CSWIP 3.2 THEORY PAPER Q&A 1. Si Sign gnin ing g off off a pro produ duct ct In an engineering fabrication industry the last activity in the sequence sequence of manufacturing is load out or dispatch. This activity cannot be initiated unless the product is signed off. As a matter of fact signing the product off is assurance of quality which is authenticated by a technically competent person such as “Senior Welding Inspector” who maes sure that complete manufacturing of product has been carried out in accordance with applicable standard and sound engineering practices.
!owever before signing the documents the senior welding inspector should s hould mae enquiry which can give him the in sites of the past while product product was being manufactured. manufactured. Typical Ty pical questions can be as followed 1. What was the repair rate during production" 2. Whether any difficulties are encountered within the #ob" 3. Which is the critical area in this #ob or product" 4. Whether any concession or waiver were given$ if yes why" 5. !ow were the weather weather conditions" 6. Whether there were any safety issues$ fatalities$ ma#or accidents%incident etc&" 7. Whether there were any labour problems" 8. What was the general moral and standard of wor amongst the inspection team's(" )urther to this he can start reviewing of documents and he should mae sure that he attaches the following documents as a minimum 1. *uality control plan + ensure all stages are completed and signed off 2. Inspection chec list + ensure all all stages are completed and signed off off 3. ,erify material certificates such as mill test certificates- material traceability records lap reports etc& 4. ,e ,erify rify the following f ollowing procedures procedures which are to be attached and have all been approved a. Welding e. !ardness b. epair f. 12I c. /0T g. !ydrotest d. 1W!T h. 3oating%1ainting 5. ,e ,erify rify the qualification level and validity of the welder and /0T personnel 6. ,erif rifyy the ins inspec pection tion re repor ports ts of fol follow lowing ing dis discip ciplin lines es and ens ensur uree tha thatt the theyy cov cover er all appropriate #oints and structure a. ,isual b. /0T c. 0imensional control etc& 7. ,erif rifyy cal calibr ibrati ation on cer certif tifica icates tes of equ equipm ipment entss and ins instru trumen ments ts suc such h as pre pressur ssuree gau gauge$ ge$ inspection tools and welding equipments etc& 8. ,erify hardness test reports 9. ,erify 12I reports 10. ,erify 1W!T reports and charts 11. ,e ,erify rify !ydro test reports and charts 12. ,e ,erify rify painting and coating inspection reports 13. ,e ,erify rify as built drawings are completed 14. ,e ,erify rify weld maps are available for traceability 15. ,e ,erify rify name plate$ pl ate$ rubbing details are available when applicable 16. ,e ,erify rify concession request$ /3$ site query etc& 17. ,erify permit to wor 18. 19. As a part of his own inspection he may be obliged to witness final hydrotest$ visual inspection of completed parts. As a matter of quality assurance he may view some radiographs at random and may even conduct radiograph r adiograph audit. 20.
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CSWIP 3.2 THEORY PAPER Q&A 21. )inally$ transit and tie down procedur procedures es should all have been approved by the relevant engineer prior to the final acceptance of the product and issue of any signed certificate of conformance. 2. Duties Duties of the Senio Seniorr Wel Weldin ding g Inspec Inspector tor 22. 23. Plan 24. It is an agreed pre4determined pre4determined structural path way that needs needs specific aim. All pro#ects inspection needs the following planning. a. 5stablishing inspection test plan and plan for all stages of inspection b. 5stablish requires requires W1S and 1* c. 1lan for requires requires resources. resources. I.e. manpower$ manpower$ inspection tools$ tools$ etc.$ d. 0eveloping quality control control procedures procedures e. 1lan the wor schedule i.e. type of inspection and and at what times. f. 3ommunication with superior and others.
25. 26. Organize 27. To mae all necessary arrangement arr angement required to carry out or fulfil plan$ this may involve the following. a. Any training and certification required. required. b. Staffing plan i.e. assigning wor and area to inspectors c. 1rocure 1rocurement ment of inspection equipment and its calibration d. Transportation to and fro from site e. Accommodation and messing f. Inspectors leave cycle
28. 29. Supervise 30. 6nce the plan has been organi7ed it is essential that t hat controls are e8ercised so that the plan is successfully implemented a. Supervise and evaluate inspectors wor. b. 3hec inspection equipment condition c. 6rgani7e the inspection activities to be completed in time d. Ta Tae e effective decision for solving quality related problems e. Share your nowledge with technical discussion with all inspectors f. 2otivate the staff to meet standard of of quality g. 3ommunicate with other department to improve procedure$ procedure$ investigate and advice on quality problems. h. 9eep a record record of day to day inspection activates activates and pending inspection to be completed i. Supervise to maintain IS6 related documents. 31.
32. Auditing 33. To carry out a periodic and systematic chec on a system process to ensure ens ure that it has been carried out as specified 34. 35. Staff a. All staff to be internal audited to ensure that they are maintaining all documents as per IT1 b. Whether all IS6 related documents are maintained c. Whether all welder details are up to date 36. 37. Equipent a. Inspection tools to be checed for calibration and condition condition b. We Welding lding machine over calibration and condition 38. 39. Docuentation a. 3hec all inspection documents are maintained as per procedure
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CSWIP 3.2 THEORY PAPER Q&A 21. )inally$ transit and tie down procedur procedures es should all have been approved by the relevant engineer prior to the final acceptance of the product and issue of any signed certificate of conformance. 2. Duties Duties of the Senio Seniorr Wel Weldin ding g Inspec Inspector tor 22. 23. Plan 24. It is an agreed pre4determined pre4determined structural path way that needs needs specific aim. All pro#ects inspection needs the following planning. a. 5stablishing inspection test plan and plan for all stages of inspection b. 5stablish requires requires W1S and 1* c. 1lan for requires requires resources. resources. I.e. manpower$ manpower$ inspection tools$ tools$ etc.$ d. 0eveloping quality control control procedures procedures e. 1lan the wor schedule i.e. type of inspection and and at what times. f. 3ommunication with superior and others.
25. 26. Organize 27. To mae all necessary arrangement arr angement required to carry out or fulfil plan$ this may involve the following. a. Any training and certification required. required. b. Staffing plan i.e. assigning wor and area to inspectors c. 1rocure 1rocurement ment of inspection equipment and its calibration d. Transportation to and fro from site e. Accommodation and messing f. Inspectors leave cycle
28. 29. Supervise 30. 6nce the plan has been organi7ed it is essential that t hat controls are e8ercised so that the plan is successfully implemented a. Supervise and evaluate inspectors wor. b. 3hec inspection equipment condition c. 6rgani7e the inspection activities to be completed in time d. Ta Tae e effective decision for solving quality related problems e. Share your nowledge with technical discussion with all inspectors f. 2otivate the staff to meet standard of of quality g. 3ommunicate with other department to improve procedure$ procedure$ investigate and advice on quality problems. h. 9eep a record record of day to day inspection activates activates and pending inspection to be completed i. Supervise to maintain IS6 related documents. 31.
32. Auditing 33. To carry out a periodic and systematic chec on a system process to ensure ens ure that it has been carried out as specified 34. 35. Staff a. All staff to be internal audited to ensure that they are maintaining all documents as per IT1 b. Whether all IS6 related documents are maintained c. Whether all welder details are up to date 36. 37. Equipent a. Inspection tools to be checed for calibration and condition condition b. We Welding lding machine over calibration and condition 38. 39. Docuentation a. 3hec all inspection documents are maintained as per procedure
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CSWIP 3.2 THEORY PAPER Q&A b. 3hec all /0T record recordss c. 3hec welder qualification record d. andomly interpret adiographic adiographic for all personals. !. Descri"e Descri"e and s#etch s#etch the follo$ing follo$ing defects defects lainatio laination% n% laps% "ands "ands and their their difference differencess 40. &aination 41. :aminations are planes within the steel plate across 'through thicness( which there is no metallic bond 'separated in layers(. They are typically a result of non4metallic inclusions and gas pocets formed in the ingot when it has been cast cast and as it solidifies. 42. 43. In the steel mill the molten steel poured in moulds to form ingots. While solidification is taing place huge amount of gases are released. It is quite possible that some of these gases and non4metallic inclusions such as o8ide coating of the bubbles$ slag inclusions$ refractory inclusions from erosion of the furnace may remain trapped in the solidified steel. This ingot when rolled the gas pocet and inclusions inside get flattened in the forms of lamination. 44. 45. This discontinuity adversely affects through thicness strength of steel and is not traceable by 21I or T. The only way to detect lamination is ;T. This discontinuity may also contribute to lamellar tear in thicer section. 46. 47. &aps 48. :aps are basically chun of metal that has flown from the desired profile during operations such as rolling and hot forming. This chun of material is connected to the base metal at some locations and overhanging portion of the chun simply lies l ies on the metal met al without being the homogeneous part of it. As it is surface defect it can be found visually and can be confirmed by 21I. 49. 50. Differences' lamination is a sub4surface defect lap is a surface defect. :ap can be found in visual inspection and confirm by 21I. :amination can be confirmed by ultrasonic test only. 51. 52. (ands 53. As the ingot is forged and rolled the segregation are elongated and reduced in cross section. s ection. If further processing is carried out$ they may appear as very thin parallel lines of bands and is generally nown as banding.
