(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.
(A) Convection heat transfer by stirring the fluid and cleaning the heating surface (X)
(B) Conduction heat transfer by reduction in the material thickness and increase in the thermal conductivity (X) (C)Radiation heat transfer by increasing the temperature and reducing the emissivity ()
(D) None of these (X)
Answers: A reduction in thermal resistance during heat transfer does not occur in the Radiation heat transfer by increasing the temperature and reducing the emissivity.