Heat treating M2

S

skillgannon

Joined
Apr 27, 2009
Messages
991
I ended up with a 2 day weekend and got off work early enough to pick up a 50 lb block of dry ice. I'm hoping to make a couple of test blades. Will dry ice be good enough to start working up a recipe? What would be a good starting place for M2? I might try a low temper and high temper test blade.
 
Interested to see your results on low vs high temp tempering.
I have some M4 from AKS that I'm going to be delving into here in the near future. The AKS site recommends aus temps for M2 and M4 of 2150 to 2200 for cutting tools and then temper at least at 1000. I was going to follow that protocol but wondered if there was a low temp option like with 3V etc.
 
skillgannon said:
What austenizing temperature did you use?
Click to expand...

I’ll have to look it up. I have a cheat sheet. It was high, over 2000f, maybe 2100f?

I’m heading for breakfast with the in-laws. I’ll call you when I get back in a few hours.

Warren
 
Robert Erickson said:
Interested to see your results on low vs high temp tempering.
I have some M4 from AKS that I'm going to be delving into here in the near future. The AKS site recommends aus temps for M2 and M4 of 2150 to 2200 for cutting tools and then temper at least at 1000. I was going to follow that protocol but wondered if there was a low temp option like with 3V etc.
Click to expand...

It depends on the amount of alloying. Cryo only goes so far. It works up to v4e/4v levels of alloying with testing of results. I’ve heard of it with M4, but I don’t know if there’s any testing on that. At the z-wear level, sub zero doesn’t get a full conversion but it does with cryo. People get good results with S35VN with sub zero, even though you don’t get full conversion, so testing is required.
 
Thanks Warren, I was planning on doing cryo with LN on the M4 but I was wondering about a low temp tempering options like 3V etc.
 
Chuck at aks told me he’s going to send some more steel for me to test. I think M4 and 4v would likely be in the mix. Maybe a11 or Vanax. I’ve done the most common steels already.
 
Robert Erickson said:
Thanks Warren, I was planning on doing cryo with LN on the M4 but I was wondering about a low temp tempering options like 3V etc.
Click to expand...


Ah, yes, I think I tried to answer two questions in one, and didn’t answer either very well. Hopefully Larrin will be able to get micro graphs to see the structures in the future.

I’m not sure if cryo will do a full conversion with M4, as it has a lot of alloying. Hopefully m4 will be in the next batch.
 
skillgannon said:
What austenizing temperature did you use?
Click to expand...
I’ve been using 2075 I think, with a 30 minute soak! I don’t have my notes off hand! Tried dry ice, but now I’m using Ln. With dry ice, that aus temp, and 400 temper, you should hit around 61-62 rc.
 
I can tell you that 4V responded very well to the low temp non-secondary hardening approach when given LN as a continuous part of the quench. I wasn't sure it would work but careful testing demonstrated it works very well. So I suppose something like M2 might also be possible? It's unorthodox but it's worth a try.

According to the books, conventional heat treat for M2 used for things like drills and cutters (without LN) is something like 20% RA after three high temp tempers. That's in the finished final tool, 20% stabilized RA. That's pretty tenacious so I think a low temp non-secondary approach to the alloy might be borderline. I'd certainly use LN as a part of the quench instead of dry ice.
 
Thanks. I just have to
Nathan the Machinist said:
I can tell you that 4V responded very well to the low temp non-secondary hardening approach when given LN as a continuous part of the quench. I wasn't sure it would work but careful testing demonstrated it works very well. So I suppose something like M2 might also be possible? It's unorthodox but it's worth a try.

According to the books, conventional heat treat for M2 used for things like drills and cutters (without LN) is something like 20% RA after three high temp tempers. That's in the finished final tool, 20% stabilized RA. That's pretty tenacious so I think a low temp non-secondary approach to the alloy might be borderline. I'd certainly use LN as a part of the quench instead of dry ice.
Click to expand...
Get some free time to find a place to get my dewer filled. If I have time I will make a little test blade just to see what I can get out of it with dry ice.
 
skillgannon said:
Thanks. I just have to

Get some free time to find a place to get my dewer filled. If I have time I will make a little test blade just to see what I can get out of it with dry ice.
Click to expand...
I’ve tried it with great results! Both dry ice and liquid nitrogen. I’ve been impressed with the toughness and edge retention!
 
Nathan the Machinist said:
I can tell you that 4V responded very well to the low temp non-secondary hardening approach when given LN as a continuous part of the quench. I wasn't sure it would work but careful testing demonstrated it works very well. So I suppose something like M2 might also be possible? It's unorthodox but it's worth a try.

According to the books, conventional heat treat for M2 used for things like drills and cutters (without LN) is something like 20% RA after three high temp tempers. That's in the finished final tool, 20% stabilized RA. That's pretty tenacious so I think a low temp non-secondary approach to the alloy might be borderline. I'd certainly use LN as a part of the quench instead of dry ice.
Click to expand...

I was initially worried about z-wear in the same regard. It responded quite well to the low temper protocol.

I did a set of M2 samples for Larrin’s Charpy testing in high and low temper, so we’ll get that datapoint. The z-wear showed improvement in toughness with low temper protocol, and users are saying the fine edge stability is excellent, a typical weakness in this class of steels.

I did V4e Charpy samples with low temper protocol, but only had enough steel for one set, so no comparison yet.
 
Willie71 said:
I was initially worried about z-wear in the same regard. It responded quite well to the low temper protocol.

I did a set of M2 samples for Larrin’s Charpy testing in high and low temper, so we’ll get that datapoint. The z-wear showed improvement in toughness with low temper protocol, and users are saying the fine edge stability is excellent, a typical weakness in this class of steels.

I did V4e Charpy samples with low temper protocol, but only had enough steel for one set, so no comparison yet.
Click to expand...
Have you tried the M2 in a blade? How was it compared to Z-wear? I bought some thicker stock for a few test knives and hunting knives but I bought some 2"x.100 for kitchen knives. If it's as good as I hope it will make some kick butt chef knifes st a good price.
 
skillgannon said:
Have you tried the M2 in a blade? How was it compared to Z-wear? I bought some thicker stock for a few test knives and hunting knives but I bought some 2"x.100 for kitchen knives. If it's as good as I hope it will make some kick butt chef knifes st a good price.
Click to expand...

I’ve got one profiled, but that’s as far as I got. I’m looking forward to testing knives in M2.
 
You must log in or register to reply here.
Back
Top