Heat treat

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buckaroo2219

Joined
Feb 13, 2013
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I have a question for you guys who use an oven to heat treat your blades. Do you put your blades in the oven at the beginning of the heat and let the oven reach the desired temp and then time the soak. Or let the oven ramp to the critical temp then put blades in and let temp come back up and start timing. I built my own oven and have not been able to find any definite info on this.
 
Let the oven stabilize at the proper temp prior to putting the blade in...then allow
time for the blade to come up to temp....THEN start timing your soak.
 
I think that's something you need to test for your individual oven and steel.

If I put A2 in once the oven is already warm, equalize and then soak then I get the blades out at 60.5HRC and they're very tough.

However, if I put the blades in when the kiln is cold and ramp at 1000ºF per hour, then soak the same as above, I get the blades out at 62.5HRC... and they're just as tough!

Several datasheets for A2 state that it should be ramped to temperature @ 400ºF/hr. The time the steel takes coming up to temperature definitely has an effect as the carbon and other elements will start diffusing through the steel before the austenitizing temperature is reached.

You should probably experiment with both ways and possibly different ramp speeds and see what happens.
 
Well, I have a question for Gough, for your O1 do you let it come to temp and put it in? Or do you put it in and let it come up to temp slowly? Any help would be great, thanks.
 
Everglade Blade said:
Well, I have a question for Gough, for your O1 do you let it come to temp and put it in? Or do you put it in and let it come up to temp slowly? Any help would be great, thanks.
Click to expand...

I would recommend putting it in and letting it come up to temp with the kiln, assuming that the steel is well protected from oxidation. However please note that I haven't experimented with O1 as much as I have with A2.

There's some threads detailing the testing that I did and the results here: http://www.bladeforums.com/forums/s...de-testing-results-summary-and-lessons-learnt

I haven't done too much detailed testing about slow ramps versus fast, but from what little I've done it seems that the slower ramps are better, ie: letting the steel come up to temp with the kiln (or even slowing down that process) will yield harder/tougher blades.

I definitely recommend trying some test pieces or test blades both way as different steels will react in different ways.
 
Thanks, I've been letting it come up slowly, with some really good results. I guess Ill stick to that. I'm just trying to get the best results.
 
Manufacturer recommends a 1250° preheat for 01, before ramping up to 1475°. I use 01 exclusively, and start it out cold to 1250° for an hour, then to 1400° for 15 minutes to allow the oven to catch up well. then on to 1475° for a 20 minute soak before quench. Before any of this, I have already given it a one hour stress relief at 1250° and air cooled. Usually the day before. I found this step reduces warp.
 
Thanks, I just tried something new, I slow heated to 1200 left for 2 hrs, then ramped to 1475 let soak for 15 min, then quench.
 
A 2 hour pre heat is not necessary. 30 minutes at temp is good enough. All you're doing in that step is shooting for a full and even temp in the steel, plus the side effect of the oven leveling out. A stress relief heat is longer, but one hour at temp is enough for that. It does need to air cool to get the benefit though. No real need for decarb protection in the stress relief, but when taking the blade to 1475° and soaking for a while, decarb and scale protection is very helpful when you get to the clean up later on. ATP-641 is cheap and works very well on 01.
 
Thanks for the information. I am using up the last of my 1095 and will be moving to 01 A2 and 440. I have used them before but always sent them out for HT. Building my oven was the most fun I had in awhile.
 
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