Welding symbols

120102f

Welder

Welding Symbols

Welding Technology and Properties of Metals

First Period

Table of Contents Objective One ............................................................................................................................................... 2 Purpose of Welding Symbols .................................................................................................................... 2 Objective Two ............................................................................................................................................... 3 Weld Symbol and Welding Symbol................ ................. .................. ................. .................. ................... . 3 Objective Three ............................................................................................................................................. 5 Symbol Construction................................................................................................................................. Construction ................................................................................................................................. 5 Designations for Common Processes.................. .................. .................. .................. .................. ............ 15 Combined Weld Symbols ....................................................................................................................... 16 Multiple Reference Lines ........................................................................................................................ 17 Objective Four ............................................................................................................................................ 19 Rules for Dimensioning Welding Symbols.................. .................. .................. .................. ................... .. 19 Objective Five ............................................................................................................................................. 29 Non-Destructive Examination Examination Symbols................ .................. .................. .................. .................. .......... 29 Self-Test ...................................................................................................................................................... 34 Self-Test Answers ....................................................................................................................................... 47

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Welding Symbols Rationale Why is it important for you to learn this skill?

Welding symbols provide an efficient means of placing complete welding information on shop drawings. It is critically important that the welds are completed as required so that the finished weldment performs to specified standards. Information regarding all aspects of welding and non-destructive testing symbols must be completely understood by all personnel involved in the fabrication of welded products.

Outcome When you have completed this module, you will be able to:

Interpret welding symbols.

Objectives 1. 2. 3. 4. 5.

Explain the purpose of welding symbols. Define weld symbol, welding symbol and supplementary symbols. Interpret weld symbols and welding symbols. Identify the dimensioning of welding symbols. Interpret non-destructive testing symbols.

Introduction This module provides information to enable you to correctly understand and interpret welding symbols and non-destructive testing symbols.

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Objective One When you have completed this objective, you will be able to:

Explain the purpose of welding symbols.

Purpose of Welding Symbols Welding symbols provide a shorthand method for conveying complete welding information from the designer to the welder. Welding symbols are common on blueprints and other shop drawings. Companies may modify a few of the symbols to fit their own particular needs. The welding symbols outlined in this module are used universally across North America. They have been developed by the American Welding Society (AWS). The Canadian Standards Association (CSA) has adopted the AWS symbols and added some modifications and symbols of their own. These modifications are noted where applicable. Welding symbols are a schematic or symbolic representation of a weld joint preparation or of the weld joint with the weld in place. Numbers, letters, symbols and notes are added as required. They provide sufficient information to allow correct weld completion according to design standards.

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Objective Two When you have completed this objective, you will be able to:

Define weld symbol, welding symbol and supplementary symbols.

Weld Symbol and Welding Symbol The AWS standard on symbols makes a distinction between a weld symbol and a welding symbol.

Basic Weld Symbol The weld symbol indicates the desired type of weld (Figure 1). The groove weld is further subdivided according to the type of preparation used. A weld symbol represents the shape of the weld as you would see it in cross-section.

Figure 1 - Basic weld symbols.

Supplementary Weld Symbol A supplementary weld symbol is never used without a basic weld symbol. The supplementary symbols are used only when additional information is necessary for proper weld completion (Figure 2).

Figure 2 - Supplementary symbols.


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Welding Symbol The welding symbol is an assembled symbol that combines multiple weld symbols into one. It gives all the information necessary for preparing and/or welding the joint. Most welding symbols consist of three or more of the following eight elements (Figure 3): 1. reference line, 2. arrow line, 3. basic weld symbols, 4. dimensions and other data, 5. supplementary symbols, 6. finish symbols, 7. tail and 8. specifications, process or other references. Welding symbols must consist of the first two listed elements. Any of the other six elements are used only when such information is necessary.

Figure 3 - Locations of the elements of a welding symbol.


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Objective Three When you have completed this objective, you will be able to:

Interpret weld symbols and welding symbols.

Symbol Construction The construction of weld symbols and welding symbols must adhere to a set of basic rules to support a standardized scheme of delivering information. A uniform standard reduces the change of introducing errors. The rules for constructing weld symbols and welding symbols in this section are with regard to: reference line,  arrow line,  orientation of weld symbols,  broken arrow line,  surfacing weld symbol,  fillet weld symbol,  plug or slot weld symbol,  basic groove weld symbols,  back weld or backing weld symbols,  supplementary weld symbols,  common welding and cutting process designations,  combined weld symbols and  welding symbols which contain multiple reference lines and their applications. 

Reference Line The reference line forms the base for welding symbols. It is always drawn horizontally.

Arrow Line The arrow line may extend from either end of the reference line at any angle other than horizontal. More than one arrow line may be used (Figure 4) provided that: all joints to which the arrows point have identical welds and  all arrow lines originate from the same end of the reference line. 

