Letter 9074

Avoiding blackening during stainless steel welding 

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What is the best way to avoid blackening of stainless steel surface during welding?

Vish.S
Fortuna Associates - Bangalore, India

Carbide precipitation occurs when stainless steel is heated to 1600 degrees. That is the separation of the chrome from the ferrite grains. In the normal welding process the process reverses upon quenching. If the metal cools too slowly the process will not reverse and the stainless will turn black. It will also rust. Try a lower welding temperature or faster travel speed or both.

John Rendleman
- Grand Tower, Illinois, U.S.A.

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