Question

Why is nitriding not used for plain carbon steels?

(a) Formation of oxides

(b) Formation of cracks

(c) Formation of iron nitrides

(d) Formation of spots

This question was addressed to me in an international level competition.

My doubt is from Nitriding, Cyaniding and Carbonitriding in division Heat Treatment of Engineering Material & Metallurgy

Answer 1

Correct option is (c) Formation of iron nitrides

For explanation I would say: Nitriding is generally not preferred for plain carbon steels. This is due to the formation of iron nitrides formed to a considerable depth below the surface of the steel. This causes embrittlement of the material.