Figure 4 - Multiple arrow lines.


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Symbol Orientation Weld symbols originate from the reference line and are placed below, above or on both sides of the reference line depending on the location of the welds. These three points of reference can be: 1. arrow side, 2. other side and 3. both sides.

Arrow Side Welds that are to be placed on the side of the joint where the arrow line points must have the corresponding weld symbol on the bottom of the reference line (Figure 5). This is known as the arrow side.

Figure 5 - Welds on the arrow side of the joint.

Other Side Welds to be placed on the side of the joint opposite where the arrow line points have the weld symbol on the top of the reference line (Figure 6). This is known as the other side.

Figure 6 - Welds on the other side of the joint.


NOTES

Both Sides When welds are placed on both sides of the joint, the weld symbols are placed on both sides of the reference line (Figure 7). This is known as welded both sides.

Figure 7 - Welds on both sides of the reference line.

Broken Arrow Line A broken arrow line is used with J groove and bevel groove preparations when it is necessary to indicate which member of the joint is to be prepared (Figure 8). If only one member of the joint requires preparation, the broken arrow line points to it. When it is obvious which member is to be prepared, the broken arrow line is optional (but preferred).

Figure 8 - Use of the broken arrow line.

Surfacing Weld Symbol A surfacing weld does not indicate the welding of a joint and has arrow side significance only. The symbol is drawn only on the arr ow side of the reference line with the arrow drawn to clearly point to the surface on which the weld is to be deposited (Figure 9).

Figure 9 - Surfacing weld symbol.


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Fillet Weld Symbol The fillet weld symbol is an isosceles triangle drawn with the left leg perpendicular to the reference line. The hypotenuse is drawn at 45° to the reference line. It does not matter what side of the reference line the arrow line is drawn from. The vertical leg of a fillet weld symbol is always on the left side of the triangle (Figure 10).

Figure 10 - Fillet weld symbols.

NOTE

All angular lines on weld symbols and the tail are drawn at 45  to the reference line.

Plug or Slot Weld Symbol The symbol for both plug welds and slot welds is a rectangle drawn on the reference line (Figure 11). The arrow line should touch the centreline of the weld joint. Detailed information of the joint is supplied either through dimensioning or by a detailed drawing.

Figure 11 - Plug or slot weld symbol.

Groove Weld Symbols There are five symbols which directly relate to the type of groove welds: 1. square groove weld symbol, 2. Vee groove weld symbol, 3. bevel groove weld symbol, 4. U groove weld symbol and 5. J groove weld symbol.

Square Groove Weld Symbol This symbol is used for butt joints when no plate edge preparation is required, although dimensioning may be used to specify an amount of penetration when no preparation is specified (Figure 12).

Figure 12 - Square groove weld symbols.


NOTES

Vee Groove Weld Symbol The Vee groove symbol (also known as V-groove) is drawn with the point of the Vee touching the reference line (Figure 13). The Vee groove symbol is inverted when it is on the arrow side of the reference line. A double Vee preparation has the points of the Vees touching at the same point on the reference line.

Figure 13 - Vee groove weld symbols.

Bevel Groove Weld Symbol This weld symbol is used when only one side of the joint requires preparation. It is common on Tee joints and corner joints. When necessary, the arrow line is broken and the arrow then points to the side of the joint requiring the preparation. This symbol is often used with the fillet weld symbol for Tee joints and corner joints where full penetration is required. The bevel groove symbol is drawn with the point touching the reference line (Figure 14). Like the fillet weld symbol, the left leg is always vertical no matter which end of the reference line the arrow line is attached to. When a double bevel joint is shown, the vertical legs are drawn in line with each other.

Figure 14 - Bevel groove weld symbols.

U Groove Weld Symbol The U groove weld symbol is drawn on a short vertical line that touches the reference line (Figure 15). This joint configuration is common where heavy material is to be welded or when the joint is back gouged for welding the second side.

Figure 15 - U groove weld symbols.

CSA standards use a dotted U or J to indicate preparation of the groove by the carbon arc-air process (CAC-A) (Figure 16). This preparation may be done either after the joint has been fitted or on the second side after the first side has been welded.

Figure 16 - Dotted U groove weld symbol (CSA only).


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J Groove Weld Symbol Like the bevel groove, the J groove requires preparation on one side of the joint only. A broken arrow line is used when it is necessary to designate which side of the joint is to be prepared (Figure 17). The broken arrow is used with the J groove and the bevel groove. The J symbol is drawn to represent one half of a U joint with the vertical leg on the left side. The J groove weld symbol always has the vertical leg on the left side regardless of where the arrow line is.

Figure 17 - J groove weld symbols.

