Heat Treating S7 Dies

Jonathans

Jonathans

Joined
Jan 9, 2008
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I'm working on a set of S7 dies for my air hammer. They are 3.75" square and 3" thick each.
I found some heat treating information from Cincinnati Steel that lays out oil quenching temps
That achieve Rockwell C hardness from 52 (1550) to 62 (1950). A lot of guys do not harden their dies, but then state that they didn't get better service from the tool steel then mild steel. I want to harden mine, but have concerns as to how hard they should be, optimally. Can anyone with commercially made dies tell me what they are hardened to?

The data I have also states that for cold work, temper at 400 degrees. For hot work, temper one hour per inch of thickness at 1000 degrees. Does that sound right?
 
Edited for clarity;



I am not aware of those austenitizing temperatures being used for S7.

For tempering, use lower range temps for things you want to be hard, and upper temper range for things you want tough. Dies need toughness.
 
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Stacey,
Thanks for that. So for the HT, do you recommend 1550 with a rc target of 52, or 1950 with a rc target of 62?
 
S7 austenitizes at 1750F with a 60 minute soak for die thickness. Temper twice for 2-3 hours each cycle at 1000F for a Rc50-51 hardness.

I am not aware of any HT that uses 1550 or 1950 for S7. I amended my earlier post, as I was only referring to the temper ranges.
 
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