minimum weld size.
Illustration 41
g03362047
10. For visual cracks detected at the outer window plate to 4 bar link casting, like that shown in Illustration 41, proceed with the repair using the following information for guidance.
Illustration 42
g03362049
J-groove weld joint with integral backing (R) 16 mm (0.60 inch) (S) Window plate (T) Steel casting
11. Illustration 42 depicts the cross sectional view of the weld joint. Follow the excavation and preparation guidelines shown in Illustration 32, 33, 34, and 35 in order to reinstate weld to original size and shape. Note: Use caution when excavating cracks. Steel backing is incorporated into the casting geometry, retain the steel backing in order to ensure a complete joint penetration repair.
Proactive Post Weld Treatment In order to prevent cracking at the fillet welded attachments, treatment to the fillet weld toe is necessary to improve fatigue life. TIG dressing is the preferred post weld treatment method.
Illus tration 43
g03361502
View of the right-hand exterior side
Illus tration 44 View of the left-hand exterior side
g03362315
1. TIG dress the fillet weld toe of the attachments contained in the rectangle shown in Illustration 43 and 44. Note: TIG dress the entire length of the fillet weld toe, including around the ends of the start and stops for stops for each of the attachments. Note: The fillet weld toe for the tank mount and the tube through the frame (outer weld) should already be TIG dressed. If not, then TIG dress these weld toes.
Illus tration 45
g03362320
View of the right-hand interior side (U) 75 mm (3.00 inch) (V) 75 mm (3.00 inch)
2. In addition, TIG dress continually a total distance of 150 mm (6.00 inch) around the righthand corner of the pump drive bracket as shown in Illustration 45. For detailed information regarding TIG dressing refer to the ""Post Weld Treatment - TIG Dressing" " Section.
Repair Option B The following information pertains to visual inspection results that warrant weld repairs/modifications to the inside/outside of the frame and post weld treatments to external attachments. This repair applies to both sides of the frame.This frame.This repair option is the most invasive repair and does does require require access to the inside of the frame components. Note: Both sides of the frame can be worked simultaneously.
Pre-Heat: As Pre-Heat: As a precaution for the thicker sections of material, maintain 100° C (212° F) preheat/interpass temperature for the top/bottom rail to casting connections. The thinner side sections can be welded at room temperature 20° C (68° F). When you need to remove components in order to repair the chassis, refer to the appropriate Disassembly and Assembly Manual. Table 12 Disassembly and Assembly Manuals Sales Model
Machine Systems
Power Train
KENR8579
KENR8397
UENR1142
UENR1143
793F 793F XQ 793F CMD (Command For Hauling) Table 13 Required Parts
(1 )
Item
Qty
Part Number
Description
1
2
431-7565 431-7565
Plate (1)
2
24
441-3206
Plate (1)
3
4
441-3208 441-3208
Plate (1)
4
1
378-9104
Bracket As
5
1
295-3006
Bracket As
Serviceable part can be ordered or fabricated
Fabricate Tank Mount Fixtures 1. Before removing any hardware, construct locating fixtures to capture the location of the front tank mounts in relation to the rear tank mounts which will remain on the frame. Note: Material required for fixtures can be a common structural steel such as ASTM A36.
Fabricate the Right-Hand Side Tank Mount Fixture
Illustration 46 Base plate (A) 19 mm (0.75 inch) (B) 2X 874 mm (34.40 inch) (C) 4X 22 mm (0.90 inch) diameter (D) 120 mm (4.70 inch) (E) 2X 18.725 mm (0.74 inch) (F) 940 mm (37.00 inch) (G) 2X 82.55 mm (3.25 inch) (H) 2X 33 mm (1.30 inch)
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Illustration 47 Vertical plate (J) 50 mm (2.00 inch) (K) 160 mm (6.30 inch) (L) 9.5 mm (0.40 inch)
g03362443
Illustration 48
g03362447
Gusset (M) 110 mm (4.30 inch) (N) 130 mm (5.10 inch) (P) 9.5 mm (0.340 inch)
Illustration 49 Semi-completed right-hand tank mount fixture (R) 135 mm (5.30 inch) (S) 155.25 mm (6.10 inch) (T) 110 mm (4.30 inch) (U) 160 mm (6.30 inch)
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Illustration 50
g03362500
Rod (V) 275 mm (11.00 inch) (W) 25 mm (1.00 inch)
1. Fabricate (tack weld) the plate assembly shown in Illustration 49 and attach plate assembly to the rear tank mount (with mounting hardware) so that the plate assembly lies across the front tank mount surface. The holes on the plate assembly may not line up perfectly with the threaded holes in the front tank mount.