Back Weld or Backing Weld Symbols Weld beads that are used as a back weld or a backing weld on single welded groove joints are indicated with the back or backing weld symbol. The symbol is a semi-circle placed on the reference line (Figure 18). The back or backing weld is welded from the opposite side of the groove weld. Dimensions of the back or backing weld are not shown on the reference line, but may be shown on the drawing if desired.

Figure 18 - The back weld or backing weld symbol.

When single reference lines are used, a note is required in the tail of the welding symbol to indicate whether the weld is a back weld or a backing weld. A backing weld is completed first, before welding the groove weld.  A back weld is done last, after the groove has been welded. 

Supplementary Weld Symbols These symbols are used only when additional information about the weld is required. The most common supplementary weld symbols are: 1. weld all around, 2. field weld, 3. joints with backing or spacers, 4. melt through, 5. contour and finishing and 6. the tail.

Weld All Around Symbol A joint that requires welding all around one side (or both sides, if shown) is designated by an open circle where the arrow joins the reference line (Figure 19).

Figure 19 - Weld all around symbol.

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This symbol is most often found when the weld involves changes in direction, for example in the welding of a W shape onto a reinforcing pad (Figure 20).

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Figure 20 - Weld all around example.

Field Weld Symbol Large projects often require that sub-assemblies be fabricated in the shop and then joined at the job site. The field weld symbol indicates the joints that are to be completed at the job site. The field weld symbol is a solid flag. The symbol is located at the intersection of the arrow line and reference line. It must be at right angles to the reference line. CSA W59 recommends that the field weld symbol point toward the weld symbol as shown in Figure 21.

Figure 21 - The field weld symbol.

Joints with Backing or Spacers Welding symbols that indicate joints which use spacers or backing material illustrate this with a rectangular symbol. The welding symbol differs in its placement, which can be on the top or bottom of the reference line or in the centre of the reference line.


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Joints with Backing

A joint with backing is shown with a groove weld symbol on one side of the reference line and a rectangle on the opposite side that includes a notation (Figure 22). AWS letter designation uses the following: R means backing to be removed after welding and  M means material specifications to be located in the tail. 

Figure 22 - Weld symbols for joints with backing.

CSA letter designation uses one of the following: M for material identification (by means of an assigned letter),  MR for material identification, but removed after welding,  S for steel or other material as specified,  SR for the same as S, but removed after welding,  T for tape or  F for flux.  Joint with Spacers

A joint that incorporates a spacer is shown with the groove weld symbol. It is modified to show a rectangle within the symbol (Figure 23). The same AWS and CSA letter designations are applied as those that indicate backing.

Figure 23 - Weld symbols for joints with spacers.


NOTES

Melt Through Symbol The melt through symbol (Figure 24) is used when groove welds are done from one side only and full penetration is required.

Figure 24 - The melt through symbol.

Contour and Finishing Symbols When the surface contour of a weld is specified, a contour symbol is added to the weld symbol. Three contour symbols (Figure 25) are: 1. flat, 2. convex and 3. concave. The symbol represents the required weld profile. It is placed over top of the weld symbol.

Figure 25 - Contour symbols.

When the weld surface is to be finished to the specified contour by mechanical or some other means, a letter is added adjacent to the contour symbol (Figure 26). The letters are: M for machine,  C for chip,  G for grind,  H for hammering,  R for for rolling or  U for unspecified. 

Figure 26 - Symbols for method of finishing.


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Tail The tail is added to the end of the reference line opposite the arrow line when reference is made to: specification data,  the cutting or welding process,  other reference material about the weld that cannot be placed in symbol form and  information pertaining to the weld that is located elsewhere on the drawing,  which saves repeating the information in the welding symbol. For example, the symbol in Figure 27 calls for a 12-inch single-Vee groove weld on the arrow side made to specification 31, part A. In this case, you would look elsewhere on the drawing for the information pertaining to specification 31, part A.

Figure 27 - The tail of a welding symbol.

As another example, the symbol in Figure 28 calls for a fillet weld to be made on the arrow side of the joint, using the shielded metal arc welding process, designated by the letters SMAW.

Figure 28 - Using the tail to specify the welding process.

Some companies have developed their own codes for information contained in the tail of the welding symbol. For example, if the majority of a company's fillet welds are 6.4 mm (1/4") in size, the company can say this is a typical size of most fillet welds. The abbreviation TYP (typical) (typical) or CO STD (company STD (company standard) in the tail of the symbol 1 would then indicate a 6.4 mm ( /4") fillet weld. CSA Standards and some companies use the abbreviation GTSM in in the tail of the symbol to specify gouge specify gouge to sound metal before before back welding (Figure 29).

Figure 29 - Significance of GTSM.


