Bhpv Project Work

BHPV Project

INTRODUCTION

Govt. Polytechnic, Visakhapatnam

1

BHPV Project

INTRODUCTION Bharat Heavy Plate and Vessels Limited is established in 1969 by the subsidiary of “BHARAT HEAVY ELECTRICALS LIMITED” by the government of India in A.P. to fabricate process plant equipment for the fertilizer, petroleum, chemical, petro-chemical and alloyed industries. BHPV`S beginnings were humble; it had a turnover of just 5 lakhs in 1971 – 72 when commercial production first commenced. Since then, BHPV has come a long way and exceeded a turnover of 200 crores expanding its product line to include high technology equipment and systems like multi layer vessels, turn key cryogenic plants, storage and distribution systems, industrial boilers, waste heat recovery systems, oil and gas processing systems etc. Today, BHPV is the backbone of the Indian’s process industries. Be it 1.

Steel or Fertilizer

2.

Chemicals or Refineries

3.

Petrochemicals or Oil

4.

Gas processing systems

5. Nuclear/ Defense /Space

BHPV place a leading role, with a range of products comparable to the best in the world, manufacture to its own designing or to the specific designing of the customer consultants.


2

BHPV Project

The BHPV product line is exhaustive it encompasses processes plant equipment, cryogenic equipment and industrial boilers. This range of equipment is manufactured in collaboration with some of the world’s leading process equipment manufactures. BHPV`S COLLABORATORS:

Skoda export, Czechoslovakia, for the installation of equipment and training of personnel. L`Air Liquide France, for cryogenic storage systems and air and gas separation plants, Tonnage oxygen plants up to 2200 TPD capacity, nitrogen wash plants and purge gas recovery units. Unitech of USA, for multiple effect evaporation plants. Bignierschmid-laurent of France for the manufacture of large-sized cryogenic storage tanks. Deals of France for the manufacture of boiler feed water Deaerators. Bharat Heavy Electricals Limited, India, for the manufacture of industrial boilers. ABB Lummus heat transfer, Netherlands for high pressure (including breech lock) heat exchangers, air cool exchangers, turbine exhaust condensers, dry cooling towers and fired heaters Hahn & clay in the heavy industries, U.S.A. for layered high-pressure vessels. BS & B Engineering Co., Inc., U.S.A. for oil and gas processing systems.


3

BHPV Project

COLLABORATION AND ABSORPTION OF TECHNOLOGIES: Some of the significant collaborations B.H.P.V. entered include: 

M/s BSL, France in respect of Field erected Cryogenic Storage Tanks  M/s Delas, France in respect of Deaerators.  M/s ABB Lummus, Netherlands for Heat Transfer Systems.  M/s Hahn & Clay, USA for Advanced Multilayer Technology.  Case- to-case tie-ups, B.H.P.V. entered into include:  Evaporators from M/s Ecodyne Corporation, USA.  Paper & Pulp Digesters from M/s Kamyr AB, Sweden.  Gas Collection Modules from M/s KTI Corporation, USA.  Large Space Simulation Chamber from M/s HVEC, USA.  Primary Reformer from M/s Halder Topsoe, Denmark.  Waste Heat Boiler from Borsig, Germany.  Feed Water Heater from Delas, France.  Argon Recovery Unit from M/s L’Air Liquide, France etc.  Hydrocracker Reactors from M/s Neo-PIGNANI, Italy.  Vacuum Ejector Systems from M/s Korting Hanover, Germany.  LPG Handling & Storage System from M/s Noell-LGA, Germany.  Ammonia Storage System from M/s KTI, Germany etc. By absorbing know-how from various world-renowned collaborators, B.H.P.V. upgraded its status from a mere fabricator of process equipment to that of an Engineering Company of International repute.


4

BHPV Project

CLIENTS OF BHPV:

The term process industry covers fertilizer, steel, oil exploration and refinery, chemical and petro-chemical industry. By systematically building up its capabilities, is today catering to the entire need of the steel plant industry. Naturally, its client list reads like a who’s who of Indian industry. Almost all fertilizer plants in the country including giant units of the fertilizer corporation of India, National Fertilizers Limited, Hindustan Fertilizers and chemicals, Rashtriya Chemicals and Fertilizers Ltd., Indo-Gulf Chemicals and Fertilizers Ltd. Gujarat State Fertilizers Corporation Ltd., Indian Formers Fertilizers co-operative Ltd., Bindal Agro Chemicals Ltd., Tata Chemicals and Fertilizers Ltd., have repeatedly sought BHPV equipment. BHPV has been among the foremost suppliers of process equipment for oil refineries. Mammoth organizations like Indian Oil Corporation, Hindustan Petroleum Corporation, Bharat Petroleum Corporation, Madras Refinery Ltd., Cochin Refinery Ltd., have all placed orders with BHPV for a wide range of equipment. For the petro-chemical and chemical industries BHPV’s contribution has been just as striking. BHPV counts Indian Petrochemicals Corporation Ltd., Bangaigaon Refinery and Petro-chemicals Ltd., Maharashtra Gas Cracker Complex, Tamilnadu petro products Ltd., Indian Drugs and Pharmaceuticals Ltd., Hindustan Antibiotics-all leaders in their field- as its regular customers.


5

BHPV Project

BHPV`s contribution extends to many industries such as 1. Oil Industry 2. Steel Industry 3. Aluminum Industry 4. Paper Industries too. Industry leaders like the oil and natural gas commission, the Steel Authority of India Ltd., Rashtriya Ispat Nigam, Bharat Aluminum Company, National Aluminum Company, and Hindustan Paper Corporation.

BHPV`s

esteemed

client

includes

national

dairy

development board, Bharat Heavy Electrical Ltd., National Thermal Power Corporation, besides various heavy water projects and Nuclear Power Corporation. In short, BHPV has earned a massive vote of confidence from the entire spectrum of process plant.


6

BHPV Project

BHPV – AN OVERVIEW: Primary Objective: To manufacture customer built capital equipment for the process industries such as fertilizers, petro-chemicals, petroleum refineries, chemicals etc. Incorporation of the Company

: 1966

Technical Collaboration

: M/s SKODA EXPORT, Provided by Czechoslovakia.

Commencement of Construction : 1968 Completion of Construction

: 1971

Commencement of Production

: 1971

Initial Project Cost

: Rs. 17.5 crores

Initial Product Mix

: Heat Exchanges, Columns, and Pressure Vessels, Technological, Structures, piping

Installed Capacity

: 23,210 M.T.

Turnover for the year 1996-97

: RS. 300 crore

RESOURCES: Financial (As on 31st July, 2000) Authorized Capital (Rs Crores) : 35.00 Crores Paid up Capital (Rs Crores) : 29.30 Crores Gross Block (Rs Crores) : 73.36 Crores (Provisional)


7

BHPV Project

PRODUCTION FACILITY: Factory Area

: 197 Acres

Total Covered Area

: 90,000 Sq. Meters covered area of Production

Production Shops

: 56,000 Sq. Meters

Power Requirement

: 3,000 KW from APSEB

No: of Ancillary Units

: 11

PRODUCTS MANUFACTURED BY BHPV: BHPV manufactures various types of Pressure Vessels and Columns, Air Fin Coolers, Storage Spheres, Transportation Tanks and Deaerators, Heaters, Paper and Pulp, Heat Exchangers etc., for a host of applications. 1. PRESSUE VESSELS AND COLUMNS: From multi-layer construction with design pressure of 280 kg/sq.cm to simple low and medium pressure columns are manufactured. Tall and heavy columns with lengths up to 90 meters and weights up to 450 tons. Pressure ranges from vacuum to 55 kg/cm2. With the back up of experience engineers and a host of heavy capacity cranes and other equipment, BHPV undertakes site fabrication and electron on heavy equipment of any size and weight. Pressure vessel range includes agitator vessels, jacketed vessels & autoclaves limpet coils.


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BHPV Project

2. AIR FIN COOLERS: Air fin coolers of forced draft type for refineries, petro chemicals, and fertilizers. Complete units with fans, driving systems, structural scheme, louvers and paneling. 3. STORAGE SPHERES: Storage spheres of any size and thickness including low temperature service. BHPV also undertakes erection and site stress relieving of these spheres.


9

BHPV Project

4. TRANSPORTATION TANKS: Transportation tanks of stainless steel and carbon steel, rail or truck mounted including low temperature applications are manufactured here 5. DEAERATORS AND FEED WATER HEATERS: BHPV manufactures complete feed water heater systems including Deaerators, high-pressure heaters and low-pressure heaters. 6. PAPER & PULP: Batch in continuous pulp digesters & multiple effect evaporation plant. Today BHPV, with its vast manufacturing capability, can manufacture process equipment of almost any size. In addition, it has the requisite handling facilities and being located at Visakhapatnam has excellent facilities for transporting all size vessels. In case of extra large equipment that cannot be transported, BHPV undertakes site fabrication & erection. 7. HEAT EXCHANGERS: Heat exchangers from low pressures atmospheric lined collars to high pressure heat exchangers with test pressure as high as 450 kg/cm2, almost all types of tubular exchangers for practically every requirement in chemical, fertilizers, petro-chemicals, refinery and heavy water plants have been fabricated and supplied.


