Heat treating SS without using sleve or gas

Jim McGuinn

Jim McGuinn

Joined
Sep 8, 2013
Messages
385
Will I tried it, I cutout 2 blanks one 440C and the other CPM154CM drilled all the holes but no grinding on the bevels. I HT them as usual but didn't use ane foil or argon to protect from oxygen. Plate quenched them between aluminum plates and tempered. Grinding off the scale wss no problem, grinding bevels was slower. But sometimes this is a good thing. I posted 3 YouTube videos under heading "Heat treating CMP 154 CM"

Tell me what you think,
 
At 1900 F you create large amounts of scale and below that decarburizatio ! Did you grind off the decarb ? What about soak time ? How long ? Argon , vacuum or foil is there to minimize the problems !!! CPM deserves better treatment than that to get the best from a high tech steel !!!
 
Jim McGuinn said:
[................
Tell me what you think,
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I think you did something that anyone you asked would tell you not to do. There are good reasons they would tell you not to do that. Finish the knives if you wish, but there is no doubt you damaged the steel.

As mete asked, How long was the soak time?
 
On the cpm 154cm I took it to 1400 for 10 min. Then up to 1980 and held it for 20min. This was a blank that was about.180" it was then flat ground full length on both sides. In removing the scale and flat grinding the blank i removed .021"Which I would have done even if I had used foil. Below I have listed some reasons for doing it this way.

1. I hate foil, sharp edges, cost, and I was out of it.

2. I wanted to quench between aluminum plates. Where the ends of the foil are folded over keeps me from getting full contact with plates.

3. Grinding prior to HT does the same thing where edge of blade does not contact cooling plates.

4. I do a tappered tang so most all of the blank is going to be ground anyway
 
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Here are links to the videos.

[video=youtube;zXD0wsvdpHU]Https://www.youtube.com/watch?v=zXD0wsvdpHU&feature=youtube_gdata_player[/video]


[video=youtube;ux1tzhUpDy0]https://www.youtube.com/watch?v=ux1tzhUpDy0&feature=youtube_gdata_player[/video]

[video=youtube;LKAMHGeqGKM]https://www.youtube.com/watch?v=LKAMHGeqGKM&feature=youtube_gdata_player[/video]
 
Many respected makers do all their grinding post-HT, especially when doing full flat grinds and/or tapered tangs. Nothing wrong with that.

I don't know any who buy premium steel and simply refuse to protect it from decarb. Oxygen-free furnaces and tool wrap were developed for very important reasons, as mete and Stacy can explain better than I.

Jim McGuinn said:
Tell me what you think
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I think if I was that concerned about a couple dollars' worth of foil, I would stick with 1084 and quench it in canola oil.
 
I guess thats the part I'm not understanding. Is it hurting the steel or is it just that the scale has to be removed? I can see that it would be a problem if the blade had been ground all the way.

But if this damages the steel beyond the outer surface then I definitely don't want to do it again.

In that case I'll be looking into a paragon kiln with the argon injection.
Its not the cost of the SS foil so much as the other things I mentioned.
 
To get the best out those steels you need a sub-zero quench as well.
That's why I outsource my HT, those firms do nothing else all day then HT and have equiptment that a single knifemaker can not afford.
Personaly i don't like the idea of a top steel with a mediocre HT and thus not the best preformance.
 
In my opinion you are fine. Many grind the bevels to say .030 before ht and I would be concerned about decarb at those thicknesses. One thing to note is that I would grind some of the edge profile down because although you grind away the decarb on the sides of the bevel, there will be some going into the edge.
 
JMJones said:
In my opinion you are fine. Many grind the bevels to say .030 before ht and I would be concerned about decarb at those thicknesses. One thing to note is that I would grind some of the edge profile down because although you grind away the decarb on the sides of the bevel, there will be some going into the edge.
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Yes I agree and did that, the only spot I couldn't grind was the jimping I'll hit the high points lightly and leave the bottoms for anice contrast. I have had other cpm154cm blades ht the conventional way tested and they were between 58 and 58.5 rc
 
I had the opportunity to have this blade tested the other day and it checked in at 59 RH. A half to one point above the other blades I had used the foil on.:)
 
Isn't it CPM154, not CPM 154cm? I don't care personally, but a few people made a stink about makers that incorrectly identify the steel a while back. Buyers cited that they wouldn't buy a knife from a maker that got the designation incorrect.

I haven't researched this myself (again, it matters little to me), but I know it bothers some buyers.
 
Strigamort said:
Isn't it CPM154, not CPM 154cm? I don't care personally, but a few people made a stink about makers that incorrectly identify the steel a while back. Buyers cited that they wouldn't buy a knife from a maker that got the designation incorrect.

I haven't researched this myself (again, it matters little to me), but I know it bothers some buyers.
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Technically that's correct, but Aldo's website lists it that way so they are quoting directly from the source they bought it from.


An extra CM seems like a funny thing for a buyer to hang up on.
 
ATS-34 is a Hitachi stainless knife steel The same steel made in the USA is called 154CM ( Crucible Materials). CPM-154 is their particle metallurgy version of that steel. CPM stands for Crucible Particle Metallurgy. So CPM-154CM would be very redundant.....it is CPM-154.
 
154CM ?? would you believe Climax Molybdenum ? They developed the alloy then sold it to Crucible.
 
I don't want to go back and search for it right now, but I think they claim they do a couple of extra things to it and add the "CM" to distinguish it.
 
bladsmth said:
ATS-34 is a Hitachi stainless knife steel The same steel made in the USA is called 154CM ( Crucible Materials). CPM-154 is their particle metallurgy version of that steel. CPM stands for Crucible Particle Metallurgy. So CPM-154CM would be very redundant.....it is CPM-154.
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Several years ago Devin Thomas told me the history of 154CM. I could not remember the specifics so I sent him an e-mail. Here is his response:

154CM means 15% chrome and 4% moly. 15-4 C M = 154CM. The alloy is now 14-4 but originally it had a little more chrome. Ed Severson told me once that the original grade was developed by Climax Metallurgical and that the CM was meant to represent that also.​

We call the alloy CPM 154 or CPM154.

Chuck
 
It's Climax Molybdenum !! I know , only a metallurgist can spell it and pronounce it ! LOL Even the abreviation is Moly not Molly. One of the wives heard us discussing Moly thinking we were talking about a hot new secretary named Molly ! LOL
 
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