Illustration 51
g03368363
View of the tank mount fixture location (RH side)
2. Position the rod shown in Illustration 50 on top of the rail section and against the fixture to capture the height of the front tank mount. Tack weld rod to the fixture. The tank mount fixture will be used to relocate the front tank mount for the right-hand side after repairs have been completed. Refer to Illustration 51 for an example of the fabricated fixture located on the frame.
Fabricate the Left-Hand Side Tank Mount Fixture Note: The same process will be followed for the left-hand side as was outlined for the righthand side.
Illustration 52 Base plate (A) 19 mm (0.75 inch) (B) 2X 1487.5 mm (58.60 inch) (C) 4X 26 mm (1.00 inch) diameter (D) 180 mm (7.10 inch) (E) 2X 26 mm (1.00 inch) (F) 1540 mm (60.60 inch) (G) 2X 128 mm (5.00 inch) (H) 2X 26.25 mm (1.05 inch)
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Illustration 53 Vertical plate (J) 50 mm (2.00 inch) (K) 160 mm (6.30 inch) (L) 9.5 mm (0.40 inch)
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Illustration 54
g03362514
Gusset (M) 110 mm (4.30 inch) (N) 130 mm (5.10 inch) (P) 9.5 mm (0.340 inch)
Illustration 55 Semi-completed left-hand tank mount fixture (R) 135 mm (5.30 inch) (S) 155 mm (6.10 inch) (T) 110 mm (4.30 inch) (U) 160 mm (6.30 inch)
g03362515
Illustration 56
g03362517
Rod (V) 375 mm (15.00 inch) (W) 25 mm (1.00 inch)
1. Fabricate the parts shown in Illustrations 52, 53, and Illustration 54 and tack weld together to achieve the semi-completed fixture shown in Illustration 55. 2. Fabricate (tack weld) the plate assembly shown in Illustration 55. Attach the plate assembly to the rear tank mount (with mounting hardware) so that the plate assembly lies across the front tank mount surface. The holes on the plate assembly may not line up perfectly with the threaded holes in the front tank mount.
Illustration 57
g03368372
View of the tank mount fixture location (LH side)
3. Position the rod shown in Illustration 56 on top of the rail section and against the fixture to capture the height of the front tank mount. Tack weld rod to the fixture. The tank mount fixture will be used to relocate the front tank mount for the left-hand side after repairs have been completed. Refer to Illustration 57 for an example of the fabricated fixture located on the frame.
Remove Outer Window Plates
Illustration 58 View of the right-hand side
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Illustration 59
g03363086
View of the left-hand side
1. Prior to removing the outer window plates remove and retain all hardware located on the outer window plates, refer to Illustration 58 and Illustration 59. Note: The approximate weight of the bracket assembly (fuel tank front mount) is 45 kg (100 lb).
Illustration 60 View of the outer window plate on the left-hand side (A) Rear outer window plate
g03369880
(B) Tube assembly
2. Access to the inside of the rail assembly requires removing rear outer window plate (A) shown in Illustration 60.
Illustration 61
g03362574
View of the rear window joint details (AA) Joint detail (AB) Joint detail (AC) Joint detail (AD) Joint detail
3. In order to gain access to the inside of the rail assembly remove the welds by air arc gouging as shown in Illustration 61. Excavate welds connecting the window plate to the tube assembly and the frame. 4. Attach a suitable lifting device to rear outer window plate (A). The approximate weight of rear outer window plate (A) is 55 kg (121 lb).