10

BHPV Project

BHPV Quality: BHPV reputed for quality and workmen ship of its products. BHPV quality control department consists of 4 wings.  Quality Assurance  Quality control  Physical testing and Metallographic  Non destructive testing BHPV has received a number of international recognitions. BHPV is reputed for quality and workmanship of its product. BHPV has received a number of international accreditations. Such as:  ASME

U & U2 STAMPS ON

 Pressure Vessels  ASME

‘S’ Stamp for Industrial Boilers

 STAMI CARBON

Urea Reactors

 HALDOR TOPSOE

Ammonia Reactor, High Pressure Heat Exchangers

 ARABIAN AMERICAN

Process Plant

 OIL COMPANY As a part of Total Quality Management Program, B.H.P.V. has acquired ISO 9001 certification during the year 1993-94 particularly to


11

BHPV Project

boost up its exports and to be competitive in the international market. Re-certification of ISO 9001 has been obtained in 1996 & 1999. STRENGTH AND WEAKNESS: STERENGTHS: 1. Highly skilled and dedicated work force. 2. Good industrial relations. 3. BHPV reputed for quality. Recognisations: ASME U, U2, S and R Lloyds class-I certification 4. Well equipped shops. 5. Strong erection and commissioning set up with cranes etc. 6. Good R&D set up. 7. Large design group. 8. Unit is nearer to a major sea port. WEAKNESSES: 1. Inadequate engineering capability. 2. Lack of systems engineering capability. 3. Project management. 4. Some worn out and out dated facilities need replacement.


12

BHPV Project

PROJECTS OF NATURAL IMPORTANCE UNDER EXECUTION BHPV is reputed for quality and workmanship of its product. BHPV has received a number of international accreditations. Such as: S. No. 1. 2 3. 4. 5. 6. 7. 8. 9 10. 11. 12. 13. 14. 15.

Customer

Project/Equipment

Atmospheric Column & Vacuum Column LAS/SS/Duplex NF Heat BPCL, Mumbai Exchangers HFCL, Namrup First Distiller, Separator, Holders Replacement of Air Cooled ONGC, Mumbai Exchangers of process gas Compressors at BHS Plat Form CPCL, Chennai Supply of Nitrogen plant 5.5M dia. Thermal Vacuum SAC, Ahmadabad System IOCL, New Delhi SRU, ARU, SWS IOCL, New Delhi HPN, SWS, SRU, HGU BPCL, Mumbai Atmospheric & Vacuum Heater CPCL, Chennai 130 TPH Boiler Package FACT, Cochin Thermal Oil Heater Revamping of 50 TPH Oil / Gas HPCL, Vizag Fired Boilers IGCAR, Sodium Heater Tank & Its Kalpakam Accessories Supply of steam Condensing NPCIL, Mumbai Equipment – 2 nos. etc. Indo–Gulf Corp. Reformer Gas Waste Heat Ltd. Boiler. BPCL, Mumbai


Value (Rs crores) 34.80 22.71 1.95 4.79 10.10 32.15 77.05 1.86 1.18 2.27 2.20 5.09 0.58 108.00 5.12

13

BHPV Project

CUSTOMER & COMPETITOR PROFILE MAJOR CUSTOMERS:

 Fertilizer Industries  Petroleum Refineries  Petrochemical Complexes  Steel Plants  Chemical Industries  Power Sector  Nuclear, Defence & Space MAJOR COMPETITORS:

-

-

I.O.L

-

INOX

-

L&T

-

Linda, Germany

-

B.O.C, UK

-

Air Products, USA & UK

-

KOBE, Japan

-

Nippon Sanso, Japan

-

HOPM, China

-

PRAXAIR, USA

-

Larsen & turbo

GR Engg -

Lloyd Steel

-

BHEL

-

BABCOCK THERMAX

-

ACC Babcock Ltd


for Cryogenics & Systems.

For Process Plants

For Industrial Boilers.

14

BHPV Project

RESEARCH & DEVELOPMENT: Research & Development department was established in 1975 and is well equipped with high tech equipment to cater to Applied Research and Product Development. R&D has developed 136 Projects so far. Some of the products commercialized include:  Titanium Anodes  Titanium Air Bottles  Cryo Vats  Individual Quick Freezing Unit  Super Insulated Piping  Cryo Storage Tank  D.M. Water Plants  BHPV has undertaken Development of Heat Exchangers for Light Combat Aircraft (LCA) Phase-II has been received from Aeronautical Development Agency, Bangalore. SOME AWARDS RECEIVED FOR EXCELLENCE IN R&D INCLUDE:

-CIS Award for R&D achievement in 1992-93. The “Chelikani Atchuta Rao Memorial Award” from FAPCCI for individual achievement in R&D effort in 1996 to Mr.B.S.V.Prasad


15

BHPV Project

PRESENT STRENGTHS:  Excellent Design & Engineering Capabilities Manufacturing facility.  The State-of-the-art manufacturing facilities.  Accomplished image as a supplier of Quality Products in the Domestic and International markets.  High degree of customer confidence  Technological tie-up arrangements  Well-trained and qualified work force and Engineers.  Sound work culture & harmonious Industrial Relations.  Extensive computerization and Projects Management Skill  Capability to supply Projects & Systems on turnkey basis. PLANS & STRATEGIES:  To grow as an Engineering, Procurement and Construction Company and on LSTK Contracts  To enlarge Export Business  To focus on Human Resources Development  To resort to extensive computerization And Automation for reduction of cycle time.  Improvement of quality  Reducing costs.


16

BHPV Project

 To

forge

strategic

business

alliances

with

International

Companies to derive technological advantages and Marketing advantages.  To strive for continuous updating of technologies to be on par With International Companies.  To change the work culture to be compatible with current Market demands. INTRODUCTION OF THE PRODUCT: Steam Generators are vital package units for almost every industry for either steam for process or power. B.H.P.V a premier organization for manufacture of process equipments such as pressure vessels, heat exchangers and columns has entered into the field of steam generation as a part of diversification in the year 1981. Prior to entering the steam generation field B.H.P.V. has successfully manufactured and supplied to BHEL some of the vital equipments such as drums, water walls, power piping etc., B.H.P.V. CAPABILITIES:  Thermal  Product design.  Instrumentation  Fuel systems  Structural Design  Manufacturing technology  Quality Assurance  Control Procedures. Govt. Polytechnic, Visakhapatnam

17

BHPV Project

 Erection

The manufacturing technology and various other standards adopted by CE have been fully implemented in BHPV and proved its capability as one of the leading boiler manufacturer. EQUIPMENT FABRICATION TO SYSTEMS SUPPLY: Systems Packages: BHPV has acquired on one hand a vast experience in design, manufacture, supply, installation of process equipment and has developed an expertise in handling large turnkey systems in the areas of cryogenic & combustion systems. Systems Engineering: BHPV has developed over the years a strong system design group adequately manned by qualified and experienced engineers both in process and mechanical design. System design group has capability of designing various systems for the oil and gas sector, Metallurgical industries, paper and pulp etc. BHPV has already supplied a number of systems to ONGC, IOCL, HPCL and other oil sector industries as well as other industries such as NALCO, Hindustan paper corporation etc. These include: 1.

Skid mountaineer test separators

2.

Gas dehydration, Packages Filter separators,

3.

Desalters and Heater Treaters

4.

Gas collection modules


18

BHPV Project

5.

Evaporation plants Vacuum ejector systems etc.,


19

BHPV Project

SYSTEM RANGE:

The systems that BHPV offers to oil and gas sectors are: 1. Separators: •

Horizontal 2 & 3 phase

•

Vertical 2 & 3 phase

•

Defoaming 2 & 3 phase

•

Micro scrubbers

•

Oil Skimmers

2. Heaters: •

Horizontal Direct Fired (HSFH)

•

Liquid Bath Indirect (WBIH)

•

Salt Bath (SBH)

•

Propane Vaporizers (IHPV)

•

Steam generators

•

Low pressure (SG)

3. Oil Treaters: • Vertical Heater Treaters • Horizontal Heater Treaters (HDT) • Electro static Heater Treaters (HET) • Electro static Desalters (HED) Low Temperature Separators(Joule-Thompson

4.

(JT)): •

Heated Bottom


20

BHPV Project

•

Hydrate Inhibited

5. Glycol Dehydrators: •

Contactors

•

Regenerators

•

Direct Fired

6. Oil and Gas Manifolds and Gathering Stations 7. Dry Desiccant Adsorption (DDH) 8. Desulphurization of Gas and Liquid: • Amine • Hot Potassium Carbonate • Direct Oxidation 9. Sulphr Recovery: • Claus 10. Gas Liquids Recovery Plant: • Hydrocarbon Stabilizers • Fractionators • Expander • Refrigerated


21

BHPV Project

PRESSURE VESELS


22

BHPV Project

PRESSURE VESELS Pressure vessel is a closed container containing fluid under pressure (internal or external) more than the atmospheric pressure used for channeling and storing fluids and for performing various unit operations. Mounded storage vessel comprises the storage of pressurized gases at ambient temperatures in horizontal cylindrical vessels placed near ground level and covered with suitable backfill. Several vessels may be located side by side in one mound. The decision for the earth covered type of installation is mainly justified by the safety advantages in respect to external influence on the vessel; such has high temperature in case of fire and dynamic pressure from near by explosion. The design procedure of the mounded storage vessel conforms to ASME-Boiler and Pressure vessel code, section VIII pressure vessels – Division II . The various stresses (due to pressure, seismic, mound and dead loads) on mounded storage vessel are calculated. Stress analysis of mounded storage vessel is done with the help of the FEA (Finite element analysis) package ANSYS. Induced stresses obtained from manual calculations using fundamental formulae and induced stresses obtained from FEA using ANSYS were compared.


