Heat Treatment MCQ - Machinist(Set-1) with Answers

21) Which one of the following groups of quenching media is in order of their severity of the cooling rate, i.e. from slow to rapid cooling ?

Answer is:

forced air, oil, brine solution

22) Which one of the following processes is adopted to improve the internal structure of steel, which has been subjected to severe hammering ?

Answer is:

Normalizing

Which one of the following processes is adopted to improve the internal structure of steel, which has been subjected to severe hammering ?

23) Which one of the following structures of steel is obtained due to the drastic cooling from the austenite structure ?

Answer is:

Matensite

24) Which one of the following processes by which steel is heated to the required temperature and then cooled slowly in the furnace itself ?

Answer is:

Annealing

Explanation:

The annealing process is carried out by heating the steel above the critical range, soaking it for sufficient time to allow the necessary changes to occur, and cooling at a predetermined rate, usually very slowly, within the furnace.

25) What is the main purpose of annealing ?

Answer is:

To improve machinability

Explanation:

Purpose of Annealing process is to
- To soften the steel.
- To improve the machinability.
- To increase the ductility.
- To relieve the internal stresses.
- To refine the grain size and to prepare the steel for subsequent heat treatment process.