Anybody Got HT Specs for The New CPM 154

After final temper @ 500 F both blades test 58.5 - 59 HRc. Both blades are 3/16 inch thick. One is 7 3/4 OAL, the other 10 1/2 inch OAL. Both blades were deep cryo'ed minimum 16 hours. Both were austenitized @ 1950 F / 20 minutes and both were plate quenched to below hand warm and both were snap tempered 1 hour @ 300 F prior to immediately freezing upon cooling to room temp.. First temper was @ 545 F which tested 59.5 - 60 HRc.

Testing was performed on 120 grit flat tang surface.

RL
 
I've got to say that those numbers are a little strange. I'll be sending some of this steel to Paul in a couple weeks, but he'll likely be tempering mine where he tempers all my standard 154CM, 950F. That gives Rc61 on the regular steel. The low temper on 154CM that some makers favor is usually 400-450F. If you look at the temper charts for 154CM, hardness drops off between those two points. I favor the high point because I get a little more toughness at the expense of some corrosion resistance.

Since the new composition differs only by the addition of 0.2% Vanadium for grain refinement, I don't see any reason to change the protocol. I also get the same results with RWL-34 which is virtually identical to CPM-154.
 
From Crucible Service Centers own data sheet on 154CM, under Temper: "As with all martensitic stainless steels, tempering at 800 - 1100 F (425 - 600 C) will result in sensitization which causes a minor reduction in both corrosion resistance and toughness. We recommend that this tempering range be avoided."

RL
 
I never temper 154 CM that high and I don't leave it in that long either :confused:
I've found the longer you soak it,,
the harder it will be
and the higher the Temper temp has to be to bring it back
I'm Talking 154 CM
10 min at 1900 and 450 temper double draw..with cryo in between
I never saw the reason to waste the extra heat and time and chancing grain growth,
which is what I end up with, with the extra time in before quench.

with this new stuff if you don't get the Grain growth this will be a plus as I see it..JMHO
 
I know what they say Roger, but some have experience that differs from theirs. They're still kinda new at knifemaking... ;)

Paul Bos did a blind study a few years ago with four experienced knifemakers. All preferred the high temper blade for toughness. The only toughness complaints he heard about the steel were with the lower temper.
 
Jerry Hossom said:
I know what they say Roger, but some have experience that differs from theirs. They're still kinda new at knifemaking... ;)

Paul Bos did a blind study a few years ago with four experienced knifemakers. All preferred the high temper blade for toughness. The only toughness complaints he heard about the steel were with the lower temper.
Click to expand...

Jerry
toughness complaints ? as in braking or not holding an edge? or ??

also
most of the way I do my blade is the same way TKS does theirs
has anyone in your group? found a problem with Jim's blades with
I don't know how many year's now? Lance told me years ago the way they do it..
 
Toughness as in not chipping. I don't know anything about TKS HT service. The reason I use Paul is 1) he's been heat treating for about 40 years or more, 2) his equipment is the best I know of, 3) he does a minimum of two hardness checks on every blade to make sure the process is going properly as well as getting the right final answer, and 4) he worries as much about my blades as I do.
 
nor am I except that I am pleased with the way these two turned out and that my tempering range hit them just where the maker asked for (58 to 59).

RL
 
great Plug
Paul has about ten years on me.
if they have to be done by someone else and makers don't feel
their own work is up to par, Paul's the man for sure
But I believe others do a very fine job also.

if I hadn't been a tool and die maker years ago, doing I'm own heat treating
I'd probably be sending them out too. But I I'd feel a bit funny if I didn't do it myself now. I can say though I am learning all the time back then it was the high Carbon tool steels.
 
No, please stay. Its just that I default to vendor recommendations. I see nothing more I could add here of benefit but do hope the thread continues if there is a continued interest. It will be interesting to see if anyone else agrees that Crucible is wrong about their tempering recommendation.

RL
 
Roger,
Don't worry about Jerry and I. We've agreed to disagree and that's ok.
FWIW, I plan to do it the same way as what I sent and how you did it, Roger.
OK, I'm backing out of this one again :)
 
Roger, I wasn't questioning your numbers. You're giving your customer what he wants, and that's all that matters. I just didn't see how your blades came out two points lower than RJ's, using almost the same schedule. You tempered higher on the first temper, but it came down more at the second lower temper that was the same as his. Curious.

I don't do my own HT simply because with my blades I can't do it as well as Paul's atmospherically controlled ovens. I used to do my own and quit when I found his was better than mine. My tapered tangs and deep grinds don't give quench plates much to hold onto. Plus, when I started using Paul, quench plates weren't discussed anyway. Now that I am using his service, I don't want to mess with a good thing.

Besides that, Kit and I just like to pee on each others pants leg. :D
 
Jerry, I am not convinced a rapid air quench would have caused a difference. Only until very recently I strongly dissagreed with plate quenching beveled blades and for the very same reason you observe. After finally breaking down and giving it a fair chance I believe I have converted. So far, my experience with plate quenching beveled blades shows that the beveled areas cool quicker than I had experienced with my rapid air setup (a small vertical but crude wind tunnel). One outstanding thought is that the flat area must cool enough before the areas not contacting can cool by transmission through those flat areas in contact. That is something I still wonder about. For now at least I do like the blades always being completely straight.

As for the second temper causing a small drop in hardness, I expected and aimed for that. Although not knowing it would drop it enough to hit the aim point I knew I could repeat the temper if needed but that if I did the second temper too high I would be faced with repeating the entire heat treat.

RL
 
I taper my tangs out to the grind line, so the only flat I have is above the grind and there's not a lot of that. Paul's forced air cooling is a cold nitrogen blast into an evacuated chamber after he pumps out the argon. It's fast. In any case, I'm not likely to change now, and gave my heat treating oven to someone who wanted to do it themselves.
 
interesting thread,, I agree with Roger the input is good...
the first atmospheric oven I heat treated in was in .. I think 1977 .
big one about 25 feet long, and a 30 foot conveyer tempering oven
a very interesting set up, My dad set it up when it was bought new for the factory..

I finish grind after anyway so I'm not pursuing anything over what a clean
foil warp finish can give me right now,
as with the way kit does it, from
a bar after the fact, there is no reason (< edited to add IMHO) to go for a atmospheric heat treating other than that's the way Paul does it. of course the plus would be cooling with the Nitrogen for Paul..
I'm not saying it's a wrong or right way to go we have guys there that
want to do it them selves so it makes for a thread that there is more than one way to skin a cat. ;)

man you guys must have some wet pant legs :D
 
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