23

BHPV Project

1.2 HISTORY OF PRESURRE VESSELS: Pressure vessels are a group of critical equipments of different types of construction used in modern industries for various operations like storage, process etc. of various fluids. These equipments can be  Atmospheric Storage Tanks  Pressurized Tanks  Process columns and Vertical Pressure Vessels  Horizontal Pressure Vessels  Heat Exchangers  Process Heaters  Boilers Through out the world the use of process equipment has expanded considerably. In petroleum industry, pressure vessels are used at all stages of processing oil. At the beginning of cycle, they are used to store crude oil. Much different types of these pressure vessels, process the crude oil into oil and gasoline for the customer. The use of pressure vessels in chemical industries is equally extensive. Pressure vessels are made in all sizes and shapes. The smaller one may be no longer than a fraction of an inch in diameter; where as large pressure vessels may be of dia 150ft. or more in India .Some are buried in ground or deep in oceans, most are positioned on ground or supported on platform and some are found as storage tanks and hydraulic units in


24

BHPV Project

aircrafts .The internal pressure to which process equipment is designed is varied as size and shape. The usual range of pressure for monoblock construction is about 15 psi to 5000 psi. Although there are many vessels designed for pressure below and above that range .The ASME boiler and pressure vessel code section VIII Div.II, specifies a range of internal pressure from 15 psi at bottom to no upper limit. However at an internal pressure above 3000 psi with ASME code section VIII Div.I, special design consideration may be necessary.


25

BHPV Project

MOUNDED STORAGE VESSEL: For the storage of combustible liquids under atmospheric pressure and liquefied gases under high pressure, the horizontal cylindrical steel vessel with earth cover has been applied with in last years. Mounded storage is applied because it provides additional safety compared to above ground storage of gases in spheres or bullets. Its major advantage is that a BLEVE (boiling liquid expanding vapour explosion). Other benefits of the mound are  Protection of the vessels against: o Heat radiation from near by fire o Pressure wave originating from an explosion o Impact by flying objects o Sabotage etc. Govt. Polytechnic, Visakhapatnam

26

BHPV Project

 It satisfies environmental and aesthetic requirements,  It results in reduced site area due to less strigent inter spacing requirements  The safety distance to the site boundary can be reduced considerably. The design lifetime of mounded storage vessel is 25 years. Depending upon site conditions, ground water level and operational requirements, the vessels may be installed either at ground level or excavation, after which they shall be backfilled. Since the vessels shall be installed above ground as an earth mound, hence the term “mounded storage”. Vessels in open under ground vaults and excavations are not considered to be mounded storage vessels. The vessels are provided with connections (e.g. manholes, pressure relief valves and instrument connections) protruding through the top of the mound. Only if dictated by operational requirements may a bottom discharge in an inspectional tunnel be considered. The vessels shall be completely covered; only the top connections (manholes and /or dome) may protrude through the mound. If more than one vessel is placed in a single mound then the minimum distance between the vessels depends on the construction activities like welding, coating, back filling and compaction of the backfill material. A distance of 1 m is considered to be a minimum requirement. The maximum diameter is usually determined by factors such as design pressure, fabrication, post weld heat treatment requirements,


27

BHPV Project

transport limitations, subsoil conditions and economy of design (8 meters may be regarded as a practical upper limit). For vessels, which are founded on a sand bed, the length of the vessel should be no more than 5 times the diameter, in order to prevent the design shell thickness being governed by longitudinal bending of the vessel due to possible differential settlements or constructional tolerances of vessels and foundations. The maximum allowable length is usually determined by the subsoil conditions (especially if differential settlements re expected), size of available site and economy of the design. The above restrictions limit the maximum gross volume of a vessel to approximately 3500 m3. There is no limitation to the minimum size of the vessel, except for practical considerations. COMPONENTS AND THEIR DESCRIPTION -: 1. SHELL-: These are the cylindrical sections to contain the process fluids and to withstand pressure and temperature of process fluids. These sections are also to support the internal and external attachments. 2. END COVERS -: A) Dished ends -: Dished ends are the formed heads or closers used in the fabrication of pressure vessels. These are the heads for closing the cylindrical shells. The principal advantage of the dished heads is the Govt. Polytechnic, Visakhapatnam

28

BHPV Project

large reduction in the discontinuing in shape at the junction between the cylindrical vessels and the closures, resulting in a reduction of discontinuity stress at or near the junction. Examples of dished ends are torispherical, elliptical, hemi-spherical, flat dished ends etc. i) Torispherical dished end-: Decreasing the local stresses, which occur in the inside corners of the head, can increase the pressure rating of torispherical dished ends. This may be accomplished by forming the head so that the inside corner radius is made at least equal to three times the metal thickness for code construction. The knuckle radius should in no case shall be less than 6% of the inside diameter, also the radius of dish may be made equal to or less than the diameter of the head. These heads are fabricated on the basis of using the using the outside diameter as the nominal diameter. ii) Elliptical dished heads-: The elliptical dished heads are formed on dies in which the diametrical cross section is an ellipse. If the ratio of major to minor axis is 2:1 the strength of the head is approximately equal to the strength of the cylindrical shell having the corresponding inside and outside diameter. iii) Hemispherical heads -: For a given thickness, hemispherical heads are the strongest of the formed heads .These heads can be used to resist approximately twice the pressure rating of an elliptical dished heads or cylindrical shell of the same

thickness

and

diameters.

The

degree

of

forming

and

accompanying costs are greater than for any of the heads previously Govt. Polytechnic, Visakhapatnam

29

BHPV Project

described; also the available sizes formed from single plate are more limited. b) Flat ends-: Flat ends or flat heads are also used for closing the mounded vessels. But they are limited in the application of pressure vessels. For the same temperature and pressure, the required thickness of flat heads is more than he dished ends. These flat heads will be either directly welded to the shell or connected by bolting connection. These flat heads are generally used for low pressure vessels. 3. NOZZLES-: Nozzles are the branch connections, which are welded to the shell. The pipe lines, which bring the fluid to and from the mounded storage vessel, will be attached to these branch connections. Also the nozzles are useful lf connecting o pressure gauge, relief valves, thermo wells and other such instrument and control equipments. 4. FLANGES-: Flanges are used for making connections for piping and nozzle attachments. Flanges may be either forged or made of plate material. Flanges can be divided into the following standard types for all pressure ratings a) Weld neck b) Slip on c) Lap joint Govt. Polytechnic, Visakhapatnam

30

BHPV Project

d) Screwed and e) Blind flanges etc. 5. STIFFENING RINGS -: A cylindrical vessel under external pressure has an induced circumferential compressive stress equal to twice the longitudinal compressive stress because of external effects alone. Under such condition the vessel is apt to collapse because of elastic instability. The collapsing strength of such vessels may be increased by the use of uniformly spaced internal or external circumferential stiffening rings. Stiffening rings are the circular rings welded to the vessel externally or internally. 6. REINFORCEMENT PADS -: All openings such as nozzles, holes, manholes and hand holes made in the shell in which the openings is over 50mm diameter should be reinforced by reinforcement pads .It is a circular plate with a circular hole .Due to weakening effects on shell and because of openings made in the shell for nozzles etc, and wherever compensations are required, normally reinforcement pads are provided by welding another plate around the hole to add sufficient metal to compensate for the weakening effect of the opening. 7. MANHOLES-: Manholes are necessary in closed vessels to permit inspection, cleaning, repairs etc. Manholes may be located on the shell or on the roof or at both locations. Manholes on shells have the disadvantage that Govt. Polytechnic, Visakhapatnam

31

BHPV Project

they usually cannot be opened unless the vessel is empty and therefore not used as much as roof manholes for inspection.

HEAT EXCHANGERS


32

BHPV Project

HEAT EXCHANGERS 1. Introduction: Heat Exchangers are essential equipment of any process plant. These are devices for exchange or transfer of heat from one fluid to other. Plant operation economics are chiefly controlled by the effectiveness of the utilization and recovery of heat or cold by suitable heat transfer equipment. 2. Types of Heat Exchangers: There are No. of heat exchanger types based on method of heat transfer and constructional features. The process designer has to select the best suitable type that meets the performance & operational requirements. Following is the list of heat transfer equipment: S.No 1.

Type of heat transfer equipment Shell & tube H.E -Fixed tube sheet exchanger -U-Tube exchanger -Floating heat exchanger

2.

Single tube exchangers -Double pipe exchanger -Trombone cooler -Coils in vessel

3.

Parallel plate exchanger -Gasketed plate exchanger -Spiral plate exchanger


33

BHPV Project

-Lamella exchanger -Plate evaporator 4.

External heating type -Jacketed vessel -Steam tracing

5.

Heat transfer without surfaces -Flash evaporators -Direct contact condensers -Cooling towers -Heat transfer of fluids -Direct heating -Submerged combustion

6.

