New alloys; hot or hype? (advanced class)

W

Walt Welch

Joined
Oct 7, 1998
Messages
1,838
There are frequent discussions, and at least one or two going on now about the selection of steel for knife blades. One thing common to all of these discussions is a lack of complete data.

Forming opinions without a proper data base is fraught with peril.

I would like to start a discussion of the current new alloys (ferrous and non ferrous), and really examine the data critically, then when and if possible, correlate with real world experience.

To accomplish this effectively, some previous knowledge is required. If you haven't already done so, go to the knowledge base of this Forum, and read the FAQ's; particularly those on blade steel and blade geometry. Further, peruse the Crucible Particle Metallurgy site in its' entirety. It is fairly complex as a whole, but each separate section is lucid. Here is their URL:

http://www.crucibleservice.com/cscd/crumain2.htm

Right on the above page you have an article on the fabricating and heat treating of tool steels. Read this, then click on 'Tool Steels,' and read 'Selecting High Performance Tool Steel.'

Through the good offices of Ed Schott, I have obtained the complete data sheets on CPM 440V, 420V, and 3V. I have prevailed on Spark to post these, so that all of us will have access to these data. They are quite instructive, listing abrasion resistance, toughness, and many other qualities as well. In addition, these steels are compared with traditional steels.

Here are the questions I would like to explore, although any additions are welcome.

Does the trade-off between hardness and toughness still exist in the new steels, and if so, how does it compare with traditional steels. Ditto hardness and corrosion resistance. Why was 440V discontinued by CPM? Why did BM choose M2 over M4 tool steel, given M4's supposed superiority?

I frankly don't think we will find one 'best' alloy, but perhaps a best alloy for a given purpose may be possible.

So, all of you students do your homework, and come back for further data as it is posted, then let's let the chips fly! Walt
 
Walt,

I think you have hit the nail on the head. My own frame of reference is rather limited. I know the knives I have used personally and how they performed but, that does little when I look at a steel I haven't owned before. Through good fortune and the knowledge of other forum'ites, I have had the pleasure of avoiding some junk and added a few good knives to my personal collection that will be treasured for years to come.

Let the sparks fly!
Sid
 
GREAT proposal.

Let's get educated about these materials. And you're the ideal guy to head it up.

The biggest problem will be dealing with the performance discrepancy between what should be true and actual reports from the field. Similar to the ongoing controversy about the effectiveness of various gun calibers and balliistics. Tests and statistics say one thing, but guys on duty report varying and what they believe to be contradictory results.



------------------
Regards,
Ron Knight

Yeah I'm crazy, but what do you want me to do about it
 
Well, there are so many alloys and good tool steels out there that I can never make up my mind on what is best. A-2, D-2, O-1, M-2, 52100B, 440V, 420V, 3V, ATS, BG-42, VG-10, AUS-10,8A,6, 440A,B,C, 5160, 50100B, O-2, 420, 425, Dendritic 440, and so on and so on and so on.

My ideal steel would be a 440V/420V damascus 300+ layer. Tough and extremely good edge holding. But it does not exist. Maybe laminates of these extremely hard steels is the way to go.
 
I am sure Walt is right. It is all about picking the type of knife that is best suited for the use. This of course involves blade steel, handle material, blade length, Blade shape, blade grind, and so on and so forth. There is no free lunch as they say. The more knowledge an individule has in this hobby of ours the better.


Regards,

Tom Carey
 
Your questions are the same questions asked no matter what type of tool is made.

As far as data on materials, I can probably give you about all the data you may need.

I am Crucible's metallurgist and have just recently been given the resposibility of the knife market. I'm under the opinion that there is no perfect steel and that each alloy has it's pros and cons in a knife application.
To answer one of the above questions 440V is still available as is 420V but there is a reason 420V is the primary grade now and it has nothing to do with knives.
 
Doc,
You wrote;
" I frankly don't think we will find one 'best' alloy, but perhaps a best alloy for a given purpose may be possible."

And for me, I feel CPM3V looks like the "ne plus ultra" of steels for Khukris,Bowies,swords,or Camp knives requiring superlative impact resistance combined with superb edge holding. CPM3V appears to offer the wear resistance of M-4 with the legendary toughness of S-7 ,even surpassing L-6 also known for wonderful toughness.
An ideal combination of attributes,I believe,specifically for the genre of blades I listed above.
I also considered CPM9V, which offers slightly greater wear resistance with just a little bit less toughness, but does so at a lower 53-55 Rockwell compared to the more useful Rockwell range of CPM3V 58-61 vis a vis the edge hardness.