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CSWIP 3.2 THEORY PAPER Q&A 5. lac of credibility to the organi7ation 57. 6bserving all above$ it is imperative that lifting the low morale this can be done as follows 1. Arrange the meeting of entire sub coordinates coordinates staff for discussion on the sub#ect matter. matter. 2. )rom their response response I can form a collective opinion for low morale 3. )urther to this I may have private discussion with each individual individual which can help me to 7ero in on his problems. 4. This problem is then sorted out as general problem and individual problems. 5. As regard to the personal problems I can assure the team that I will do everything possible in my capacity to rectify it. 6. I should bring to the attention of the employees employees in gentle but firm manner that$ their individual problems must not affect the morale. 7. I will try to see company=s company=s help for for their personal problem. 8. These they should be noticed that the high morale will reflect in good salary rise$ better facilities etc. 9. If low morale continues then the management will will be obliged warning letters$ demotions and worst case termination also 58. ,. *ou suspected suspected that that a radiograph radiographic ic tea under under supervision supervision of of *our inspector inspector has has radiograp radiographed hed the sae $eld sea and onl* changing the lead letters a. What $ould "e *our initial course of action+ Or $hat action $ould *ou ta#e to confir this+ b. If *our suspicion is proved to "e correct% $hat $ould "e *our further course of action+ Or $hat action $ould *ou ta#e upon *our conforation+ 59. 60. Actions to confir 1. 3onduct the radiographic audit in the batches and if similar looing radiographs are found then they should be verified at #ob against the welds comparing by profile or by any parent metal mars. 2. If many such suspected radiographs are found then the full audit of all radiographs should be performed. 3. 1hysically inspect three or four #oints to random mar with correct identification number and tae new radiographs by using new radiographic crew. crew. 4. 5valuate the new radiographs and compare with the previous taen radiographs of the respective #oints. 5. The outcome of this investigation could be of two types a. are case of duplication duplication b. 6ccurrence of duplication in many cases 61. In the first case it is most liely to be a human error- hence the matter can be resolved by maing /0T supervisor aware of facts. 62. In the second case it is an intentional action performed to help somebody= somebody=ss interest$ which is obviously a set bac to the quality. 63. 64. Actions upon conforation 1. Inform the occurrence to the higher authorities or supervisor and produce ob#ective evidence 2. Identify the crew which has taen with wrong identification 3. aise /3 4. Arrange to remove and replace replace the crew crew immediately 5. Arrange to reshoot all #oints by using new new crew 6. 5stablish proper monitoring system to avoid reoccurrence reoccurrence of of such problems 7. Arrange to close /3 65. A meeting of all inspectors to be conducted and they should be issued a strong warning letter to improve the level of their performance to avoid such incident in future. 66.
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CSWIP 3.2 THEORY PAPER Q&A -. What is the course of investigation for vessel rupture $ith loud "ang+ 67. or in the base metal then one can further investigate the following avenues 69. If in base metal 1. chemical composition and physical properties certificates s upplied by manufacturer 'material test certificates( 2. heat treatment records and lap test reports if any 3. hardness of the base metal and thicness in the rupture 7one 4. suitability of material for the given service conditions 70. If in weld%!A> 1. 3hec the W1S used for welding 2. ,isual inspection reports and weld logs 3. adiographic reports 4. !eat treatment records and charts 5. !ardness reports 71.
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CSWIP 3.2 THEORY PAPER Q&A 78. Assuming that the transition #oint in this discussion complied with both of the above two categories. )ollowing care should be taen during welding 79. 80. Transition #oint with different base metal? 1. proper selection of electrode to avoid dilution of the weld metal 2. proper selection of current range and polarity type of current 3. bac purging required$ if any 4. cleanliness 5. pre4heat$ 1W!T 6. Welding process 81. 82. Transition #oint with different thicness 1. The thicer member should be gradually t apered off to match the thicness of thinner member such that said taper will not e8ceed @? 2. The completed weld should be blended in such a way it will follow the gradual transition 3. 1roper heat treatment should be chosen taing consideration of thicness of thicer member 83. 6n steels$ the !A> of the weld tends to be more brittle i.e. it has lower notch toughness than the actual weld metal. The !A> area is therefore more prone to cracing especially when hydrogen is induced$ although it must be noted that the tensile strength of the !A> is normally high in comparison with the weld and parent material. ;nfortunately it a fusion welding process is being used then the !A> cannot be eliminated. 84. 1roblems occur during welding a transition #oint 1. 3onsumable selection 2. !ot cracing due to thermal e8pansion of steel 3. 3old cracing due to uneven e8pansion and contraction of thic and thin member or different material properties 4. 3orrosion will occur in SS side in !A> 85. . What is laellar tearing+ descri"e "riefl* causes and control easures for laellar tearing 86. 3rac type ? lamellar tearing 87. :ocation ? below the weld$ !A> 'T B 3orner Coints( 88. Steel types ? !igh sulphur B phosphorous steel 89. Susceptible microstructure ? cold rolled 90. 91. It is a step lie crac occurring in the parent metal or !A> of steel with poor through thicness ductility$ where the fusion boundary of the weld is parallel with plate surface. It is usually associated with restrained #oints on corner$ tee or fillet welds #oining thic plate. 92. 3auses 1. poor through thicness ductility 2. non4metallic inclusion in the direction of rolling 3. restrained #oint 4. through thicness stress 5. high sulphur%phosphorous content 6. presence of hydrogen 93. 94. :amellar tearing occurs when two conditions e8ist at the same time? a. A susceptible rolled plate is used to mae a weld #oint b. !igh stresses act in the through4thicness direction of the susceptible material 'nown as the short4transverse direction( 95. 3ontrol 1. educing the si7e of weld 2. modify #oint design 3. control restraint 4. use of forged materials for critical wor
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CSWIP 3.2 THEORY PAPER Q&A 5. Drind the parent metal and fill with ductile weld metal. A buttering layer of high ductility weld metal may be deposited where the vertical member is to be welded. 6. Asses the through thicness ductility by short transverse tensile test 7. Inspect the plate for non4metallic inclusions 8. 3arry out full chemical analysis to mae sure sulphur is less than E.EFG 96. 13. What is solidification crac# descri"e "riefl* causes and controlling easures+ 97. 3racing that taes place during the weld solidification process is termed either hot cracing or solidification cracing and occurs in all steels which have high sulphur content 4 sulphur causes low ductility at elevated temperatures. 98. 99. In order for a crac to develop the solidifying metal must be sub#ected to a high tensile stress$ this may by present as a result of weld metal contraction combined with high restraint. Solidification cracs usually occur longitudinally down the centre of the weld because of the segregation of impurities and have a blunt profile. 100. 101. 3entreline solidification cracs tend to be surface breaing at some point in their length and can be easily seen during visual inspection because they tend to be relatively wide cracs. 102. Solidification cracing occurs when three conditions e8ist at the same time? 1. Weld metal has a susceptible chemical composition 'sulphur and phosphorus( 2. Welding conditions used give an unfavourable bead shape 3. !igh level of restraint or tensile stresses present in the weld area 103.
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CSWIP 3.2 THEORY PAPER Q&A 4. 3ontamination in weld #oint 5. ;nfavourable welding condition 6. !igh dilution process 7. Improper Width to depth ratio 109. 110. 3ontrol measures 1. 3ontrol the sulphur content 2. :imit the heat input$ hence minimising e8pansion and contraction 3. Increase the grain boundaries by adding delta ferritic 4. 2inimise restraints 5. ;se low dilution process 6. Weld #oints are thoroughly cleaned immediately before welding 7. 2aintain proper width to depth ratio 12. E4plain solidification crac# in stainless steel 111. Solidification cracing is a hot cracing mechanism that occurs during solidification of weld metal in austenitic stainless steels. Austenitic stainless steels have large grain structure compared to ferritic steel grains. 0uring solidification low melting point impurities collect around these large austenitic grain structures in the weld centreline. These large grains have small gain in boundaries compared to ferritic steels. This lac of grain boundary area between the grains may be insufficient to maintain cohesion and cracs occur in the centreline of weld along its length. 112. 113. 3auses 1. Weld metal has a susceptible chemical composition 'low melting point impurities( 2. Welding conditions used give an unfavourable bead shape 3. !igh level of restraint or tensile stresses present in the weld area 4. 3ontamination in weld #oint 5. ;nfavourable welding condition 6. Improper Width to depth ratio 114. 115. 3ontrol measures 1. 3ontrol the low melting point impurities 'sulphur%phosphorous( 2. 5nsure the weld #oints are thoroughly cleaned 3. :imit the heat input$ hence minimising e8pansion and contraction 4. Increase the grain boundaries by adding delta ferritic 5. 2inimise restraints 6. ;se low dilution process 7. Weld #oints are thoroughly cleaned immediately before welding 8. 2aintain proper width to depth ratio 1!. What is $eld deca* descri"e the causes and prevention easures+ 116. Weld decay occurs in unstabilised austenitic stainless steel with FFEH3 to FEH3 range of the !A>. At this temperature range carbon is absorbed by chromium and chromium carbide precipitated at the grain boundaries as a metal cools down. This precipitation of chromium carbides consumed the alloying element cause a local reduction in chromium content$ which has the effect of lowering the resistance to corrosive attac and allowing occurring. 117. 118. 3ontrolling measures 1. using of stabilised steels 'with addition of /i or Ti( 2. ;se low carbon stainless steels i.e. J@K:$ JE: 'carbon content below E.EJG( 3. !eating to about @@EEH3 where chromium carbide will be dissolved. Then steel is normally quenched from this temperature to stop re4association. 119.