Extended surfaces -Air cooled exchanger -Plate fin exchanger -Tank heating with finned tubes -Solids heating with a bank of longitudinally finned tubes -Air heater

SHELL AND TUBE HEAT EXCHANGERS: From medium to high-pressure heat exchangers with a test pressures as high as 450 kg/cm2 and temperature ranging from –650C to –9000C. Almost all types of tubular exchangers for practically every Govt. Polytechnic, Visakhapatnam

34

BHPV Project

requirement in chemical, fertilizer, petro-chemical, refinery and heavy water plants have been fabricated and supplied. BHPV has over 15 years experience in manufacturing a wide Variety of Heat Exchangers, numbering over 2000, with its own Design, as well as to third party designs and supplying them to almost all process plants in the country. HEAT EXCHANGER ENGINEERING CAPABILITY: BHPV is the member of Heat Transfer and Fluid flow Services (HTFS), U.K. and Heat Transfer Research Institute (HTRI), U.S.A. The designs are based on the most reliable on competitive specifications, from standard process heat exchangers to high technology exchangers required in petro-chemical, fertilizer, oil refinery and other process plants. Shell and Tube heat exchanger designs cater for process pressures from vacuum to 600 bars and more than 600 bars for process temperatures from cryogenic to 13000 C or more than 1300oC in various materials of construction Such as  Carbon steel  Low alloyed steel, high alloyed steel  High alloyed steel  Non-ferrous materials  Titanium, Zirconium and other patented materials. Govt. Polytechnic, Visakhapatnam

35

BHPV Project


36

BHPV Project

HEAT EXCHANGER MANUFACTURING CAPABILITY: It is based on the service conditions, and as dictated by equipment design, BHPV can manufacture and supply Heat Exchangers as large as: 

4-meter shell diameter



450-ton weigh



600-mm thick tube sheets



Shell thickness upto 100 mm-



Monowall: Plate construction Beyond 100 mm



Monowall: Forged construction Beyond 75 mm

 Multi layer construction 16 METERS LONG: BHPV has manufactured and supplied high pressure shell and Tube Heat Exchangers incorporating the following high pressure seals: They are: 

Delta



Double Cone



Diaphragm



Lens



Lip Seal



Sealing plate package

 Gray Lock Govt. Polytechnic, Visakhapatnam

37

BHPV Project

In case of high-pressure seals with large diameter studs at flanged joints, special studs tensioning devices are provided for uniform tightening of studs for effective seating of the seal for leak tightness. BHPV processes special computer programs for analysis of tube bundle vibration. BHPV utilizes CNC drilling machine for drilling tube sheets there by maintaining the tolerances required. Programmable tube-totube plate welding facility is available for better productivity and higher accuracy in BHPV. BHPV AND LUMMUS HEAT TRANSFER SYSTEMS (LHTS): BHPV has entered into collaboration with Lummus Heat Transfer Systems (LHTS) for transfer of technology in design, manufacture and supply of shell and tube heat exchangers including 1. High-Pressure Breech Lock Exchangers, 2. Air-Cooled Heat Exchangers, 3. Air Cooled Turbine, Exhaust Condensers, 4. Dry Cooling Systems and 5. Fired Heaters. LHTS is a wholly owned subsidiary of combustion engineering, with heat require at The Hague, Netherlands. LHTS has over 50 year experience, which helps guide BHPV competently through complex decisions in designing the best and most competitive heat transfer equipment.


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BHPV Project

LHTS is the largest and most qualified engineering company in this field and continuous to develop new technologies. Under this collaboration agreement, BHPV can now provide total engineering service of heat transfer systems hardware and compete against another internal manufactures. As a member of HTFS-UK and HTRI-USA, with the proven manufacturing expertise in heat exchanger and now with the backup of transfer of latest heat exchanger technology from NHTS, BHPV emerges with high degree of technical competence to solve any problem that the client may experience in heat transfer systems. Clients will receive our guarantee on performance and workmanship. HEAT

EXCHANGERS

WITH

SPECIAL

HIGH

PRESSURES BREECH LOCK CLOSURES: There is a growing demand for heat exchangers that perform efficiently under high temperatures and pressures. Leak tightness at flanged joints to avoid danger of explosion is very critical in the case of exchangers handling lethal fluids, and this calls for a high performance sealing mechanism. It is vitally important that the exchangers are constructed to facilitate disassembly and re-assembly because they handle corrosive fluids and periodic inspections are necessary. BHPV

offers

heat

exchangers

with

the

above

critical

requirements. Under license from Lummus heat transfer systems, Netherlands, Breech lock closure type heat exchangers with competitive design and international quality standards are being maintained in BHPV Visakhapatnam, India. Breech lock closure type heat exchangers Govt. Polytechnic, Visakhapatnam

39

BHPV Project

offer an excellent sealing performance under high temperature and highpressure conditions. The exchangers for that a unique channel construction and offer the following advantages: 1. It is possible to re-tighten the internal tube sheet to the shell gasket from outside during operation. 2. The channel forging via a special threaded ring construction absorbs the hydro static pressure load on the channel cover not by heavy bolding. 3. The bolts in the channel cover are only sized for gasket compression

loading, This results in relatively small size bolts that can be tightened using normal wrenches, thus eliminating the lead for hydraulic bolts tensioning devices required on conventional bolted flanged Exchangers. The channel cover is relatively thin. 4. The numbers of flanged joints are reduced to a minimum due to the integral constructions of pressure parts. 5. When the internal surface of the channel is stainless steel weld overlaid, the risk of overlay disbanding & stress-include cracking is minimized due to the elimination of internal attachment welds, threaded holes in the pressure forging and tension force on the weld overlay. 6. The channel cover is not needed to be cladded because of a stainless steel diaphragm. Assembling is quick and easy and can be carried out by unskilled labor, because: i. No breaking or cutting of welded parts required. ii. No gasket grinding or welding required.


40

BHPV Project

iii. No bolt tensioning equipment is required; therefore, no complicated strain gauge measurements are required and are a large number of tightening cycles necessary. FIRED HEATERS: BHPV manufactures large verticals, cylindrical types and box type heaters for fertilizers, refineries and petro chemical units. BHPV has entered in to a full-fledged collaboration agreement with M/S.ABB LUMMUS HEAT TRANSFER of the Netherlands, a fully owned subsidiary

of

combustion

engineering

Inc.,

USA

for

design,

manufacture, supply, erection and commissioning of fired heaters. BHPV is fully geared to take up the following types of fired heaters. They are: 

Startup heaters



Recycle heaters



Charged heaters



Hot oil heaters



Crude and vacuum heaters



Steam super heaters



Coker heaters



Vis-breaker heaters



Catalytic reformer heaters

 Reboilers


41

BHPV Project

After establishment as a renowned supplier of process equipment’s, Air separation plants and boiler systems, BHPV has entered into a full-fledged collaboration agreement with M/s. LUMMUS HEAT TRANSFER SYSTEM (LHTS) of Netherlands, a fully owned subsidiary of M/s. Combustion Engineering Company USA, for design, manufacture, erection and commissioning of Fired Heaters. The heater efficiency can be improved by using Recuperative type air preheaters connected to existing/newly designed heaters. The designs are based on proprietary computer programs, so that customers can have the most reliable and cost competitive fired heaters with this backup BHPV emerges with a high degree of technical competence to solve any problem that a client may experience in boiler and fired heaters. BHPV has already supplied a number of fired heaters, which are operating successfully to the utmost satisfaction of the customer. With the experience already gained in the manufacturing, erection, commissioning of fired heaters. BHPV is now in a position to take-up the total system and a turnkey bases with the backup of M/s. LHTS. BHPV has executed a number of contracts with its excellent project management systems. BHPV is equipped with most modern machinery for manufacture of various items required for fired heaters to achieve the required quality standards commensurate with the functional requirements. WASTE HEAT RECOVERY STEAM GENERATORS (WHRSG): Govt. Polytechnic, Visakhapatnam

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BHPV Project

BHPV supplied 2x70 T/hr. Waste heat recovery steam generators to Indian petro-Chemical Corporation Ltd., Baroda with design backs up of Holland construction group (HCG), Netherlands. The WHRSG are used behind 2x36 MW gas turbines of general electric, USA enhancing cycle efficiency from a mere 25% with gas turbines alone to about 40% in conjunction with WHRSG. With the boom in natural gas production leading to settling up of captive as well as grid power generation units using gas turbines. BHPV is fully greated up to supply WHRSG units of various capacities, vital for increase of fuel efficiency. BHPV’S SPECIAL PROJECTS: Large Space Simulation Chamber Project (LSSC): Physical conditions in our space are substantially different from these existing in the atmosphere surrounding the earth. Before sending a satellite in to outer space. It is essential to test all its characteristics under conditions that approach-as closely as possible-those which the satellite has to with stand. This is done in Large Space Simulation Chamber (LSSC). BHPV has set up a L.S.S.C. at Bangalore for ISRO satellite center (ISAC). The entire project was done on turnkey basis with technical backup from high vacuum Equipment Corporation, etc. It is unique in India very few chambers elsewhere in the world have so many features in one chamber. Design methods of various components: Govt. Polytechnic, Visakhapatnam

43

BHPV Project

Which fall under ASME code is covered by other lecturers. The designs of components that are special to heat exchangers are discussed here. For a systematic design calculation comprehensive formats are developed which are appended together with design data sheet prepared by process designer.


