A) tempering
B) annealing
C) quenching
D) case hardening
Correct Answer: D
Solution :
Case hardening In case hardening technique, iron rods embedded in charcoal powder are heated repeatedly. This technique is used in making axles of railway wagon. Annealing A process in which the newly shaped articles are cooled slowly. If they are cooled quickly they become brittle on account of the high internal strain. Tempering The method of reheating a quenched steel to relieve internal stresses, reduce hardness, and tensile strength and restore ductility and resistance to impact loading. It is carried out within the temperature range \[200-{{550}^{o}}C\] for plain carbon steels. Quenching In this method a steel article is heated to redness and then suddenly cooled by plunging into water, the steel becomes hard and brittle.You need to login to perform this action.
You will be redirected in
3 sec