NOTES

Designations for Common Processes The AWS letter designation is a standardized method of specifying welding or cutting process in the tail of a welding welding symbol. These are widely used used and recognized across North America. Table 1 shows the AWS letter designation for for some common welding processes. Process Type Brazing Gas welding Resistance welding Arc welding

Process Torch brazing Oxy-acetylene welding Resistance spot welding Stud welding Plasma arc welding Submerged arc welding Gas tungsten arc welding Gas metal arc welding Flux cored arc welding Metal core arc welding Shielded metal arc welding

Letter TB OAW RSW SW PAW SAW GTAW GMAW FCAW MCAW SMAW

Table 1 - AWS letter designations for welding processes.

Table 2 shows the AWS letter designation for some common cutting processes. Process Type Arc cutting

Oxygen cutting

Process Arc cutting Air carbon arc cutting cutting Plasma arc cutting Oxyfuel cutting Metal powder cutting

Letter AC CAC-A PAC OFC POC

Table 2 - AWS letter designations for cutting processes.


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Combined Weld Symbols There are many possibilities for weld symbols to be combined. One combination is fillet welds applied over square or bevel groove welds on Tee joints. To indicate root penetration on fillet welds, a groove weld symbol is used with the fillet weld symbol. Weld symbols are used in combination to show penetration or effective throat on joint types requiring fillet welds with or without groove preparation (Figure 30).

Figure 30 - Combination symbols.

The fillet weld symbol is stacked on top of the square groove weld symbol. The weld symbols must be placed in the logical order of progression, starting from the reference line. For example, in Figure 30A the first weld is the square groove weld, so the square groove symbol is placed on the reference line first. After the square groove is welded, you would next weld the fillet weld. This joint configuration requires no preparation. Figure 30B shows a welding symbol that does require preparation. The bevel is prepared and welded first and then finished with a fillet weld in the Tee joint.


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Multiple Reference Lines Multiple reference lines give added capabilities to the welding symbols. They provide information relative to: the sequence of welding operations,  supplementary data applicable to the weld symbol or  test symbols regarding the examination of the weldment after co mpletion of  welding. Two or more reference lines may be used. The operation that you complete first is shown on the reference line nearest the arrow. Each subsequent operation on the reference line is stepped away from the arrow line (Figure 31).

Figure 31 - Multiple reference line sequence.

If a sequence is specified for a joint, as described by the welding symbol shown in Figure 32, there are two sequencing alternatives that may be considered.

Figure 32 - Combination symbol.


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Figure 33 shows the possible sequences. To distinguish the correct weld sequence you need to know if the semi-circle weld is a backing weld (done first) or a back weld (done last). This information is given in the tail of the welding symbol.

Figure 33 - Multiple reference line symbol.

When multiple reference lines are applied to the basic weld symbol, the weld all around and field weld symbols may be added to one or all of the reference lines. The tail may also be added (Figure 34).

Figure 34 - Supplementary symbols may be used with multiple reference lines.


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Objective Four When you have completed this objective, you will be able to:

Identify the dimensioning of welding symbols.

Rules for Dimensioning Welding Symbols Dimensions for the size of a weld are placed to the left of the weld symbol. This may include the depth of preparation and penetration, the effective throat and/or the actual weld size. The units of measure in the welding symbols are the same as on the drawing. Dimensions for the length of weld are placed to the right of the weld symbol. This is most common with fillet welds, especially for intermittent welding (also known as stitch welding). Dimensions for joint spacing and edge preparation for groove welds are located within the groove weld symbol. In most cases, the dimensioning examples in this module are in millimetres (mm). They have been omitted from the weld orientation detail of most line drawings to save space and reduce clutter. You must be competent in interpreting the dimensions shown on the four basic weld types: 1. surface welds, 2. plug and slot welds, 3. fillet welds and 4. groove welds.

Surface Weld Dimensioning Either a single- or a multi-pass surfacing weld may be used to build up a surface. When the amount of buildup is specified, this is shown as a dimension to the left of the weld symbol (Figure 35). A contour symbol, finish symbol and method of finish symbol may also be used. These are placed in line with and below the surfacing weld symbol.

Figure 35 - Surfacing weld dimensioning.


NOTES

When no height of weld buildup is specified, the dimensions are omitted on the reference line. When a portion of the area of a surface is to be built up, the location and orientation are shown on the drawing. The surface weld symbol is always drawn on the arrow side of the reference line. NOTE

A surfacing weld does not indicate the welding of a joint.

Plug Weld and Slot Weld Dimensioning Several dimensions are included on welding symbols where plug weld and slot weld symbols are used. These dimensions indicate: location,  size,  preparation,  quantity and  amount of weld fill. 

Plug Welds The dimensions of plug welds (Figure 36) are shown in symbols as follows. The size of a plug weld refers to the diameter of its hole at the base of the weld. It  is shown to the left of the weld symbol. The depth of fill is shown inside the symbol.  The centre-to-centre spacing ( pitch) is shown to the right of the symbol.  The degree of countersink (if used) is shown in line with the symbol. 

