View Single Post
 
Old 03-23-2017, 06:10 AM
steelslaver's Avatar
steelslaver steelslaver is online now
US Veteran
 
Join Date: Oct 2013
Location: Central Montana
Posts: 13,625
Likes: 12,742
Liked 39,091 Times in 9,966 Posts
Default

Very true
Those colors and temperatures and colors do run pretty true for tempering steel like 1095 and W2 the most common older plain high carbon tool steels in a regular atmosphere.

For hardening the color is a red shade that can be detected in low light by the well trained. Another interesting fact about heat treating is that all steels become austenitic at about 1425 f and a magnet will no longer tick to them. This is just bellow the proper temperature for simple carbon steels to be quenched from. In the days before pyrometers and well controlled ovens these methods were often used.

Now days a electronic device known as a PID will allow you to control an electric oven to within 1 degree, even gas heated ovens can be controlled with them using a solenoid valve to control the gas flow. This allows for much more controlled and precise HT. Plus a lot of precision HT is now done in an controlled atmosphere with no oxygen to react with the carbon. If O2 is present at higher temps there will be a thin soft layer on the part, lacking carbon, after quench that needs to be removed to get to the harden steel. Kind of the opposite of color case hardening where the part is buried in a carbon rich material, heated andd allowed to soak and become carbon rich.

Many modern stainless steels need temps above 1800 and some as high as 2050f to properly harden. plus tempering into the 800f range. Most of the parts on a revolver even a non stainless one are relatively soft and I suspect tempered to somewhere near 800f. For hard wear surfaces like sears around 400f would give an Rockwell C of around 60 with 1095. 450 f (RC 58) less apt to chip an edge for maybe the bolt and hand? With something like 4140 or 4150 the RC numbers would be lower because of the lower carbon content. I would love to see S&W heat treat and steel specs.

Last edited by steelslaver; 03-23-2017 at 06:28 AM.
Reply With Quote
The Following User Likes This Post: