Question

Which of the following is a characteristic of hot rolling?

(a) Refines grain structure

(b) Economic

(c) Slow speed

(d) Uniform size

I have been asked this question in examination.

This intriguing question originated from Cryogenics, Hot and Cold Working of Metals in section Mechanical Working Processes & Phase Transformations of Engineering Material & Metallurgy

Answer 1

Correct answer is (c) Slow speed

To elaborate: Hot rolling is carried out at temperatures above 0.7 Tm. It is stopped about 100-200oC above the critical temperature to prevent strain hardening. This process has a high speed of rolling, is economic, refines the coarse grain, and produces uniformity in the size of products.