Figure 36 - Plug weld dimensioning.


NOTES

Slot Welds Slot welds use the same symbol as plug welds. The size of the slots can be detailed on the drawing or placed in the welding symbol (Figure 37). The (5) indicates 5 slots are required.

Figure 37 - Slot weld dimensioning.

Fillet Weld Dimensioning Dimensions for fillet welds are either supplied in the general notes on the drawing, or they are included in the welding symbol to indicate their size and length.

General Dimensioning Notes A general note may appear on a drawing governing the dimensions of the f illet welds, for example All fillet welds to be 9.6 mm ( 3 / 8") in size, unless otherwise noted. The fillet weld symbol is used, but the dimensions are o mitted except where they differ from those in the general note. If one side differs, the dimensions for both sides must be shown.

Fillet Weld Size The size of equal leg fillet welds is shown to the left of the weld symbol. This refers to the length of both legs of the triangle formed by the fillet (Figure 38).

Figure 38 - Size of fillet welds.


NOTES

The size of fillet welds with unequal legs is to the left of the weld symbols (Figure 39). The numbers refer to the length of the legs of the triangle formed by the fillet. Unless the leg orientation is obvious, the leg orientation of the fillet must appear on the drawing.

Figure 39 - Unequal leg fillet weld dimensioning.

Fillet Weld Length The length of a fillet weld is shown to the right of the weld symbol (Figure 40). When a fillet weld is to extend to the full length of the joint, the length  measurement is omitted. When a fillet weld is to extend a specific length of the joint, it may be indicated  by symbols and dimension lines on the drawing.

Figure 40 - Length of fillet welds.

Fillet welds do not always have to be welded continuously across a member. To save time and money, they may be welded intermittently on one side or on both sides. The intermittent welds types are: 1. intermittent fillet welds, 2. chain intermittent welds, 3. staggered intermittent welds.


NOTES

Intermittent Fillet Welds

Intermittent fillet welds are placed intermittently on one side of the joint. Dimensioning is on the right side of the fillet weld symbol, which shows the length of each weld and the pitch. Figure 41 shows the length of weld as 50 mm and the pitch as 100 mm.

Figure 41 - Intermittent fillet weld dimensioning. Chain Intermittent Welds

Chain intermittent fillet welds are located on both sides of the joint with the welds located directly opposite each other. Sizes must be shown on both sides of the reference line (Figure 42). If a fillet weld symbol does not show length and pitch on one side, then the weld on that side is a continuous weld. The weld symbols are located directly opposite each other on the reference line.

Figure 42 - Chain intermittent fillet weld dimensioning.


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Staggered Intermittent Welds

Staggered intermittent fillet welds are staggered or offset from one side to the other along the length of the joint (Figure 43). As with chain intermittent welding, the sizes must be shown on both sides of the reference line. The weld symbols are staggered on opposite sides of the reference line.

Figure 43 - Staggered intermittent fillet weld dimensioning.

Welds Across Solid Members Arrow side and other side cannot cross through a solid member in a joint. In Figure 44, Joint A and Joint B require separate welding symbols.

Figure 44 - Welds across solid members.

Groove Weld Dimensioning Dimensions for groove welds are given in the general notes on the drawing, or they are included in the welding symbol. They accurately specify: the effective throat and weld size,  the root opening and bevel angle,  the groove dimensions,  the dimensions for double-groove welds (where applicable) and  the dimensions of combination welding symbols (where applicable). 


NOTES

Effective Throat and Weld Size Weld size usually refers only to the depth of preparation for the groove weld. The effective throat of groove welds is the total thickness of material fused in the weld. This includes the depth of preparation plus additional penetration of the weld. If the effective throat is not specified, then either effective throat or weld size can be used for the weld thickness. In Figure 45, the effective throat specification ( E) should appear in brackets on the right side of the depth of preparation ( S). They share a common location in the welding symbol. The quantity ( E) is measured from the top of the plate to the deepest point where the weld penetrates the joint. Weld reinforcement is not included in the effective throat measurement. The omission of depth of preparation and the effective throat dimension indicates complete joint penetration on single groove and symmetrical double groove welds.

Figure 45 - Weld size and effective throat.

Root Opening and Bevel Angle Dimensions for the root opening and bevel angle are placed inside the groove symbol with the root opening dimension closest to the reference line (Figure 46).

Figure 46 - Root opening and bevel angle.


NOTES

Groove Weld Dimensions A general note may appear on a drawing governing the dimensions of the groove welds, for example All Vee groove welds shall have a 60° groove angle and root opening of 3 mm unless otherwise noted . The groove weld symbol is used, but the dimensions are omitted except where they differ from those in the general note. For single and double groove welds that extend completely through the member being joined, no size is shown to the left of the weld symbol (Figure 47).

