61 rc too hard?

Matt Rochester

Matt Rochester

Joined
Nov 28, 2014
Messages
1,864
Well I'm rethinking the hardness of a few knives I have in Cpm154. 4 are bird and trout knives and I think they will be ok. 3 are general purpose hunting/camping style. They are .110" so chopping shouldn't be a chore for them. Is 61 rc too hard? Just trying to figure out what hardness I need for different styles. Thanks.
 
Smaller knives are frequently 61-62. A good steel like that with a good HT can be run a little harder than many expect.

I'd run 3V that hard on a camp knife no problem, but CPM 154 might be a little chippy for a camp knife at 61. I'd test it and see.
 
Can I just temper it again at 450 instead of 400 without normalizing or anything? That should bring it to 59 or 60.
 
My understanding is that CPM154 is one of the toughest high higher alloy stainless steels (that is also good for knives) out there along with CTS XHP at the expense of a bit of abrasion resistance compared to say S35VN, etc. I have heard the same thing about Elmax and also heard that Elmax becomes a different steel above 60 in that it is still fairly tough, but has the abrasion resistance maybe 80% of that of the crazy stuff like M390 or S90V. So I am wondering why 61Rc would be considered to hard for larger knives? We hear the same thing from some manufacturers about 1095 needing to be like 56-57 to be tough when we know that is not true.
 
Matt R said:
Can I just temper it again at 450 instead of 400 without normalizing or anything? That should bring it to 59 or 60.
Click to expand...

To the question - yes, you could just re-temper to lower the hardness.

The bigger question would be why? A normal knife at Rc61 in CPM-154 would be right on target.
 
That's what I was looking for. My target was 60-62rc and I hit 61 so my HT was good. I was just wondering if 61 was too hard for this style knife but I guess its not. I'm going to go with it. By the way, this stuff is a dream to grind. I don't understand how, at 61rc, it grinds easier than 440C at 57? Anyway, I really like it. Thanks.
Stacy E. Apelt - Bladesmith said:
To the question - yes, you could just re-temper to lower the hardness.

The bigger question would be why? A normal knife at Rc61 in CPM-154 would be right on target.
Click to expand...
 
I have a S30V blade hardened to 62. As a user, I love the harder steel/
 
jdm61 said:
My understanding is that CPM154 is one of the toughest high higher alloy stainless steels (that is also good for knives) out there along with CTS XHP at the expense of a bit of abrasion resistance compared to say S35VN, etc. I have heard the same thing about Elmax and also heard that Elmax becomes a different steel above 60 in that it is still fairly tough, but has the abrasion resistance maybe 80% of that of the crazy stuff like M390 or S90V. So I am wondering why 61Rc would be considered to hard for larger knives? We hear the same thing from some manufacturers about 1095 needing to be like 56-57 to be tough when we know that is not true.
Click to expand...

I tested a knife that was made with Elmax @ 61Rc and it held an edge very well. I have some S35VN that I will be trying at 61Rc which I'm expecting will do extremely well also.
 
Stacy E. Apelt - Bladesmith said:
S35VN is great art Rc 61. I have Brad at Peter's do all mine at that hardness.
Click to expand...

By the way, I just had an excellent experience with Peter's Heat Treating. I sent in a batch of blades that I have been working on over several months. I had them all documented in my paperwork as being CPM S35VN and reported them as being so when submitting the required form to Peter's. Brad called me to explain that several of the blades ended up being one point greater Rockwell C hardness than expected, so he investigated. He said that he had used their spectrometer and determined that these suspect blades were actually CPM 154CM instead of CPM S35VN. This makes sense to me because I have also used 154CM frequently. After a short discussion, the 154CM blades will remain close to 62 Rc although Brad offered to temper them back another point at no cost.

Without Peter’s Heat Treating, I would have never recognized this discrepancy and (in my mind) miss-represented my work to my customer.

Custom Batch-Work knife making record keeping can easily get convoluted despite the most meticulous attention to detail. Good vendors are helpful.
 
You must log in or register to reply here.
Back
Top