Illus tration 62
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View of joint detail (AA) (A) Rear outer window plate (B) Tube assembly (C) 16 mm (0.60 inch) (D) 6 mm (0.25 inch)
Illus tration 63 View of joint detail (AB) (E) 8 mm (0.30 inch) Backing strip (F) 16 mm (0.60 inch)
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Illus tration 64
g03362598
View of joint detail (AC) (A) Rear outer window plate (G) 16 mm (0.60 inch) (H) 50 mm (2.00 inch) (J) Rail
Illus tration 65
g03362616
View of joint detail (AD) (A) Rear outer window plate (K) 16 mm (0.60 inch) (L) Steel casting
5. Excavate welds connecting rear outer window plate (A) to tube assembly (B) and to the frame. Note: Refer to Illustrations 62, 63, 64, and 65 for guidance on plate thickness and joint details.
Illus tration 66
g03387518
View of the left-hand side forward window plate (E) 8 mm (0.30 inch) Backing strip (M) Forward outer window plate (AE) Joint detail (AF) 50 mm (2.00 inch)
Illus tration 67 View of joint detail (AE) (M) Forward outer window plate (N) 16 mm (0.60 inch) (P) 35 mm (1.40 inch) (R) Internal stiffener
g03362705
6. After rear outer window plate (A) has been removed, attach a suitable lifting device to forward outer window plate (M) and remove forward outer window plate (M) as shown in Illustration 66. The approximate weight of forward outer window plate (M) is 74 kg (163 lb). Illustration 67 gives guidance on remaining joint detail and plate thickness. 7. Remove an additional 50 mm (2.00 inch) (AF) of weld metal beyond weld joint (both top and bottom).
Inspection and Repair Procedure
Illustration 68
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View of left-hand side with both outer window plates removed allowing full access to the inside of the frame
Illustration 69
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View of the left-hand side (A) Backing strip (B) Plate (volcano) (C) Tube assembly (D) Gusset
1. Visually inspect the inside of the main rail for visible cracks. Pay particular attention to two backing strips (A), plate (volcano) (B), tube assembly (C), and five gussets (D) . 2. Use dye penetrant (PT) or magnetic particle (MT) tests to verify visual finding. Note: IF THERE ARE ANY THROUGH THICKNESS CRACKS FOUND ON TUBE ASSEMBLY (C) OR PLATE (VOLCANO) (B), CONTACT THE PRODUCT GROUP SERVICE ENGINEER FOR GUIDANCE.
Illustration 70
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View of left-hand side groove weld inspection areas (B) Plate (volcano)
3. Visually inspect the interior groove weld connecting the 4 bar link casting to the volcano plate (B). Refer to Illustration 70.
Illustration 71 Cross sectional view of the 4 bar link casting to the plate (volcano) connection
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(BA) Plate (volcano) (BB) Outside of rail (BC) Casting (BD) Inside of rail (BE) Casting dimension (BF) Offset
4. The casting (BC) has a profile tolerance which allows the possibility that the casting surface may not align with the surface of the plate (volcano) (BA) and may result in an offset (BF) between the two surfaces as shown in Illustration 71. Note: Dimension (BE) varies for each casting.
Illustration 72
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Weld profile and/or transition (BA) Plate (volcano) (BB) Outside of rail (BC) Casting (BD) Inside of rail (BG) 16 mm (0.63 inch) (BH) 9 mm (0.35 inch)
5. If an offset (BF) exists, the weld profile should extend or transition from plate (volcano) (BA) surface to casting (BC) surface, regardless of the offset difference.
6. Multi-pass (stair stepped) welds should be used in order to provide a gradual transition from the lower surface to the higher surface. Refer to Illustration 72. Note: If gouging or grinding of existing weld metal is required DO NOT exceed 10 mm (0.40 inch) in depth (as measured from the surface of plate (volcano) (BA). Beyond that depth is parent material. Note: The space between plate (volcano) (BA) and casting (BC) welds (indicated by the arrow in Illustration 72) is not connected.
Illustration 73
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View of backing strip (A) attached
Illustration 74
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View with backing strip (A) removed
7. Several modifications are going to be required to the inside of the box section and tube assembly. If backing strips (A) are present as shown in Illustration 73, backing strips (A)
will need to be removed. Backing strips (A) are located on both the top and the bottom. Note: Five gussets (D) connecting the tube to the volcano plate will also need to be removed. Remove gussets (D) prior to removing backing strips (A) in order to provide adequate work space on top and bottom.
