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Why is stainless steel screw black?
Black stainless steel screws are caused by too much heat generated when cold heading or rolling teeth. Usually in the cross slot part. In the production process, we can realize the timely distribution of heat through the supply of lubricating oil, or the speed of the machine can be adjusted appropriately. In addition to technical reasons, it may be that the material problem of the stainless steel screw itself will also cause the surface of the stainless steel screw to be black.