44

BHPV Project

1. Tube Sheet: It is the most important part of a heat exchanger. These are flat plates which will be drilled with a multitude of holes into which tubes are fixed by expansion or by welding. It provides a rigid support to all the tubes and keeps the shell & tube side fluid separated. It has to withstand the pressure, temperature & corrosive nature of both fluids as well as any surges in operating conditions due to upset or emergency. Its design cost for utmost caution. TEMA standard gives due consideration for the stresses developed due to pressure & differential thermal expansion because of tube & shell side temperature. In fixed tube sheet heat exchanger the stresses developed in tubes, shell & tube plate are calculated to ensure that allowable stresses are not exceeded. TEMA standard gives rules for determining tube sheet thickness when subjected to thermal gradient. The thermal stresses due to differential thermal expansion is expressed as an equivalent differential expansion pressure Which takes into account the flexibility of the tube sheet, shell & tubes. The equivalent differential expansion pressure is combined with the operating pressure to arrive at the tube sheet thickness. A means of reducing the thermal stresses in fixed tube sheet heat exchanger is the inter position of a fairly flexible element called expansion bellow in the comparatively stiff shell. The expansion bellow permit under strained expansion/contraction of shell. A comprehensive format for design of fixed tube sheet is developed & appended formals for other type of tube sheets are also appended. It may be noted that ASME code is gradually introducing the design rules of tube sheets.


45

BHPV Project

2. Tube to Tube Sheet Joint: The connection of the tubes of tube sheets is the most critical element of element of a shell & tube exchangers because its reliability depends upon the integrity of the many parallel tube to tube sheet joints. Consequently each of the many joints must be virtually free of defects. Tube to tube sheet joints are subjected to heavy shear stresses during testing and operation arising out of the weight of tube bundle & contained fluid thermal loading due to differential expansion of shell & tubes and between tube to tube situated in different zeros of tube bundle. The tube joints are also subjected to disorganizing forces due to impingement of high velocity fluids on the tubes, vibration of tubes & exchanger etc., the joints are also exposed to chemical corrosion, stress corrosion & crevice corrosion. The tube joint must be able to with stand all the above static, dynamic thermal stresses during all operating conditions. It should ensure a strong and stable leak proof joint to isolate the working fluids from one another absolutely. 3. Baffles & Support plates: These plates serve as baffles to deflect to shell side fluid over tubes and also as tube supports to maintain correct tube pitch and prevent flow induced vibrations.


46

BHPV Project

MACHINERY


47

BHPV Project

Shearing Machine: It is mainly used for to remove the excess or required part of sheets or plates by means of shearing. Available machinery capacities:- Maximum width is

- 3150mm

Maximum thickness – 20mm General limitations of shearing machine: The edges of C.S and S.S shell plates of heat exchangers are to be compulsory be machined by edge planning machine after shearing operation irrespective of the thickness. Rolling Machine: Scope: Plates up to 50mm thickness maximum may be rolled. The maximum width of plates that may be accommodated is 3000mm. Incase of other rollers, individual capacities may be referred from the technical specifications. Hot rolling is restricted due to machine difficulties.


48

BHPV Project

Maximum Rolling Capacity is 60 mm in cold condition and 170 mm in hot condition. Stress relieving: After complete the job some stresses induced in job. These stresses induced due to various operations like rolling, bending, pressing etc, This stress removing by heat treatment. Stress relieving process mainly in furnaces.

•

BHPV has the largest heat treatment furnace in India, the

size being 5.5 meters width, 5.5 meters height and 36.5 meters long. •

One more furnace of 200 Tones capacity and 15mts. Bogie

length has been added. Govt. Polytechnic, Visakhapatnam

49

BHPV Project

CRANES: The maximum crane lifting capacity is 120 tones, but loads up to 250 tones can be lifted with improvisation. Maximum Rolling Capacity is 60 mm in cold condition and 170 mm in hot condition. Plate edge planning Machine: Plate edge planning machine is mainly used for to bevel or plane the surface of the plate. 1. Maximum length of the Plate up to – 12000mm 2. Maximum thickness - 800mm VERTICAL TURNING AND BORING MACHINE: It is mainly consisting of rotating circular table used for turn & bore the large type of circular parts & Dished ends, provide bevel to the edges of circular parts.


50

BHPV Project

A number of Vertical and Horizontal Boring Machines with a Maximum capacity of 5 Meters diameter and 200 MM Spindle dia. Various types of Vertical turning & Boring machines are available in BHPV. VTB machines & its capacities Light machine shop (LMS): Small Vertical turning & Boring machine – Ø 850/900mm Height - 1No. Small Vertical turning & Boring machine - Ø 1050/1100mm Ht.

-1No.

Small Vertical turning & Boring machine - Ø 1250/1100mm Ht

- 4Nos.

Heavy machine shop (HMS): Medium VTB machine

- Ø2500/5000Ht. – 2NOs.

Large VTB machine

- Ø4000/5000Ht - 2Nos.

Large VTB machine

- Ø5000/5000Ht - 2Nos.

HORIZONTAL BORING MACHINE: It is consist of horizontal spindle mainly used for bore the pipes, bevel the ends of the pipes, machining the flat surfaces.


51

BHPV Project

LIGHT MACHINE SHOP: Small horizontal boring machine

- Ø80mm - 2 no.

Medium horizontal boring machine

- Ø125mm - 1 no.

Horizontal Boring machine - 200mm - Ø200

- 1 No.

Horizontal Boring machine - 160mm - Ø160

- 1 No.


52

BHPV Project

HYDRAULIC PRESS: Function: It is mainly used for provide various shapes to plates like conical, Dished, Tory conical etc,. Mechanism: It is completely hydraulic control system. Very large forces can be created in this system. Heavy load applied by hydraulic pressure pump is provide flow energy to the oil. Pump adds pressure to the oil.

A hydraulic system is generally concerned moving of press male part. Female part is fixed one. Capacity of Press: Deep Drawing Hydraulic Press of 1600 T capacity and a number of Welding Rotators of capacity up to 250 tones.


53

BHPV Project

WELDING MACHINERY: Welding equipment such as Manual Arc, Sub merged Arc, TIG, MIG, Plasma including the latest high productive welding equipment such as Twin Head submerged arc welding, Narrow Gap submerged arc Welding and Bi-cathode TIG welding, Tube Finning Machine Submerged Arc welding Machine:

CNC DRILLING MACHINE: Single Spindle CNC Deep hole Drilling Machine with Gun Drilling attachment and 2 Nos. CNC drilling machines, which can employ conventional drills. Another CNC Deep hole drilling machine has been installed recently by HMT.


54

BHPV Project

It is mainly used for to provide tube sheet holes. It is completely computerized drilling machine. Drilling is done in three processes. 1. Pre drilling 2. Drilling & 3. Reaming or finishing. Above three operations are performed in single operation. Initially the programmed is feed in the computer. With that program machine is operated. It is very accurate and faster. Capacities: Component material: carbon steel, Stainless steel, Clad material. Dimensions: Maximum diameter is-3000mm, Thickness-600mm Drilling capacity: 40mm dia maximum is steel No of spindles – 2 Spindle pitch – 200 to 300mm Spindle speed: 150 to 3000rpm. Position tolerance: ±0.025mm over 1000mm. Repeatability: ± 0.0125mm. Drift on drill holes: 0.05mm in 100mm, 0.15mm in 400mm, 0.20mm in 600mm. Overall dimensions of the machine: 19.5m X 10.5m X 7.1m. Total connected power: 120KW. Govt. Polytechnic, Visakhapatnam

55

BHPV Project

Total weight of the machine: 90Tonnes.


56

BHPV Project

MATERIALS


57

BHPV Project

PHYSICAL PROPERTIES 1. Ultimate tensile strength 2. Yield strength 3. Elongation 4. Strength at elevated temp. 5. Hardness 6. Impact strength 7. Creep 8. Fatigue strength 9. Ductility 10. Malleability 11. Co-efficient of thermal expansion 12. Thermal conductivity

13.Electrical resistivity CHEMICAL PROPERTIES 1. Chemical composition 2. Addition of main alloys like Cr, Ni, etc. 3. Addition of micro alloys like Va, Ta, etc. 4. Carbon Equivalent, C.E. C.E = C + Mn + Cr + Mo + V + Cu + Ni CLASSIFICATION OF MATERIALS Materials are broadly classified as 1.

Carbon Steels

2.

Low Alloy Steels

3.

Stainless Steels

4.

Clad Steels

5.

Special Steels ( Properties enhanced by H.T ) a. Non – ferrous Materials


58

BHPV Project

CARBON STEELS 1.

Alloy of carbon and iron

2.

Largest Group and commonly used

3.

Cheaper

4.

Easy to fabricate

5.

Ductile

6.

Good Weld ability

7.

Low corrosive service

8.

Low or intermediate strength ( UTS = 40 to 60 kg/mm2)

9.