NOTICE Use caution when removing gussets (D). Avoid removal of base material on both the tube and the volcano plate. In the event of base material removal, fill divots by welding and sand smooth to profile (use 80 grit minimum or finer).
8. After gussets (D) are removed, steel backing strips (A) must be removed (if present). 9. Arc air gouge most of steel backing strip (A) and the fillet welds holding the steel backing strip (A) into position. Do not gouge into the parent material. 10. Remove the remainder of the material by grinding/sanding (use 80 grit minimum or finer). 11. Sand all surfaces smooth to profile. Note: The inside surface area, where steel backing strip (A) was located, should be a seamless tapered transition between the casting and the steel rail section. The surface should be sanded and without sharp gouging and grinding marks. Refer to Illustration 74.
Illustration 75 (AA) Gusset (AB) 126.8 mm (5.00 inch) (AC) 88.4 mm (3.48 inch)
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(AD) 14 mm (0.55 inch) (AE) 180 mm (7.10 inch) (AF) 14.5 mm (0.57 inch) (AG) 20 mm (0.80 inch) (AH) 5 ± 1 mm (0.20 ± 0.04 inch) X 45 degree both sides (AJ) 122.5 mm (4.82 inch) radius (AK) 112 mm (4.41 inch) radius
12. Five gussets (D) as shown in Illustration 69 which were removed will be replaced by 12 new gussets. Refer to Illustration 75 for dimensions for gusset fabrication if needed. The material is ASTM A572 Grade 42/50 steel. If the part was ordered use 12 new gussets (2) in the required parts list.
Illustration 76 (AL) Spacer (AM) 51.4 ± 3 mm (2.02 ± 0.12 inch) (AN) 75 ± 5 mm (2.95 ± 0.20 inch) (AP) 20 +/- 1 degree
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(AR) 12 mm (0.47inch)
13. Use the dimensions in Illustration 76 and fabricate spacer (AL) using ASTM A36 material.
Illustration 77
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(AA) Gusset (AL) Spacer
NOTICE For both the right-hand and left-hand sides of the truck, most Gussets (AA) will always be positioned on the tube toward the front of the truck.
14. Insert the first gusset (AA) perpendicular to the bottom rail as shown in Illustration 77. Tack weld gusset (AA) into position and then locate the adjacent gussets using spacer (AL) .
Illustration 78 Location and welds for 12 gussets (AA) 10 mm (0.40 inch) fillet weld over 5 mm (0.20 inch) bevel groove weld (AS) 20 degree
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Illustration 79
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Location of gussets in relation to the first gusset (AA) that was installed
15. Illustration 78 and Illustration 79 show the location of 12 gussets (AA). Install 12 gussets (AA) and tack weld into position. 16. Weld gussets (AA) into position. Use a balanced welding technique to control distortion by placing one weld pass only at each location for each gusset working your way around to the next gusset in a clockwise fashion. 17. Proceed with succeeding weld passes until the finished weld size is achieved. Avoid welding one gusset to completion at each location.
Illustration 80
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18. Remove plate located at the end of the tube assembly in order to gain access to the inside of the tube. 19. Grind/sand the remaining remnants of weld metal on the inside diameter of the tube assembly. 20. Visually inspect the surface of the tube assembly internal diameter to a depth of 400 mm (15.75 inch) from each end. Use dye penetrant (PT) or magnetic particle (MT) tests to verify visual findings. Note: If there are any through thickness cracks found on the tube, call the 793F Product Group Service Engineer for guidance.
Illustration 81
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(AT) 363.3 mm (14.30 inch) (AU) 12 mm (0.47 inch) (AV) 10 ± 1 mm (0.40 ± 0.04 inch) x 45 degree (AW) Plate
21. Fabricate two tube plates using the dimensions shown in Illustration 81 using ASTM A572 Grade 42/50 material. If the part was ordered use two new plates (3) in the required parts list.
