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Old September 12, 2019, 21:45   #43
gunplumber
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Quote:
Originally Posted by Jaxxas View Post
Don't know much about barrel steel but usually steel normalizes at around 1500 F and above........
YMMV
So, I know many things, but I also know what I don't know, and rarely confuse them.

So back in the day, when one could not get para bolt carriers, I made them by welding tubes to FAL bolt carriers machined flat. What I noticed was that the welding caused them to warp so the rails were no longer flat/parallel. But - in collaboration with a old-school cold war Polish Machinist friend of mine, I put in the oven at 500F for several hours and they "relaxed" to within .003" of where the started.

So while I don't profess to have any intuitive understanding, I have best practices recommendations that manifested as beneficial dimensional changes in the finished product.

Also, back in my nickel plating days, parts were baked afterwards starting at 500F and gradually reducing (I have a chart somewhere) to gas off excess hydrogen.

It seems to me that 1500 F would be beyond cherry red, so I'm trying to see the point in it.

Again, not a metallurgy guy. But I read stuff. Isn't most post heat treat tempering done around 700F?
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