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CSWIP 3.2 THEORY PAPER Q&A 1). What is liquation crac#ing descri"e the causes and prevention easures+ 120. 3rac type ? :iquation crac 121. :ocation ? !A> 122. Steel type ? :ow quality sulphur content steels 123. 124. :iquation cracs occur in steels$ which have high sulphur content. When welding low quality high sulphur content steels$ it is possible that areas containing iron4sulphide ')eS( in the !A> will liquefy. These low melting point iron4sulphides usually accumulate at the grain boundaries. If this melting occurs in the presence of high contractional stress$ then the boundaries will be pulled apart and liquation cracs occur. 125. 3auses 1. !igh sulphur content 2. !igh restraint 3. !igh contractional stresses 126. 127. 3ontrol 1. ;se high quality refined steel 2. 3ontrolled heat input 3. 2inimise restraint 4. ;se preheat 128. 1,. What is reheat crac#ing descri"e the causes and prevention easures+ 129. 3rac type ? eheat cracing 130. :ocation ? 3oarse grained !A> and weld metals 131. Steel type ? :ow alloy steel$ creep resistance steels 132. Susceptible microstructure ? 5mbrittled coarse grains 133. 134. eheat cracing is also nown as rela8ation cracing. It mainly occurs in !A> of welds particularly in low alloy steels during post weld heat treatment or service at elevated temperatures. 135. 136. 2ost alloy of steel sub#ect to an increase of embrittlement of the coarse grained region of the !A> when heated above KEEH3. The problem is worse with thicer steels containing 3r$ 3u$ 2o$ ,$ /b and Ti. Sulphur and phosphorus also have an influence. Typical steels susceptible would be the L M 3r. 2o. , type. 58ample creep resistance steels 137. 138. 0uring post weld stress relief and at high operating temperature the residual stresses would be relieved by creep deformation which involves grain boundary sliding and grain deformation. If due to metallurgical conditions these actions cannot occur$ then grain boundaries may be open up into cracs 139. 140. 3auses 1. areas of high stress concentration and e8isting weld defects 2. the toes of badly shaped fillet welds$ incomplete root penetration welds 3. high creep resistance 141. 142. 3ontrol 1. toe grinding$ elimination of partial penetration welds 2. re#ection of poor weld profile 3. heat quicly through the susceptible temperature FEH4FFEH 3 4. use high preheat temperature and stage wise 1W!T during welding large fabrication to reduce the ris of reheat cracing in t he final stress relieving 5. use of weld metal with high ductility 143.
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CSWIP 3.2 THEORY PAPER Q&A 1-. Descri"e the phenoenon of hic or under "ead crac#ing and prevention easures 144. 0uring fabrication by welding$ cracs can occur in some types of steel$ due to the presence of hydrogen. The technical name for this type of cracing is hydrogen induced cold cracing '!I33( but it is often referred to by other names that describe various characteristics of hydrogen cracs? 1. 3old cracing 4 cracs occur when the weld has cooled down 2. !A> cracing 4 cracs tend to occur mainly in the !A> 3. 0elayed cracing 4 cracs may occur sometime after welding has finished 'possibly up to Nh( 4. ;nder bead cracing 4 cracs occur in the !A> beneath a weld bead 145. 146. These types of cracs often originate from sub4surface locations under the weld in !A>. !ydrogen cracing in the !A> of steel occurs when conditions e8ist at the same time? 1. !ydrogen level O @Fml%@EEg of weld metal deposited 2. Stress O E.F of the yield stress 3. Temperature P JEEH3 4. Susceptible microstructure O EE!, hardness 147. These four conditions 'four factors( are mutually interdependent so that the influence of one condition 'its= active level( depends on how active the others three factors are. 148. 149. The phenomenon of !I3 is as follows 150. 0uring welding small amount of free hydrogen is generated due to decomposition of moisture from the air$ electrode coating$ shielding gas or contaminations on the surface to be welded. This hydrogen can dissolve in the molten steel and from there diffuse into e8tremely hot but solidified base metal. If the cooling is sufficiently slow$ this evolved hydrogen has enough time to escape to the atmosphere by diffusion. !owever if the cooling is rapid some hydrogen may get trapped in !A>. This hydrogen produces a condition called as “!ydrogen 5mbrittlement” in the locations of its entrapment$ which are dislocations and voids between grains. Also it generates very high hydrostatic pressure in the space of its confinement. This pressure combined with shrinage stress due to cooling produce tiny cracs in metal immediately ne8t to weld bead$ which are sub4surface initially but eventually propagate to surface. 151. 152. Avoid or 3ontrol measures for !I33 153. hardening( 12. Applying pre4heat so that the !A> cools more slowly 'and does not show significant !A> hardening(- in multi4run welds$ maintain a specific inter4pass temperature 13. 1ost heat to slow down the cooling rate
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CSWIP 3.2 THEORY PAPER Q&A 155. 1. Descri"e the under "ead crac#ing and prevention easures in 5/6 steels 75uenched and 6epered8 156. *%T steels are normally full alloyed steels which have high hardenability due to high carbon equivalent. Such steels subsequent to welding if allowed cooling down rapidly produce brittle microstructure in !A>. In such circumstances if the hydrogen gets involved in the process and trapped in brittle microstructure will produce a condition called as “!ydrogen 5mbrittlement” in the location of its entrapment which are dislocations and voids between grains. Also it generates very high hydrostatic pressure in the space of confinement. This pressure combined with shrinage stress due to cooling produce tiny cracs immediately ne8t to weld bead$ which are subsurface initially but eventually propagate to surface. ' as stipulated above in phenomenon of under bead cracing and thereby cause under bead cracs in *uench and Tempered steels.( 157. 1revention 1. giving sufficient heat input by means of pre heating 2. maintain proper inter4pass temperature 3. reduce the rate of cooling by means of post heating and adequate 1W!T 4. ;se low hydrogen process for welding 5. 1erforming welding in stress free conditions 158. 10. Descri"e the under "ead crac#ing and prevention easures in hsla steels 159. ;nlie in *%T steels$ !S:A steels are ferritic in nature. The properties of these steels are achieved by small amounts of alloying elements dissolved in their ferritic structure. )or this very reason they are soft and ductile as compared to *T steels. Such steels$ subsequent to welding if cooled too rapidly$ may undergo a change of microstructure from ferritic to martensitic namely in !A>. 6nce martensitic is formed it is hard and brittle. In such circumstance if any hydrogen pic4up taes place it may very well lead to phenomenon of !I3 or under bead cracing 160. 1revention 1. ensure that base metals have enough ductility 2. ensure that base metals have sufficient low G of carbon$ manganese and other alloying element which cause appreciable martensite formation 3. reducing the rate of cooling of weldment 4. performing the welding in stress free conditions 5. use of low hydrogen process 161. 1. Descri"e the three fracture echaniss 162. Welds may suffer three different fracture mechanisms? 1. )atigue 2. 0uctile 3.
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CSWIP 3.2 THEORY PAPER Q&A 2. It is encompassed by crescent mars or beach mars 3.
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CSWIP 3.2 THEORY PAPER Q&A 187. /ormal welds develop residual stresses? 1. along the weld + longitudinal residual stresses 2. across the weld + transvers residual stresses 3. through the weld + short transverse residual stresses 188. 21. Descri"e distortion 189. 0istortion is caused by stress. 0istortion related to the change of shape of a component$ which results from welding. This change in shape may be temporary 'elastic( or permanent 'plastic(. If two pieces of materials e.g. plates$ which are to be #oined$ are free to move during welding distortion will occur. If the two pieces of material are not free to move 'restrained( the force will remain as residual stresses 'no distortion( 190. 191. Types of distortion 1. longitudinal shrinage 2. transverse shrinage 3. angular distortion 4. bowing 192. 193. )actor which affect distortion 1. material properties and condition 2. heat input 3. Amount of restraint 4. Coint design 5. 1art fit4up 6. Welding procedure 194. 2ethod of reducing distortion 1. 1re4setting$ pre4bending 2. )orced restraint e.g. welding fi8tures$ fle8ible clamps$ strong bacs 3. ;sing balancing welding technique e.g. bac strip welding$ bac step welding 4. ;sing by design e.g. 5limination of welding$ Weld placement$ educing the volume of weld metal$ educing the number of runs 5. educing the heat input 195. 22. Descri"e distortion in a siple $eld $ith single :v; preparation 196. The action of the residual stresses in weld in welded #oints is to cause distortion. 3onsider a simple weld with single “,” preparation. 197. 198. The following movements can be detected 1. contraction in the weld and !A> along with the length 2. bowing due to the greater volume of weld metal at the top of the weld 3. peaing due to the “,ee” angle 4. ripple 'in sheet( away from the weld 5. contraction in the weld metal and !A> transverse to the weld 199. 200. 3ontrol of distortion is achieved in one or more of the following ways 1. pre4setting or pre4bending + so that the metal distorts into the required position 2. clamping + to prevent distortion$ but this increases the level of residual stress 3. welding sequence + i.e. balanced welding$ bac step or bac strip welding 201. 2!. Destructive testing or echanical testing 202. The tests are called destructive tests because the welded #oint is destroyed when various types of test piece are taen from it. 203.