And oh yeah,Doc, what was your favorite all around lubricant again?
biggrin.gif


Stay safe and all the best, Phil <----<



[This message has been edited by Phil Squire (edited 14 March 1999).]
 
Speaking as a Materials engineer, I have no doubt that the new steels afe far more than just hype-they are quite real, and offer some real benefits. the Particle Metallurgy that crucible employs has made it possible to greatly increase the total percentage of alloying additions, because it eliminates the problems of carbide formation and segregation that occur in steels produced by conventional hot rolling.

In addition, the uniform/clean/fine nfrained microstructure produced by their process will certainly increase toughness over the same grade produced by conventional means, because large carbides and inclusions are often where corrosion starts and failures occur.

Always, when considering what steel is best, you need to consider far more than just the steel. the blade size and geometry, thickness, and intended use of the knife all play a role in detyermining what is the best steel to use. So, I will say again, there is no best steel, but, certainly there are best steels for a given application. This is why there are thousands of alloys out there instead of just a few-and, every industrial application has the same issues, not just knife blades.

CPM3V has looked great to me for years, and, not I am procuring one of the first two sheets of this material that are available, without ever having tried the material.

The stainless CPM grades offer some excellent properties, but, are going to fall short of the tool steel varieties as far as toughness, just as the current stainless steels generally lag the tool steels in toughness.

BG42 is still going to be a fine steel, and I will not throw it out for the stainless CPM grades just yet. I still believe it is possible to try and cram too many things into a piece of steel that is going to be used for a knife blade, and BG42 really has a nice BALANCE of properties. It really always comes down to balance, IMHO.

Time will tell, as it always does. And, remember, whiz bang steel doesn't guarantee a great knife-it demands even more extroidinary control of the heat treating/tempering process that is so often performed in a less that ideal fashion with even simple steels. So, there are far more opportunities for blades that are way off in the end, because the window for proper heat treating response is greatly diminished as alloy content is increased. Doubtless, this will be glossed over by many, because they really believe they are doing the heat treating correctly when, in fact, they are not.

Any mechanic can tune up a Chevy, and, a Chevy will probably beat out a Lamborghini that runs on 2 cylinders. Of course, when the Lambo is running well, nothing can touch it. Same goes for steels.

RJ Martin
 
RKnight hit the nail on the head...i have print outs of all the crucible steels....remember they want to sell their product...what counts is where the rubber hits the road....D2 was developed for industrial die purposes and yet is one of the best knife steels in the world....vascowear was developed to cut paper and after making a number of knives with it i wish it had never been invented... but it works great and corrodes right before your eyes....thats why i like phil wilsons approach...the man is an engineer by golly...and yet his approach is to field test everything....also....440c was the junko steel of the 70s until someone came up with cryo....and it is an excellent steel when heat treated properly.....there are sooo many variables.....should we have only one person heat treat every steel so we will have a consistant batch? the late great harvey mcburnette told me that in the commercial knife world so many blades get heat treated at once that the ones on the outside dont get hot enought...the ones in the middle get too hot...and theres a magic circle in the middle that get the right temp. thats in a big commercial oven.... i say...field test.....every thing else is just numbers on paper.....
 
ED. S does this mean that you guys are going to start stocking your steels in thickness for
knifemakers? If you are please let me know so I don’t order any more mill runs.

R.J. hit it with a BIG hammer, the best steel is a P.O.S if the heat treat is off and with the
high alloy steels it can be difficult to get right especially in the garage with less than
perfect equipment.

 
RJ, one concern of mine was the the possible lack of toughness in the CPM steels due to the processing. However, from published tests CPM3V seems to knock that theory out the door. That stell may be one of the toughest steels out there. I just wonder how well it can hold an edge.
 
HOOOHAAA!!! YES YES YES; here we were, all ready to go stumbling through the murk, and look at the assets which have shown up to light the way for us!!

Ed Severson; CPM's metallurgist!! YES YES YES; well met indeed, sir. We are honored by your presence. Could you do us a big favor and make ALL the CPM data sheets available to us? Spark is the website manager, and would the person with whom you can most easily arrange this. Once again, welcome.
(I think I like this guy already; he starts out with a mystery; WHY was 440V demoted; NOTHING to do with knives! Let's see what we can weasel, er, ah, OBTAIN from him on this mystery. heh heh)

Cobalt; you say that a CPM-420V - 440V laminate doesn't exist. You are correct. However, laminates of particle metallurgy steels DO exist! Go to the Benchmade site, and scroll down on the left to 'metallurgy.' A german metallurgist tells you how to make the stuff! Your wondering about how well CPM-3V holds an edge raises a good point. How well can you expect it to, with about 1/3 the carbon, about 1/2 the Cr, 1/3 the V, and a 1/3 increase of Mo, compared to CPM-420V?
(To the tune of 'Where have all the Flowers Gone?) 'Where have all the carbides gone?'

