CSWIP 3.2 Welding Inspector Exam Part 1 - Specific Theory – 1 Hour Hour 15 15 Min Min 1 Question on Signing off a product or Duties of a Senior Welding Welding Inspector ! out of 5 Part II - Weld Sy"#ols $1% sy"#ols& – 1 Hour Part III - 'racture (nalysis (nalysis $% speci"ens& – 1 Hour Hour Part I) - *DT +eport +eport Scrutiny $! reports& reports& – 1 Hour Hour Part ) - ,ral $,nly $,nly #asic #asic things& things& – 15 15 Min Min Following part part of exam will not be covered covered in the class class Part )I - +adiographic +adiographic 'il" Interpretation Interpretation $ fil"s& – 1Hour Part )II - Multi choice .uestions – +adiography $%/ .uestions& .uestions& – !/ Min Part )III - Sensiti0ity calculations calculations $5 .uestions& Densito"eter ali#ration $5 +eadings&
Signing off a product In an engineering fa#rication industry the last acti0ity in the se.uence of "anufacture is load out or dispatch2 This acti0ity cannot #e initiated unless the product is signed signed off2 (s a "atter "atter of fact signing the product product off is assurance of of .uality 3hich is authenticated authenticated #y a technically co"petent person person such as 4Senior Welding Welding Inspector 3ho "a6es sure that co"plete "anufacturing of product has #een carried out in accordance 3ith applica#le standard and sound engineering practices2 Ho3e0er #efore signing the docu"ents he should "a6e en.uiry 3hich can gi0e hi" the insights in the past 3hile product 3as #eing "anufactured2 Questions can #e as follo3ed7 1& What What 3as 3as the the repair repair rate rate during during produc productio tion8 n8 %& Whether Whether any any concess concession ionss or 3ai0er 3ai0er 3ere 3ere gi0en9 gi0en9 if yes yes 3hy8 3hy8 !& Ho3 Ho3 3ere 3ere the the 3eat 3eathe herr cond condit itio ions ns88 :& Whether Whether there there 3ere any any safety safety issues9 issues9 fataliti fatalities9 es9 "a;or "a;or accidents accidents < inciden incidents ts etc8 5& Wheth Whether er ther theree 3ere 3ere any any la#ou la#ourr pro# pro#le" le"s8 s8 'urther to this he can start re0ie3ing of docu"ents and he should "a6e sure that he attaches the follo3ing docu"ents docu"ents as a "ini"u"2 1& Quality control plan – ensure all stages are co"plete co"plete and signed off off %& Inspection chec6 list list – ensure all stages are co"plete co"plete and signed off off !& )erify )erify "aterial certificates such such as "ill "ill test certificates etc2 :& )erify )erify the follo3ing procedures 3hich are to #e attached ha0e all #een appro0ed appro0ed a& Welding Welding #& +epair c& *DT d& PWHT e& Hardness f& PMI g& Hydro test h& oating 5& )erify )erify the .ualification le0els and 0alidity of the 3elders and *DT personnel & )erify )erify the inspection reports of follo3ing follo3ing disciplines and ensure ensure that that they co0er all appropriate appropriate ;oints ;oints and and structure structure a& )isual )isual #& *DT c& Di"ensional Di"ensional control etc2 =& )erify )erify the cali#ration certificates of e.uip"ents and instru"ents such as pressure gauge9 3elding "achines etc29 >& )erify )erify hardness test reports ?& )erify PMI reports 1/& )erify PWHT reports 11& )erify hydro test reports 1%& )erify (s-#uilt dra3ings are co"pleted 1!& )erify )erify 3eld "aps are a0aila#le for tracea#ility 1:& )erify )erify na"eplate9 ru##ing details are a0aila#le 3hen applica#le 15& )erify )erify the concession re.uest9 site .uery etc2 1& )erify per"it to 3or6 1=& )erify painting and coating inspection reports (s a part of his o3n inspection he "ay #e o#liged to 3itness final hydro test9 0isual inspection of co"pleted parts2 (s a "atter of .uality assurance he "ay 0ie3 so"e radiographs at rando" and "ay e0en conduct radiographic audit2 1)
Lamellar Tearing It is a step li6e crac6 occurring in the parent plate or H(@ of steels 3ith poor through thic6ness ductility9 ductility9 3here the fusion #oundary of the 3eld is parallel 3ith plate surface2 It is usually usually associated 3ith restrained restrained ;oints on corner9 corner9 tee or fillet 3elds ;oining ;oining thic6 plate2 Causes
a& #& c& d& e& f&
Poor Poor thro throug ugh h thic thic6n 6nes esss duct ductil ilit ity y *on-"etallic inclusion inclusion in the direction of of rolling +est estrain rained ed ;oi ;oint Thro Throug ugh h thi thic6 c6ne ness ss stre stress sses es High High sulp sulphu hurr cont conten entt Pres Presen ence ce of hy hydrog rogen
