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 Hardening
and Tempering |
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| By hardening a heat-treatment is meant, in
which steel is rapidly cooled down from the austenite stage (a temperature
of over 723° Centigrade) in order to prevent the
occurrence of the pearlite and ferrite stages. The result is a
martensitic structure, which is
characterized by a greater degree of hardness. The hardening process is followed by that of drawning or low temperature tempering, which is intended to restore to the steel a certain degree of toughness. This technique is used for precision components in high-accuracy engineering, for tools for both hot- and cold-work, and for other highly stressed components such as knives, scissors, saws, punching and cutting tools, connecting rods, etc. In the course of hardening and tempering the hardening is followed by an annealing at higher temperatures (up to 700° Centigrade.). The purpose of the heat-treatment is to endow the steel with as high a solidity as possible while maintaining an equally high ductility. A heat treatment is especially recommended in those cases where the components are subject to the influence of abruptly acting forces or the safety components must resist strong deformation. |
All
heat-treatment depends for its success above all on a
uniform heating of the component at the prescribed
temperature, a faultless quenching, and a uniform and
exact tempering.
Hardening furnace charge shortly before immersion in the oil bath |
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Web-Design & Translation: Zeres GmbH, Bochum (Germany) Copyright © 1997 Zeres GmbH, Bochum (Germany) |
