Heat Treatment


Heat treatment of steels

Heat treatment is a series of operations in the course of which a solid material is totally or partially exposed to themal cycles to bring about a change in its properties and/or structure.  The chemical composition of the material may possibly be modified during these operations.

Most of the steels we supplied are in the soft annealed conditions which require hardening and tempering processes after machining in the shops.  The hardening temperatures, the protective atmospheres, and the types of quenching media are normally specified in the technical brochures of the respective steel grades, while the tempering process is indicated in their respective tempering charts.  Stress relieving is also a form of heat treatment; it is carried out to relieve stresses accumulated in the workpieces after conventional machining, and also after electrical discharged machining (sink or wire EDM).

Currently, our heat treatment service is provided via competent commercial heat treatment companies.

When tempering is carried out on highly alloyed materials, it is recommended they be tempered 3 times, with the 3rd temper acting also as a stress relieving process.  The tempering temperatures for these materials should also be on the high side.  In tempering martensitic stainless steels, if good corrosion resistance is of priority, they are normally tempered using lower temperatures; however, if better toughness is desired, then higher temperatures are used for the tempering process.  Temperatures near and at "secondary hardening peaks" should be avoided in tempering.  If the workpieces require good dimensional stability in operations, cryogenic or subzero treatments are recommended.

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