Figure 47 - No dimensions are needed with fully fused joints.

For groove welds that extend only partly through the members being joined, the size is shown on the left of the weld symbol. Figure 48A identifies a weld that has a Vee joint preparation of 12 mm and an effective throat of 12 mm on the arrow side. Figure 48B shows a double bevel to be done on the right side plate. The arrow side is to have a joint preparation of 9 mm with an effective throat of 9 mm. The other side has a joint preparation of 6 mm with an effective throat of 6 mm.

Figure 48 - Dimensions with partially fused joints or when each side is different.


A groove weld with a specified root penetration is indicated by showing the depth of preparation and the effective throat in brackets to the left of the weld symbol (Figure 49).

NOTES

Figure 49 - Specified root penetration.

The symbol indicates a 6 mm depth of preparation plus a 3 mm penetration for an effective throat of 9 mm on the other side of the joint.

Double-Groove Weld Dimensions Each weld symbol must be accompanied in the welding symbol by all the data essential for the preparation, fit-up and execution of welding. This principle applies to all double-groove welds. It makes no difference whether the data is identical on each side of the reference line or not. Since it is common to both sides, the size of the root opening needs to appear only once (Figure 50). When you add up the depth of preparation and root penetration shown in Figure 50, the weld does not extend through the thickness of the joint members.

Figure 50 - Specified penetration in a double groove weld.


NOTES

Dimensioning Combination Welding Symbols To dimension combination welding symbols, place the dimensions beside their respective weld symbols (Figure 51).

Figure 51 - Dimensioning of combination welding symbols.

Figure 52 indicates that effective throat is gained by penetration into a square groove preparation and combined with fillet welds. The groove welds in Figure 52 penetrate into each other by 3 mm at the centre. The total effective throat of the groove portion of the weld cannot be greater than 15 mm (plate thickness).

Figure 52 - The square groove symbols indicate penetration with fillet welds.


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Objective Five When you have completed this objective, you will be able to:

Interpret non-destructive testing symbols.

Non-Destructive Examination Symbols Non-destructive examination (NDE) symbols indicate the type of test(s) the weld will be subjected to upon completion. The AWS has assigned an individual letter designation to all common non-destructive examination methods. These designations identify the pertinent examination method. Table 3 shows the basic non-destructive testing methods and their letter designations. Non-Destructive Test Acoustic emission test Eddy current (electromagnetic test) Leak test Magnetic particle test Neutron radiographic test Penetrant test Proof test Radiographic test Ultrasonic test Phased array ultrasonics Visual test

Letter Designation AET ET LT MT NRT PT PRT RT UT PA VT

Table 3 - AWS non-destructive examination letter designations.

Elements and Location To convey the required test information, the non-destructive examination symbol must contain some or all of the following elements: reference line,  arrow line,  examination method letter designation,  dimensions, areas and number of examinations,  supplementary symbols,  tail and/or  codes, specifications and other references.  Standard supplementary symbols for all around and field operations remain the same as for welds. The NDE examination symbols identify: 1. test location symbols, 2. direction of radiation symbol, 3. combined welding and NDE symbols and 4. dimension of NDE symbols.


NOTES

Figure 53 shows a master graph of NDE examination symbols.

Figure 53 - Master graph of testing symbols.

Test Location Symbols The significance of arrow side, other side and both sides for basic welding symbols applies to testing symbols. Test symbols may be applied in three locations with respect to the reference line (Figure 54): 1. the arrow side, 2. the other side or 3. centred on the reference line.

Figure 54 - NDE test symbol locations.


When examinations are to be performed on both sides of the part, pertinent letter designations must be specified on both sides of the reference line, even if the examination methods are identical (Figure 55).

NOTES

Figure 55 - Significance of NDE testing symbols on both sides.

If the NDE symbols have no arrow or other side significance, they must be centred on the reference line (Figure 56).

Figure 56 - Symbol location having no arrow or other side significance.

Direction of Radiation Symbol An additional symbol for direction of radiation (Figure 57) indicates where the radioactive source is to be positioned relative to the weld joint.

Figure 57 - Direction of radiation symbol.

For example, it is possible to use this symbol to indicate the direction and positioning of the radiation source by specifying the radiation source angle (Figure 58).

Figure 58 - Radiographic source testing angle specification.


NOTES

Combined Welding and NDE Symbols Combining welding and NDE symbols has a practical advantage. It ensures that shop fabrication personnel obtain full information for welding and indicates the quality of work required. The examination of final welds can only be performed after welding is completed. Multiple reference lines must be used to specify the sequence of operations (Figure 59).

Figure 59 - Combined welding and testing symbols.

More than one examination method may be shown in the symbol as in Figure 60.

Figure 60 - Use of different testing methods.