Control
a& #& c& d& e& f& g&
Modify dify Ao Aoint int desi desig gn ontrol restraint Bse forge forged d prod product uctss for for criti critical cal 3or6 3or6 Crind the parent "etal "etal and fill 3ith ductile ductile 3eld "etal2 "etal2 ( #uttering layer layer of high high ductility ductility 3eld "etal "etal "ay #e #e deposited deposited 3here the 0ertical "e"#er is to #e 3elded2 (ccess (ccess the the throug through h thic6n thic6ness ess ducti ductility lity #y short short tensile tensile test Inspec Inspectt the the plate plate for nonnon- "eta "etalli llicc inclu inclusio sions ns arry out full full che"ica che"icall analysis analysis to "a6e sure sure sulph sulphur ur is less less than than /2/5 /2/5
2)
Solidification Cracing ! "erritic Steel)
Solidification crac6ing is a hot crac6ing "echanis" that caused during solidification of 3eld in ferritic steels9 containing high sulphur content2 During 3elding sulphur in the plate "ay #e re"elted and 3ill fuse 3ith iron to for" iron sulphide $'eS&2 These iron-sulphides are lo3 "elting point i"purities9 so that collect around the grain #oundaries9 3hich are under great stress due to the action of contractional forces2 The #onding #et3een the grains "ay no3 #e insufficient to "aintain cohesion and crac6s 3ill result running through the length of the 3eld c entreline2 Causes
a& #& c& d&
High sulphur content High dilution process High car#on content in 3eld "etal High contractional stresses
Control
a& #& c& d& e&
ontrol the sulphur content Bse lo3 dilution process Bse consu"a#les 3ith high "anganese Eeep Manganese – sulphide 7 car#on ratio as lo3 as possi#le Mini"ise restraints
3) Weld #eca$ % Solidification cracing in austenitic stainless steel Solidification crac6ing is a hot crac6ing "echanis" that occurs during solidification of 3eld "etal in austenitic stainless steel2 (ustenitic stainless steels ha0e large grain structure co"pared to ferritic steel grains2 During 3elding lo3 "elting point i"purities collect around these large solidifying austenitic grain structures in the 3eld centreline2 These large grains ha0e s"all gain #oundaries co"pared to ferritic steels2 This lac6 of grain #oundary area causes all of the li.uid i"purities to concentrate in s"all area2 Due to high contractional forces these grain #oundaries are in great stress and the #onding #et3een the grains "ay #e insufficient to "aintain cohesion and crac6s occur in the centreline of 3eld along its length2 Causes
a& Fo3 "elting point i"purities #& High dilution process c& High contractional stress Control
&) Li'uation Cracs Fi.uation crac6s occur in steels9 3hich ha0e high sulphur2 When 3elding lo3 .uality high sulphur content steels9 it is possi#le that areas containing iron-sulphide $'eS& in the H(@ 3ill li.uefy2 These lo3 "elting point iron-sulphides usually accu"ulate at the grain #oundaries2 If this "elting occurs in the presence of a high contractional stress9 then the #oundaries 3ill #e pulled apart and li.uation crac6s occur2 Causes
a& High sulphur content #& High restraint c& High contractional stresses Control
() e*eat Cracing +eheat crac6ing is also 6no3n as relaGation crac6ing2 It "ainly occurs in H(@ of 3elds particularly in lo3 alloy steel during post 3eld heat treat"ent or ser0ice at ele0ated te"peratures2 Most alloy of steel su#;ect to an increase of e"#rittle"ent of the coarse grained region of the H(@ 3hen heated a#o0e // Deg2 2 The pro#le" is 3orse 3ith thic6er steels containing r9 u9 Mo9 )9 *# and Ti2 Sulphur and Phosphorus also ha0e an influence2 Typical steels suscepti#le 3ould #e the % J r2Mo2) type2 Ga"ple reep-resisting steels2 During post 3eld stress relief and at high operating te"perature the residual stresses 3ould #e relie0ed #y creep defor"ation 3hich in0ol0es grain #oundary sliding and grain defor"ation2 If due to "etallurgical conditions these actions cannot occur9 then grain #oundaries "ay open up into crac6s2 Causes
a& (reas of high stress concentration and eGisting 3eld defects2 #& The toes of #adly shaped fillet 3elds9 inco"plete root penetration 3elds2 c& High creep resistance2 Control a) Toe grinding9 eli"ination of partial penetration 3elds +) +e;ection of poor 3eld profile c) Heat .uic6ly through the suscepti#le te"perature i2e2 :5/ – 55/ Deg2 2
