Ranking of Steels in Categories based on Edge Retention cutting 5/8" rope

jdm61 said:
The more interesting stuff might be the PSF 27, the German spray formed modified D2 type steel.
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We've been selling this steel for 3 months. Test reports from knifemakers have been good.

I want to test to see if the the performance matches the data sheet. If it comes close it will be an excellent steel.
 
Jim,

For larger hard use knives like an AD-10 or similar custom knives, would M390 be an appropriate steel? I always thought something like Elmax would be better because of the added toughness. Care to comment? Thanks
 
jstn said:
Jim,

For larger hard use knives like an AD-10 or similar custom knives, would M390 be an appropriate steel? I always thought something like Elmax would be better because of the added toughness. Care to comment? Thanks
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Because of shear thickness of the ad10 any steel would perform well. Survive knives has gone to m390 from elmax and he has a video of him hanging from an m390 blade that is thinner then the ad10, I would say that you would do just fine with an m390 blade.
 
chad2 said:
Because of shear thickness of the ad10 any steel would perform well. Survive knives has gone to m390 from elmax and he has a video of him hanging from an m390 blade that is thinner then the ad10, I would say that you would do just fine with an m390 blade.
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Thanks Chad, I had been wondering about this since I watched a Cliff Stamp video where he talked about Duratech 20v being a poor choice for XM-18's because they are meant for hard use. I wasn't sure how accurate that assessment was, and the Survive knives in M390 came to mind. I have an AD-10 ordered in Elmax and I am wondering if M390 would be a better choice.
 
I think either would be fine, but in my mind ELMAX has a greater increase in toughness than M390 does in wear resistance assuming they both have a great heat treat(which they will). I think they will both be fine, but I would prefer ELMAX.
 
jstn said:
Thanks Chad, I had been wondering about this since I watched a Cliff Stamp video where he talked about Duratech 20v being a poor choice for XM-18's because they are meant for hard use. I wasn't sure how accurate that assessment was, and the Survive knives in M390 came to mind. I have an AD-10 ordered in Elmax and I am wondering if M390 would be a better choice.
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With the size of an ad10 and the thickness, you are probably going to want more edge retention then toughness so m390 for this size of knife is a better choice. But I would probably prefer elmax also because I like edge toughness and ease of sharpening more then I like edge retention.
 
chad2 said:
With the size of an ad10 and the thickness, you are probably going to want more edge retention then toughness so m390 for this size of knife is a better choice. But I would probably prefer elmax also because I like edge toughness and ease of sharpening more then I like edge retention.
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I will likely stick with Elmax since I am not an expert sharpener and don't like to deal with chips, which would be less likely with Elmax. Thanks again for the input!
 
Alpha Knife Supply said:
Based on what data?

Chuck
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http://www.google.com/url?sa=t&rct=...-KiDlAUDXqL9qQx6pb2wb4w&bvm=bv.48705608,d.aWc

I don't know if the above google-link will work, but according to unnotched impact testing, M390 absorbs MORE energy prior to fracture than Elmax when both are tempered above 60 Rc - Elmax can handle only ~35 J/cm2 vs M390's 40+. However, once the hardness falls below 60 Rc, M390's toughness drops below 30 J/cm2 while Elmax's increases above 40 to where M390's toughness was before.

In effect, M390 is tougher than Elmax if both are hardened above 60 Rc. HOWEVER (again), the difference in behavior between steels with only 5 - 10 J impact toughness is not likely to be noticed as impact thresholds from activity commonly fall either below both or above both. You are comparing the energies between 30 apples falling 1 meter to the ground and 40 apples - think you'd notice the difference? Now compare those 40 apples to 100 - approximate toughness of CPM-3V at 60 Rc via Charpy C-notch. The difference should be clear. BOTH M390 and Elmax are "brittle" in comparison to steels like 3V or shock steels like S7. NEITHER M390 or Elmax is a good choice where toughness is of primary concern... unless of course you don't anticipate threshold energy levels to exceed the tolerances of either, which can be accomplished by leaving the geometry a little bit thicker :thumbup:
 
I was going to comment that the toughness differential between Elmax and M390 is probably insignificant depending on the heat treatment, but I figured I'd get a lot of push back.
It turns out I didn't have to because Chiral said it far better than I would have anyway. :) Thanks!
 
Boy, Howdy! Another opinion that leads me to believe that Jerry Hossum and others may be spot on when they say that 3V may be as close to the "perfect knife steel" as we can get for hard use knives as long as uber-corrosion resistance is not one of your goals..
chiral.grolim said:
http://www.google.com/url?sa=t&rct=...-KiDlAUDXqL9qQx6pb2wb4w&bvm=bv.48705608,d.aWc

I don't know if the above google-link will work, but according to unnotched impact testing, M390 absorbs MORE energy prior to fracture than Elmax when both are tempered above 60 Rc - Elmax can handle only ~35 J/cm2 vs M390's 40+. However, once the hardness falls below 60 Rc, M390's toughness drops below 30 J/cm2 while Elmax's increases above 40 to where M390's toughness was before.

In effect, M390 is tougher than Elmax if both are hardened above 60 Rc. HOWEVER (again), the difference in behavior between steels with only 5 - 10 J impact toughness is not likely to be noticed as impact thresholds from activity commonly fall either below both or above both. You are comparing the energies between 30 apples falling 1 meter to the ground and 40 apples - think you'd notice the difference? Now compare those 40 apples to 100 - approximate toughness of CPM-3V at 60 Rc via Charpy C-notch. The difference should be clear. BOTH M390 and Elmax are "brittle" in comparison to steels like 3V or shock steels like S7. NEITHER M390 or Elmax is a good choice where toughness is of primary concern... unless of course you don't anticipate threshold energy levels to exceed the tolerances of either, which can be accomplished by leaving the geometry a little bit thicker :thumbup:
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A lot of good info out there from you guys. I figured this thread would be the best place to ask the question:D A switch to M390 may be in order.
 
Also, thanks to Jim for this thread and all the other posters on it. This is IMO the most useful thread on the forums and one I check regularly for the vast amount of useful info.
 
jdm61 said:
Boy, Howdy! Another opinion that leads me to believe that Jerry Hossum and others may be spot on when they say that 3V may be as close to the "perfect knife steel" as we can get for hard use knives as long as uber-corrosion resistance is not one of your goals..
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CPM 3V is still my favorite steel. The toughness allows the knife to have excellent edge geometry. However, after using a knife made from K294 I find myself wanting 3V to have more edge holding. I want to test CPM 4V, Vanadis 4 Extra and PD1 for comparison.

Chuck
 
That is what interests me in the 4V or Vanadis 4E. Still have toughness somewhere between that of A2 and L6, but with the abrasion resistance of S35VN, etc. The only concern I might have is whether or not you would still have that same ability to get a very fine, yet very stable and strong edge that you get with 3V? The first couple of "hard use" knives that I made in 3V, I guess I didn't know any better so I just automatically took the edge down to .020 and had Peters harden it to 60Rc. ;) The feedback that I have gotten had been very good.
Alpha Knife Supply said:
CPM 3V is still my favorite steel. The toughness allows the knife to have excellent edge geometry. However, after using a knife made from K294 I find myself wanting 3V to have more edge holding. I want to test CPM 4V, Vanadis 4 Extra and PD1 for comparison.

Chuck
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