Examination methods with and without arrow side significance can be combined, but the symbol must reflect the significance (Figure 61). The tail of the symbol may be used for procedural specifications or other references essential to the application of the examination methods.

Figure 61 - Symbols with and without arrow side significance.


NOTES

Dimensioning NDE Symbols Dimensions applied to testing symbols may indicate the length of section to be tested or the percentage of section to be tested. Length or percentage is shown only when a partial section is tested. A specified length subject to examination should be placed on the right side of the letter designation for the selected examination method (Figure 62). To indicate the exact location of a specific length of the joint to be examined, the information must be on the drawing.

Figure 62 - Specification of length of examination.

If the entire length of a joint is to be examined, this length need not be specified in the symbol. Occasionally, a given percentage of the total length of a joint will be subject to examination. The location of the segment is usually determined just prior to examination. The symbols in Figure 63 indicate the percentage of each weld to be tested. It is not to be interpreted as an indication of the percentage of testing for all welds.

Figure 63 - Location of partial testing notation.

To specify a given number of examinations at random locations, the number of required tests is placed in brackets and positioned as in Figure 64. The required length to be examined may also be included.

Figure 64 - Number of tests required.

The all around symbol specifies examination of the weld around the whole joint, and the field test symbol indicates testing done on the job site (Figure 65).

Figure 65 - Test all around and field test symbols.


NOTES

Self-Test 1. The purpose of welding symbols is to: a) make the drafting job complete. b) convey necessary welding information from designer to welder. c) specify the type of weld to use. d) convey necessary weld dimensions. 2. Define weld symbol.

3. List the four (4) types of welds included in the basic weld symbols. a) b) c) d) 4. Define welding symbol.

5. List the eight (8) elements of a welding symbol. a) b) c) d) e) f) g) h) 6. Of the eight (8) elements of a welding symbol, which two (2) must always appear? a) b)


NOTES

7. Briefly describe and explain these supplementary welding symbols. a) weld all around

b) field weld

c) contour and finish

d) melt through

8. Briefly explain the following terms. a) arrow side

b) other side

c) both sides

9. What is the purpose of a broken arrow line?

10. The tail on a welding symbol is used for: a) determining arrow side or other side. b) joints using fillet welds only. c) information that cannot be put into symbol form. d) indicating which side of the joint must be prepared.


NOTES

11. List three (3) weld symbols that have one leg perpendicular to the reference line. a) b) c) 12. In a correctly drawn welding symbol, the reference line must: a) have a single arrow only. b) be drawn horizontally. c) be drawn with a tail. d) have all weld symbols on the arrow side. 13. A field weld is shown on the welding symbol by a: a) solid black circle. b) notation in the tail. c) ring around the weld symbol. d) solid black flag. 14. A surfacing weld symbol is always drawn on the ___________________ side of the reference line. a) arrow b) other c) right d) left 15. A weld symbol must depict the: a) three most essential elements of the weld. b) desired shape of the weld to be applied. c) joint dimensions and welding process. d) member that is to be prepared and where it is welded.


NOTES

16. In Table 4, draw the welding symbol for each description on the left. Description a) b)

Symbol

single J groove weld, other side, fillet weld arrow side fillet weld both sides, arrow side made flat by chipping

c)

fillet weld arrow side, single bevel groove weld other side

d)

single U groove weld, all around, arrow side fillet weld all around, other side, field weld to specification J-2

e) f)

single square groove weld, arrow side

g)

double Vee groove weld, finished flat by welding arrow side

h)

single J groove weld arrow side, single U groove weld other side

i)

single Vee groove weld other side, back weld arrow side single bevel groove weld arrow side, melt through is to be ground flat

j) k)

surface to be built up by welding

l)

plug weld on other side, machine flat slot weld on arrow side to specification

m)

23

n)

double square groove weld, arrow side made convex by chipping, other side made flat by grinding.

o)

staggered intermittent fillet weld to specification a3 double J groove weld with fillet weld on arrow side

p) q)

fillet weld on other side, single bevel groove weld and fillet weld on arrow side

r)

single Vee groove weld other side, single U groove weld arrow side

s)

chain intermittent fillet welds, 50 mm long, 200 mm pitch, both sides, arrow side ground flat

t)

double bevel groove weld with fillet weld on other side

u)

double U groove weld, arrow side welded flat

v)

single bevel groove weld other side, single J groove weld arrow side

w)

double J groove welds with fillet welds both sides single square groove weld and fillet weld on arrow side single bevel groove weld on other side

x)

Table 4


NOTES

17. Describe the welds represented by the welding symbols in Figure 66.

Figure 66

38 120102fp7.0.docx

© 2014, Her Majesty the Queen in right of the Province of Alberta

NOTES

Figure 66 (continued)


NOTES

18. Use Figure 67 to answer the questions. From the welding symbols in the left-hand column, show the preparation, dimensions and outline of the completed weld in the right-hand column. Use dotted lines to show preparation and solid lines to show the weld.

