Question

Which of the following is true for induction hardening?

(a) Requires less time

(b) Hardness and depth is difficult to control

(c) Only external surfaces can be hardened

(d) It gives a scaling effect

The question was posed to me in class test.

This interesting question is from Selective Hardening in division Heat Treatment of Engineering Material & Metallurgy

Answer 1

Correct answer is (a) Requires less time

Easiest explanation: Induction hardening has a major advantage that it requires very less time, typically of the order of 10 seconds. It is easy to control the surface hardness and depth and can be automated. Here, both external and internal surfaces can be hardened. Since it does not give any scaling effect, the machining is reduced.