Illustration 82 Location of internal plate (AW) Plate (AX) 266 mm (10.47 inch)
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Illustration 83
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Welding internal plate 10 mm (0.40 inch) fillet weld over 10 mm (0.40 inch) bevel groove weld
22. Using the dimensions in Illustration 82 insert plate (AW) into the tube assembly. A 90 degree magnet or square should be used in order to ensure that plate (AW) is perpendicular to the tube assembly. Note: Use various sizes of stick electrodes such as (1/16, 3/32, or 1/8) between the bottom of plate (AW) and the tube assembly in order to equalize the gap around the circumference of plate (AW) in relation to the inside diameter of the tube assembly. Note: Welding of plate (AW) should be done in quarters and opposite to each other in order to control distortion. For example, weld from 6 O'clock to 3 O'clock, then 9 O'clock to 12 O'clock, then 6 O'clock to 9 O'clock, and finally 3 O'clock to 12 O'clock. Weld one pass at each location, moving on to the next until the finished weld size is obtained.
Illustration 84
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10 mm (0.40 inch) fillet weld over 10 mm (0.40 inch) bevel groove weld (AW) Plate (AX) 27 mm (1.06 inch)
23. Install plate (AW) onto the outside of the tube assembly where the plate was previously removed. Note: The front edge of plate (AW) should be 27 mm (1.06 inch) in from the end of the tube assembly. Equalize the gaps and use the same welding techniques as previously described in order to attach plate (AW) to the tube assembly.
Illustration 85
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View of a crack which propagated through the bottom rail section
24. If there is cracking in the outer window plate and has propagated through the bottom rail section and/or through the inside window plates as shown in Illustration 85, refer to the following steps for crack excavation, preparation, and repair. Note: If cracking is located in the bottom or top rail directly above or below the tube assembly connection, the following repair should be completed before installing the 12 new gussets (AA) around the tube assembly as shown in Illustration 79. Otherwise gussets (AA) will interfere with the repair. The following steps also apply to any through thickness cracks at the 4 bar link casting to the main rail connection. Note: Use run on/off tabs as shown in Illustration 37. 25. In order to repair the cracks, adhere to the following steps. Start repair from inside of rail section.
Illustration 86
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(BJ) Gouged profile (BL) Crack (BK) Section thickness
26. Gouge/grind to half of section thickness.
Illustration 87 (BL) Crack (BK) Section Thickness (BM) 70 degree (BN) 35 degree
27. Finish grind to profile.
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Illustration 88
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(BL) Crack (BK) Section thickness
28. Weld prepared side and sand flush to parent material.
Illustration 89
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(BK) Section thickness
29. Excavate the opposite side to sound metal. 30. Use PT (dye penetrant test) or MT (magnetic Particle Test) in order to verify that all cracks have been removed.
Illustration 90
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(BK) Section thickness
31. Weld the opposite side.
Illustration 91
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(BK) Section thickness
32. Weld both sides complete and sand flush. 33. When welding is complete, sand both sides flush to profile of parent material. Evidence of a repair should not be visually noticeable. Note: Visually and ultrasonically inspect weld repairs using acceptance criteria found at the beginning of this document. Refer to ""Requirements for Ultrasonic (UT) Testing" " Section for UT testing.
Illustration 92
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View of prepared edges
34. Clean/grind/sand all joint edges to be welded as shown in Illustration 92. Note: Prior to installing the outside window plate ensure that there are no small, crack-like defects at the ends of the groove welds connecting the 4 bar link casting to the top and bottom 50 mm (2.00 inch) rail sections.
Illustration 93
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View of area requiring MT inspection
35. Use magnet particle testing (MT) in order to test the area identified in Illustration 93 (top/bottom both sides).
Fabricate and Install Window Plate
Illustration 94
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(A) 2X 260 mm (10.25 inch) (B) 339.5 mm (13.40 inch) (C) 410 mm (16.10 inch) (D) 336 mm (13.20 inch) (E) 16 mm (0.63 inch) (F) 45 +5 -2 (G) 6 ± 2 mm (0.24 ± 0.08 inch) (H) 1445.5 mm (56.914 inch) (R) Window plate
1. Use the dimensions in Illustration 94 and fabricate a new window plate. Use ASTM A572 Grade 42/50 steel for the new window plate. If the part was ordered use new plate (1) in the required parts.
