CWB Welding Inspector Level III Study
Guide Questions And Answers
Which bof bthe bfollowing bmetals bhas bthe bhighest bthermal bconductivity?
(a) bcarbon bsteel
(b) bstainless bsteel
(c) baluminum b- bcorrect banswers✔✔(c)
The bEllingham bdiagram
(a) bis ba bplot bof bthermal bconductivity bagainst btemperature,
(b) bshows bthe bfree benergy bof boxide bformation bagainst btemperature.
(c) bshows bthe brate bof boxidation bof bmetals bagainst btemperature. b- bcorrect
banswers✔✔(b)
True bor bFalse?
A bmetal bwith ba bhigh bnegative bfree benergy bof boxide bformation bwill bgenerally
brequire bgreater bshielding bfrom bthe batmosphere bduring bwelding. b- bcorrect
banswers✔✔True
Electricity bcan bbe bconducted bby:
(a) batoms band belectrons.
(b) belectrons band bions.
(c) bonly bions. b- bcorrect banswers✔✔(b)
Which bof bthe bfollowing belements bis boften bpresent bin bsubmerged barc bfluxes bto
bimprove barc bstability?
(a) bcopper
(b) bpotassium
(c) bnickel
(d) btungsten b- bcorrect banswers✔✔(b)
Thoria bis badded bto btunsten belectrodes bfor bwhat bpurpose? b- bcorrect banswers✔✔To
bincrease bthermionic bemission bby blowering bthe bwork bfunction.
True bor bFalse?
All bpure bmetals bhave bthe bsame bcrystal bstructure. b- bcorrect banswers✔✔False.
bMetals bgenerally bhave bone bof bthree bbasic bstructures.
, Which bcrystal bstructure(s) bis b(are) bcomposed bof bclose-packed bplanes? b- bcorrect
banswers✔✔FCC band bHCP
The breal bstrength bof bmetals bis blower bthan bthe btheoretical bvalue bbecause:
(a) breal bcrystals balways bfracture balong bspecific bcrystal bplanes.
(b) bgrain bboundary bsliding boccurs.
(c) bthe bpresence bof bdislocations bfacilitates bslip. b- bcorrect banswers✔✔(c)
Multiplication band bsubsequent bcongestion bof bmoving bdislocations bcauses:
(a) belastic bextension.
(b) bwork bor bstrain bhardening.
(c) ba bdrop bin bthe byield bstress. b- bcorrect banswers✔✔(b)
Which bof bthe bfollowing belements bare bmost blikely bto bform binterstitial bsolid
bsolutions?
(a) bcopper
(b) bnickel
(c) bcarbon b- bcorrect banswers✔✔(c)
If bFCC biron bhas ba bdenser bstructure bthan bBCC biron, bwhy bdoes bit bhave ba bhigher
bsolubility bfor bcarbon? b- bcorrect banswers✔✔The bpreferred bsite bfor bcarbon bin bBCC
biron bis bsmaller bthan bthat bin bFCC biron.
If btwo bmetals bhave bcomplete bmutual bsolid bsolubility bhow bmany bphases bare bformed
bin bthe bsolid- bone bor btwo? b- bcorrect banswers✔✔One
How bmany bphases bare bthere bin ba beutectic- bone bor btwo? b- bcorrect
banswers✔✔Two
Without breferring bto bthe btext, bdraw bthe bphase bdiagram bfor ba beutectic bsystem bwith
blimited bmutual bsolid bsolubility bof bthe btwo bcomponents. b- bcorrect banswers✔✔Refer
bto bFigure b6.6(Module b20-2014, bpage b18)
Using bthe bportion bof bthe biron-carbon bphase bdiagram bin bFigure b6.10(Module b20-
2014, bpage b21), buse bthe blever brule bto bdetermine bthe bprecentage bof bferrite band
beutectoid bpearlite bpresent bin ba bslowly bcooled b0.2% bcarbon bsteel. b- bcorrect
banswers✔✔About b25% bpearlite band b75% bferrite. bHere bthe btie bline bbegins bat
b0.0%C b(α bferrite) band bends bat b0.08%C b(pearlite).
The bfulcrum bfor bthe blever brule bis bat b0.2%C
% bpearlite b= b(0.2%C b- b0.0%C)/).8%C b- b0.0%C) bx b100%
% bpearlite b= b(0.2/0.8) bx b100%
% bpearlite b= b25%
Which bof bthe bfollowing bmetals bhas bthe bhighest bwork bhardening bcoefficient?