d) Bse high pre-heat te"perature and stage 3ise PWHT during 3elding large fa#rication to reduce the ris6 of reheat crac6ing in the final stress relie0ing e) Bse of 3eld "etal 3ith high ductility
,) P*enomenon of -IC or nder+ead Cracing These types of crac6s often originate fro" su#-surface locations under or near the 3eld in H(@2 This crac6ing is caused #y t3o "ain factors2 a& High ar#on or lo3 alloy content of steel that is allo3ed to cool too rapidly2
#& Presence of hydrogen during 3elding (lso presence of stress concentrations in the neigh#ourhood of 3eld can pro"ote under#ead crac6ing to a great eGtent2 The pheno"enon is as follo3s2 During 3elding9 s"all a"ount of free hydrogen is generated due to deco"position of "oisture fro" a ir9 electrode coating9 shielding gas or conta"inations on the surface to #e 3elded2 This hydrogen can dissol0e in "olten steel and fro" there diffuse into eGtre"ely hot #ut solidified #ase "etal2 If the cooling is sufficiently slo39 this e0ol0ed hydrogen has enough ti"e to escape into air #y diffusion2 Ho3e0er if the cooling is rapid so"e hydrogen "ay get trapped in H(@2 This hydrogen produces a condition called as 4Hydrogen e"#rittle"ent in the locations of its entrap"ent9 3hich are dislocations and 0oids #et3een grains2 (lso it generates 0ery high hydrostatic pressure in the space of its confine"ent2 This pressure co"#ined 3ith shrin6age stress due to cooling produce tiny crac6s in "etal i""ediately neGt to 3eld #ead9 3hich are su#-surface initially #ut e0entually propagate to surface2 /) nder+ead Cracing in 0uenc*ed Tempered Steels Q < T steels are nor"ally full alloyed steels 3hich ha0e high hardena#ility due to high car#on e.ui0alent2 Such steels su#se.uent to 3elding if allo3ed to cool do3n rapidly produce #rittle "icrostructure in H(@2 In such circu"stances if the hydrogen gets in0ol0ed in the process and trapped in #rittle "icrostructure as stipulated a#o0e in pheno"enon of Bnder#ead crac6ing and there#y cause Bnder#ead crac6s in Quench and Te"pered steels2 Preention
a& #& c& d&
Ci0ing sufficient heat input #y "eans of pre-heating2 +educe rate of cooling and ade.uate PWHT2 Bse of lo3 hydrogen processes for 3elding2 Perfor"ing 3elding in stress free conditions2
4) nder+ead cracing in -SL5 steels Bnli6e in Q
a& #& c& d& e&
nsure that #ase "etals ha0e enough ductility nsure that #ase "etals ha0e sufficiently lo3 of ar#on9 "anganese and other alloying ele"ent 3hich cause apprecia#le a"ount of "artensite for"ation2 +educing the rate of cooling of 3eld"ent Perfor"ing the 3elding in stress free conditions Bse of lo3 hydrogen processes
6)
"racture 7ec*anism 'racture can #e di0ided into three #asic types2 a& #& c&
'atigue Ductile Krittle
( fatigue fracture is the outco"e of cyclic loading and unloading 3hich induces fatigue in the "etal2 'ollo3ing appearances of eGposed surfaces "anifests these 6inds of fractures2 a& #&
Surface is s"ooth It is enco"passed #y crescent "ar6s or #each "ar6s
( ductile fracture is an outco"e of plastic defor"ation of "aterial to the point of rupture2 It is "anifested #y9 a& #&
Surface is torn and rough Shear lips at :5 Deg2 applied stress
( #rittle fracture is result of co"position of hard9 #rittle "aterial and an i"pulsi0e snappy load2 It is "anifested9 a& Kright9 crystalline #ut rough surface2 #& 4) shaped che0rons on the surface9 points to3ards the point of initiation2 ,ut of a#o0e types fatigue is al3ays the first "ode of failure2 If failure is in second "ode i2e2 ductile or #rittle9 then these failures 3ill al3ays #e follo3ing fatigue and not 0ice-0ersa2 ,ther3ise there could #e purely ductile or purely #rittle failures also 3hich are "anifested #y the appearances as "entioned a#o0e2
18) esidual Stresses Metals contract during solidification and su#se.uent cooling9 #ut if this contraction is pre0ented or inhi#ited residual stresses 3ill de0elop2 Most "etal products contain residual stresses9 often up to the yield point2 Pipe products for eGa"ple are usually 0ery highly stressed2 The tendency to de0elop residual stresses increases 3hen the heating and cooling are localised2 So 3elding 3ith its 0ery localised heating and the presence of li.uid and solid "etal in
contact can #e eGpected to induce 0ery high le0els of residual stresses2 +esidual stresses can #e difficult to "easure 3ith any real accuracy9 #ut a rough guide is that 3hen the 3eld "etal eGceeds % inch! $1: c"!& then the total residual stress is a#out yield point in "agnitude2 *or"al 3elds de0elop residual stresses7 a& (long the 3eld - Fongitudinal residual stresses #& (cross the 3eld - Trans0erse residual stresses c& Through the 3eld - Short trans0erse residual stresses
11) #istortion Distortion is caused #y stress distortion related here to the change and shape of a co"ponent9 3hich results fro" 3elding2 This change in shape "ay #e te"porary $elastic& or per"anent $plastic&2 If t3o pieces of "aterials e2g2 Plates9 3hich are to #e ; oined are free to "o0e during 3elding distortion 3ill occur2 If the t3o pieces of "aterial are not free to "o0e $restrained&9 the force 3ill re"ain as residual stresses2 T$pes of distortion7
Material properties and condition Heat input Fac6 of restraint
7et*od of reducing distortion
a& #& c& d& e&
Pre-heating 'orced restraint Bsing a #alancing9 3elding techni.ue e2g2 Kac6 strip 3elding 9 #ac6 step 3elding Bsing a different ;oint design to reduce the a"ount of 3eld deposited +educing the heat input
12) #istortion The action of the residual stresses in 3elded ;oints is to cause distortion2 onsider a si"ple 3eld 3ith a single 40ee preparation2 The follo3ing "o0e"ents can #e detected2 a& ontraction in the 3eld and H(@ along 3ith the length #& Ko3ing due to the greater 0olu"e of "etal at the top of the 3eld c& Pea6ing due to the 40ee angle d& +ipple $in-sheet& a3ay fro" the 3eld e& ontraction in the 3eld "etal and H(@ trans0erse to the 3eld ontrol of distortion is achie0ed in one or "ore of the follo3ing three 3ays7 a& Presetting – So that the "etal distorts into the re.uired position #& la"ping – To pre0ent distortion9 #ut this increases the le0el of residual stresses c& Welding se.uence i2e2 #alanced
13) 7ec*anical Testing a&
#& c& d& e& f& g& h& i&
Trans0erse tensile test 7 To "easure the trans0erse tensile strength under static loading 1& ( reduced speci"en assesses the tensile strength of the ;oint2 %& ( radius reduced speci"en assesses the tensile strength of the 3eld "etal2 rucifor" test7 To "easure the relati0e tensile strength of ;oints 3ith fillet 3elds under static loading2 *K7 Foad through 3elds (ll 3eld tensile strength7 To "easure the tensile strength of 1& lectrodes of filler 3ire < fluG co"#inations %& Quality of the 3eld "etal as deposited2 ST+(- Short Trans0erse +eduction (reas to access la"ellar tearing Kend tests $Trans0erse and longitudinal&7 To deter"ine the 1& Soundness of the 3eld "etal %& Weld ;unctions !& Heat affected one2 *ote 7 (ll speci"ens to #e re"o0ed and prepared 3ithout causing significant distortion or heating Side #end test 7 To deter"ine the soundness of a ;oint in cross section harpy 4) notch7 To deter"ine the energy a#sor#ed at a specified te"perature to fracture the speci"en2 *ic6-#rea6 test 7 To fracture the ;oint through the 3eld "etal to per"it eGa"ination of the fracture surfaces 'illet 3eld fracture test7 To fracture the ;oint through the 3eld "etal to per"it eGa"ination of the fracture surfaces2 *ote7 Sa3n notch in co"pression Macro – eGa"ination 7 To eGa"ine the 3hole ;oint for soundness
1&) Lamination and Laps Kasic difference #et3een la"ination and lap is that la"ination is a su#-surface discontinuity and lap is surface discontinuity2 Lamination7 In the steel "ills the "olten steel is poured into "oulds to for" ingots2 While the solidification is ta6ing place huge a"ounts of gases "ay re"ain trapped inside the solidified steel2 This ingot 3hen rolled9 the gas poc6ets inside gets flattened in the for" of la"ination2 This discontinuity ad0ersely affects through thic6ness strength of the steel and is not tracea#le #y MPI or +T2 The only 3ay to detect la"ination is #y BT2 This discontinuity "ay also contri#ute to la"ellar tearing in thic6 sections2 Laps7 Faps are #asically chun6s of "etal that has flo3n fro" the desired profile during operations such as hot for"ing2 This chun6 of "aterial is connected to the #ase "etal at so"e location and o0erhanging portion of the chun6 si"ply lies on the "etal 3ithout #eing the ho"ogeneous part of it2 (s it is surface defect it can #e found 0isually and can #e confir"ed #y MPI2
