Help with HT

[Stanton Knives]

My oven is done and functional, I still cant figure if the controller is in C or F yet lol.

I've read the ht tutorial from Max Burnet.

Is there a decent step by step of heat treating for someone with an oven?

What sort of magnet/tool do you use for the non-magnetic test? Is it just a magnetic pick up tool that looks like a pen?

Thanks.

[AcridSaint]

Any magnet will do to see if the steel is non-magnetic, but you shouldn't need one if you're using a temperature controller. Can you tell us more about the steel you're using?

[pipecrafter]

What Cap said - you shouldn't need a magnet. Set your PID controller to the temp you want and let your oven come up to temp. Put the blade in the oven and give the oven time to come back up to temp (you'll see this on the PID as it rises back up). Depending on the steel you're treating you may need to let it soak for more than a few minutes. All that will be left is quench and temper.

[Stanton Knives]

The steel is o-1. Ok I was not understanding the soaking with controller method. Sounds good. Hows this sound? (based on something I found on the net)

Hardening:

Pre-heat slowly to 1200?F - 1250?F, then soak steel thoroughly. Increase heat more rapidly to quenching temperature of 1450?F-1500?F.

Hold steel at quenching temperature for one half hour per inch of greatest cross section.

Quench in oil-bath (Oil temperature should be 150?F).


Temper immediately after tool reaches 150?F after quenching. See chart for tempering temperatures. Steel required for general purposes are normally tempered at 350?F. Broaches and reamers are tempered between 390?F-450?F, coining and jewelry dies between 425?F-450?F. Large dies are tempered at 425?F-450?F for maximum shock resistance.

More questions:
How long is the tempering process?
Do I have to "normalize" the knife before heat treat?
Any type of surface protection?
How much oil? In a pan edge down or edge only or in bucket and dunk it?

[Doug Lester]

The oil temperature may be a little high, I usually start out at about 125 degree +/-. The higher your volume of quenchant, the less change there will be by plunging red hot steel into it. I usually have about 3 gallons in my turkey frier. You should deffinantly normalize you blades before quenching but it doesn't need to be done immediately before quenching, but I doubt that it would hurt to do do. I usually normalize x3 before I anneal my blades. Grinding could produce some stress in the blade so another annealing just before quenching might not hurt but I've never done it.

For tempering I use three two hour cycles allowing the blade to cool to near ambient temperature between. I have used a surface protectant the I got from Midwest Knifemakers Supply and I've heard of people just sprinkling the blade with borax. If you use the borax, get it off the blade after quenching because it will etch your blade.

Doug Lester

[WBE]

Normalize 3 times at 1325?, about 10 minutes each cycle, letting it air cool to ambient in between. Then ramp it up to 1485, soak at temp for 20 minutes. forget the per inch stuff. It takes temp + time to get everything into a good solution. Quench point down in a medium fast oil at 130?, moving the blade fore and aft. Remove when you are sure it is under 450?. If you get warp from the quench, you have about 5 minutes to hand straighten it wearing gloves or wrapping in a rag. Normalizing at 1325? will stress relieve it and make the grain as small as it will get. Canola, or mineral oil will work, Parks AAA is the best. You really should have decarb protection. PBC powder, or the liquid version is what I went to. Good stuff. Temper from 425? to 450?, 2, 2 hour tempers is plenty. If you forged the blade, there are extra steps to be taken.

[mete]

www.cashenblades.com/Info/Steel/O1.html
This is a good start. Preheat is not normally needed except for high Cr steels like A-2.The preheat recommendations are for larger x-sections.
O-1 has V normally so triple normalize for grain reduction isn't needed .The steel is supplied spheroidize annealed so if anything a 1200 F stress relief can be used after grinding , before HT.
Depend on instruments not magnets.
Temper is usually 2 hours and for O-1 2+2 is best.
Quench completely with agitation in at least 1 gallon of oil , usually at 130-140 F.

[Stanton Knives]

Excellent guys! Most appreciated.

Will get busy on this very soon!