# Stainless heat treat discoloration



## Seffers93 (Dec 19, 2020)

Hey guys,

Quick question about a piece of stainless. This is my first time working with stainless. AEB-L. Sent out for professional HT and came back with this discoloration. Just wanted to see if this is normal or if the steel got burnt

Thanks in advance!

Seth


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## VICTOR J CREAZZI (Dec 19, 2020)

Full discloser, I have zero experience heat treating stainless.

I do know that high alloy steels are wrapped in stainless foil (heat treating foil) to keep oxygen away. I suspect that the foil envelope had a small leak on this blade. Assuming that you can polish it out I would not expect any other damage.


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## Seffers93 (Dec 19, 2020)

VICTOR J CREAZZI said:


> Full discloser, I have zero experience heat treating stainless.
> 
> I do know that high alloy steels are wrapped in stainless foil (heat treating foil) to keep oxygen away. I suspect that the foil envelope had a small leak on this blade. Assuming that you can polish it out I would not expect any other damage.



Thanks for the insight! Much appreciated!


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## Dominick Maone (Dec 19, 2020)

It is normal. These are all AEB-L professionally heat treated. When they close the foil there is always a bit of oxygen left in the envelope that causes this. It is decarburization I believe. Sometimes they will put in baby powder or a piece of paper to help eat up the oxygen.


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## Seffers93 (Dec 20, 2020)

Dominick Maone said:


> View attachment 107058
> View attachment 107059
> View attachment 107060
> 
> It is normal. These are all AEB-L professionally heat treated. When they close the foil there is always a bit of oxygen left in the envelope that causes this. It is decarburization I believe. Sometimes they will put in baby powder or a piece of paper to help eat up the oxygen.



Good to know! Thank you!


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## inferno (Dec 20, 2020)

its oxidation. the color indicates the depth of the oxide. you get a similar results when tempering on open air. and you can judge the temp by the color. again the color indicates the depth of the oxide. the color is because of destructive and constructive optical interference. its on the order of nanometers.









Wave interference - Wikipedia







en.wikipedia.org


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## inferno (Dec 20, 2020)

moar








Thin-film interference - Wikipedia







en.wikipedia.org


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