Illustration 95
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(J) Joint detail (K) Joint detail (L) Joint detail (M) Joint detail
Illustration 96 View of joint detail (J) 16 mm (0.63 inch) Bevel-groove weld (N) 30 degree bevel (P) 6 mm (0.24 inch)
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Illustration 97
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View of joint detail (K) 16 mm (0.63 inch) J-groove weld (R) Window plate (S) 15 mm (0.60 inch) minimum (T) Steel rail
Illustration 98 View of joint detail (L) 16 mm (0.63 inch) fillet weld over a 10 mm (0.40 inch) bevel-groove weld (U) Tube assembly (V) 45 degree bevel (W) 6 mm (0.24 inch)
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(X) Equalized gap around tube assembly
Illustration 99
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View of joint detail (M) 16 mm (0.63 inch) J-groove weld (Y) Steel casting (Z) 15 mm (0.60 inch) minimum
Note: Build up the integral backing strip for weld joint detail (M).
Illustration 100 View of gap condition 1 (R) Window plate (Y) Steel casting
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Note: If there is a visible gap between the integral backing and window plate (R) as shown in Illustration 100, buildup the surface as needed and sand to profile.
Illustration 101
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View of gap condition 2 (R) Window plate (Y) Steel casting (BA) 2 mm (0.08 inch) maximum gap
2. If a gap exceeds more than 2 mm (0.08 inch) between the underside of window plate (R), and the integral backing as shown in Illustration 101 build up the surface and sand to profile in order to close the gap.
Illustration 102 View of gap condition 3 (R) Window plate (BB) Steel rail
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(BC) 2 mm (0.08 inch) maximum gap
3. If the opposite condition exists as shown in Illustration 102, where the casting is setting higher than steel rail (BB) and there is a gap greater than 2 mm (0.08 inch) between window plate (R) and steel rail (BB), remove material from the casting in order to obtain a gap less than or equal to 2 mm (0.08 inch). The integral backing on the casting should not be reduced in thickness less than 8 mm (0.31 inch). 4. Use a suitable lifting device in order to position fabricated window plate (R) ensuring weld joint dimensions as shown in Illustrations 96, 97, 98, and Illustration 99. The approximate weight of window plate (R) is 130 kg (287 lb). 5. Once proper fit of window plate (R) has been obtained, secure window plate (R ) with tack welds (6 mm (0.24 inch) fillet welds by 50 mm (2.00 inch) long) on all sides and at tube assembly (U) . Minimize welding distortion by welding no more than one pass at each joint location until weld size is obtained. 6. Blend sand all weld start and stops. 7. Visually and ultrasonically inspect all complete/full joint penetration groove welds to ensure conformance to acceptance criteria found at the beginning of this document. Refer to ""Requirements for Ultrasonic (UT) Testing" " Section for UT testing. 8. Visually inspect all fillet welds (and partial joint penetration groove welds) to ensure conformance to acceptance criteria found at the beginning of this document.
Installation of Hardware
Illustration 103 View of the left-hand side 8 mm (0.30 inch) fillet weld
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(4) Bracket assembly (front tank mount)
1. Locate and attach the left-hand side bracket assembly (4) in relation to rear tank mount using fixture assembled before removing outer window plates. 2. Secure bracket assembly (4) to the frame with tack welds. 3. Weld complete as shown in Illustration 103.
Illustration 104 View of the left-hand side hardware 6 mm (0.24 inch) fillet weld 2 places (D) 8X-7415 Plate (W) 230 mm (9.05 inch) (X) 1055 mm (41.54 inch) (Y) 85 mm (3.35 inch) (4) Tank mount
4. Locate plates (D) using the dimensions in Illustration 104. 5. Secure plates (D) using the welds shown in Illustration 105.
