Temper and temper quench question

[SVanderkolff]

I am in the process of making a lock back folder. The back spine will be 3/32" thick 440C with a built in spring. From what I have read I will need to heat treat the spine to 1900 and then air quench. Followed by a temper of 2 hours at 1100. First off does this sound right to get a spring temper for the back spine and secondly, what is the quench after tempering. If I am tempering at 1100 degrees F then should I take the spring out and air quench , should it be oil quenched or possibly allowed to cool really slowly by simply turning off the kiln and leaving the back in there. Also do I need to foil wrap the back spring at 1100 degrees F.
Thanks for the help.
Steve

 

[mete]

There shouldn't be any need for foil at 1100 F ,all you'll get is some discoloration. You don't want to slow cool from temper as unwanted reactions may occur.

 

[Stacy E. Apelt - Bladesmith]

From temper in the upper ranges on stainless steel, let it air cool to around 800F ( black heat) and then dunk in water to cool the rest of the way. For carbon steel, which is usually tempered between 350F and 500F, just dunk it in water right out of the oven.

While the change in structure in letting either slowly cool in air is small, there is a slight benefit to rapid cooling from temper.

Never oven cool from temper, especially from the upper temper range.