CWB LEVEL 3 MODULE 21 PRACTICE QUESTIONS (2026/2027) UPDATE|EXAM QUESTIONS WITH MULTIPLE CHOICES |VERIFIED & REVISED ANSWERS (NEW)!!!

CWB LEVEL 3 MODULE 21 PRACTICE
QUESTIONS (2026/2027)
UPDATE|EXAM
QUESTIONS WITH MULTIPLE
CHOICES |VERIFIED & REVISED
ANSWERS (NEW)!!!
Themmaximummsolubilitymofmcarbonminmamironmis:

(a)m2%.

(b)m0.002%.

(c)m0.02%.

(d)mTheremismnomsolubility.m-mCORRECTmANSWERm(c)m0.02%.



Truemormfalse?

Whenmamsteelmismheatedmintomthemaustenitemregion,mallmcarbonmandmmostmothermcompoundsmdiss
olve

tomformmamsinglemphase.m-mCORRECTmANSWERmTrue



Truemormfalse?

Pearlitemismamsinglemphase.m-mCORRECTmANSWERmFalse



Whatmismthemresultingmstructuremofmam0.6%mcarbonmsteelmslowlymcooledmfromm900°Cmtomroom

temperature?m-mCORRECTmANSWERmAboutm25%mproeutectoidmferritemandm75%mpearlite



Mostmfinemgrainmsteelsmretainmtheirmfinemgrains:m(

(a)mupmtomthemmeltingmtemperature.

(b)mupmtomthemgrainmcoarseningmtemperature,mbutmabovemthatmbehavemasmcoarsemgrainmsteel.mC

, (c)monlymupmtomthemtransformationmtemperature.m-mCORRECTmANSWERm(b)



Whymismmartensitemproducedmrathermthanmpearlitemwhenma

steelmismrapidlymquenchedmfrom,m900°C?m-
mCORRECTmANSWERmInsufficientmtimemformcarbonmtomdiffusemtomformmcarbides




Themhardnessmofmmartensitemdependsmmainlymonmthe:

(a)malloymcontent.

(b)mratemofmcooling.

(c)mcarbonmcontent.

(d)msizemofmthempart.m-mCORRECTmANSWERm(c)



Canmbainitemnormallymbemproducedminmcontinuousmcoolingmofmamplainmcarbonmsteel?m-
mCORRECTmANSWERmNo




Increasingmthemcarbonmcontent:

(a)mlowersmthemmartensitemstartmtemperaturemM.

(b)mraisesmthemM.

(c)mhasmnomeffectmonmM.m-mCORRECTmANSWERm(a)mlowersmthemmartensitemstartmtemperaturemM.



Calculatemthemidealmcriticalmdiameterm(hardenability)mformamsteelmwithm0.2%C,m0.25%Si,m1

.0%Mn,

0.5%Cr,m0.5%Mo,m1.0%Nim(assumemanminitialmgrainmsizemofmASTMm8).mUsemsectionm2.5.3mandm2.5.4

asmamreference.m-mCORRECTmANSWERm5.0



UsingmFigurem2.34,mestimatemthemfastestmratemamweldmcouldmcoolmwithoutmthemHAZmbecoming

hardermthanm350mHVmforma