Question

Which of the following is not applicable for liquid carburizing?

(a) Uniform temperature

(b) Dirty work surface

(c) Temperature controlled by pyrometers

(d) High cost of carburizing

The question was asked during an interview for a job.

Question is taken from Carburizing in chapter Heat Treatment of Engineering Material & Metallurgy

Answer 1

Correct choice is (b) Dirty work surface

To elaborate: Liquid carburizing takes place due to the decomposition of sodium cyanide at the surface of the steel. It has major advantages that the temperature of the salt bath is uniform, the surface of work remains cleans, and that the temperature can be accurately controlled by pyrometers. It also has the disadvantage that the salt pots require batch processing and the cost of carburizing salt is high.