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CSWIP 3.2 THEORY PAPER Q&A 204. 0estructive tests can be divided into L groups$ those used to? 1. 2easure a mechanical property + quantitative tests 2. Assess the #oint quality + qualitative tests 205. 206. 2echanical tests are quantitative because a quantity is measured + a mechanical property such as tensile strength$ hardness and impact toughness. 207. *ualitative tests are used to verify that the #oint is free from defects + they are of sound quality 4 and e8amples of these are bend tests$ macroscopic e8amination and fracture tests 'fillet fracture and nic4brea(. 208. 209. Test ob#ectives 210. ,arious types of mechanical test are used by material manufacturers% suppliers to verify that plates$ pipes$ forgings etc& have the minimum property values specified for particular grades. 211. 0esign engineers use the minimum property values listed for particular grades of material as the basis for design and the most cost4effective designs are based on an assumption that welded #oints have properties that are no worse than those of the base metal. 212. The quantitative 'mechanical( tests that are carried out for welding procedure qualification are intended to demonstrate that the #oint properties satisfy design requirements. 213. 214. Tensile Test + Transverse tensile tests 215. To measure the transverse tensile strength under static loading 1. A reduced specimen assesses the tensile strength of the #oint 2. A radius reduced specimen assesses the tensile strength of the weld meta 216. Tensile Test + 3ruciform test 217. To measure the relative tensile strength of #oints with fillet welds under static loading ':oad through welds( 218. 219. All weld Tensile Test 220. To measure Rield Strength B Tensile Strength of 'G 5longation also measured B usually also G eduction of Area( 1. 5lectrodes of filler wire % flu8 combinations 2. *uality of the weld metal as deposited 3. STA + Short transverse reduction areas to access lamellar tear 221. 222.
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CSWIP 3.2 THEORY PAPER Q&A 236. To fracture the #oint through the weld metal to permit e8amination of the fracture surface 'Swan notch in compression( 237. 238. 2acro e8amination 239. To e8amine the whole #oint for soundness 240. 241. 3T60 '3rac Tip 6pening 0isplacement Test( 242. 3T60 is a test method for the determination of a metals resistance to the initiation of a crac resulting from notch defects. 243. 3T60 measures the elastic4plastic toughness of the metal in the ductile4brittle transition. The propagation of a crac in a welded structure depends upon factors including the materials used. The si7e and sharpness of any notch present$ operating temperature$ the degree of restraint and welding procedure requirements. 244. 245. 3T60 test permits full si7e specimens to be used irrespective of metal thicness to which a notch of given width and depth is applied. The specimen is sub#ected to a high speed resonance load cycling on a three point bending rig. A clip gauge is fi8ed to the mouth of the notch accurately measures the slow opening of the crac and a force sensing device enables the applied load to be plotted against displacement on a graph. 246. 2). E4plain haz < heat affected zone 247. 0uring welding using fusion welding process there is a huge temperature difference between the weld and parent material. . The e8tent of changes in microstructure will depend on the following. 1. 2aterial composition especially carbon content 2. !eat input + the higher the heat or arc energy$ the wider !A>. 2etallurgical properties will also be affected. 3. The rate of cooling + higher the rate of cooling$ harder the !A> especially 3.5. of the steel is high. 249. The !A> in a weld 7one on steel consist of up to four separate regions$ starting from the area immediately to the weld. 1. 3oarse grained region + heat between @@EEH3 and melting point 2. Drain refined region 4 QEEH3 to @@EEH3 3. egion of partial transformation 4 FEH3 to QEEH3 4. egion of spheroidi7ation + #ust below FEH3 250. 2,. Descri"e "riefl* sa$ $ire/flu4 = sa$ consua"les 251. AWS AF.@.Q is a specification for carbon steel electrode and flu8es for SAW. The coding system shows the flu8 capabilities when combined with a specific electrode. 252. 58ample coding 253. )AK + 52@L9 or 53@ 'Trade /ame( 254. ) + Indicates flu8 255. + Indicates the weld metals minimum ultimate tensile strength in 9psi 8 @E '8@EE9psi($ when using the flu8 with the electrode identified. 256. A + 0esignates the condition of heat treatment to the weld or which test were conducted “A” is for as welded and “1” for 1W!T 257. K + Indicates the lowest temperature in degree )ahrenheit 8 @E at which a charpy value of L C was achieved. 258. 5 + Indicates a solid electrode. 53 would indicate a composite electrode 259. 2 + This may be :$ 2$ or ! indicating :ow$ 2edium or !igh manganese content
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CSWIP 3.2 THEORY PAPER Q&A 260. @L + This may be one or two digits and nominal carbon content of the electrode i.e. @L E.@LG$ E.EG 261. 9 + Indicates the electrode is made from semi4illed steel. 262. 263. Additional flu8 Information 264. All flu8es to this specification must be of a granular nature and capable of flowing freely when used. 1article si7e is to be a matter of agreement between the purchaser and supplier. The flu8 must permit the production of smooth with depth of undercut. )lu8es are classified on the basis of mechanical properties of the weld metal which they produce and therefore have to be shown in con#unction with the electrode used. )lu8es used to this specification may contain fusible compounds of various proportions. Some flu8es contain de4 o8idisers$ others do not and flu8es may react differently with different electrodes and are voltage used. A change of arc voltage during welding will change the amount of flu8 melted and may therefore change the composition of the weld metal. The effect of this change allows flu8ed to be described as neutral$ active or alloy. 265. 266. /eutral flu8es 267. /eutral flu8es are those which do not produce any significant change in the weld metal chemical analysis irrespective of arc voltage % arc length changes. )lu8es of this type contain little or no de4o8idisers and rely on electrode for de4o8idation. They are mainly used for multi4pass welds 268. 269. Active flu8es 270. Active flu8es contain manganese and silicon as de4o8idisers and the effect of those on the weld metal will change as the arc voltage changes. These flu8es are used mainly for single pass welds. 271. 272. Alloy flu8es 273. Alloy flu8es are those which can be used with a carbon steel electrode to produce a low alloy weld metal as such they come under the scope of AWS aF.LJ$ low alloy steel electrodes and flu8es for SAW. 274. 275. )lu8 basicity or classification 276.
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CSWIP 3.2 THEORY PAPER Q&A 286. 0isadvantages 287. The main disadvantage is the difficult in adding de4o8idants and )erro4alloys. These would be lost during the high temperature manufacture. The maintenance of a controlled flu8 depth is considered critical. 288. 289. Agglomerated flu8 290. All the flu8 materials are dry mi8ed and then bonded with either potassium or silicate. They are then baed at a temperature below the fusion or melting point and therefore remain as a powder$ which is sieved for si7e and pacaged. 291. 292. Advantages 293. 3an be colour coded 294. 5asy addition of de4o8idants and )erro4alloys 295. )lu8 depth not co critical 296. 297. 0isadvantages 298. Tendency for flu8 to absorb moisture and difficult to re4drying procedure 299. 1ossibility of molten slag$ causing porosity 300. 0ifficult recycling i.e. removal of impurities and sieving 301. 2. A failure has "een occurred in service at )3>c $hat is *our evaluation on this+ 302. Service temperature of the order of EH3 tells that the failure most probably has occurred due to lac of strength or toughness at that temperature. 3ompared to base metal a weld is always of irregular shape and hence considered as irregularity or discontinuity in surface profiles. Any discontinuity serves as a stress raiser when it comes across lines of stresses. The strength of material % metal would drops at the locations of high stress concentration especially when temperature drops significantly. In brief metal tends to lose its “notch toughness”. !ence our area of investigation should be notch toughness of given weld at low temperature. This can be approached in following ways. 1. ,erifying that W1S has recommended proper consumables to be used and all the essential variables were adhered to. 1. heat treatment records and lap test reports if any 2. eview batch certificates for consumables used chemical composition and physical properties certificates supplied by manufacturer 'material test certificates( 3. hardness of the base metal and thicness in the rupture 7one 4. suitability of material for the given service conditions 2. :ocation of failure should be inspected and point of initiation should be established 303. If the location of failure initiation happens to be without any defect vi7.$ undercut or porosity then failure can be attributed to sheer lac of low temperature strength and consumable giving higher low temperature strength may be recommended and improvement in weld profile may also be advised. !owever if the point of initiation happens to be a defect such as porosity or any sub surface defect then corresponding radiograph for that section of weld may be closely e8amined and interpreted. In such cases more stringent acceptance criterion may be recommended in addition to recommendations mentioned above. 304. 20. If *ou detect an arc stri#e $hat is the course of action+ 305. If any arc strie is found on the parent metal is should be ground smooth and 21I is to be conducted on the location$ if it is a ferrous material. )or S.S 1T is t o be conducted. 306. 2. What are the docuents required to do repair+ 307. Approved repair welding procedure$ qualified welders$ method of e8ploration of defect$ method of defect removal$ repair report. 308.