Phil; your comments are always welcome, but perhaps you should heed my warning about not forming opinions with a limited data base.

The data sheet for CPM-3V reveals that it does NOT match the wear resistance of CPM-M4, at least on the Wear Resistance Adhesive scale (crossed cylinder adhesive wear resistance; higher the number, the better).
3V has a wear resistance of 6, 7, and 8, at respective Rc's of 58, 60 and 62. CPM-M4 has a wear resistance of 20-25 at a Rc of 62.

Further, the CPM-3V does not match the 'legendary toughness of S7.' The Charpy test reveals a toughness for 3V of 85, 60, and 40 ft. lbs, at Rc's of 58, 60, and 62. (Hmmm..do you suppose there could be something to the harder, the more brittle alloys get?)

Despite these quibbles, however, I do agree with you that CPM-3V would make an incredibly good machete/khukri/chopping implement. An expensive one, to be sure, but a good one. Your numbers are not that far off, and I believe that 'real-world' experience would prove your faith in 3V to be well placed.

However, Phil, I give you full marks for thinking in a logical, productive fashion. I know I can use you as an example, as you are so well regarded. Further, Phil, in answer to your question about my favorite lube: I favor mineral oil, for Cougar and the other MO fanatics. It keeps them 'regular.' It might even help their knives, if they apply it to them, that is.
wink.gif


I should at this point, reveal something about myself. I am a dilletante. Truly. The only thing I know about metallurgy I picked up on the net and right here. I have never torture tested any of my knives. Further, I own a number of very 'low alloy' steels; O1 blades made by Mad Dog.

So, realize, please, that I am limited in my knowledge. Those of you who have real world experience are far ahead of me in knowledge. Guys like Phil, Harv, Joe Talmadge, Cobalt, Cougar, Tom Mayo, and most of the rest of you really actually know MORE than I do. I am just acting as a facilitator here, trying to get people together to exchange information. So, feel free to contradict me when I stray from the path of righteousness and truth.

A special welcome also to r j martin. A Materials Engineer, no less. What an incredibly fortunate addition to our list. I look forward to your input and future valuable posts.

In closing (cheers from posters noted
wink.gif
), I think that we have had incredible luck in gathering in just one day, an incredible team, one with experience, knowledge, enthusiasm, and willingness to learn. We may actually accomplish something useful. Damn useful. Thanks to you all, Walt
 
To all who think there isnt laminate 440-V, there is a smith by the name of Mike Norris who offers his damascus with a D-2 or 440-V core. I havent seen any but have personally spoke with him about it.
Good thread Walt, now I know what you do in your spare time, think about knives!

------------------
www.simonichknives.com
 
Send us any and all information that you want/ have and we'll be more than happy to make it available on this site, it's what we are here for: the dissemination of knife related knowledge.

Help us help you and all that.

Spark

------------------
Kevin Jon Schlossberg
SysOp and Administrator for BladeForums.com

Insert witty quip here
 
I'd be willing to sacrifice super edge holding abilities for enhanced rust/stain protection for "pocket" knives.
So far, 440C and BG-42 seem to be the best for my use. Toss them in your pockes, sweat, get rained on, use and not immediately clean the blade......you know, practical stuff.
Unfortunately with today's hot steels, you also need to carry a Tuf-Cloth with you.
Bead blasting has saved the industry lots of money on production costs, but has left consumers with rust magnets.
I've got some old stilettos with 440C that have NEVER rusted or stained. They get little attention, but still have a good edge on them and look new.
Same applies to the Klotzli, VBM-UDT, Boker/Nealy. All are 440C and never produce rust or stain problems.
Good topic Walt. Will be following it to learn more. In the meantime, all my bead-blasted ATS-34 knives are staying indoors where they are safe.;(
Bill
 
Bill, CPM claims 420V has corrosion resistance better than 440C, with 10 times the abrasion resistance and only about a 10% reduction in impact toughness.

However if you take a look at the link posted by db you will see that real field testing does not show the CPM steels to have the edge hold abilities that you would assume the numbers on the spec sheets imply. This makes me wonder about the corrosion resistance and impact toughness as well.

If CPM does want to seriously market their steels as for use in the knife industry why don't they just donate a bunch of 3V, 420V, 15V, etc. to a maker and have him whip up some knives and send them out for some testing.

Spec. sheets are all fine and make for very interesting reading but that is about all. If you don't have actual field performance feedback then you are on very unstable ground.

