There are some steels that get to high hardnesses above 900° F, but you would have to know what specific alloy your trunnion was made of, and it is unlikely expensive steels that temper in that range would be used for gun parts. Most steel used in guns are low alloy or tool steels like 4140 or O1.
I can't see how nitriding an entire HK rifle upper could possibly be safe.
Last edited by Handy; 07-26-2017 at 06:50 PM.
So unless you're suggesting that all HK trunnions are made of stainless steel or some oddball tool steel, it is fair to say that we are talking about some common grade of oil quenching steel that is NOT going to end up much above 40 HRC if re-tempered at over 900° F. Especially if it is from a 40 year old surplus rifle or a company supply parts to make $600 clones.
Instead of directing your hard ass towards me, how about you bring brethren armament back to this thread. They actually got some guns nitrided.
The RCM trunnions are 9310, and I am waiting to hear back with the heat treat spec. It might only be case hardened.
Hopefully Bretheren will reply and explain how it worked and how it came out-maybe pics?
3k rounds without any issues. I am not a metallurgist. We tried it out, and it turned out great.
I can get pics up in a bit.
I am also not a metallurgist. But I don't sell metal guns that I have re-heat treated in a 1000° tank of molten salt as if I have a staff metallurgist.
For anyone wondering what happens to steel that is only surface hardened with nitriding: