Heat treatment is the materials engineering technique of controllably heating and cooling a metal or alloy to alter its internal microstructure and thereby change its mechanical properties, such as hardness, strength, ductility or toughness, without changing its shape. Processes grouped under the term include annealing, quenching, tempering and normalizing, each following a different heating and cooling schedule to produce a particular balance of properties for a given application. Heat treatment has been practiced since ancient metalworking, when smiths learned that reheating and cooling iron and steel changed how well it held an edge, and it remains fundamental to modern manufacturing of everything from automotive components to cutting tools.
Facts
Core PrincipleThermal and metalworking processes used to alter the physical, and sometimes chemical, properties of a material 1 FAQs
Why is steel tempered after it is quenched?
Quenching leaves steel brittle; tempering trades some hardness for ductility.
Quenching, which rapidly cools steel from above its critical temperature, leaves it extremely hard but also brittle. Tempering is the usual next step: the steel is reheated to a point below its critical temperature, which lowers its hardness and raises its ductility while it keeps its martensitic structure. How much hardness is traded away depends on the tempering temperature and time, which are precisely controlled for that reason.
Connections
Associated With
Aluminum, Materials Many aluminum alloys are strengthened by solution heat treatment and aging.
Duralumin, Materials Duralumin gains its strength by age hardening after heat treatment.
In Field
Source Heat treating, Wikipedia
Sources
1. Heat treating, Wikipedia
Introduction
Heat treating (or heat treatment) is a group of industrial, thermal and metalworking processes used to alter the physical, and sometimes chemical properties of a material.
In Field: Materials Engineering, Lead section
Heat treating (or heat treatment) is a group of industrial, thermal and metalworking processes used to alter the physical, and sometimes chemical properties of a material.
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