Suitable for elevated temperature up to 400° C

10. Suitable for low temperature up to minus 60° C

11. UTS falls at high temperature 12. Some ASME Materials :

Plate

- SA 516 Gr.60/70, SA 537 Cl.1, SA 285 Gr.C

Pipe

- SA 106 Gr.B, SA 333 Gr. 1/6

Forging - SA 350 Gr. LF2, SA 105 LOW ALLOY STEELS 1.

Alloy elements up to 9%

2.

Alloying elements : Cr, Mo, Ni

3.

Alloys increase strength

4.

Cr, Mo improves resistance to scaling, oxidation and graphitization at high temperature

5.

Cr-Mo steels resist , sulfidation, hydrogen attack

6.

Higher creep / rupture strength than C.S

7.

Suitable up to 650ºC


59

BHPV Project

8.

Ni - alloy steel possess good notch – toughness properties and suitable for low temp.

9. up to minus 196ºC 10. Greater care is needed during fabrication and welding 11. Some ASME Materials :

Plate

- SA 387 Gr.11/12/22 (Cr - Mo alloy) SA 204 Gr.A/B/C, SA 302 (C-Mo alloy) SA 203, SA 353 (Ni - alloy)

Pipe

- SA 335 P1/P11

Forgings

- SA 182 Gr. F11/F12 SA 336 Gr. F11/F22

Pipe fittings

- SA 420 WP 11 /WP 12

STAINLESS STEEL: 1. Cr. Content more than 11 % but less than 30 %

2.

Excellent resistance to corrosion

3.

Good impact strength at low temp.

4.

Strength and oxidizing resistance at elevated temp.

AUSTENITIC STAINLESS STEEL: 1.

Alloy of Cr - Ni - Fe

2.

Largest group (SS 304, SS 316, SS 321, SS 347, SS 309)

3.

Good strength

4.

Ductile

5.

High corrosion resistant

6.

High impact strength at low temp.

7.

Non – Magnetic

8.

Strength and hardness increase by cold working

9.

Some ASME Materials:


60

BHPV Project

Plate

- SA 240 Type 304 / 316 / 321 / 347

Pipe

- SA 312 TP 304 / 316 / 321 / 347

Forging

- SA 182 Gr. F304 / F316 / F321 / F347

FERRITIC STAINLESS STEEL: 1.

Cr. Content

: 16 - 30 %

2.

Wear resistant

3.

Oxidation resistant

4.

Low ductility at low temp.

5.

Suitable for less corrosive environment

6.

Used for cladding / lining, column internals like trays

7.

Cheaper compared to austenitic S.S

8.

Magnetic

9.

ASME Material : SA 240 TP 430

MARTENSITIC STAINLESS STEELS: 1. Cr. Content - 11- 16%

2. Hard enable by heat treatment 3.

Magnetic

4.

Least corrosive resistant of S. S grade

5.

ASME Material : SA 240 TP 410 a. CLAD STEEL

6.

Base : C.S or LAS a.

Clad : Corrosive resistant lining( S.S, monel etc)

7.

Low cost

8.

Methods of cladding : Hot rolling, explosion cladding

9.

Bonding strength greater than 20 000 psi in shear

10. Hot or cold formed. Govt. Polytechnic, Visakhapatnam

61

BHPV Project

11. Light loaded internal supports can be attached to clad surface. 12. Some ASME Material : SA 516 Gr.60/70

+ S.S 304 Clad

SA 387 Gr.11 Cl.2 + S.S 410S Clad SA 516 Gr.60/70

+ SB 127 Clad

SPECIAL STEELS: 1.

Mechanical properties enhanced by heat treatment

by quenching and tempering 2.

Higher strength

3.

Used for high pressure application

4.

Used where weight reduction is essential

5.

Very difficult to fabricate. More care needed in

fabrication & welding Some are C.S materials; but most of the materials

6.

are LAS. 7.

Some ASME Materials : SA 517 Gr. A to P, SA 724 Gr.A

CAST IRON: 1.

Alloy of C,Si ,Fe

2.

Ductility is low

3.

Can be cast to complicated shapes

4.

Can take compressive loads.

5.

Not permitted in pressure vessel applications.


62

BHPV Project

NON-FERROUS MATERIALS Non – ferrous metals / alloys are used wherever following properties are required, notwithstanding their higher cost. 1.

Higher Corrosive Resistant to most of the process liquids.

2.

Ability to withstand very high temperature.

3. Increased life of equipment. 4.

Good thermal conductivity.

5.

Improved mechanical strength.

6.

High melting point.

7.

Low density.

8.

Some materials.

MONEL (Ni - Cu)

- SB 127, 164, 165

INCONEL (Ni - Cr - Fe)

- SB 163, 166, 167

ALUMINIUM TITANIUM

- SB 265, 337

CUPRO-NICKEL (Cu - Ni)

- SB 151, 171

SERVICE REQUIREMENTS: 1. Ambient service 2.

High temperature service

3.

Low temperature service

4.

Corrosive service

5.

Hydrogen Induced Cracking

6.

Sour service

AMBIENT SERVICE: 1.

Operating conditions are at ambient conditions.

2.

C.S materials are commonly used


63

BHPV Project

REQUIRED MATERIAL PROPERTIES: 1.

Tensile strength at elevated temp.

2.

Creep/ rupture strength at elevated temp.

3.

Resistance to scaling.

4.

Resistance to corrosion.

5.

Coarse grained material

MATERIALS: 1.

LAS are best suited for elevated temp. They have good scaling resistance and strength.

2.

S.S can also be used for elevated temp.

3.

Carbon steels are not suitable for elevated temp. Above 400°C, carbon steels, materials have low creep resistance, decarburize faster, graphitize, excessive scaling.

APPLICATIONS: 1.

Reactors in petrochemical, petroleum, fertilizers industries.

2.

power generation equipments

LOW TEMPERATURE SERVICE: In low temperature service, equipments operating at temp, below 0°C REQUIRED MATERIAL PROPERTIES: 1.

Notch toughness at low temp .i.e. ability to deform plastically at stress concentration to resist brittle fracture at notches.


64

BHPV Project

MATERIALS: 1.

C.S materials are suitable up to minus 60°C.

2.

LAS materials like Ni-alloys are suitable up to (-) 196°C.

3.

S.S is ideally suitable up to (-) 255°C.

APPLICATIONS 1.

Liquid oxygen/liquid nitrogen storage facility.

2.

Cryogenic applications


65

BHPV Project

WELDING TECHNOLOGY


66

BHPV Project

WELDING JOINT DESIGN AND WELDING SYMBOLS INTRODUCTION Mechanical components, vessels or any structures are manufactured by assembly / joints of two or more parts due to the following reasons.  Limitation on maximum size of raw material  Complexity of shape  Combination of raw materials  Limitation on size of component parts for transportation  Ease of replacement in service. Joints can be made mechanically using bolts, rivets, keys or using adhesives or by welding. Choice of a specific type of joint and joining process depends on designer’s knowledge of joining techniques, fabrication facilities, and state of development of material forms. Today, welding is the most commonly used method of fabrication of structural works, pressure vessels etc. WELDED JOINTS Welded joint has number of merits over other conventional fabrication processes. They are 

Welded joints provide leak proof joint.



Welding is more flexible and has numerous basic cost

savings over other forms of operations. Govt. Polytechnic, Visakhapatnam

67

BHPV Project



Welding is 3 or 4 times stronger than other fabrication

processes. 

Welded parts are more resistant to shock and impact forces.



Capital equipment is less for welding compared to other

manufacturing processes. Some of the demerits of welding are  Weld ability of some materials are not good.  Dismantling of joints is difficult. Hence welding is not preferred where dismantling is necessary during service or maintenance.  Defects like cracks, porosity in welds affect strength of welds.  Welding may results in distortion of parts being jointed. TYPES OF WELD JOINTS: Weld joints can be classified as follows based on position.  Butt  Tee  Lap  Corner  Edge


68

BHPV Project

Types of Weld Joints EDGE PREPARATION: If the metal is thin, say 3mm, then it is possible to make a full penetration weld between abutting edges. For thick sections, full penetration can be achieved by beveling the weld edges or by providing backing strip. Suitable bevel detail is selected to provide minimum weld deposition and full penetration. Partial penetration weld joint can be used for less critical services. Normally, edge preparation is made by gas cutting / machining for all C.S. materials. For S.S. materials, edge preparation is done by either machining or plasma cutting.


69

BHPV Project

TYPE OF WELDS For design purpose, welds can be divided into three basic types, calling for different design methods and different design stresses. They are groove, fillet and plug welds. The weld joint must be designed to provide strength adequate to transfer the design stresses. GROOVE WELDS Groove welds provide better joint and takes more load. It can be used in butt, tee or corner welds. A square butt weld is economical to use, provided satisfactory soundness and strength can be achieved. However, its use is limited by the thickness of joint. For thick joints, edge of each member must be prepared to a particular geometry to provide accessibility for welding and ensure desired soundness and strength. In the interest of economy, that joint design should be selected with root opening and groove angles that require smallest amount of weld metal and still give sufficient accessibility for sound welds. Welds in J- and U-groove joints may be used to minimize weld metal requirements when the savings are sufficient to justify the more costly preparation of the edges.

