CWB Level 3 Module 21 Welding Metallurgy of Steels Questions with 100% Correct Answers

CWB Level 3 Module 21 Welding Metallurgy of
Steels Questions with 100% Correct Answers
What forms the largest group of commercially
important alloys? Correct Answer: Steel


Steels are alloys of iron with less than ____ % of carbon
plus a wide range of other elements Correct Answer: 2 %


Elements which form interstitial solutions with iron Correct
Answer: Carbon, nitrogen, boron and hydrogen


Elements which from substitutional solutions with iron
Correct Answer: Manganese and Silicon


Below 910 C, Iron is in _________ structure Correct
Answer: BCC


B/w 910 C and 1390 C iron takes____ structure Correct
Answer: FCC


Above 1390 Cand upto the melting point 1534 C , its
______ structure Correct Answer: BCC


What are allotropic forms of iron ? Correct Answer: BCC,
FCC structures at different temperatures

, True stable form of carbon in iron is ____ Correct Answer:
graphite


Eutectic is formed at ________ wt of Carbon Correct
Answer: 4.3%


Austenite / gamma phase in iron dissolves up to ______ %
of Carbon Correct Answer: 2%


With no carbon present, austenite starts to form at which
temperature? Correct Answer: 910 C


With 0.8% wt carbon, austenite starts to form at which
temperature? Correct Answer: 723 C


The region where the carbon is dissolved in BCC iron is
very narrow? Correct Answer: Ferrite phase / Alpha


What is the amount of carbon in Ferrite region? Correct
Answer: 0.02 wt % at 723 C


Ferrite cannot be considered as __________ Correct
Answer: Pure iron


At what % of carbon and temperature does eutectoid
forms? Correct Answer: 0.8% C and 723 C