440c and Foil = Meow!

silver_pilate

silver_pilate

Joined
Oct 30, 2002
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Out to the shop tonight, and I heat treated a blade for my sister's Birthday present. It's 440C and a slightly smaller version of the EDC knives I've been making a few of recently. It's 1/8" 440C with a 2&7/8" blade and 6&7/8" OAL. Finished out, it will have purpleheart handles and a little leather sheath.

This is the first I've been able to use my SS foil and quench plates. I cleaned the blade and inside foil with alcohol, placed a small wad/roll of toilet paper in at the butt end, and then double crimped the edges and hamered them flat. I let the oven run for a while at 1600 to get everything up to temperature, and then I placed the blade packet in. I ramped the oven up to 1870 degress and once everything equalized, soaked for 15 minutes at temp. After the soak, I pulled the packet and clamped it between my two 1"x6"x12" aluminum plates and directed a fan at the plates' edges. After everthing cooled to room temp, I took out the packet, cut it open and:

IMG_0006.jpg

(sorry, pic from my cell phone)

It's tempering in the oven at 400 right now. I've got to say, not using oil was a nice touch, and it came out clean and hard. The rainbow will quickly sand right off and no decarb to have to work through.

I gotta say I'm starting to like stainless more and more! The CPM154 I've been working with lately (no HT's yet) is also a pleasure to work with. Though slightly more difficult to grind than my O-1 (I think I'm just really used to O-1), it drills and sands much easier and has a great looking finish. I'm looking forward to using it more often. I've got a few blades ready to HT in the CPM154, and we'll see how they turn out.

Anyway, thanks for looking.

--nathan
 
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I agree, not grinding decarb is great. Blade looks great. I use A2 in place of O1, same steel with a little chrome which allows a air quench.
 
Nathan,one question on how you wraped your blades in the ss foil.
Do you just make a envelope with the foil or do you wrap it to wear there is no voids in any of the curved areas of the knife?
 
The packet ends up looking like a rectangle. I fold it over the spine, and then double fold the ends and edge of the packet. I managed to get it folded close up to the knife, as you want as little air in the packet as possible. The wad of toilet paper takes care of some of the O2. With as thick as the SS foil is, there isn't a good way I can think of to wrap it so there are no voids where the finger notch is and where the blade edge curves to the tip. And you don't want to create pin holes in the foil.

Any suggestions?

--nathan
 
is there a place that has ss foil at a reasonable price? seems pretty expensive for what it is.......
 
Nathan
Just my .02 but you should soak longer at temp. I soak all stainless for at least 35 min.
My cpm154 I soak at temp for 40 min. It takes that long for everything to get into solution.
Stan
 
Stan, I appreciate the advice. I plan on soaking my CP154 for 40 minutes or so, but from what I've read, I thought I'd be OK with the shorter soak with 440C. Most of the really long soak times you read for 440C are referring to thicker materials (1"+). With the thin stock used in blade craft and with 440C carbides being a large part chromium carbides (which, from what I understand dissolve more readily than some others), I've been lead to believe a shorter soak of 10 minutes or so would be adequate.

Of course, with my oven holding temps accurately, a longer soak shouldn't hurt anything, so I may do just that next time.

Any other thoughts on heat treating 440C? What do you think, should I soak it longer, or is 15 minutes enough?

--nathan
 
Steve, it can be pretty expensive for what it is, but it works like a charm. I got mine from Texas Knife Supply. For me, it beats the mess of a anti-scale coating, and the convenience for heat treating stainless steels, where very high temperatures and long soak times can play hell, is worth it to me.

--nathan
 
I also suggest grinding your blades post H/T especially folder blades. Everything comes to temp evenly and with the use of cooling plates ,everything cools evenly. It also helps keeping your blades flat. I cool my blades clamping them in the Kurt vise on my mill. I know the jaws are flat and I can put alot of pressure on my blade very quickly to help keep warpage to a minimum if any. Just a thought .
 
Nathan: Don't worry about the tiny bit of air in your foil packets-Just make sure the folds are well executed and you will be fine. Also, I'd suggest not putting anything combustible inside the packet.
Soaking for 30 or 40 minutes @ temp is no problem for stainless knife steels-People worry too much about oversoaking but if you have good temperature control over-soaking is certainly better than under-soaking.

Have fun heat treating-It's the most magical part of knifemaking.
 
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