Stress relieving is a special heat treating process used for the purpose of maintaining the specified characteristics and dimensions of your components.

At Morgan Performance, we can machine any item to any specs. The process of machining and cutting can naturally induce stress on a material. If uncontrolled, these stresses can sometimes cause the characteristics or dimensions of the machined component to change beyond and acceptable amount.

Stress Relieving Maintains Integrity

Sometimes, cracking can even occur when the parts are clamped during service. Additionally, stress can change hole locations, causing them to go out of tolerance. The bigger and more complex the part, the more the stresses. Stress relieving is often used to minimize these stresses and the risks of dimension changes.

We offer stress relieving — and other heat treating services — to ensure your parts and components provide the safety, longevity, and performance you expect. Parts most likely to need stress relieving:

  • Large and complex weldments
  • Castings with a lot of machining
  • Parts with tight dimensional tolerances
  • Machined parts that have had a lot of stock removal performed

Call 281-370-2465 or contact us online to discuss your project and get a quote. 

The Stress Relieving Process

Stress relieving is done by heating the parts in a furnace to a temperature roughly 650 ºC (1202 ºF) for either an hour or until the whole part reaches that temperature. This temperature is about 75 ºC (165 ºF) below the transformation temperature of steel, which is about 727 ºC (1340 ºF).

This exposure eliminates more than 90% of the internal stresses. To stress relive alloy steels, the temperature must be increased. Once removed from the furnace, the parts air cool in still air.

For rough machining, stress relieving is generally done afterwards, but for final finishing such as polishing or grinding, it is done before.

Stress Relieving Facts:

  • Stress relieving can make welded structures tension free.
  • Stress relieving does not change a material’s structure, nor does it significantly affect its hardness.
  • To stress relieve hardened and tempered parts, and to avoid an impact on their hardness, they must be treated around 50°C below the temperature used for previous tempering.
  • Stress relieving before nitrocarburising should be done at a temperature greater than 600°C.
  • Stainless steels normally need a high temperature solution heat treatment.
  • Stress relieving can be performed in a furnace with protective gas if necessary to protect surfaces from oxidation. In extreme conditions vacuum furnaces may be used.
  • Depending on the alloy, the temperature for stress relieving brass components is 250  500°C, and for copper parts is 150 - 275°C.