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CSWIP 3.2 THEORY PAPER Q&A !3. What $ould "e the result of using teperature 1!33>c in heat treatent+ 309. Steel which are overheated above @LEEH3 may suffer a permanent loss of toughness$ distortion and also forms large quantities of mill scale on their surface. 310. !1. What are the differences "et$een a $elding procedure approval and a $elder qualification test+ 311. The welding procedure approval test is carried out by a competent welder and the quality of weld is assessed using non4destructive and mechanical testing techniques. The intention of the test is to demonstrate that the proposed welding procedure will produce a welded #oint which will satisfy the specified requirement of weld quality and mechanical properties. 312. Welder approval test e8amines a welder=s sill and ability in producing a satisfactory weld. The test may be performed with or with a qualified procedure$ '/ote? without an approval welding procedure the welding parameters must be recorded.( welder approval must be done prior to start the welding in production site. Welder should be qualified to do the tas. 313. !2. ?an a non@approved $elder "e eplo*ed to perfor $elding test+ 314. Res 315. !!. Descri"e t$o ethod of producing approval procedures+ 1.
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CSWIP 3.2 THEORY PAPER Q&A 5. 3hec consumable certificate such as filler wire$ electrodes$ flu8es and gases going to be used for welder test. 6. 3hec fi8ing position of the test piece that is @D$ LD$ JD$ D$ FD and KD etc. 7. 2ar the bottom and top position in case of pipe 8. 2easure heat input. 9. )inal weld visual inspection 10. 2ar welder=s name date W1S /o and position 11. 1repare test report and submit to supervisor for record and /05 processing. 319. !-. Define quantitative test and qualitative test 320. *uantitative Test 321. )or measuring a “quantity” 'quantity test a mechanical property( 322. Typical mechanical testes - tensile test - hardness test - charpy , notch test B 3T60 323. 324. *ualitative test 325. )or assessing #oint “quality” 'quality test good fusion B free from defects( 326. Typical qualitative tests - bend test - macro e8amination 'micro e8amination for some metals( - fillet fracture B nic brea test 327. !. What does a $elding procedure consist of+ 328. Welding procedure consist of 1. essential variables 2. non4essential variables 3. supplementary essential variables 329. 330. 5ssential variables 331. A change in welding parameters which effects the mechanical properties of a weld are called essential variables. 5.g. process$ type of material$ electrode % flu8$ shielding gas$ preheating$ 1W!T etc& 332. /on4essential variables 333. 3hanges in welding parameters$ which will not affect the mechanical properties of the weld metal$ are called non4essential vari ables. 5.g. groove angel$ method of cleaning etc. 334. Supplementary essential variables 335. Supplementary essential variables are variables that have an effect on the impact properties of a #oint. They are classed as /on45ssential if impact testing is not required. The welding procedure shall be attached with 1* to show the evidence that the procedure meets the mechanical properties desired by the code % specification. 336. !0. Bive t*pical e4aple of $elder qualification range for a a. thic#ness b. diaeter c. process 337. Thicness 4 When welder is tested on thicness “T” he is qualified to weld two times the thicness “LT” 338. 0iameter + when welder is tested on diameter “0” he is qualified to weld pipe si7e “0%L” and above 339. 1rocess + welder is qualified to weld only which process he has been tested
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CSWIP 3.2 THEORY PAPER Q&A 340. !. E4plain $h* the qualit* of the parent etal a* affect the incidence of $eld etal crac#ing+ 341. :ower quality or dirty contaminated steels have a higher residual content e.g. sulphur$ phosphorus etc. due to the lower melting point of these impurities segregated into the centreline of the weld pool during the solidification and will form a plane of low ductility which may crac when acted upon by the normal transverse residual stress. 342. )3. E4plain purpose of preheat 343. 1reheating involves heating the base metal$ either entirely or #ust the region surrounding the #oint to a specific desired temperature$ called the preheat temperature 344. 1urpose 1. reduce the ris of hydrogen crac 2. reduce the hardness of the weld heat affected 7 one 3. reduce shrinage stresses during cooling and improve the distribution of residual 345. If preheat is locally applied it must e8tend to at least Fmm from the weld location and be preferably measured on the opposite face to the one being welded. 346. The selection of preheat temperature should be based on three factors listed in order of importance 1. composition and hardenability of the base or parent metal 2. the feasibility of post weld heat treatment 3. the si7e$ thicness and configuration of the part to be welded 347. The temperature of the part can be checed by use of temperature indicating crayons 'temp4stics( tough pyrometers or thermocouples. 348. )1. E4plain PW6 349. 1ost weld heat treatment is a process in which the metal in the solid state is sub#ected to one or more controlled heating cycles after welding. This 1W!T is normally carried out for the purpose of stress relief and ensuring that the !A> hardness is not too high for particular steels with certain service applications. 1W!T may also be used to produce certain properties such as softening after cold woring. 350. )ew more advantages of 1W!T 1. Improve the resistance of the #oint to brittle fracture 2. Improve the resistance of the #oint to stress corrosion cracing 3. 5nable welded #oints to be machined to accurate dimensional tolerances 351.
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CSWIP 3.2 THEORY PAPER Q&A 360. *uality control inspection as an “activity such as measuring$ e8amining$ testing or gauging one or more characteristics of a product or service$ and comparing the results with specified requirements in order to establish whether conformity is achieved for each characteristic”. 361. 362. In@process inspection 363. Inspection B surveillance carried out during production 364. on@copliance 365. 366. A written report that states that a clause or instruction in the contract documents$ code or standard cannot be or was not met. 367. 368. ? 369. A non4conformance report documents the details of a non4conformance identified in a quality audit or other process review. The ob#ective of the report is to mae an unambiguous$ defensible$ clear and concise definition of the problem so that corrective action can and will be initiated by management. 370. 371. ?oncession 372. An agreed deviation 'with the customer or client( from a pre4agreed path$ or specification 373. 374. Inspection specification 375. A document containing or referring to all information required in the level of inspection for a product. 376. ?ertificate of conforance 377. 378. A signed certificate$ declaring that a product has been produced in accordance with a specification 379. 380. Defect 381. A welding imperfection that falls outside of a level of acceptance criteria in an applied standard 382. Finor defect 383. 384. ;nliely to cause failure of the product 385. Faor defect 386. 387. :iely to cause failure$ but small ris of loss of life 388. 389. ?ritical defect 390. 58tremely liely to cause failure$ with high ris of loss of life 391. 392. Audit copliance 393. It determines quality system complies with the applicable quality control procedures 394. 395. Faterial specification 396. The specification applicable to a raw material which is used in the fabrication of a product 397. Auditor 398. 399. The certified quality auditor is a professional who understands the standards and principles of auditing and the auditing techniques of e8amining$ questioning$ evaluating and reporting to determine a quality system=s adequacy and deficiencies. 400.
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CSWIP 3.2 THEORY PAPER Q&A ?ali"ration' 401. 402. 6perations for the purpose of determining the magnitude of errors of a measuring instrument$ etc. 403. 404. Galidation' 405. 6perations for the purpose of demonstrating that an item of welding equipment$ or a welding system$ conforms to the operating specification for that equipment or system 406. Accurac*' 407. 408. 3loseness of an observed quantity to the defined$ or true$ value 409. )!. As a tea leader $hat steps *ou $ill ta#e for iproving qualit*+ a. If a e"er has to "e replaced $hat all things to do+ b. What are the things *ou $ill "rief in start of a o" for *our ne$ e"er+ 410. Actions to Improve quality 1. I conduct periodic and systematic audit$ based on audit finds such non4conformance$ any other quality related issues$ tae preventive actions and avoid such things occur in future. 2. 3onduct quality related meetings with inspectors$ other department members$ and loo for any ideas to improve quality or any quality related concerns they have in their #ob$ tae necessary preventive actions. 3. Any complaints from clients % T1I or feedbac from clients$ tae necessary preventive actions. 4. Technical information related to quality- circulate to all concern departments members 5. 3onduct training programs for speciali7ed #obs and critical #obs 6. 1rovide motivation$ motivated employees provide a better woring environment in addition to the product or service output benefits 411. 412. Actions with replacing member 413. Det hand over note from replacing member including the following 1. !and over note including completed status$ which was handled by him$ current #ob status$ any quality related issues such as site query$ concession request$ /3 log etc. 2. 0ocument management etc. 3. 3ontact details of client representative$ contractor personal email address$ contact telephone numbers 4. 3ontact details of replacing member for future reference 414. 415. Actions for new member 1. Welcome and introduced to all staff including higher authority 2. Safety induction e8plain minimum 115$ emergency e8it$ and emergency contact numbers 3.
