Home Heat Treating O1 Steel

[682bear]

I'm working on a set of vise jaws... making them from O1 steel... I've never tried heat treating before. I have an O/A torch... I hope it still works, I haven't used it in a few years.

Any info, instructions, tips, tricks, etc. would be appreciated...

Thanks- Bear

 

[mattthemuppet2]

Make a little pile of bricks or the like to keep the heat on the part and keep a magnet on a stick handy. Heat it past bright red and test it with a magnet. If it doesn't stick, pick up the piece and drop it in a largish container of clean oil (any will do). If it does stick, heat it some more. My issue has always been getting the part hot enough, but you shouldn't have that issue with OA.

Once it's cooled down, stick it in the toaster oven at 350F or thereabouts for 1/2h or so to temper it back a bit. Others will chime in (hopefully) with a more precise temperature, but that'll do for the moment.

 

[T Bredehoft]

I use 400 deg (f) for an hour, but it ammounts to about the same thing. Try it both ways, (two different pieces) see what you like best.

 

[pontiac428]

Don't drop it in the quench, hold it with pliers and swirl it around until it cools. I made a planer blade for a friend out of O1 some time back and told him to bring me a quart of jack oil. Cheap and additive free. I've been re-using the quench ever since. Just do it outside...

 

[benmychree]

"Real" quenching oil is quite thin and has a high flash point, the low viscosity makes for high heat transfer, heavy oils do not, it has been noted that the oil should not be cold before quenching, but warm and not hot. If much quenching is to be done, the volume of oil should be large enough that the oil should not overheat. I like to bubble compressed air into the bottom of the quench tank to cause circulation of the oil, avoiding having to swirl the part around, which may cause distortion of the part.
0-1 should be heated to 1450 -1500 deg. F and quenched in oil and tempered to 350 - 500 deg. F for a Rc hardness of 62 -57; suggested tempering: cutting tools 300 - 350 deg F,solid dies and punches400 - 450 deg F, spring temper 750 - 800 deg F.
All this from my heat treating notebook from my days at Kaiser steel in Napa Ca. where I worked and did the heat treating back in the 1960s.

 

[benmychree]

The magnet trick above is adequate for temperature test for simple jobs where you do not have better means of temp. control; a enclosed furnace with a set point control is best, it allows the part to be "soaked" at heat for an extended period of time to develop the most complete structural conversion of the molecules for the best physical characteristics of the completed part. Same can be said for the tempering phase.

 

[SLK001]

Here's the proper procedure for O1.

 

[Parlo]

I would aim for around 57 Rc for this application. After hardening degrease the part and clean up one face. Lay the part on a piece of steel that is between two bricks and heat from underneath. This will heat the part slowly, once it turns brown, quench again.

 

[682bear]

There is a lot of good information here... thanks, everyone!

I'll have to see if I have enough acetylene left in my tank... if not, I'll have to make an investment... at the rate I've been using it, a full tank will last me the rest of my life!

-Bear

 

[BGHansen]

The torch will work fine, I've done it many times with good results. I arrange some fire brick as mentioned above into a cavity to try to hold the heat in. For tempering, I use a Thermolyne hot plate, but toaster oven works too (maybe better). If you're going to do a lot of heat treating, I'd look at an electric muffle furnace. Last time I flame hardened 2 punches and dies it ate 25 psi out of my acetylene tank. My last fill to 300 psi cost about $100; 25 psi is worth around $8. My Thermolyne muffle furnace is 2000 W and takes about 30 minutes to heat up to 1600 F. That's $0.13 at our current electric rates to take the contents up to cherry red. Of course, my furnace cost around $200 off Craig's List which would have been 2 bottles of acetylene.

I also attached a temp chart for tempering steel. Got it someplace off the web.

Bruce