-Cliff
 
I've been following this thread with great interest and am posting mostly not because I have anything to contribute, but rather just to assure Walt that there's lots of us eagerly reading. ;-)

One weird word of caution has to do with placing too much emphasis on knowing what something is prior to testing it thoroughly in the field. A couple years ago, I'd have bet good money that _all_ 440A was junk. Actually, I'd probably have bet the same for all 440C. Since then, I've seen and proved to my own satifaction that there are makers out there who somehow know how to tweak some surprising results out of some plenty ordinary steels.

In fact, just looking at the specs on the sheet, there's simply no way that lowly Sandvic 12C27 has enough carbon points to even really enter into a knife steel discussion, yet there are thousands of happy knife using Scandinavians that aren't plagued with that knowledge. Frankly, that lowly soft alloy would be on my short list of steels for a knife that I might have to sharpen on a convient rock or something. All I'm trying to say is that everything is relevant. The skill of the maker/designer is relevant and the skill/projected use of the user is relevant.

Cheers, and I'll go back to happily lurking on this thread,
mps
 
Guys: Just a few more comments. Charpy impact is not the final word on toughness, or the only way to measure toughness. I am still learning about this, and evaluated steels comparatively using Charpy values for years before I learned otherwise. M2 is not a tough steel on the charpy scale, but it makes a fine knife blade-I used it on many knives. The CPMM4 will no doubt ROCK as a knife blade material, even though it is designed for high temp use. I have several bars of it and can't wait to use it.
I really like A2-I've made hundreds of knives from it, all users, and, so I judge the specs according to how steels stack up to A2. A2 kicks butt over most stainless alloys for toughness, so, when 3V beats it by a substantial margin, I get excited-even though it isn't as tough as S7. And, I consider A2 to have more than adequate wear resistance, so, again, 3V gets me going. Honestly, how much of these properties are enough?
Yes, all steel makers do everything possible to make their products look fantastic-the hype is incredible. Again, I cannot overemphasize the fact that it is the final product that matters, not the potential of the steel as stated on paper. Obtaining the stated properties is totally dependant on the heat treating. With some of these steels, just a few degrees or seconds literally can make or break the heat treatment. I am already making plans on how I will have my heat treatment process results verified-how many specimens to do and what lab to send them to. All this stuff takes time and money, and must be taken seriously, or using these alloys just a selling point and not a guarantee of superior performance.

I will say, that it IS fascinating, and certainly worth learning about. It is definitely NOT simple, and, as others have said, reality is often lots different than data in specs. We are really lucky to have so many great materials to use. I understand that Crucible is going to try to put some more Knifemaker friendly data together, and I've offered to look it over when it's ready. They are really trying to help us!!

RJ Martin
 
Doc,

I appreciate the time you took in clarifying the Charpy and Wear Resistance values of CPM3V compared to L6 and M4. I predicated my comments on the bar chart of relative wear resistance and toughness bar values at Crucible's website. Regrettably, without your Rosetta Stone [the data sheets],and me not being omniscient, I will continue to post comments based on a "limited data base" and "some previous knowledge", despite said comments being "fraught with peril",namely your particle of wisdom, " but perhaps you should heed my warning about not forming opinions with a limited data base. " Moreover,I find your comment about fellow members threads "One thing common to all of these discussions is a lack of complete data.", inappropriate,wrong,and unfortunate. So, add me to your list of presently ticked-off admirers.

Let's not mince words. I did not appreciate and considered the warning comment, at the least imperious ,and at worst not gentlemanly.

Similarly, comments of a possibly disingenuous....("and most of the rest of you really actually know MORE than I do."etc.),pedantic,patronizing..("However, Phil, I give you full marks for thinking in a logical, productive fashion.")inaccurate....(" I know I can use you as an example,")..[For what? Baiting with unkind openers followed by transparent"buttering up"?] nature are not appreciated because they are,IMO,unnecessary and unwelcome and not even remotely tangential to Rockwell values.

Once again, it is important to point out gross or even minor errors of fact as this is a forum of knowledge and "truth" and your points are both accurate and well taken. I do,however,take exception to your manner of delivery , as to me this is not "righteousness" and requires my response based on your solicitation of quid pro quo contradiction and usual request for comments,criticisms,and suggestions.
Additionally, I do not consider myself to be in the same league as Joe Talmadge,Harv,and Cobalt among others in the realm of knives or materials science knowledge. I trust you meant Phil Gibbs.
I am and will remain a humble student in perpetuity. That is why I frequent bladeforums and knifeforums, and responded to your interesting thread.
Now I still have to go look up the Charpy value of s7
smile.gif


Stay safe and all the best, Phil <----<




[This message has been edited by Phil Squire (edited 16 March 1999).]
 
You must log in or register to reply here.
Back
Top