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CSWIP 3.2 THEORY PAPER Q&A 3. 2ay have technical problem$ communication problem lie language problem or personal problem lie leave overdue$ sic family reason 4. Analysis the root cause of problem and solve 5. ,erify the correct system is followed$ it not establish the system 6. 3ontinuous monitoring the inspectors activities 419. ),. Bive "rief descri"e of the difference "et$een acro and icro e4aination also state the purpose of the e4aination+ 420. 0ifferences 1. macro e8amination magnification is @E8 or l ower 2. micro e8amination magnification is greater than @E8 usually @EE8 or higher 3. macro specimen need rough and ground with E grit finish 4. micro specimen need very fine grinding at KEE grit and polish % etching to produce a mirror finish 421. 1urpose of e8amination 1. 2acro e8amination? to determine depth of fusion$ depth of penetration$ effective throat$ weld soundness$ degree of fusion$ presence of discontinuity$ weld configuration$ number of weld pass etc. 2. 2icro e8amination? to determine micro structural constituents$ presence of inclusions$ presence of microscopic defects$ and nature of cracing etc. 422. )-. Descri"e "riefl* the duties of senior $elding inspector 423. A senior welding inspector may be required to manage and control and lead a team of welding inspectors who will loo to him for guidance$ especially on sub#ects of a technical nature. The SWI will be e8pected to give advice$ handle problems$ tae decisions and lead from the front. The SWI will therefore require leadership sills in addition to technical e8perience. Senior welding inspector is responsible for the following 1. Signing off the product 2. 1repare department budgets for personnel facilities and supplies 3. Assign wor to the inspectors 4. Supervise and evaluate their wor 5. 2otivate staff to meet standards of quality and efficiency 6. Interlin with other departments to improve procedure and advice on quality problems 7. eceive complying item$ understand the problems and establish corrective measures 8. eview plant equipment condition$ inspection reports for fitness to use during service 9. 1repare scrutini7e documentation for quality 10. 1articipate in inspection and planning$ reviewing and approve procedure which is prepared by inspection department 11. 0evelop tea wor$ advice on training and other personnel qualification requirements 12. 5nsure adequate safety precaution for all personnel 424. In other circumstances he may have a more technically demanding role that requires detailed nowledge or particular activities 425. The technical sills required are? 1. 9nowledge of technology 2. 9nowledge of code of practice 3. 9nowledge of planning 4. 9nowledge of organi7ation 5. 9nowledge of auditing 426. 9nowledge of technology + required is similar to the welding inspector but with additional cope and depth of 1. 3ommonly used /0T technique 2. adiographic interpretation 3. *A%*3 nowledge
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CSWIP 3.2 THEORY PAPER Q&A 4. G means reduction of area at the point of fracture or transverse ductility 'OLEG high resistance to lamellar tear( h. AG means elongation of the gauge length or elongation ductility i. j. To approve a butt welding procedure most of specifications such as IS6 @FK@ and AS25 S53. IU require tensile tests to be carried out. k. l. These are generally cross #oint 'transverse( tensile tests of square or rectangular cross section that as the name suggests$ are oriented across the weld so that both parent metals$ both heat affected 7ones and the weld metal itself are tested. The tensile test piece typical of the type specified by 5uropean standards$ such us 5/ QF$ that specify the dimensions of the test pieces require all e8cess weld metals to be removed and the surface shall be free from scratches. Test pieces may be machined to represent the full thicness of the #oint but for very thic #oints it may be necessary to tae several transverse tensile test specimens to be able to test the full thicness. m. n. While it is possible to measure the yield strength$ the elongation and the reduction of area of transverse tensile test specimens the fact that there are at least three different areas
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CSWIP 3.2 THEORY PAPER Q&A with dissimilar mechanical properties maes such measurements inaccurate and unreliable$ although this is sometimes carried out purely for information purpose. o. p. The specifications mentioned above require the ;TS and the position of the fracture to be recorded. q. If the test piece breas in the weld metal$ it is acceptable provided the calculated strength is not less than the minimum tensile strength specified$ which is usually the minimum specified for the base metal material grade. r. In the AS25 IU code$ if the test specimen breas outside the weld or fusion 7one at a stress above QFG of the minimum base metal strength the test result is acceptable. s. t. In most situations the weld metal stronger than the parent metal + it is overmatched + so that failure occurs in the parent metal or the !A> at a stress above the specified minimum. . v. w. x. y. z.
On a aterial certificate follo$ing ters a* APPEAS' noralised quenched and tepered as rolled z qualit* aa. What are the eanings of these ters+
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ab. ac. /ormalised ad. It is a process of heating steel to about EH4FEH3 above upper critical temperature holding for proper time and then cooling in still air on slightly agitated air to room temperature. The resultant microstructure should be pearlite. It is done for grain structure refinement$ homogeni7ation$ removal of residual stress and improved machinability. )or plain steel the temperature for normali7ing is KEH4Q@FH3$ and for alloy steels it is EH4QLFH3 ae. af. *uenched and Tempered ag. *uenching is a process of rapid cooling from austenising temperature$ which results in the transformation of austenite to martensite. 0uring cooling$ heat musts be e8tracted at a very fast rate from the steel piece- and is possible when a steel piece is allowed to come in contact with some medium which absorbs heat from steel within short period. The medium use for quenching is nown quench out. The quenchants used are liquids$ air and gases are used in special case. ah. *uenching is a hardening treatment which develops ma8imum hardness$ e8cellent wear resistance and high strength levels in the steel$ at the same time it adversely affects properties such as ductility. Toughness and impact strength and also imparts brittleness because of internal stress developed by quenching. Such a process$ which consists of heating hardened steel below the lower critical temperature$ followed by cooling in air is nown as tempering. Tempering lowers strength and wear resistance of the hardened steel marginally. ai. As rolled aj. As rolled means having improved low temperature toughness. A high strength steel plate of improved low temperature toughness useful for maing an grade line pipe provided with the addition of E. 4LG by weight of nicel and E.EEEF + E.EEEG by weight of 3a.$ which may be used in the as rolled state and manufactured through tow step controlled rolling the secondary step rolling of which is carried out at a temperature lower than conventional rolling. ak. al. > *uality am. “>” quality means low sulphur steel with a tested level of ductility through the “>” a8is of the plate as opposed to the transverse on longitudinal a8is$ “>” quality is determined by through thicness tensile test hence sometimes nown as through thicness tested plate. an. ao. On a construction site a e"er of *our staff has issued an instruction that all FFA electrodes have to "e "a#ed at 2,3>? "efore use. the electrode in question are of the follo$ing t*pes' ap. a$s ,.1 e-31! aq. "s en ) e)2!" 7in standard pac#ing8 ar. "s en ) e)2,ni " 7in vacuu pac#s8 as. "s en ) e!,2c 1. Do *ou agree $ith this instruction+ 2. give reasons for *our ans$er at. a. I would not agree the instructions given that the above mentioned 22A electrodes to be baed at LFE degree 3elsius before use a!. The reasons for my answer as described below? 1. the first given electrode details are AWS F.@ 5KE@J$ it is a rutile electrode$ since they have high combined moisture and also contains up to @EG cellulose they cannot be baed as they will not give a low !ydrogen weld deposit.
2. The second electrode is
a. b. c. d. e.
a. b. c. d. e.
"c. &ist five ites of inforation that could "e recorded on an ultrasonic test report% $hich $ould "e never present on radiographic report+ couplant type probe details? type$ angle$ si7e and frequency scanning method%type correction sensitivity 'VLdb( db 'disable( bd. "e. What is the consideration for qa/qc and inspection departent if it is required to increase the toughness and tensile strength of $elds on a specific t*pe of coponent+ Select high tensile and toughness welding consumables and alloying elements which will increase the toughness and tensile strength of the component. Select the welding parameters to control the heat input and followed by 1W!T$ this will increase the tensile strength and toughness. Select suitable welding process. Select the suitable #oint design. 2ae sure all the required parameters are followed in production. bf.
a. b. c. d. e. f.
"g. Without approval of dra$ing piping fa"rication has "een copleted. What $ill "e *our course of action+ aise a non4conformance report. 3hec with approved drawing. If minor changes noted$ which will not affect the product design requirement accept as it is provided a deviation request to be raised and approved. The changes to be incorporated in the as build drawing. If any ma#or changes noted compared with approved drawing$ to be refabricated as per approved drawing. 3oncern person involved$ to issues a warning letter$ 3onduct meeting with all inspectors and mae them awareness$ such as things recur in future. bh. "i. During an audit no aterial certificate $as found. o$ $ould *ou proceed+ bj. If material test certificate not available as the supplier to provide it. If it is not available with supplier then material should be sent to lab for verifying its chemical and mechanical properties. The lab report shall be attached instead of 2T3. bk. "l. Wh* it is desira"le to seal in a laination $hich is found to "rea# during edge preparation+ bm. :amination is to be seal welded prior to welding because these areas will open up during welding due to the heat produced while welding. bn. "o. In a $elder approval test should the procedure "e e4plained to the $elder+ bp. /o. it is not necessary. bq. "r. State the o"ectives of bs. A reduced transverse tensile test bt. A radius reduced transverse tensile test b. A reduced transverse tensile test specimen assesses the tensile strength of the #oint. A radius reduced transverse tensile test specimen assesses the tensile strength of the weld metal. b!. "$. What is the purpose of all $eld tensile test and a radius reduced tensile test+ b%. An all weld tensile test is to measure the tensile strength of electrodes%flu8 combination and quality of weld metal as deposited. b#. A radius reduced tensile test is to assess the tensile strength of the weld metal. "z. State three factors $hich contri"ute to or control the echanical properties of $rought steel+ ca. Wrought steel grain much refinement during the hot%cold woring and many defects are also removed. This improvement is mared in t he rolling direction but is usually results in a loss of strength through the thicness. cb. cc. What is the etallurgical production cause of laellar tearing+ cd. :amellar tear could cause due to the presence of inclusions of sulphur$ phosphorus and higher percentage of carbon. ce. cf. Does a $rought plate contain residual stresses due to anufacture+ cg. Res. ch.
