Posted by Valerie on November 24, 1997 at 18:14:38:

In Reply to: S-7 tool steel posted by Steve Bronstein on November 22, 1997 at 22:32:30:

: anybody know the proper heat treatment procedure.

Here are some responses that were posted on the artmetal list: Thanks to my cohorts on artmetal!

Steve, et al;

Here's the Carpenter Co. recommendations for tempering S7:

Hardening: Maintain furnace at a temperature of 1700/1750 degrees Fahrenheit. Let the tools

heat naturally to the furnace temperature, soak for 20 minutes plus 5 minutes

per inch of maximum thickness and quench.

Tempering: The best combination of hardness and toughness is obtained by

tempering at about 400F. This should give you about Rc 55-57. This tempering

temperature is suggested for cold-work applications. Tempering at 900/1000 is

usually desirable for hot-work applications. This will give you about 51-52

Rc.

Personally, I usually take it to a nice orange and let it air cool. Comes out

pretty hard at that. I have had some fracturing on the pounding end of

chisels but the edges hold up well. I have had problems getting it well

annealed. It's hard to keep it from air hardening. If you can obtain it in the annealed condition, then

just taking the edges or ends to orange and letting it air cool will provide

you with some pretty durable edges or whatever...

Don Plummer

Phoenixville, PA

S-7 is an air hardening steel. After forging, quench in air

and grind/polish to finished shape. Immediately draw to

500 degrees for two hours. You should have a very tough tool

with this. Don't wait to draw the temper or you may

wind up with cracks.

Good luck.-Andy V.

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