1() Transition :oints a& #&
Transition ;oints could #e of t3o categories7 Different #ase "etals Different thic6ness (ssu"ing that the transition ;oint in this discussion co"plied 3ith #oth of the a#o0e t3o categories2 'ollo3ing care should #e ta6en during 3elding2 a) #ifferent +ase metal
1& %& !& :& 5& &
Proper selection of electrode to a0oid dilution of the 3eld "etal Proper selection of current range and polarity type of current Kac6 purging re.uired 9if any leanliness Pre -heat 9 PWHT Welding process
+) #ifferent t*icness7
1& The thic6er "e"#er should #e gradually tapered off to "atch the thic6ness of thinner "e"#er such that said taper 3ill not eGceed 17: %& The co"pleted 3eld should #e #lended in such a 3ay that it 3ill follo3 the gradual transition !& Proper heat treat"ent should #e chosen ta6ing consideration of thic6ness of thic6er "e"#er ,n steels9 the H(@ of the 3eld tends to #e "ore #rittle i2e2 it has lo3er notch toughness9 than the actual 3eld "etal2 The H(@ area is therefore "ore prone to crac6ing especially 3hen hydrogen is induced9 although it "ust #e noted that the tensile strength of the H(@ is nor"ally high in co"parison 3ith the 3eld and parent "aterial2 Bnfortunately if a fusion 3elding process is #eing used then the H(@ cannot #e eli"inated2
1,) CT;# !Crac ;pening #isplacement Test) T,D is a test "ethod for the deter"ination of a "etals resistance to the initiation of a crac6 resulting fro" notch defects2 T,D "easures the elastic –plastic toughness of the "etal in the ductile –#rittle tra nsition2 The propagation of a crac6 in a 3elded structure depends upon factors including the "aterials used2 The sie and sharpness of any notch present9 operating te"perature9 the degree of restraint a nd 3elding procedure re.uire"ents2 T,D test per"its full sie speci"ens to #e used irrespecti0e of "etal thic6ness to 3hich a notch of gi0en 3idth and depth is applied2 The speci"en is su#;ected to a high-speed resonance load cycling on a three point #ending rig2 ( clip gauge is fiGed to the "outh of the notch accurately "easures the slo3 opening of the crac6 and a force sensing de0ice ena#les the applied load to #e plotted against displace"ent on a graph2 -5< % -eat 5ffected
a& #& c&
Material co"position9 especially car#on content2 Heat input – The higher the heat input or arc energy9 the 3ider H(@2 Metallurgical properties 3ill also #e affected2 The rate of cooling - Higher the rate of cooling9 harder the H(@ especially if the 22 of the steel is high2 The H(@ in a 3eld one on steel consists of up to four separate regions9 starting fro" the area i""ediately ad;acent to the 3eld2 1& %& !& :&
oarse grained region $ heat #et3een 11// Deg2& and "elting point& Crain refined region $?// to 11// Deg2 & +egion of partial transfor"ation $ =5/ to ?// Deg2 & +egion of spheroidiation $ ;ust #elo3 =5/ Deg2 &
1/) S5W Wire "lux details = S5W Consuma+les (WS (521=2>?7 Specification for car#on steel electrode and fluGes for S(W The coding syste" sho3s the fluG capa#ilities 3hen co"#ined 3ith a specific electrode Ga"ple coding9 '=( – M1%E or '(: – 1 $trade na"e& '- Indicates fluG = – Indicates the 3eld "etals "ini"u" ulti"ate tensile strength in Epsi G 1/9 3hen using the fluG 3ith the electrode identified ( – Designates the condition of heat treat"ent to the 3eld or 3hich tests 3ere conducted 4( is for as 3elded and 4P for PWHT – Indicates the lo3est te"perature in Degree 'ahrenheit G 1/ at 3hich a charpy 0alue of %= A 3as achie0ed – Indicates a solid electrode2 3ould indicate a co"posite electrode M- This "ay #e either F9 M9 or H indicating Fo39 "ediu" or high "anganese content 1% – This "ay #e one or t3o digits and no"inal car#on content of the electrode e2g2 1% N /21%9 >N /2/> E – Indicates the electrode is "ade fro" se"i-6illed steel 5dditional flux information7
(ll fluGes to this specification "ust #e of a granular nature and capa#le of flo3ing freely 3hen used2 Particle sie is to #e a "atter of a gree"ent #et3een the purchaser and supplier2 The fluG "ust per"it the production of s"ooth 3ith depth of undercut2 'luGes are classified on the #asis of "echanical properties of the 3eld "etal2 They produce and therefore ha0e to #e sho3n in con;unction 3ith the electrode used2 'luGes used to this specification "ay contain fusi#le co"pounds of 0arious proportions2 So"e fluGes contain de-oGidisers9 others do not and fluGes "ay react differently 3ith different electrodes and arc 0oltage used2 ( change of arc 0oltage during 3elding 3ill change the a"ount of fluG "elted and "ay therefore change the co"position of the 3eld "etal2 The effect of this change allo3s fluGes to #e descried as neutral9 acti0e or alloy2
>eutral "luxes are those 3hich do not produce any significant change in the 3eld "etal che"ical analysis irrespecti0e of arc 0oltage < arc length changes2 'luGes of this type contain little or no de-oGidisers and rely on the electrode for de-oGidation2 They are "ainly used for "ulti pass 3elds 5ctie "luxes contain "anganese and silicon as de-oGidisers and the effect of those on the 3eld "etal 3ill change as the arc 0oltage changes9 these fluGes are used "ainly for single pass 3elds2 5llo$ fluxes are those 3hich can #e used 3ith a car#on steel electrode to produce a lo3 alloy 3eld "etal as such they co"e under the scope of (-52%! 9 Fo3 alloy steel electrodes and fluGes for S(W2
(WS
'luG #asicity or classification Kasic oGides tend to #e "ore sta#le than acidic oGides2 'luGes for S(W "ay #e classified as follo3s2 1& (cid – Ceneral purpose use and for dirty $rusty& steel %& *eutral !& Se"i #asic – I"pro0ing .uality :& Kasic 5& High #asicity – MaGi"u" 3eld toughness and perfor"ance
14) Consuma+les % S5W process "used "lux 'used fluGes are "anufactured as follo3s2 The ingredients are "iGed and "elted at high te"peratureL the "iGture is the poured on to large chill #loc6s or directed into a strea" of 3ater to produce granules 3hich ha0e a hard glassy appearance2 The "aterial is then crushed9 sie0ed and pac6aged2 5dantages7 a& Cood che"ical "iG achie0ed2 #& They do not attract "oisture $not hygroscopic& this i"pro0es handling9 storage9 use and 3eld a#ility2 (ny "oisture present is easily re"o0ed #y lo3 te"perature drying2 c& The easy re"o0al of i"purities and fine particles etc29 3hen recycling2 The "ain disad0antage is the difficulty in adding de-oGidants and ferro-alloys2 These 3ould #e lost during the high te"perature "anufacture2 The "aintenance of a controlled fluG depth is considered critical2 5gglomerated "lux (ll the fluG "aterials are dry "iGed and then #onded 3ith either potassiu" or silicate2 They are then #a6ed at a te"perature #elo3 the fusion or "elting point and therefore re"ain as a po3der9 3hich is sie0ed for sie and pac6aged2 5dantages a& an #e colour coded #& asy addition of de-oGidants and 'erro-alloys c& 'luG depth not so critical #isadantages a& Tendency for fluG to a#sor# "oisture and difficult re-drying procedure #& Possi#ility of "olten slag9 causing porosity
c&
Difficult re-cycling i2e2 the re"o0al of i"purities and sie0ing2
16) ?ou suspect t* at an >#T radiograp*ic team under t*e superision of $our inspectors *as radiograp*ed t*e same 9eld seam and onl$ c*anging t*e lead letters a) W*at 9ould +e $our initial course of action@ +) If $our suspicion is proed to +e correctA 9*at 9ould +e $our furt*er course of action@
onduct the radiographic audit in #atches and if si"ilar loo6ing radiographs are found then they should #e 0erified at ;o# against the 3eld2 If "any such suspected radiographs are found then a full audit of a ll the radiographs should #e perfor"ed2 The outco"e of this in0estigation could #e of t3o types2 1& +are case of duplication %& ,ccurrence of duplication in "any cases In the for"er case it is "ost li6ely to #e a hu"an errorL hence the "atter can #e resol0ed #y "a6ing *DT super0isor a3are of facts2 Ho3e0er in the later case it is an intentional action perfor"ed to help so"e#odyOs interests9 3hich is o#0iously a set #ac6 to the .uality2 Hence depending upon the eGtre"ity of fraudulence follo3ing proposal can #e "ade to the higher authority as disciplinary "easures2 1& %& !& :&
Warning letter ut pay"ent order Ter"ination of *DT ser0ice contract De#arring the *DT contractors ( "eeting of all inspectors to #e conducted and they should #e issued a strong 3arning to i"pro0e the le0el of their perfor"ance to a0oid such incidents in future2
28) It *as come to $our attention t*at t*e morale of $our inspection team appears to +e lo9. a) W*at could $ou *ae o+sered to determine t*is@ +) W*at 9ould occur if t*is 9as not rectified 'uicl$@ c) W*at could $ou do to lift lo9 morale@
a&
Fo3 "orale can #e identified #y the follo3ing sy"pto"s 1& High rate of a#senteeis" %& Sluggish response to the situation !& asual approach to3ards 3or6 :& *egligence $Poor record 6eeping9 not inspecting 3elds etc2& 5& o"plaints fro" client < TP(
#& Fo3 "orale "ay result in the follo3ing 1& Fac6 of control o0er production acti0ities fro" .uality point of 0ie3 %& Higher re;ection rates #y client < TP( !& Su#standard 3or6 output :& Delay in 3or6 schedule 5& Fac6 of credi#ility to the organisation c& ,#ser0ing all a#o0e9 it is i"perati0e that lifting the lo3 "orale is stitch in ti"e9 this can #e done as f ollo3s 1& (rrange the "eeting of all your su#-ordinate staff for fran6 discussion on the su#;ect "atter %& 'ro" their responses you can for" a collecti0e opinion for lo3 "orale !& 'urther to this you "ay ha0e pri0ate discussion 3ith each indi0idual 3hich can help you to ero in on his pro#le"s2 The pro#le" is then sorted out as general pro#le" and indi0idual pro#le"s2 (s regards to general pro#le"s9 you can assure the tea" that you 3ill do e0erything possi#le in your capacity to rectify it2 'or eGa"ple lac6 of good 3or6ing apparatus9 salary pro#le"s9 lea0e schedules etc2 (s regards to indi0idual pro#le"s9 it should #e #rought to the attention of the e"ployees in gentle #ut fir" "anner that their indi0idual pro#le"s "ust not affect the "orale2 *e0ertheless on co"passionate grounds you 3ill try to see6 co"panyOs help for his personal pro#le" also2 'urther to this they should #e noticed that the effect of high "orale 3ill reflect in good salary rise9 #etter facilities etc2 Ho3e0er if lo3 "orale continues then the "anage"ent 3ill #e o#liged 3arning letters9 de"otions and in 3orst cases ter"ination also2
21) Inter granular corrosion It occurs in unsta#ilised austenitic stainless steel 3ith // – >5/ Deg2 2 range of the H(@2 (t this te"perature range car#on is a#sor#ed #y the chro"iu" and chro"iu" car#ide is precipitated at the grain #oundaries as "etal cools do3n2 This causes a local reduction in chro"iu" content9 3hich has the effect of lo3ering the resistance to corrosi0e attac6 allo3ing to occur2 Control 1& %& !&
Bse sta#ilised stainless steels 3ith the addition of *i or Ti Bse lo3 car#on stainless steels $#elo3 /2/:& Heating at a#out 11// Deg2 3here chro"iu" car#ide 3ill #e dissol0ed2 Then steel is nor"ally .uenched fro" this te"perature to stop re-association2 Focation7 Weld H(@ $Fongitudinal& Suscepti#le "icrostructure7 Sensitised grain #oundaries
22) Course of inestigation for a essel ruptured 9it* loud +ang 7 With only this "uch of initial infor"ation one can construe that the failure "ust #e catastrophic in nature9 3hich "eans in all li6eliness "ode of failure has to #e #rittle2 Ho3e0er there could #e "ore than one "ode of failure i2e2 the initiation could #e in a fatigue "ode follo3ed #y #rittle2 Kecause of this reason it is ad0isa#le to personality 0isit the 0enue of failure and to do so"e 0isual inspection of eGposed surfaces2 If the failure happens to #e of purely #rittle nature then follo3ing 3ill #e the sy"pto"s2 1& %& !& :&
+ough and crystalline surface he0ron "ar6s ha0ing 4) shape pointing to3ards point of initiation other3ise if failure in initiated in fatigue "ode then it 3ill #e "anifested #y S"ooth surface ha0ing dull teGture Half round 4rescent or Keach "ar6s It is also i"portant to note 3hether the initiation of rupture is in 3eld < H(@ or in #ase "etal2 If the failure happens to #e in #ase "etal then one can further in0estigate in follo3ing a0enues2 1& he"ical co"position and physical properties certificate supplied #y "anufacturer %& Heat treat"ent records and la# test reports if any !& Hardness of #ase "etal and thic6ness in the rupture one :& Suita#ility of "aterial for gi0en ser0ice conditions ,n the other hand if the failure is in 3eld
2&) In serice failure of a 9eld at B&8 #eg.C Ser0ice te"perature of the order of - :/Deg2 tells that the failure "ost pro#a#ly has occurred due to lac6 of strength or toughness at that te"perature2 o"pared to #ase "etal9 a 3eld is al3ays of irregular shape and hence is considered as irregularity or discontinuity in surface profiles2 (ny discontinuity ser0es as a stress raiser 3hen it co"es across lines of stresses2 The strength of "aterial < "etal drops at the locations of high stress concentration especially 3hen te"perature drops significantly2 In #rief "etal tends to lose its notch toughness2 Hence our area of in0estigation should #e notch toughness of gi0en 3eld at lo3 te"perature2 This can #e approached in follo3ing 3ays2 1& %& !&
)erifying that WPS has reco""ended proper consu"a#les to #e used and all the essential 0aria#les 3ere adhered to )erify heat treat"ent records $if any& +e0ie3 and scrutinie la# test reports including that of charpy 0 notch tests for all 3eld speci"ens
:& 5&
+e0ie3 #atch certificates for consu"a#les used Focation of failure should #e inspected and point of initiation should #e esta#lished If the location of failure initiation happens to #e 3ithout any defect 0i29 undercut or porosity then failure can #e attri#uted to sheer lac6 of lo3 te"perature strength and consu"a#le gi0ing higher lo3 te"perature strength "ay #e reco""ended and i"pro0e"ent in 3eld profile "ay also #e ad0ised2 Ho3e0er if the point of initiation happens to #e a defect such as porosity or any su#surface defect then corresponding radiograph for that section of 3eld "ay #e c losely eGa"ined and interpreted2 In such cases "ore stringent acceptance criterion "ay #e reco""ended in addition to reco""endations "entioned a#o0e2
0uestions of ;cto+er 288( in 7uscat
1& %&
!& :&
5&
Signing off the product a& he"ical co"position of Q
T 7ultic*oice 1&
(n R-ray tu#e 3ith s"all focal spot is considered #etter than one 3ith a large focal spot 3hen it is desired to o#tain 7 a& Creater penetrating po3er #& #etter definition c& less contrast d& greater fil" density
%&
The ad;ust"ent of tu#e current in con0entional R-ray tu#e circuits is "ade #y a& ad;usting the fila"ent heating current #& ad;usting the target to cathode distance c& Inserting resistance in the anode lead d& ,pening the shutter on the R-ray tu#e port
!&
'ilters used at the port of the R-+ay tu#e a& Intensify the R-ray #ea" #y contri#uting secondary radiation #& 'ilter short 3a0elength R-ray #ea"s to pro0ide softer radiation c& Pro0ide the "ost readily ad;usted "eans of "odifying R-ray intensity d& filter out Fong 3a0elength rays than short 3a0elength rays
:&
In order to utilie the principles of geo"etric enlarge"ent a& the source to speci"en distance "ust #e one-half the source to fil" distance #& the source of radiation "ust #e eGtre"ely s"all c& a "agnetic focusing coil "ust #e used near the port of the R-ray tu#e d& the speci"en "ust #e of unifor" thic6ness
5&
( cur0e relating density 3ith the logarith" of eGposure or of relati0e eGposure is called a& a sensiti0ity cur0e #& a density eGposure cur0e c& an H D cur0e d& R-ray intensity cur0e
& In fil" radiography penta"eters are usually placed a& #et3een the intensifying screen and the fil" c& on the fil" side of the test o#;ect
#& on the source side of the test o#;ect d& #et3een the operator and the radiation source
=& When radiographing a part 3hich contains a large crac69 the crac6 3ill appear on the radiograph as a& a dar69 inter"ittent or continuous line #& a light9 irregular line c& either a dar6 or light line d& a fogged area on the radiograph >& 'rilling or loosening of the e"ulsion fro" the #ase of the fil" is "ost li6ely caused #y a& 3ater or de0eloper on unprocessed fil" #& lo3 te"perature of processing solutions c& de0eloper solution conta"ination d& 3ar" or eGhausted fiGer solution ?& (s a chec6 on the ade.uacy of the radiograph techni.ue9 it is custo"ary to place a standard test piece on the source side of the speci"en2 This standard test piece is called a a& reference plate #& lead screen c& penetra"eter d& illu"inator 1/& Static "ar6s 3hich are #lac6 tree-li6e or circular "ar6s on the radiograph are often caused #y a& fil" #eing #ent 3hen inserted in the cassette or holder #& Scratches on the lead foil screens c& foreign "aterial or dirt i"#edded in screens d& i"proper fil" handling techni.ues 11& The acti0ity of the de0eloper solution is "aintained sta#le #y a& constant agitation #& "aintaining processing solution 3ithin the reco""ended te"perature range c& a0oiding conta"ination fro" the 3ash #ath d& addition of replenisher