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Illustration 105 View of the right-hand side hardware and welds 6 mm (0.24 inch) fillet weld 4 places 8 mm (0.30 inch) fillet weld 2 places 12 mm (0.48 inch) fillet weld (5) Bracket assembly (left rear tank mount) (C) Plate (top cooler mount) (D) 8X-7415 Plate (E) 254-2995 Plate
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Illustration 106
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View of the right-hand side hardware (F) 236.1 mm (9.30 inch) (G) 80.3 mm (3.16 inch) (H) 39 mm (1.54 inch) (J) 125 mm (4.92 inch) (K) 420.3 mm (16.55 inch) (L) 116.2 mm (4.57 inch) (M) 136.2 mm (5.36 inch) (N) 225 mm (8.86 inch) (P) 410 mm (16.14 inch) (R) 85 mm (3.35 inch) (S) 501.5 mm (19.74 inch) (T) 85 mm (3.35 inch) (U) 380.5 mm (14.98 inch)
6. Locate top cooler mount (C) using right front tank mount. 7. Locate all other plates (on right-hand side) using the dimensions in Illustration 106.
Illustration 107
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View of 8X-7415 Plate (BA) 10.5 mm (0.41 inch) diameter with M12 X 1.75 - 6G THD (BB) 20 mm (0.80 inch) (BC) 60 mm (2.40 inch) (BD) 80 mm (3.20 inch) (BE) 20 mm (0.80 inch) (BF) 40 mm (1.60 inch) (BG) 25 mm (1.00 inch)
Illustration 108 View of 254-2995 Plate (BH) 120 mm (4.72 inch) (BJ) 100 mm (4.00 inch) (BK) 20 mm (0.80 inch) (BL) 10.5 mm (0.41 inch) diameter with M12 X 1.75 - 6H (BM) 25 mm (1.00 inch)
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Note: For earlier model trucks, the (large) lower cooler mount block (RH side) has been replaced with three smaller blocks. The three smaller blocks consist of one 8X-7415 Plate and two 254-2995 Plate . Use the dimensions in shown in Illustration 107 and Illustration 108 in order to fabricate the plates (blocks) if needed. 8. Secure all plates using the welds shown in Illustration 105.
Proactive Post Weld Treatment In order to prevent cracking at the fillet welded attachments, perform treatment to the fillet weld toe to improve fatigue life. TIG dressing is the preferred post weld treatment method. Illustration 109 and Illustration 110 depict the attachments which require TIG dressing on the right-hand and left-hand side of the frame.
Illustration 109 View of the right-hand exterior side
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Illustration 110
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View of the left-hand exterior side
1. TIG dress the fillet weld toe of the attachments contained in the rectangle shown in Illustration 109 and 110. Note: TIG dress the entire length of the fillet weld toe, including around the ends of the start and stops for each of the attachments.
Illustration 111 View of the right-hand interior side (U) 75 mm (3.00 inch)
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(V) 75 mm (3.00 inch)
2. In addition, TIG dress continually a total distance of 150 mm (6.00 inch) around the righthand corner of the pump drive bracket as shown in Illustration 111. For detailed information regarding TIG dressing refer to the ""Post Weld Treatment - TIG Dressing " " Section.
Post Weld Treatment - TIG Dressing The fatigue performance of fabricated structures involving fillet welded attachments to highly stressed members is, among other things, controlled by the profile or geometry of the weld toe. Fatigue performance improvements can be achieved through alteration of the original, aswelded toe profile by several post weld treatment options. This procedure describes a method whereby an electric arc is used to reduce and/or remove unfavorable profiles/stress risers thus creating a smooth, seamless transition from one component to the next component. Note: Training: Anyone performing this procedure is advised to view the training video "Post Weld Treatment: TIG Dressing Fundamentals", course number 41737, in the Dealer Learning Management System.
Equipment Requirements Table 14 Required Equipment Tool GTAW (TIG) Power supply and a torch. Shielding Gas
Description The power supply must be able to produce 200 amps (min. 60% duty cycle) with a hand control or a foot control. Polarity - DC negative 100% Argon and flow meter Lanthanated or Ceriated or Thoriated Tungsten
Electrode
2.4 mm (0.09 inch diameter) If needed: ER70S-2 filler metal 1.5 mm (0.06 inch diameter)
Grinder Grinding Wheel
Pneumatic or electric with carbon steel wire wheel attachment Aluminum Oxide
Radius gauges
Method 1. The first steps in order to ensure proper TIG dressing are cleanliness and tungsten electrode preparation. The fillet weld and surrounding base metal must have all contaminants thoroughly removed. It is imperative that all paint, rust, dirt, oil scale, and silicate islands are nonexistent, remove by using a grinder with a carbon steel wire attachment.
