will this work for heat treating 440c?

[A.W.Stovall]

440C Stainless -

Preheat thoroughly at 1400/1500ºF and hold for 30 minutes.

Raise heat to 1950º F and hold for one hour.

Air quench at room temperature. Subzero freeze at 100º below 0.

Tempering: Temper at 400ºF for one hour, two times

without the sub zero or does someone have a better recipe
Thanks Anthony

 

[A.W.Stovall]

I used the search and found the info

 

[SBuzek]

Anthony
I go to 1250 hold 15 min,1650 hold 15 min,1940 hold for 40 min,plate quench,into cryo,temper 375 x 2 hours twice.
cryo is not necessary but 440-c really likes it.
Stan

 

[A.W.Stovall]

Thanks Stan how much is involved in setting up for cryo?

 

[SBuzek]

I bought a dewar and use liquid nitrogen but you can do it with dry ice and alcohol.
Get a cooler big enough for your knife to fit in.get a couple of pounds of dry ice,crush it up and mix in alcohol to make a slurry.
leave the knife in till the dry ice evaporates.
Stan

 

[A.W.Stovall]

I may have to try the dryice method well my first blade ever heat treated by me is tempering at this time

 

[A.W.Stovall]

when you said 375 twice , do iI let it get to room temp after the first 2 hrs then do it again?

 

[A.W.Stovall]

What type of alcohol rubbing, denatured?

 

[SBuzek]

Yes let it come to room temp between tempers,cheap rubbing,not good drinking.
Stan

 

[A.W.Stovall]

Definetly gonna have to buy some of that high temp foil its a good thing I left a lot of metal on it.

 

[Delbert Ealy]

You should temper once before cryo, then after.
Thanks

 

[JDW]

I think 1950 is a little high, and would promote grain growth, whitch in turn leads to a brittle blade. Latrobe steel says 1850-1900. I been using 1880 for 30 minutes.
Dale