The steel grade according to TCVN is $38$Cr$2$Ni$2$Mo$.$ Students must answer.

a$.$ Find out a plain carbon steel with the carbon equivalent amount according to TCVN $($Cxx$)?$ b$.$ For the Cxx steel in a$),$ determine the total ferrite and pearlite percentages?

C$.$ Calculate the critical temperature points of this Cxx steel $($A$1,$ A$3,$ Acm $($if any$)\}?$ When the Cxx steel is cooled slowly from the austenitic region, how will the p

transformation through the critical temperatures?

d$.$The average $\%$ composition of the major elements of $38$Cr$2$Ni$2$Mo and the main effects of the major alloying elements?

e$.38$Cr$2$Ni$2$Mo is most suitable to be used to make one of which following machine parts: camshaft, automobile leaf spring, gear, measuring tool, cold work a typical final heat treatment for the machine part.