(a) b70/30 bbrass
Guide Questions And Answers
Which bof bthe bfollowing bmetals bhas bthe bhighest bthermal bconductivity?
(a) bcarbon bsteel
(b) bstainless bsteel
(c) baluminum b- bcorrect banswers✔✔(c)
The bEllingham bdiagram
(a) bis ba bplot bof bthermal bconductivity bagainst btemperature,
(b) bshows bthe bfree benergy bof boxide bformation bagainst btemperature.
(c) bshows bthe brate bof boxidation bof bmetals bagainst btemperature. b- bcorrect
banswers✔✔(b)
True bor bFalse?
A bmetal bwith ba bhigh bnegative bfree benergy bof boxide bformation bwill bgenerally
brequire bgreater bshielding bfrom bthe batmosphere bduring bwelding. b- bcorrect
banswers✔✔True
Electricity bcan bbe bconducted bby:
(a) batoms band belectrons.
(b) belectrons band bions.
(c) bonly bions. b- bcorrect banswers✔✔(b)
Which bof bthe bfollowing belements bis boften bpresent bin bsubmerged barc bfluxes bto
bimprove barc bstability?
(a) bcopper
(b) bpotassium
(c) bnickel
(d) btungsten b- bcorrect banswers✔✔(b)
Thoria bis badded bto btunsten belectrodes bfor bwhat bpurpose? b- bcorrect banswers✔✔To
bincrease bthermionic bemission bby blowering bthe bwork bfunction.
True bor bFalse?
All bpure bmetals bhave bthe bsame bcrystal bstructure. b- bcorrect banswers✔✔False.
bMetals bgenerally bhave bone bof bthree bbasic bstructures.
, Which bcrystal bstructure(s) bis b(are) bcomposed bof bclose-packed bplanes? b- bcorrect
banswers✔✔FCC band bHCP
The breal bstrength bof bmetals bis blower bthan bthe btheoretical bvalue bbecause:
(a) breal bcrystals balways bfracture balong bspecific bcrystal bplanes.
(b) bgrain bboundary bsliding boccurs.
(c) bthe bpresence bof bdislocations bfacilitates bslip. b- bcorrect banswers✔✔(c)
Multiplication band bsubsequent bcongestion bof bmoving bdislocations bcauses:
(a) belastic bextension.
(b) bwork bor bstrain bhardening.
(c) ba bdrop bin bthe byield bstress. b- bcorrect banswers✔✔(b)
Which bof bthe bfollowing belements bare bmost blikely bto bform binterstitial bsolid
bsolutions?
(a) bcopper
(b) bnickel
(c) bcarbon b- bcorrect banswers✔✔(c)
If bFCC biron bhas ba bdenser bstructure bthan bBCC biron, bwhy bdoes bit bhave ba bhigher
bsolubility bfor bcarbon? b- bcorrect banswers✔✔The bpreferred bsite bfor bcarbon bin bBCC
biron bis bsmaller bthan bthat bin bFCC biron.
If btwo bmetals bhave bcomplete bmutual bsolid bsolubility bhow bmany bphases bare bformed
bin bthe bsolid- bone bor btwo? b- bcorrect banswers✔✔One
How bmany bphases bare bthere bin ba beutectic- bone bor btwo? b- bcorrect
banswers✔✔Two
Without breferring bto bthe btext, bdraw bthe bphase bdiagram bfor ba beutectic bsystem bwith
blimited bmutual bsolid bsolubility bof bthe btwo bcomponents. b- bcorrect banswers✔✔Refer
bto bFigure b6.6(Module b20-2014, bpage b18)
Using bthe bportion bof bthe biron-carbon bphase bdiagram bin bFigure b6.10(Module b20-
2014, bpage b21), buse bthe blever brule bto bdetermine bthe bprecentage bof bferrite band
beutectoid bpearlite bpresent bin ba bslowly bcooled b0.2% bcarbon bsteel. b- bcorrect
banswers✔✔About b25% bpearlite band b75% bferrite. bHere bthe btie bline bbegins bat
b0.0%C b(α bferrite) band bends bat b0.08%C b(pearlite).
The bfulcrum bfor bthe blever brule bis bat b0.2%C
% bpearlite b= b(0.2%C b- b0.0%C)/).8%C b- b0.0%C) bx b100%
% bpearlite b= b(0.2/0.8) bx b100%
% bpearlite b= b25%
Which bof bthe bfollowing bmetals bhas bthe bhighest bwork bhardening bcoefficient?
(a) b70/30 bbrass
