Elmax vs. INFI?

[clampdaddy]

All good stuff fellas. I'm pretty excited about the new blade and just a little bummed that it won't be here before the end of duck season. Curious to see if it will end up taking the place of my go too critter emptier. There have been many that tried but the ergos and blade shape of my old Buck Woodsman is about perfect in my hand.

 

[OldPhysics]

Yeah, take away the thinnes and you loose the flex and then you go SNAP!

Lets face it is not tough. This is a good descriptor except for toughness. Stainless steels with lots of carbon are very low in toughness. The lower carbon stainless steels are tougher than the high carbon stainless steels. Busse HT may make it tougher than other Elmax but with 1.7$ Carbon and 18% Chrome it will be far from tough. 440A/B and D2 will be tougher and they are not tough. So I dropped it to two stars.

Hmm. I think that's about right, but then Cobalt has always had good steel sense.

I should have recruited him to be a materials scientist years ago ......

 

[Cobalt]

Hmm. I think that's about right, but then Cobalt has always had good steel sense.

I should have recruited him to be a materials scientist years ago ......

They use to call me Face Centered Cubic at one time. But I never understood what that meant

 

[SpyderPhreak]

I reckon a fatter or even a fat elmax blade would be cool, but it would be rather brittle.

Yeah, take away the thinnes and you loose the flex and then you go SNAP!

Lets face it is not tough. This is a good descriptor except for toughness. Stainless steels with lots of carbon are very low in toughness. The lower carbon stainless steels are tougher than the high carbon stainless steels. Busse HT may make it tougher than other Elmax but with 1.7$ Carbon and 18% Chrome it will be far from tough. 440A/B and D2 will be tougher and they are not tough. So I dropped it to two stars.

Respectfully boys, I would rather disagree. While Elmax isn't as tough as INFI or SR-101, it is no slouch either. From everything I've read, it can easily surpass the toughness of 440 and D2.

I had this 6.5"-bladed custom made from 0.22" thick Elmax not long ago by BF's own James Terrio. We discussed Rc a bit, and what I wanted from the knife. I stated that I wanted excellent edge-holding along with decent toughness. I want to be able to baton or chop with it if I need to, but I want it to keep a very keen edge too. JT uses Peters for heat-treating, and after talking to Brad Stallsmith at Peters' a little bit, we decided to go with an Rc of 60 (Brad is THE Elmax HT guru, FYI). Peters tests Rc post-treat to confirm that it's within a few tenths of the target.

Anyway, that's a long-winded version of saying that Elmax is still pretty dang tough, even at a confirmed Rc of 60. While this blade is much thicker stock than what Busse uses in their Elmax models, it's full-flat ground and is at least as thin behind the edge as any of my Busse Elmax blades are. I wouldn't hesitate to do anything with this blade short of chopping rocks , and have no fear of damaging it.

Elmax is one of the toughest stainless steels on the market. While it's certainly not as tough as INFI or SR-101, it IS still pretty tough stuff, even at RC 60 or "58-60". HTH.

 

[Cobalt]

You can make any knife steel tough enough. Striders S30V fixed blades have held up to a lot of abuse. That doesn't mean that they are even close to a carbon steel in toughness and even though cpm has fantastical claimis for their s30v, I have compared it to 440a and toughness wise they are not even close regardless of any paper numbers listed. But when photobucket goes back up I will show you what I have done to 440a steel and I can pretty much bet your elmax would not have held up to that same punishment. dang photobucket.

 

[rcb2000]

Great piece from Terrio! Man I can't stop looking at it...
Really want a thin elmax slicer, FFG preferably.
I found this quote from Jerry about Elmax

Elmax is NOT the new INFI nor INFI 2.0.

It's just a new steel that we decided to have some fun with that makes for a really good slicer.

I wouldn't beat on it though....Heavy impact is not its game.

Let's Drink!!! :thumbup:

Jerry

 

[Lycosa]

And we HOGS love heavy impact.

 

[rcb2000]

Sounds like the next offering,, the HIT Heavy Impact Tomahawk!

 

[OldPhysics]

You can make any knife steel tough enough. Striders S30V fixed blades have held up to a lot of abuse. That doesn't mean that they are even close to a carbon steel in toughness and even though cpm has fantastical claimis for their s30v, I have compared it to 440a and toughness wise they are not even close regardless of any paper numbers listed. But when photobucket goes back up I will show you what I have done to 440a steel and I can pretty much bet your elmax would not have held up to that same punishment. dang photobucket.

Would love to see that.

Agree that pretty much any steel can be toughened. Just have to get enough of the right impurity into the matrix at the right concentration. It's really equal parts science and art.

I could use another really good slicer, however.

 

[Cobalt]

Would love to see that.

Agree that pretty much any steel can be toughened. Just have to get enough of the right impurity into the matrix at the right concentration. It's really equal parts science and art.

I could use another really good slicer, however.

photobucket has been down all day

 

[SpyderPhreak]

Curious to see the pics Cobalt. I'll have to see if I can go dig up the stuff that sold me on Elmax toughness. I was rather surprised.

ETA - Here is one of the threads I was thinking of with toughness and hardness data for Elmax. Seems Elmax takes appx. 42 Joules of impact energy at 60 Rc, if you're looking for hard data, which is about what I recall. I'll keep looking.

ETA2 - Here's data direct from Bohler-Uddeholm, showing appx. 21 ft-lb (28.5 J) of impact toughness at 59 Rc. Lower than I recall. (Note, this is a non-standard impact test with unusual, small cross-section, not the typical Charpy notched tests.)

 

[Cobalt]

I cannot find my pics dammit. I may have to do it all over again and video tape it. But what is even more funny is that on uddeholm's own site I cannot find toughness data on elmax?