This will be more useful in thick

section. Single bevel and J-groove welds are more difficult to weld than V-and U-groove welds because one edge of the groove is vertical. Selection of detail of weld groove depend upon the welding process, type of power used and base material properties. A careful fit-up is required for butt joints but slight mismatch may be permissible. The strength of a groove weld is based on cross sectional area subject to shear, tension or compression and allowable stress for the Govt. Polytechnic, Visakhapatnam

70

BHPV Project

weld metal. The allowable stress for groove weld is generally same as that of base material. Joint efficiency depends on the type of weld examination, the welding procedure and type of load.

Weld

reinforcement is a source of stress concentration and potential failure under repetitive load. Removal of weld reinforcement increases fatigue strength of weld.


71

BHPV Project

Complete Joint Penetration: Groove welds with complete joint penetration are suitable for all types of loadings, provided they meet the acceptance criteria for the application. In most cases, a single groove weld is not considered to have complete penetration unless it was made using a suitable backing strip or a back weld was applied. In such cases, to ensure complete joint penetration without backing strip, the root of first weld must be back gouged to sound metal before making a weld pass on the other side. Partial Joint Penetration: It has an unwelded portion at the root of the weld. The unwelded portions of groove-welded joints constitute a stress raiser having significance where cyclic loads are applied transversely to the joint. However, when the loads are applied to the welds axis, a higher stress Govt. Polytechnic, Visakhapatnam

72

BHPV Project

range is permitted. Partially penetrated joints should not be exposed to corrosive conditions. For design purpose, the effective throat is never greater than the depth of joint penetrations. FILLET WELDS: Fillet welds are used in preference to groove weld for the sake of economy. Fillet weld do not require edge preparation and fit up is easy. Fillet weld size is measured by the length of the leg of largest right triangle that may be inscribed within the fillet weld cross section. The strength of fillet weld is based on the effective throat and the length of the weld. Stress concentration at the root or at the toe can cause failure under variable loads. One sided fillet weld in tee or lap joining is generally avoided because of a very low static and fatigue strength of this weld. Face of fillet weld may vary from convex to concave to reduce stress concentration.


73

BHPV Project

Stress induced in fillet-welded joints is complex because of the eccentricity of the applied load, the weld shape and notch effects. They consist of shear, tension and compressive stresses. Fillet welds are used to join corner, tee and lap joints.

Fillet welds are generally used for transfer of shear forces

parallel to the axis of the weld and for transfer of static forces transverse to the axis of the weld. If the load require a fillet weld of size 16 mm or large, groove weld should be used possibly in combination with a fillet weld to provide a required effective throat. Govt. Polytechnic, Visakhapatnam

74

BHPV Project

Excessive fillet weld may be a major factor contributing to an increase in welding cost, residual stresses and distortion. Fillet welds may be designed with unequal leg sizes to provide the required effective throat or the welded heat balance for complete fusion with unequal base material thicknesses. Plug welding: A plug weld is circular weld made either by arc or gas welding through one member of a lap or tee joint. Plug-weld holes in thin plates are completely filled. They are only partially filled in heavier plates (i.e. above 10 mm) Plug welds are often used to fix corrosion resistant lining to the base metal of pressure vessel. They are sometimes used as strength welds in single lap joints, reinforcing pads or nonpressure structural attachments and then only in addition to other types of welds. SIZING OF PLUG WELD: ASME Sec. VIII Div.1 allows only 30% of the total load to be carried by plug welds if they are used. The allowable working load on a plug weld in shear or in tension can be computed by the following code formula. P = 0.63 (d - ¼) 2 Sa Where Sa = Allowable stress in tension of base material d = the bottom diameter of weld hole, limited to T + ¼" < d < 2T+ ¼" T = Plate thickness being welded. Govt. Polytechnic, Visakhapatnam

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BHPV Project

CORNER WELDS: Corner welds are widely used in machine design. Typical corner joint designs are illustrated in following figures.

Fig - A: This joint is difficult to position and usually requires fixturing. This joint requires large amount of weld metal. Fig - B: This joint is easy to assemble, does not require backing and needs only about half of the weld metal required to make the joint shown in Fig-A. But the joint has lower strength because effective throat of weld is smaller. Fig - C: This joint can provide the same total effective throat as with the design shown in Fig- A but with half the weld metal. Fig - D: This is suitable for thick section with partial penetration. However this requires edge preparation. Fig - E: This is suitable for thick section with deeper joint penetration. Fig - F : This is ideal for critical or cycle service where sharp corners are avoided. Govt. Polytechnic, Visakhapatnam

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CLASSIFICATION OF WELDS: Based on their reaction to loads, welds are classified as  Primary welds  Secondary welds  Transverse welds  Parallel welds Primary welds: Primary welds are those that absorb full load at the plane of the welds. Welds of these types must have same properties as that of base materials. Secondary welds: Secondary welds do not carry full load of connecting members but must absorb forces, which are in the member at the point of weld. Transverse welds: Transverse welds are those that transmit tension and compression force from one member to another. Parallel welds: Parallel welds are those that transmit shear load from one member to another. Design Allowable stresses for welded joint: Selection of proper allowable working stress or safety factor for weld is an important aspect of design. Generally allowable stress of weld material is expressed in terms of the strength of base material and efficiency factor, E, to compensate for possible variation in weld quality. Govt. Polytechnic, Visakhapatnam

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ASME Sec.VIII Div.1 Code: The joint efficiency depends on the type of weld and the degree of radiographic examination. For butt-welded joints, joint efficiency shall be as follows. Joint efficiency Spot radiography

0.85

Full radiography

1.0

No radiography

0.7

The allowable load on fillet welds connecting non pressure parts to vessel pressure parts is equal to the product of the weld area based on the minimum leg dimension, the allowable stress in tension of the material being welded, Sa, and the joint efficiency of 55 %. ASME Sec. VIII Div.2 -Code: Full radiography is required for all pressure shell welds.

The

strength of welds so inspected is considered to be the same as the strength of base material. Welds subject to fluctuating stresses must be designed and evaluated according to design values based on fatigue analysis, as described in Code Appendix-5. AISC Specification: This code is used for the design of structural construction. The permissible design stress for groove welds with full penetration can be taken the same as for the parent material if prescribed electrodes are used. Govt. Polytechnic, Visakhapatnam

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Allowable stress for fillet weld throat area is given in terms of the specified strength of weld metal, depending in the electrode used. Here the nominal composition of the electrode must be considered by the designer where selecting the joint efficiency for the weld. Indian Standard IS 816: Butt weld shall be treated, as parent metal with thickness equal to throat thickness and stress shall not exceed those permitted in parent metal. For fillet and plug welds, stress shall not exceed 1100 kg/cm2. For site weld made during erection of structural members, stress shall be limited to 80% of those given above. If wind and earthquake are taken into consideration, permissible stress may be increased by 25%. Weld joint design: Weld joint design primarily depends on load requirements. Generally the following guidelines are to be followed for better design. 1. Select the joint design that requires the least amount of weld metal, satisfying the required strength. 2. Use square-groove, partial joint penetration weld or intermittent weld wherever possible. 3. Use lap and fillet welds instead of groove welds if fatigue is not a design consideration. 4. Where repetitive loads are expected, full penetration groove welds are to be used. Surfaces should be ground smooth to eliminate possible minute discontinuities. Govt. Polytechnic, Visakhapatnam

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5. Use double-V or U-groove instead of single-V or U-groove welds on thick plates to reduce the amount of weld metal and to control distortion. 6. For corner joints in thick plates where fillet welds are not adequate, beveling both members should be considered to reduce the tendency for lamellar tearing. 7. Design the assembly and the joints for good accessibility for welding. Stress concentration factor for welds: Stress concentration in welds is due to geometry of welded joints, defects and imperfections in the welds, and also the different metallurgical structures of the weld metal, the metal in the heat affected zone and the base metal. The effect of these factors on stresses induced by steady loads in a ductile weld material can be ignored. However, if the weld is hard and brittle, or under shock, or fluctuating loads, the influence of stress concentration becomes significant. Welding symbols: Weld symbol convey design requirements to the shop in a concise manner. Welding symbol include the following.  Reference line  Arrow  Basic weld symbol Govt. Polytechnic, Visakhapatnam

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 Dimensions and other data  Supplementary symbols  Finish symbols  Specification, process or other reference All the above elements need not be used unless required clarity.