Figure 67


NOTES



NOTES

19. Use Figure 68 to answer the questions. From the weld shown in the right-hand column, show the complete welding symbol on the reference lines in the left-hand column.

Figure 68


NOTES



NOTES

20. Write down the information given on the following welding symbols listing the proper sequence for a) and b) in in Figure 69.

Figure 69


21. In Figure 70 fill in the figure on the right with the appropriate preparation, weld and finish. Use dotted lines for the preparation, and solid lines for the welds.

NOTES

Figure 70


NOTES



NOTES

Self-Test Answers 1. b) convey necessary welding information from designer to welder. 2. A weld symbol is a pictograph that indicates the desired type of weld. 3. a) b) c) d)

surfacing fillet plug or slot groove

4. A welding symbol is an assembled symbol that combines multiple weld symbols into one giving all the information necessary for preparing and/or welding the joint. 5. a) b) c) d) e) f) g) h)

reference line arrow line basic weld symbols dimensions and other data supplementary symbols finish symbols tail specifications process or other references.

6. a) reference line b) arrow line 7. a) A joint that requires welding all around one side (or both sides if shown) is designated by an open circle where the arrow line joins the reference line. b) Field welds are indicated by a solid black flag pointing to the weld symbol located where the arrow line joins the reference line. c) A contour symbol is used to indicate the desired shape of the weld surface as concave, flat or convex. It may be accompanied by a letter ( M, C or G for machined, chipped or ground) to indicate how the shape is attained. d) A solid semicircle opposite a groove weld symbol indicates that penetration through the thickness of the material is required. This weld is done from the same side as the groove weld. 8. a) The arrow side of the welding symbol refers to the side (bottom) of the reference line closest to the reader when reading the drawing. It refers to welding done on the side of the weld joint to where the arrow line points. b) The other side of the welding symbol refers to the side (top) of the reference line farthest from the reader. It refers to welding done on the side of the weld joint opposite to where the arrow line points. c) With the exception of the melt through symbol, weld symbols that appear on both sides of the reference line mean that welding is done on both sides of the weld joint. 9. A broken arrow line is used with bevel groove and J groove weld symbols to indicate which side of the joint requires the preparation. The break is preferred, but may be ignored if the joint design makes it obvious which side needs preparation. 10. c) information that cannot be put into symbol form. 11. a) fillet weld symbol b) bevel groove weld symbol c) J groove weld symbol 47 120102fp7.0.docx © 2014, Her Majesty the Queen in right of the Province of Alberta

NOTES

12. b) be drawn horizontally. 13. d) solid black flag. 14. a) arrow 15. b) desired shape of the weld to be applied.


NOTES

16. Figure 71 shows the correct symbols.

Figure 71


NOTES

17. a) b) c) d) e) f) g) h) i) j) k) l) m) n) o) p) q) r) s) t) u) v) w) x)

single J groove weld, other side, fillet weld arrow side fillet weld both sides, arrow side made flat by chipping. fillet weld arrow side, single bevel groove weld other side single U groove weld, all around, arrow side fillet weld all around, other side field weld to specification J-2 single square groove weld, arrow side double Vee groove weld, finished flat by welding arrow side single J groove weld arrow side, single U groove weld other side single Vee groove weld other side, back weld arrow side single bevel groove weld arrow side, melt through is to be ground flat surface to be built up by welding plug weld on other side, machine flat slot weld on arrow side to specification 23 double square groove weld, arrow side made convex by chipping, other side made flat by grinding staggered intermittent fillet weld to specification a3 double J groove weld with fillet weld on arrow side fillet weld on other side, single bevel groove weld and fillet weld on arrow side single Vee groove weld other side, single U groove weld arrow side chain intermittent fillets welds, 50 mm long, 200 mm pitch, both sides, arrow side ground flat double bevel groove weld with fillet weld on other side. double U groove weld, arrow side welded flat. single bevel groove weld other side, single J groove weld arrow side double J groove welds with fillet welds both sides single square groove weld and fillet weld on arrow side single bevel groove weld on other side.


18.

NOTES

Figure 72 shows the correct diagrams.

Figure 72


NOTES

19.

Figure 73 shows the correct drawings.

Figure 73


20. a) First step: U groove preparation is welded on the arrow side in the field. Second step: joint is back gouged to sound metal with a U groove configuration and welded in the field. b) First step: single bevel groove preparation is welded all around from the arrow side in the field with full penetration as indicated by the melt through symbol. Second step: a fillet weld is applied all around on the arrow side in the field.

NOTES

21. Figure 74 shows the correct diagrams.

Figure 74


NOTES



Welding symbols

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