ci. Bive the coposition for tool steel+ cj. E.G3r$ @.EG2n$ E.G3$ E.JG2o V Ti or Al V residuals ck. cl. If "end test failure has occurred $hat $ould "e *our course of action+ cm. Set aside the piece$ tae one more test piece and repeat the test. Assess the failure$ whether the failure is within the weld metal$ weld #unction or in the !A>. A retest is very much needed in case of failure. cn. co. In $hich steels can it "e e4pected that h*drogen induced crac#ing is found in the $eld etal if present at all+ cp. !igh strength 2n steels cq. cr. State four echaniss of crac#ing% $hich a* "e found in the $eld etal of ferritic steel $eldents+ cs. !ydrogen induced cracing ct. Solidification cracing c. Solidification pipe or void c!. eheat cracing c". c4. State si4 ethods of procedure to avoid solidification or centreline crac#ing+ c#. 3ontrol the sulphur content c$. ;se consumable with high manganese da. 9eep manganese4sulphide? carbon ratio as low as possible db. 2inimise restraints dc. ;se low dilution process dd. Weld #oints are thoroughly cleaned immediately before welding de. 2aintain proper width to depth ratio df. ;se preheat dg. dh. di. dj. dk.
State three ethods of procedure for avoiding solidification pipe in $eld etal+ 3orrect depth to width ratio 3orrect bead shape 3orrect surface chilling effect due to 1. /o slag covers process 2.Das not heated 3. )low rate too high
dl. d.State the four factors $hich give rise to h*drogen crac#ing and suggest ho$ control can "e e4ercised+ dn. 9actors $hich raise the ris# of h*drogen crac# do. Stress dp. !ardness dq. !ydrogen and dr. Temperature ds. 3ontrol methods dt. 2inimise stress by a. 1re4setting b.
e. educe restraints 'C preparation + reduce included angle( d. 2inimi7e hardness by a. :ower 3.5 b. :imit heat input to @.#%m ' avoid grain enlargement( use . !ence hydrogen cracing in the !A> is unliely to happen. eq. er. What is the ain pro"le of $elda"ilit* $hen using 10/0 t*pe austenitic electrodes to repair ferritic steels+ a. Solidification cracing b. Weld decay c. educes the corrosion resistance of weld metal es.
et. Wh* it is recoended that 2/13 is used for "uttering and 10/0 is used to fill $hen using austenitic electrodes for repair+ eu. 6o avoid crac#ing% it is desira"le 7at least in oints $ith high restraint8 to "utter $ith an electrode $ith high dilution tolerance and to a#e the closing $eld $ith lo$ strength electrodes. ev. e$. E4plain $h* the depth to $idth ratio of the "ead is iportant+ e%. To tae care of residual stresses in welds which developed e#. :ongitudinal along the weld e$. Across the weld fa. Through the weld fb. fc. Outline etallurgical features of $eld deca*+ fd. Weld decay? steels with high carbide forming characteristics such as these will react if the temperature is allowed to dwell about FFE °3. If this occurs then the chromium is no longer available for combination with o8ygen for the reformation of the protective o8ide and corrosion may result. fe. Weld decay? depletion of chromium carbides in stainless steel. ff. fg. fh. fi. fj. fk.
State three ethods of avoiding $eld deca*+ educe the carbon content i.e. SSJ@K: !eat treatment @@EE°3 and quench To stabili7e the steel by added Ti or /b 'to form carbides in preference to 3r carbides(
fl. Wh* "ac#ing gases are often specified $hen $elding stainless steel+ fm. To avoid contamination fn. To prevent formation of porosity fo. To avoid formation of o8ides fp. fq. Wh* car"on di o4ide not norall* uses as a shielding as $hen $elding stainless steel+ fr. To maintain low carbon fs. ft. When stainless steel is $elded to ild steel "uttering is recoended $h*+ f. To seal carbon in f!. To stop dilution fw. f4. When $elding SS to a large root gap 7!8 are often used $h*+ f#. 0istortion closes gap fz. ga. What is the essential feature of a stainless steel+ gb. 3hromium content 'minimum @@G3r is required to form SS and LQG is ma8imum( it react with o8ygen and produce chromium o8ide which is protect the steel from rust. gc. gd. What is the principle reason for the developent of residual stresses in etals+ ge. 2etals contract during solidification and subsequent cooling$ but if this contraction is prevented or inhibited residual stresses will develop. gf.
gg. ae three directions of residual stresses in $eld oints+ gh. /ormal welds develop residual stresses gi. Along the weld longitudinal residual stress gj. Across the weld transverse residual stress gk. Through the weld short transverse residual stress gl. g. What causes distortion in $elded products+ gn. The action of the residual stresses in the welded #oints is to cause distortion g. gp. Bive four consequences of using e4cessive current+ gq. 58cess spatter gr. 58cess metal profile gs. 3enter line cracing gt. ;ndercuts gu. gv. Bive four consequences of using e4cessive arc length+ gw. Jnsta"le arc gx. &ac# of penetration gy. Jneven profile "ead gz. ha. State the defects $hich occur $hen the tac# $eld is not correctl* incorporated into the $eld+ hb. :ac of penetration or fusion !c. hd. Bive three consequences of incorrect electrode angle+ he. ;ndercut hf. Spatter hg. :ac of penetration or fusion !!. hi. Bive one consequence of a8 too fast travel speed and "8 too slo$ travel speed+ !". &ac# of penetration or fusion !#. Slag inclusion !l. h.What defect associated $ith e4cessivel* large size electrodes+ hn. :ac of penetration !. hp. What defect is caused "* inadequate cleaning "et$een runs+ hq. Slag inclusion !r. hs. What defects can "e caused "* use of high $elding speeds in sa$ process+ ht. :ac of penetration or fusion h. ;ndercut !v. h$. What defects can "e caused "* the use of e4cessive gaps in sa$ process+ h%. 58cess penetration or burn through !y.
hz. What are li#el* causes of slag in the $eld etal+ ia. Slag inclusions$ insufficient inter4run cleaning$ poor bead profile 'conve8 shape( $b. ic. What adustent ust "e ade in su"erged arc $elding to reduce the "ead $idth+ id. :ower the voltage ie. Increase the travel speed 'if still within the parameters( $f. ig. What defects can "e caused "* a plate having poorl* cut oint preparation+ ih. :ac of penetration or fusion $$. i. A $eld is to "e ade on a close square "utt oint $ith e4cessivel* high current% $hat defect $ould occur+ ik. 58cess weld metal $l. i. What is the li#el* defect to "e caused "* an e4cessive flu4 "urden+ in. 1orosity $. ip.
What is the critical level of h*drogen in a $eldK can it "e easured at an* tie or after stress relief+ $q. ,l per 133g of $eld etal $r. All $eld etal h*drogen diffusion test possi"le "ut not for the actual $eldent $s.
it.
Descri"e ho$ and $h* h*drogen increases the incidence of h*drogen crac#ing+ i. !ydrogen in the weld%!A> builds up internal pressure which could be higher than yield point of metal low hydrogen would cause residual stresses. i!.
i$. Descri"e a heat treatent designed to reove h*drogen% $hen the treatent ust is applied+ i%. 1W!T for @E4LE4JE hours $y. iz.
Wh* "asic h*drogen controlled electrodes ust "e #ept at 1,3>?+ ja. 1revents reabsorbing of moisture '!ydrogen( "b.
c.
What are the causes of laellar tearing+ jd. :amellar tearing is a defect in the parent metal of a weldment due to high through thicness residual stresses and a low through thicness strength and ductility of the material arising from elongated inclusions and bands within the steel. "e.
f.
Where laellar tearing is found in a $eldent+ jg. The crac is stepped and parallel to the surface of the plate. "!.
i.
o$ do "ands 7segregation8 $ithin steel influence the incidence of laellar tearing+ jj. :ow through thicness strength and ductility are arising from bands within the steel and of high residual stress. jk.
l.
?an suscepti"ilit* to laellar tearing "e assessed "* ultrasonic DE+ jm. /o. '
o.
?an laellar tear "e detected "* DE+ jp.
r.
State three ethods of avoiding laellar tearing+ js. educe the residual stress by low restraints i.e. pre4setting rather than clamping by use of gaps. jt.
$. ae three t*pes of stainless steel+ "x. Fartensitic "y. Austenitic "z. 9erritic #a. #". State the ain $elda"ilit* pro"le of the 9e11 chroiu steels+ kc. !ydrogen cracing #d. #e. ae t$o ethods of avoiding h*drogen crac#ing in artensitic stainless steel+ kf. 3ontrol by hydrogen limitation i.e. the use of TID welding process kg. 3ontrol by hardness$ normal preheat and heat inputs$ so select a very low carbon grade. kh. #i.