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WELDING METHODS: Assembly of parts by various welding process may be adopted depending on codes requirements and customer requirements. The following points may be taken as guidelines and further details are to be had from welding technology: 1. Manual metal are welding may be adopted generally for all materials (C.S, L.A.S, S.S etc.) of thickness from 1.5mm to 150mm. In case of shell welding the minimum internal dia shall be 400mm. 2. Submerged arc welding may be adopted for materials like carbon steel, low alloy steel & stainless steel of thickness above 10mm. In case of shells welding the minimum dia should be 650mm. 3. 3.TIG welding is generally recommended for single side welding joints where there is no access from the other side on materials like stainless steel, low alloy steel, carbon steel & Aluminum etc. (Ex: Pipe joints) 4. MIG welding is generally applicable similar as above recommended for lengthy joints where there is free access for the machine. 5. Resistant welding is applicable for thick plate sections such as flanges segments and joining thin plates such as bubble cap trays. This is applicable only for non-pressure parts. 6. Electro slag welding is generally used for the welding longitudinal seams only of carbon and low alloy steel of thickness 50mm to 450mm. In case of shells welded with this process the minimum internal diameter should be 1000mm and the minimum. Length should be 1.5 meters. 7. In case of points 1 to 4 points pre-heating may be required for materials having thickness more than 25mm in case of carbon steel and all materials in case of low alloy steel. No pre heating is required in case of stainless Govt. Polytechnic, Visakhapatnam

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TERMS TO PROCESS EQIPMENT INDUSTRY


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VOCABULARY OF TERMS TO PROCESS EQUIPMENT INDUSTRY

I. MATERIALS: 1. Alloy steel: A steel containing one or more alloying elements as a result of which it develops specific characteristics. 2. Asbestos: A material fibrous, of high melting point, low thermal conductivity and Non-inflammable. It is used for filters, gaskets, fire proof installations etc. 3. Carbon steel: A composite material obtained by firmly binding together a carbon or alloy steel with a surface layer of another material or alloy. 4. Cast steel: Originally this term was applied to differentiate crucible steel from hot worked or commented bar. At present the term is used for steel castings. 5. Mild steel: Carbon steel containing generally between 0.15 and 0.25% carbon. 6. Stainless Steel: An alloy steel containing about 12% or more of Chromium with or without Nickel together with other elements and is characterized by its high resistance to corrosion.


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II. COMPONENTS: 1. Bar: A rolled or forged product of variable length, usually, square, rectangular, hexagonal or circular in cross section.

2. Billet: A semi finished product obtained by forging, rolling or by continuous casting usually square and not exceeding 125X125mm in cross section with rounded corners, and is intended for further processing into suitable finished product by forging or rerolling. 3. Bolt: A bolt is an external threaded fastener designed for insertion through holes in assembled parts and is normally intended to be tightened or released by torquing a nut. 4. Bloom: A semi finished forged, rolled or cast product intended for re rolling or forging with a cross sectional area generally more than 160cm2. 5. Bright bar or wire: Bar or wire with a bright finish obtained by cold Drawing, Machining, Grinding etc. 6. Flat: A bar of rectangular section with edges of controlled contour, the width being greater than the thickness (thickness 3mm & over, width 400mm & below). 7. Girder or beam: A type of section, beam, simple or built up to takes lateral stress. 8. Ingot: Castings of suitable shape or size intended for subsequent hot working. Govt. Polytechnic, Visakhapatnam

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9. Line Pipe: An American term usually associated with the oil industry and applying to pipes used for conveyance of oil or natural gas, excluding the pipes in the well.

10. Nozzles: Pipe lines witch bring the fluid to and from the tank are attached to short pipe connections welded into the tank shell and these connections are called Nozzles. 11. Plate: Product of rolling an ingot or slap in a plate mill. The cross section is rectangular and over 5mm thick and the width is very much greater than the thickness. 12. Pipe: Generally used to apply to tabular products where the thickness is very small compared to the diameter commonly used for pipe lines and connections for conveying fluid from point to point. 13. Rail: A type of section, straight and long used for track purpose for Railways, Tramways, as well as for heavy mobile machinery running on metal wheels. 14. Rod: A semi finished hot rolled product of relatively small cross section and very great length produced in coil form. In rounds the usual range of size in which wire rods are produced is from 5 to 14mm. 15. Screw: A Screw is an externally threaded fastener capable of being inserted into holes in assembled parts of mating with performed internal thread or forming its own thread and of being tightened or released by torquing the head.


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16. Sheet: Plate of rolling, cross section is rectangular and thickness less than 5mm, width is about 600mm and above. Usually available in coil form. 17. Slab: A Semi finished rolled product intended for re-rolling or forging. The cross section is rectangular, usually with a width more than twice the thickness. 18. Strip: Flat rolled metal with greatest thickness being approximately 0.25 inch. 19. Stud: An externally threaded fastener without head which must be assembled with a nut on side and screwed in tapped hole on the other side or with two nuts to perform its intended service. 20. Tube: Generally used to apply to tabular products where the thickness is considerably more compared to the diameter and commonly used in Heat exchangers and Boilers (for heat transfer) and in machine and air craft industries. PIPE FITTINGS: 1. Branch: The outlet or inlet of fitting not in line with the run but which may make any angle. 2. Bushing: A pipe fitting for the purpose of connecting a pipe with a fitting of a large size being a hollow plug with internal and external threads to suit the different diameters. 3. Close Nipple: Close Nipple is the one, the length of which is about twice the length of slandered pipe thread and is without any shoulder. Govt. Polytechnic, Visakhapatnam

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4. Coupling: A threaded sleeve used to connect two pipes. Also a forged round piece outside of which is welded to the shell and inside threaded to receive pipe or plug. 5. Cross: A pipe fitting with four branches arranged in pairs, each pair on one axis and the axes are at right angles. 6. Elbow: A fitting that makes an angle between adjacent pipes. The angle is always 90° unless other angle is stated. 7. Manifold: A fitting with numerous branches used convey fluids between a large pipe and a several small pipes; a header for a coil. 8. Needle valve: A valve provided with a long tapering point in place of the ordinary valve. 9. Nipple: A tabular fitting usually threaded on both ends and under 12 inches in length. 10. Plug: A threaded piece, used to close or blind the coupling. 11. Reducer: A fitting having a larger size at one end than at the other. 12. Short Nipple: One hose length is little greater than that of two threaded lengths or some what larger than a close nipple. It always has some un threaded portion between the two threads. 13. Tee: A fitting either cast or wrought, that has one side out let at right angles to the Run. 14. Union: The usual trade term for a device used to connect two pipes.


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TESTING METHODS


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TESTING METHODS: Types of tests: 1. Destructive tests & 2. Non-Destructive tests. Destructive tests: These tests are required to determine the strength of materials. Several destructive tests are available to determine the various mechanical properties. Non-Destructive tests: These tests are employed for finished products to determine internal defects like blow holes, slag inclusions etc., and surface defects. Types of Destructive tests: 1. Static test: Load is applied gradually. a) Tension test b) Compression test c) Shear test d) Hardness test e) Creep test 2. Impact test: Specimen is subjected to shock load. a) Charpy impact test b) Izod test 3. Cyclic test: Load is repeatedly varies in magnitude and direction during the test. Govt. Polytechnic, Visakhapatnam

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Tensile test: Tensile test is widely used to find the behavior of material when subjected to a slowly applied tensile load. It is conducted on Universal Testing Machine (UTM) in which load increased gradually up to fracture and stress-strain diagram is obtained with the aid of instrument attached to the machine. Compression test: This test is conducted on UTM in a similar way as tensile test, but the direction of load is reserved. Component subjected to a compressive force does not deform uniformly. If the material is plastic instead of brittle, it bulges as its mid section. Shear test: For the direct shear tests the portion of bar is clamped in a device while the remaining portion is subjected to shear load by means of suitable dies. Hardness test: Ability of material to resist indentation or penetration is called hardness. The majority of hardness tests force a indentor into the surface of the metal by means of applied load. There are three types of hardness tests 1. Brinell hardness test:

The Brinell test consists of indenting the surface of metal by a hardened steel ball under a load. The load is applied by a lever system is placed on stage with its ground face upwards. Govt. Polytechnic, Visakhapatnam

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2. Vicker’s hardness test:

The test is also called as Diamond pyramid hardness test. The test is conducted on machines with an indenter of square based Diamond pyramid of an angle of 136° between opposite faces. 3. Rockwell hardness test:

In Rockwell hardness test, the hardness is determined by the depth of the penetration of an indenter, rather than by surface area of indentation. 4. Charpy Impact Test: An impact test in which a notched test piece supported at both ends, is broken by a blow from a striker on the face opposite to and immediately behind the notch, the energy absorbed in fracturing the specimen being recorded. 5. Izod impact test: The izod impact testing machine is commonly made with a 18Kg capacity. In this case a notched specimen is held in a vice in the form of a cantilever and a heavy pendulum is allowed to strike the specimen from a fixed height. NON DESTRUCTIVE TESTING METHODS: 1. Visual inspection 2. Penetrating test 3. Magnetic detection test 4. Ultrasonic test 5. Radiography test 6. Spark test Govt. Polytechnic, Visakhapatnam

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Visual inspection: Often defects can be discovered by the naked eye or by using a low power magnifying lens can be rectified or repaired. Penetrating test: This is the method of using a sensitive fluorescent penetrate to locate cracks or porous areas on the surface of a metal which may not be visible to naked eye. Magnetic detection test: Magnetic testing is used for detecting the surface flaws in Ferro magnetic materials and alloys. The component under test is magnetized. Ultrasonic test: Used to inspect soundness of materials without destruction. This method gives the exact location of the voids or inclusions found from photo film obtained by passing radioactive rays through the metal falling on the film. Extremely fine voids is cannot be detected by this method. Radiography test: Radiography test is used to locate the internal defects in welded products, castings and forgings. It uses radiation of short wave length for detecting internal flaws.


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SOME IMPORTANT TESTING METHODS: Bent test: A test for ductility and soundness. It is carried out by bending a test piece at the middle, over a specified radius generally by a steadily applied load or by blow. Drift test: A test for plate is carried out by boring a hole of a given diameter near the edge of the plate and enlarging by a conical tool having a specified taper until either the specified increase in dia takes place or cracking occurs.


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