Advise needed on heat treating M4

flatblackcapo

flatblackcapo

Joined
Mar 25, 2012
Messages
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I am thinking about using M4 . Can anyone who has worked with M4 share some knowledge of HT recipe and good place to buy M4 in the U.S. ? I have a Evenheat KO but no LN. Thank you.
 
I just made several Kwaikens with M4. You can get info on heat treating at alpha knife supply and buy it there as well
 
AVigil said:
I just made several Kwaikens with M4. You can get info on heat treating at alpha knife supply and buy it there as well
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Thank you, sir.
Would you say that LN is necessary to get a good working ( ranch work ) blade?
I should add that the knife I want to make will have a max blade length of 4.5"
 
That's like building a high compression engine and running it on 87 octane. It'll drive you around. Mashing the go pedal might even be faster than other cars around you. But it won't perform like it could.
 
Cryo or liquid nitrogen treatments are less necessary when using the upper temper as is recommended with high speed steels like M4.
 
Thanks to all of you for your replies.

kuraki said:
That's like building a high compression engine and running it on 87 octane. It'll drive you around. Mashing the go pedal might even be faster than other cars around you. But it won't perform like it could.
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Looks like I am going to send this one out, unless I can convince the wife that we need the LN dewar.
Yep, sending it out. haha

chumaman said:
interesting reading :thumbsup:
http://docdro.id/41mc5eo
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Thanks for the interesting read. :thumbsup:
Larrin said:
Cryo or liquid nitrogen treatments are less necessary when using the upper temper as is recommended with high speed steels like M4.
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Will the balance of toughness and edge retention be better with LN?

samuraistuart said:
I had Brad do a cryo/low temper on an M4 kitchen knife and hunter for myself. I'm thrilled with it's performance. 64HRC
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Thanks, Could you shoot me a PM with info about contacting Brad?
 
chumaman said:
interesting reading :thumbsup:
http://docdro.id/41mc5eo
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It’s surprising that increased tempering was universally bad for toughness in the study. Maybe there was still some retained austenite present with the low tempers (925F). Vanadis 4 extra, for example, shows some retained austenite with that tempering temperature: http://www.bucorp.com/media/vanadis4_extra_data_sheet.pdf

Edit: See Page 281, Fig. 14-43 for the typical response to tempering. http://allaboutmetallurgy.com/wp/wp-content/uploads/2016/12/Tool-Steels.pdf
 
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samuraistuart said:
I had Brad do a cryo/low temper on an M4 kitchen knife and hunter for myself. I'm thrilled with it's performance. 64HRC
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Interesting. I discussed this with Brad about a year ago and he advised against LN & low temp. tempering for CPM-M4. Do you know what protocol he used like hardening temp, soak time, tempering temp., etc.. I've been wanting to try it for quite some time and probably will now.
 
Darrin Sanders said:
Interesting. I discussed this with Brad about a year ago and he advised against LN & low temp. tempering for CPM-M4. Do you know what protocol he used like hardening temp, soak time, tempering temp., etc.. I've been wanting to try it for quite some time and probably will now.
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Hope we can get this info! Ive been curious about M4 for awhile. I use peters as well. What does brad reccommed for M4? Cryo/high temp temper? If he doesnt reccommed the cryo and low temp?
Keep us in the loop!
 
Flatblackcapo: Brad Stallsmith....he's the heat treating doctor at Peter's heat treating.

I had called Brad and talked to him personally about doing the cryo/low temper on a few hunters and kitchen knives in CPM M4. I was expecting him to say, "Sure but it will cost you more". That was not the case. He told me he would be more than happy to incorporate the cryo/low temper protocol on my blades, just to include the request when I sent the knives (so he would know they were mine). I couldn't tell you what aus temp he used or temper temps. Agreed, would be nice to know.

Brad my have a different opinion, or better info, but what I understand is that using the high temp tempers will not precipitate the nano sized eta carbides that the cryo treatment is supposed to set up. I just wanted to give the CPM M4 the same treatment CPK knives and others were discussing with their Δ3V, which is supposed to give a finer apex stability in impact. And I get maybe that isn't a huge necessity in hunters (except for bone impact) and kitchen knives (except for the wife and her ceramic plates).
 
In a visit to Peters Heat Treating Brad told us an austenitizing temperature for a certain steel but then said that was proprietary, so they may not share the temperatures publicly.
 
I’m assuming there’s a very technical answer beyond my scope of understanding in which a steel such as M4 can be set up a certain way, austenitized a certain way, with cryo, that leaves an acceptible amount of RA for our applications. What you give up, if anything, to gain the desired better fine edge stability, if it results in that, would require a lot of testing, with equipment beyond my shop. I can see why someone might not want to share the results of that testing.
 
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