Sub zero treatment of steel is done to____________________?

(A)  Suppress martensite transformation (X)
(B)  Reduce the retained austenite in hardened steel ()
(C) Enhance its working performance in sub zero atmosphere (X)
(D) Induce temper brittleness after its hardening (X)

Answers: Sub zero treatment of steel is done to Reduce the retained austenite in hardened steel.