Stress Relieving
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Stress Relieving is a process in which parts are reheated to allow residual stresses from machining, forming, or prior heat treat processes to redistribute to improve dimensional stability and stress state.
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Industries
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Related Processes
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Common Alloys
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TMT Equipment/Variations
A standard stress relieving process will involve heating a part and holding it below the critical temperature and then slowly cooling it. Care must be taken for hardened materials to not exceed the original tempering temperature which would decrease the strength. Controlled ramp rates and thermocouple driven control can be used when required. Care must be taken when stress relieving austenitic stainless steels to avoid the sensitization range which will decrease corrosion properties. Parts can be stress relieved in air or vacuum atmospheres. |
Applications
- During machining stresses are introduced via local deformation due to the cutting process. More aggressive feed rates can increase these stresses. Other operations that introduce thermal gradients into the part or shaping operations (e.g. bending, swaging) also can introduce stresses. Stress relieving can help improve dimensional stability in subsequent machining operations, field use, and heat treat operations.
- See Post Weld Heat Treat for more details on stress relieving welds.
- During the creation of the raw material significant stresses are introduced as the material solidifies and cools. As a part is machined these stresses can be released and the part will deform. Stress relieving will help reduce this effect.
- Low temperature stress relieving can be performed for high strength parts.
- A low temperature stress relief type process is used for reducing hydrogen embrittlement after plating.
Associated Specs/Standards
- AMS 2759/11
- ASTM A106, B850
- MIL 1684
What To Consider When Specifying
- Material
- Heat Treat Condition
- Furnace Atmosphere
- Specification (if required)
Have more technical questions? Contact a TMT engineer here.