Heat
treating services include annealing, aging, quenching
and tempering to soften, harden, stress relieve, remove
contaminants or provide other material characteristics
to parts and components.
Objectives of Heat
Treatment
Heat Treatment is the controlled heating
and cooling of metals to alter their physical and mechanical
properties without changing the product shape. Heat
treatment is sometimes done inadvertently due to manufacturing
processes that either heat or cool the metal such as
welding or forming.
Heat Treatment is often associated with increasing
the strength of material, but it can also be used
to alter certain manufacturability objectives
such as improve machining, improve formability, restore
ductility after a cold working operation. Thus it is
a very enabling manufacturing process that can not only
help other manufacturing process, but can also improve
product performance by increasing strength or other
desirable characteristics.
Steels are particularly suitable for heat treatment,
since they respond well to heat treatment and the commercial
use of steels exceeds that of any other material. Steels
are heat treated for one of the following reasons:
1. Softening
2. Hardening
3. Material Modification
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Common
Heat Treatments

Softening: Softening is done
to reduce strength or hardness, remove residual
stresses, improve toughness, restore ductility, refine
grain size or change the electromagnetic properties
of the steel.
Restoring ductility or removing residual stresses is
a necessary operation when a large amount of cold working
is to be performed, such as in a cold-rolling operation
or wiredrawing.
Annealing
— full Process, spheroidizing, normalizing
and tempering — austempering,
martempering are the principal ways by which steel is
softened.
Hardening:
Hardening of steels is done to increase the strength
and wear properties. One of the pre-requisites
for hardening is sufficient carbon and alloy content.
If there is sufficient Carbon content then the steel
can be directly hardened. Otherwise
the surface of the part has to be Carbon enriched using
some diffusion treatment hardening
techniques.
Material
Modification: Heat treatment is used to modify
properties of materials in addition to hardening and
softening. These processes modify the behavior of the
steels in a beneficial manner to maximize service life,
e.g., stress relieving, or strength
properties, e.g., cryogenic treatment, or
some other desirable properties, e.g., spring
aging.
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