Consider these heat treatment processes for a high-grade steel fi
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Consider these heat treatment processes for a high-grade steel file.
1. Tempering
2. Annealing
3. Hardening
4. Casting
Which of these is most suited for production of high grade steel file?
A. Only 1 and 2
B. Only 3
C. Only 1 and 3
D. Only 4
Please scroll down to see the correct answer and solution guide.
Right Answer is: C
SOLUTION
Explanation:
Tempering
- Tempering is a heat treatment process in which the hardness of a hardened alloy is reduced by the appropriate heat treatment process.
- For example, steel hardened by the formation of martensite formation can be tempered.
- Tempering is a heat-treatment process consisting of reheating the hardened steel to a temperature below 400°C, followed by cooling.
Purpose of tempering the steel
Steel in its hardened condition is generally too brittle to be used for certain functions. Therefore, it is tempered. The aims of tempering are:
- to relieve the internal stresses
- to regulate the hardness and toughness
- to decrease the brittleness
- to restore some ductility
- to induce shock resistance
Hardening
- Case hardening is a method used to harden the outer surface of low-carbon steel while leaving the center or core soft and ductile.
- Case hardening involves heating the metal to its critical temperature in some carbonaceous material. The following methods are commonly used:
- Carburizing
- Cyaniding
- Nitriding
- Induction Hardening
- Flame hardening
- Hardening is a heat treatment process in which steel is heated to 30 – 50° above the critical range.
- Soaking time is allowed to enable the steel to obtain a uniform temperature throughout its cross-section. Then the steel is rapidly cooled through a cooling medium.
- Hardening increase the brittleness in the metal.