Wh* do icro allo*ed steels suffer h*drogen crac#ing in the $eld etal+ kj. In the micro alloyed steels the hydrogen is held in the weld metal and so hydrogen tends to be located there also. ##.
#l.
What are the factors $hich give rise to h*drogen crac#ing in allo*ed steels+ km. In the !A> the tensile residual stresses are across the weld$ so the hydrogen cracs are along the length of the weld. In the weld metal the tensile residual stresses are along the weld so the hydrogen cracs are across the weld. #n.
#o. What are the t$o t*pes of SAW flu4+ kp. )used kq. Agglomerated #r. #s. Wh* are the h*drogen crac#s in the $eld etal positioned across 7transverse8 the $idth of the $eld+ kt. !ydrogen cracing is typically formed at right angles to the stress and is positively identified by its transgranular appearance when viewed at U@EE magnification. In ferritic steels hydrogen which enters the weld metal during welding moves into the !A> and due to$ gas forming characteristics and the residual stress$ cracing may result. #u. #v. State three ites $hich a* contri"ute to e4cessive hardness in a $eldent+ k". Drain si7e k%. *uenching
k#. 3.5 carbon and alloys #z. la.
State t$o eleents $hich cause centreline crac#ing+ lb. Sulphur lc. 1hosphorous ld.
le.
State the ethods of iniizing solidification crac#ing+ lf. Increase weld metal lg. educe the welding speed lh. Increase the manganese content of the weld pool li. ;se of cooling bars lj. 3ontrol the sulphur content lk. 9eep manganese4sulphide? carbon ratio as low as possible ll. 2inimise restraints lm. ;se low dilution process ln. Weld #oints are thoroughly cleaned immediately before welding lo. 2aintain proper width to depth ratio lp. ;se preheat lq. educe the amount of metal melted out of the parent metal by 1. sill%technique of the welder 2.reduce the amperage lr.
ls.
A crac# is o"served along the centreline of the $eld etal. Bive t$o reasons for its foration+ lt. When the weld metal has been deposited and its contracts during solidification it is vital that the contraction and be fed by the depression of the outer surface l. 3ontraction fed by the weld metal surface l!.
l$. Bive three reasons $h* pipe a* for in the $eld etal+ l%. 1remature free7ing of the surface l#. 58cessive depth of bead related to width l$.
n. When ferritic is added to electrodes $hat are t$o possi"le consequences+ mo. It tends to avoid solidification cracing it does induce magnetism and maes the weld metal avoid so reducing the corrosion resistance. mp. q. Wh* are sall stringer "eads usuall* recoended for SS $eldents+ mr. To reduce the level of heat input and avoid cracing %s. t. Descri"e the theral conditions $hich give rise to $eld deca* in austenitic SS $eldents m. FFE degree 3 for si8 seconds %v. $. State the special echanical properties of 2,?r in 9e allo*s+ m%. )erritic SS is poor weldability due to cracing brittleness and temper embitterment. It is a single phase alloy which is ferritic at all solid temperatures$ so solidification cracing is a problem. %y. z. What is a specification+ na. Specification is a description of what to use in the maing of a product i.e. type of material type of process and type of consumables. nb. nc. What is the e4tent of approval in a procedure+ nd. 58tent of approval is the range over which certain variables may alter without requiring new procedure i.e. when there is a limitation in the welding qualification i.e. ne. The minimum and ma8imum diameter of the pipe that the test sample covers e.g. two inch test piece would allow down @” and upto ” nf. The test may only allow welding of consumables in the same grouping$ any other consumable would require retest ng. The use of set electrical characteristi cs would not allow change without retest nh. The direction of welding if changed may require retest ni. 3hange of material to be tested would require retesting n". n#. When is a procedure to "e re@esta"lished+ nl. When there is change in following essential variables nm. 3hange of welding process nn. 3hange of shielding gases or flu8es no. 3hange of direction of welding np. 3hange in parent metal to be welded nq. 3hange in #oint design nr. 3hange in welding consumables ns. 3hange welding parameter range nt. nu. State the four factors $hich ust "e satisfied for good $elds' n!. )usion welding factors n". )usion 'melting( + the metal must be melted which requires a high intensity of heat source. n%. The process must remove any o8ide and other contaminants from the #oint faces n#. 3ontamination by the atmosphere must be avoided n$. The welded #oint must possess adequate properties a.
o". If visual e4aination of $eld is not possi"le ho$ $ill *ou ensure that the oint is o#a*+ oc. It can be e8amined by appropriate /0T methods lie T or ;T etc& d. oe. What are inor defects+ of. 2isalignment 'linear B angular($ slag$ porosity etc& g. oh. What are the aor defects+ oi. :ac of side wall fusion$ overlap$ lamination$ lac of inter4run fusion$ lac of penetration and incomplete fusion ". o#. What is the course of action if the $eldent has "een accepted or reected+ ol. Inspection results to be recorded in an approved format. If the sample is re#ected then the type of defect and the location has to incorporated in a setch and the report to be given for further remedial action om. on. What features of steel deterine its $elda"ilit*+ oo. 3arbon content B carbon equivalent p. oq. What is the ain advantage of using 2/13 t*pe austenitic electrodes to repair ferritic steels+ or. The defects of dilution will be lower the alloy content of the weld metal during cooling so it is advisable to use it. s. ot.
What is the difference "et$een inspection for qualit* control and inspection for fitness for purpose+ u. v. w. x.
o*. Descri"e the relationship "et$een the four essential factors involved in the foration of h*drogen induced cold crac#ing. o$. pa. pb. pc. pd. pe. pf. pg. ph. pi. pj. pk. pl. pm.
pn. Discuss the reasons for the e4istence of arc "lo$ and state possi"le ethods of iniising arc "lo$. po. Welder used cellulose electrode instead of lo$ h*drogen electrode. Suggest corrective action and *our course of action in it+ a. aise /on conformity report b. )urther investigation to be done to identify any other #oints welded. c. Analysis and identify the root cause for this incident d. 3hec with approved drawing$ product specification and welding procedures specifications. If welding procedure specification available for this electrode and product design requirement accept as it is provided a deviation request to be raised and approved. e. If the specifications not allowed$ the entire #oints which is identified to be refabricated as per approved specification. f. The changes to be incorporated in the as built drawing. g. 2ove welder for training and requalification h. Issue a strong warning letter to 3oncern person involved. i. 3onduct meeting with all inspectors and mae them awareness$ such as things recur in future. j. 0ocument all the above and close the /3 pp. ae four coonl* used D6 ethods and list their advantages and disadvantages+ pq. D pr. ADGA6ABES ps. DISADGA6ABES 6 FE 6 OD pt. Gisu pu. Ine8pensive !ighly pv. Surface discontinuities al portable Immediate only Denerally only large results 2inimum training discontinuities 2inimum part 2isinterpretation of preparation scratches p$. D*e p8. 1ortability qe. :ocates surface breaing Pen py. Ine8pensive defects only :ittle etra p7. Sensitive to very small indication of depths nt discontinuities qf. 0irect visual detection of qa. Simple to use results required qb. *uic results qg. 1enetrant may qc. 3an be used on any non4 contaminate component porous material qh. Surface preparation qd. :ow operator sill critical required qi. 1ost cleaning required q#. 1otentially ha7ardous chemicals q#. Fag ql. 3an be portable qs. Surface must be netic qm. :ow cost accessible Part qn. Sensitive to small qt. ough surfaces interfere icle discontinuities Immediate with test 1art preparation results required 'removal of qo. 2oderate sill required finishes and sealant$ etc.( qp. 0etects surface and qu. Semi4 directional subsurface requiring general discontinuities orientation of field to
qq. elatively fast qr. /o harm to test piece
discontinuity )erro4 magnetic materials only qv. 1art must be demagneti7ed after test.
q$. Edd * ?urr ent
q8. 1ortable qy. 0etects surface and subsurface discontinuities q7. 2oderate speed ra. Immediate results rb. Sensitive to small discontinuities Thicness sensitive rc. Accurate conductivity measurements rd. 3an detect thorough several layers re. 3an be automated rf. 3an detect thorough surface coatings rg. :ittle pre4clean required
rp. Jltr ason ic
rq. 1ortable rr. Ine8pensive rs. Sensitive to very small discontinuities Immediate results rt. :ittle part preparation ru. Wide range of materials and thicness can be inspected
r*. adi ogra phic 6est
r7. 1ermanent record sa. Internal flaws sb. 3an be used on most materials sc. 0irect image of flaws sd. eal + time imaging se. 2inimum part preparation
rh. Surface must be accessible to probe ri. ,ery susceptible to permeability changes r#. 6nly wors on conductive materials r. Will not detect defects parallel to the surface rl. /ot suitable for large areas and %or comple8 geometry rm. Signal interpretation required rn. /o permanent record 'unless automated( ro. Sill and training required rv. Surface must be accessible to probe ough surfaces interfere with test !ighly sensitive to sound beam discontinuity orientation rw. !igh degree of sill required to set up and interpret r8. 3ouplant usually required sf. !ealth ha7ard sg. Sensitive to defect orientation sh. :imited ability to detect fine cracs si. Access to both sides required s#. :imited by material thicness s. !igh degree of sill and e8perience required for e8posure and interpretation sl. elatively slow sm. 0epth of discontinuity not
