First SS knife. Need help with HT

[trclements]

So I have made a few knives out of 1095 and I really like the steel but I am make a few knives for people now and they want stainless steel. I was looking into using 440C because of the price but after reading some more on here about how it can be considered a lower quality knife steel. I am now looking at 154-CM or ATS-34. I am guessing that the 154-CM is better based on the price. What are the advantage/disadvantages to each? Which would be a better choice for a first SS try? Is there one that you would recommend over these for about the same price?

Now the big question... How do I heat treat Stainless Steel. I have an electric oven that I can control the temperature very easily with but from what I have read here you don't quench it in oil like 1095 but you cool it between two aluminum plates? If someone could give me a simple HT recipe for one of these SS. From what I understand you can polish the steel before the HT then wrap it in SS foil to keep it from getting all the scale on it during heating. Then you heat it up and soak it at the specific temp for that steel and then take it out and place it between the cool aluminum plates and step on it, then remove the foil and replace it between the plates to continue cooling. Followed by tempering. What size of aluminum plates do I need if my blades will be at the most 2" wide by 10" long? Will any alloy of aluminum work(cheapest) or does that really matter. Is there something cheaper than aluminum such as steel that you could use for cooling plates? Thanks for any help in advance.

Trevor

Also feel free to post a link to another thread that could help me out as well.

[mete]

The plates should be at least 3/4" thick, 1" is better, any Al alloy would work. At least 1" beyond the blade dimensions , for you 4x12". The blade ,in the foil, is clamped between the plates and permitted to cool to room temperature. Then the blade is tempered. 154CM and ATS-34 are equivalent and are improvements over 440C.Recipies for those can be found in a search.

[trclements]

How do you make the SS foil envelope? How many layers of foil do you want on the outside of the knife? I have read that some people put pieces of paper inside to burn up and use the remaining oxygen that is in the pouch? About how big of a piece of foil do you need for an average sized knife to seal it up well?

Thanks for the help

[Don Robinson]

One piece of foil folded over once, roll over and crease the edges twice, along the side and both ends.

Use a wooden mallet to make sharp creases.

It's not necessary to put anything else in the package.

By the way, I prefer two heavy, flat steel plates to aluminum. Steel pulls out the heat fast and the weight of the top plate keeps the blades straight.

[SBuzek]

For ats34 or 154cm,Here is what I do
Wrap in foil
Put in cold kiln and bring to 1200 deg hold 15 min.
Bring to 1600 deg and hold for 15 min
Bring to 1950 and hold for 40 min.
Quench between alum.plates
Into cryo overnite
Temper 2 times at 400 deg.
I get 60-61 Rc doing this.
Stan

[trclements]

what is the easiest way to do cryo with dry ice. I read about doing it with a dewar and liquid nitrogen but that isn't avaliable to me. Do you just put the blade in between two chucks of dry ice for a few hours after you quench them before you temper the blades?

Trevor

[mete]

LN gives you -300 F and dry ice gives you -100 F .Many use dry ice in a liquid like acetone.
Cryo is done immediately after quench [it's really part of the quench ] and temper immediately after cryo.

[trclements]

How long would you suggest leaving it in the dry ice/acetone for?

[Don Robinson]

I've seen 4 hrs. recommended. I leave it overnight. No acetone, just between two pieces of dry ice inside a styrofoam picnic box.