Is over heating before hardening and tempering an issue?

[deermaster]

When I am shaping, and grinding the bevels before heat treat, is over heating an issue? I know after the temper, when finish grinding and polishing, over heat will ruin it, but won't the straw and blue color I get while rough shaping be canceled out by the red hot it becomes for hardening?

 

[Nathan the Machinist]

Yes, that's right, you should be fine. Overheating while grinding can lead to stress that contribute to warping during HT, but not just drawing straw and blue. I think you gotta get it glowing red to create issues.

 

[james terrio]

I've been told by my HT guy and several makers here that's it's fairly difficult to really screw up your steel by grinding heat pre-HT, and (depending on steel type) the ramp-up to austenizing temp and subsequent soak will usually even everything out. If you're really concerned, you could do a normalizing cycle before HT to be sure.

As stock-removal makers, what we think of as aggressive grinding, "high" heat and stresses doesn't hold a candle to what forgers put their steel through. Makers who forge routinely do a normalizing cycle or two before hardening.

 

[jonnymac44]

Good point James:thumbup: