1095 Heat Treat

[John L]

I've found the temps for heat treat and temper...but what are the hold times, etc? If oven is room temp, do I put steel in and ramp up to temp and immediately quench..or..get oven up to temp, place steel inside for how long? How long on temper temp? Thanks

 

[mete]

You can preheat furnace ,get steel to furnace temp [check by color] hold 10 minutes. Quench immediately with quench tank right next to the furnace.Temper in preheated oven two hours.

 

[F. Allin Kahrl]

On the other hand, if you ramp the oven with the blade in it, you could pause for a few minutes and soak at 1200º, which helps stress relieve the steel before it gets to critical temperature. Since you'll be quenching it (very stressful), it's worthwhile to get every bit of stability you can. Just know that the longer the time it spends at high temperature, the more decarb you'll have to grind off.

 

[Stacy E. Apelt - Bladesmith]

It is usually better with 1095 to stress relieve separately from the final ramp.The long exposure would lead to excessive decarb.I stress relieve at 1300 for 5 minutes, take it out and set it on a fire brick,with another one on top.Ramp the oven to critical temp plus 5 degrees (you will loose the extra heat when you open the door).Place blade back in for 5 minutes,resetting the temp to the exact temp desired.Remove and quench in oil.Temper immediately for 2 hours.Cool and temper again for two more hours.

 

[rlinger]

Speaking for myself, I would never second guess anything Mete tells me. With that said, I have been basically heat treating steels by placing in cool furnace and moderately ramping to preheat. Upon equalized preheat I ramp as quickly as possible to austenitizing. If I had two furnaces I would have the other preheated to austenitizing temperature and place preheated steel into it immediately. (a preheat is a hold at a specified temperature for a specified time and done so prior to acheiving austenitizing.)

1095 is a steel that is particularly best placed into quench extremely quickly. I recommend several dry runs from furnace to quench before attempting your first 1095 heat treat.

As Mete says be sure to have the tempering oven preheated before quenching and place into temper immediately upon the steel reaching hand warm (no less than about 125 F but not higher than about 150 F).

The above has nothing to do with stress relief. As already outlined stress relieving is a seperate proceedure.

RL

 

[Stacy E. Apelt - Bladesmith]

Something that may need to be pointed out to the inexperienced smith is that when we say close to the oven,we don't mean underneath it.When the red hot steel hits the warm oil,there is a huge burst of oil vapor.It can ignite in the heat at the oven door and create a sudden flash.
I pre-heat in the oven and bring to non-mag in the forge ,mostly, now days.That way I can have a batch of blades at pre-heat temp.It is really fast to harden 5-6 blades this way.I tried using two ovens,but the temp drop after opening the doors was too much each time.It works fine for one blade,though.