STRESS RELIEF WELDING
STRESS RELIEF BY SKILLED WELDING TECHNICIANS
Our Own Steel Treating Division
At MPD Welding Grand Rapids Inc, our steel treatment division, Fire-Kote, specializes in the stress relieving of steel and other metals.
What Is Stress Relieving In Welding And Why Is It Performed
Stress-relieving is a form of post-weld heat treatment. During the thermal stress relieving process, a material is heated to a specific temperature for a specific amount of time to reduce or eliminate residual stress.
The stress relief process after welding is very important. Stress relieving treatments can reduce distortion and high stresses from welding that can affect service performance. The presence of residual stresses can lead to stress-corrosion cracking near welds and in regions of components that have been cold strained during processing.
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Residual Stresses
When the base metal that is adjacent to the weld is unable to move, the weld will move. The restrained pieces will end up pulling from both sides causing stress and strain, eventually tearing the weld. When a weld is under a constant tensile load, this is called residual stress and can cause premature failure of products, reduce the load capacity, and speed up both fatigue and creep damage.
Various manufacturing processes such as forming, machining, grinding, heating, and plating leave their characteristic residual stress pattern implanted in the steel. Without the thermal stress relief process, these residual stresses can lead to undesirable dimensional changes during the production process as well.
How To Remove Residual Stress
We use a stress relief heat treatment process where metal is heated uniformly to its stress-relieving temperature allowing the internal stress to be lowered. The temperature for the stress relief heat treatment of weldments varies depending on the metal part in question. The temperature must be below the materials transformation temperature.
For ferrous metals, the temperature is around 1350 degrees, but for most steels, the metal stress relieving process temperature will be around 1100-1200 degrees Fahrenheit. To perform perfect stress relief for stress-free steel, the weld must be allowed to cool to room temperature before the heat-treating process. Failure to do so will result in the residual stresses that were trying to be avoided in the first place.
Summary
Stress-relieving is a common heat treatment used widely throughout the welding industry. Stress-relieving tool steels and molds before, during, and after the production of the mold will help prevent unwanted stress and cracks that can eventually lead to bad parts and downtime in the production process.
Our Steel Stress Relieving Services Include:
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Reduce distortion and high stresses caused by welding
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Reduce cracking in/near welds
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Stress relieve tool steels and molds
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Prevent unwanted stress and cracks
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Avoid bad parts and downtime
