I am reviewing parts that were heat treated by a new heat treat vendor. I am seeing a thin (generally less than 0.001"), irregular layer on the surface of many of the parts. The layer appears to contain porosity and oxide particles. I have attached some images showing the surface layer. I am wondering if anyone has an idea as to what could cause this? Could it be a scale layer that was partially deoxidized in the heat treat atmosphere?
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Kenneth Kirby
Senior Project Engineer
Snap-on, Inc.
Kenosha WI
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