 

[David Brown]

Seems tough enough to me.

Stab and pop out 2X4 wood until I dug a hole out.

Love my little steak knife.

 

[kaizo]

I cannot find my pics dammit. I may have to do it all over again and video tape it. But what is even more funny is that on uddeholm's own site I cannot find toughness data on elmax?

Are these the ones you're after? I can't remember where I found them unfortunately though.. It was a while ago:

I was asking around when I was trying to find a place to get my elmax blanks heat treated and I was told by one of the heat treating firms that they apparently have had requests to heat treat them for our marines. However he didn't mention for what purpose (or thickness) so it could be a slicer or combat knife. Although my intuition says that if they had something made specifically its probably for more on the combat end. Otherwise I'm guessing they would just procure a stainless mora that is good, cheap and readily available.

 

[SpyderPhreak]

I cannot find my pics dammit. I may have to do it all over again and video tape it. But what is even more funny is that on uddeholm's own site I cannot find toughness data on elmax?

Click the link in my 2nd edit in the post above yours. Just keep in mind that the sample piece they used is a lot smaller than what would normally be used in Charpy tests.

The rest of the info can be found at the bottom of THIS page.

Are these the ones you're after? I can't remember where I found them unfortunately though.. It was a while ago:

I was asking around when I was trying to find a place to get my elmax blanks heat treated and I was told by one of the heat treating firms that they apparently have had requests to heat treat them for our marines. However he didn't mention for what purpose (or thickness) so it could be a slicer or combat knife. Although my intuition says that if they had something made specifically its probably for more on the combat end. Otherwise I'm guessing they would just procure a stainless mora that is good, cheap and readily available.

The chart comes from the one I linked above in my 2nd post edit. See above note about sample size.

FWIW, if you still need to get some Elmax heat-treated, I would highly recommend Peters!!! :thumbup: I've heard that Brad Stallsmith there helped develop the HT protocol for Bohler-Uddeholm's Elmax, and though I can't say for sure if that's true or not, I'd certainly believe it.

 

[kaizo]

Click the link in my 2nd edit in the post above yours. Just keep in mind that the sample piece they used is a lot smaller than what would normally be used in Charpy tests.

The rest of the info can be found at the bottom of THIS page.



The chart comes from the one I linked above in my 2nd post edit. See above note about sample size.

FWIW, if you still need to get some Elmax heat-treated, I would highly recommend Peters!!! :thumbup: I've heard that Brad Stallsmith there helped develop the HT protocol for Bohler-Uddeholm's Elmax, and though I can't say for sure if that's true or not, I'd certainly believe it.

Sweet! I'll send him an email once I'm done with the blank!

Thanks for letting me know!

 

[Cobalt]

So after some reading, Elmax is about the same toughness as 420v/s90v from cpm. And thus, here is a comparison to 440C, which is not anywhere near as tough as 440a/b
Now of course there is a 4 pt difference in hardness, but all steels have their sweet spot in hardness. 440c is more than 50% tougher and if taken to


Longitudinal impact toughness, C-Notch and bend fracture strength:

440C : 1900/400 F : 58 HRC : 33 ft-lbs and 580 ksi
BG-42 : 2050/975 F : 63 HRC : 11 ft-lbs 507 ksi
S90V : 2150/975 F : 62 HRC : 19 ft-lbs and 630 ksi


I don't think anyone will argue that 440B is tougher than C.

of course theory and paper is not what it is all about. Good HT can make it all up.

 

[SpyderPhreak]

So after some reading, Elmax is about the same toughness as 420v/s90v from cpm. And thus, here is a comparison to 440C, which is not anywhere near as tough as 440a/b
Now of course there is a 4 pt difference in hardness, but all steels have their sweet spot in hardness. 440c is more than 50% tougher and if taken to


Longitudinal impact toughness, C-Notch and bend fracture strength:

440C : 1900/400 F : 58 HRC : 33 ft-lbs and 580 ksi
BG-42 : 2050/975 F : 63 HRC : 11 ft-lbs 507 ksi
S90V : 2150/975 F : 62 HRC : 19 ft-lbs and 630 ksi


I don't think anyone will argue that 440B is tougher than C.

of course theory and paper is not what it is all about. Good HT can make it all up.

That's probably about right as an average for Elmax. I've seen Charpy v-notch test data that had it rated as high as about 32 ft-lbs, but I can't find it now for the life of me. I want to say it was something from KAI USA.

I guess I was thinking 440A was about as tough as what you have 440C listed right there. Suppose I was confused. Still, Elmax with a good HT at a reasonable hardness should still hold up to most everyday use, and even some abuse without failure. I chose 60 Rc as a good compromise, and Terrio backs that knife for life unless I'm purposely doing something crazy like chopping concrete blocks. I don't expect it to be as tough as INFI or SR-101, but it should hold a good edge for longer, and is certainly more stain resistant.

 

[Cobalt]

Also, for small to medium blades it is fine on a big blade I would not consider it at all.

 

[Cobalt]

here is another source


Steel-------Hardness-----Charpy C Ft. Lbs.
CPM-S90V......@Rc56..........20
CPM-S90V.....@Rc58...........19
CPM-S60V.....@Rc56...........16
CPM-S30V.....@Rc58...........28
CPM-S35VN....@58Rc...........32
CPM-154......@60Rc............30
154CM..........@Rc58...........28
440C............@Rc56...........26
440C............@Rc58...........16
420HC...........@Rc58...........24
M390............@Rc60...........22

According to the above, at Rc 58 S90v is tougher and at Rc 56 440C is tougher. S90v being equal in toughness to elmax. So I would say that 440c and elmax are very close in toughness. Which means that 440A and B will definitely be tougher.