Illustration 112
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2.4 mm (0.09 inch) Tungsten Electrode Preparation (A) Grinding Marks (B) 2 X 3 diameter (C) 1/4 diameter
2. Prepare a 2.4 mm (0.09 inch) tungsten electrode. Refer to the dimensions that are shown in Illustration 112. The grinding marks should run parallel to each other.
3. Adjust the shielding gas flow rate to 15 - 25 CFH. Adjust the current control to approximately 200 amps. If a ramp down control is present on the power source, utilize the ramp down control to ensure that proper crater fill control is achieved. 4. A number of different techniques exist for TIG dressing due to the variation of the contour of the fillet weld toe. The contour of the fillet weld toe must be reshaped. Use a stringer or weave manipulation of the torch in order to achieve a smooth radius of the weld. A minimum radius of 5.0 mm (0.20 inch) must exist between the base material and the weld metal.
Illustration 113
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Stringer Technique (D) 0 degree work angle
Note: Use a 10 to 15 degree push angle for the stringer technique. 5. Illustration 113 represents the stringer technique of welding. The center of the arc needs to be 0.0 - 2.0 mm (0.0 - 0.08 inch) from the weld toe into the base material.
Illustration 114
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Weave Technique (E) 0 to 45 degree work angle
Note: Use a 10 to 15 degree push angle for the weave technique. 6. Illustration 114 represents the weave technique of welding.
Illustration 115
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7. Illustration 115 represents an acid etched, cross section view of a TIG dressed weld toe.
Illustration 116
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Illustration 117
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8. Illustration 116 and Illustration 117 demonstrate the expected results. 9. Once TIG dressing is completed, the area needs to be cleaned and painted in order to prevent pitting due to corrosion. Note: Poorly shaped fillet welds with 90 degree to 100 degree transition angles to the base material will require several overlapping TIG dressing runs to smooth out the weld toe transition region. Note: TIG dressing can be conducted in the vertical position as long as the TIG dressing is performed in a downhill progression. Note: If undercut or other circumstances require the addition of filler metal. Adding filler metal can be accomplished by hand feeding ER70S-2 1.6 mm (0.06 inch) into the weld pool. You then repeat the TIG dressing in order to achieve the desired toe radius and the desired profile. 10. Inspect using a radius gage to ensure a 5 mm (0.20 inch) minimum radius.
Report of Ultrasonic Inspection of Welds
Table 15 Report of Ultrasonic Inspection of Welds
Inspection Company: Date: Address: Truck Serial Number:
Part Number:
Weld/Part Identification:
Material Thickness:
Calibration Block Type:
Weld Joint Designation:
Welding Process: Quality Requirements: Refer to Table 10
Procedure/Rev.:
Couplant:
""Requirements for Ultrasonic (UT) Testing" "
Instrument: Manufacturer:
Model:
Serial Number:
Calibration Date:
Notes:
Search Unit:
Longitudinal
Shear
Frequency Size Manufacturer Angle Serial Number Table 16 Report of Ultrasonic Inspection of Welds Continued Line Number
Indication Number
Search Unit Angle
From Face
Leg
1 2 3 4 5 6 7 8 9 10
0 Db Reference Level Method Only Line
Indication
Reference
Attenuation
Indication
Number
Level
Level
Factor (1) (2)
Rating
a
-b
-c
1 2 3 4 5 6 7 8 9 10
Discontinuity Location
=d
Length
Angular
Line Number
Distance (Sound Path)
Distance Depth From Surface
From
From
X
Y
1 2 3 4 5 6 7 8 9 10 Remarks:
(1 )
Metric equation for angular distance (sound path - 25 mm) x .08 = C
(2 )
Standard equation for angular distance (sound path - 1 inch) x 2 = C
RECENT 2885611 CATERPILLAR 5011826 HITACHI 4654476 HITACHI 4669416 HITACHI 2958691 CATERPILLAR
PARTS Caterpillar Hitachi Volvo pro
AUTODATA
Discontinuity Evaluation Accept/Reject
