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Toughest steel

Other alloy elements besides carbon alter the max hardness and hardenability of steels, this is well known. Many of the spring steels have only medium carbon content, INFI does as well. It is not of any great feat to get a steel that hard (60+RC), however to get it that hard, at twice the impact toughness of S7 at maximum is another matter. In fact even if it was just at the toughness of S7 it would still be a wonderful material. It would be interesting to know the relative abrasion and corrosion resistance, still even if these were very low, it would still be a great material for a large class of blades, however obviously a very poor choice for others.

-Cliff
 
Originally posted by Cliff Stamp
Other alloy elements besides carbon alter the max hardness and hardenability of steels, this is well known.
-Cliff
Click to expand...

Heh... not in the knife crowd.
 
...however obviously a very poor choice for others.
-Cliff [/B]
Click to expand...


What others? "Very poor choice" would seem to rank it well below average, and I'm curious how can you say that? In fact CPM-1V's wear resistance is not at all bad (almost the same as D2). The respectable quantities of Vanadium and Tungsten provide excellent abrasive wear qualities, and the impact toughness protects the steel from micro-chipping. The elements besides carbon, BTW, contribute more to carbide formation than to hardness of the matrix.

INFI is a nitrided steel, a completely different chemistry than carbide forming steels. The comparison with respect to this steel in terms of carbon content isn't really inappropriate.

The impact toughness of 1V is only about 50% greater than S7. The bar charts are sometimes difficult to interpret. I apologize for the hype... :)
 
Oh yeah Jerry? Well, the toughest steel i ever used was a D-10 Catapiller dozer I ran at a gold mine. You could tear the hell out of things with it! :D
 
Actually it was a great big brand new multi million dollar machine! I guess they figured I coulndnt break it! :D You know the replaceable cutting edges on the dozer blades are S-7?
 
Maybe that was a D2 I was thinking about, or maybe you're just a whole lot younger than I thought. :)

I'd heard they used S7 for those replaceable edges. That's not what Crucible lists as the target applications for 1V though. They are targeting high stress dies and punches. Heck, they don't even mention swords and good stuff like that.
 
Cant wait to hear how the 1-V turns out. High stress dies and punches and swords! Let us know when you get a blade worked up.

A D-2 is a itty bitty dinky thing! A d-10 is as big as a house! :D
 
Thank you Jerry for clearing that up. I knew there was more to that.

Also, I agree with Jerry on a somewhat similar topic about judging hardness in steels that work around the high carbon/medium carbon borderline.

I might add by saying that such a steel is more than capable of reaching a rating like 60HRC even at .50%C. The reason for more carbon past about .5 is to form carbides and increase wear resistance. For example, I specialize in hand forging 1045 and S-5. 1045 (.42-.50%C) is more than capable of reaching HRC62 from an aus temp of 1550°F. (Although I use a 57/58HRC). That is why you see some hardened and tempered steels with a lower hardness but drastically higher wear resistance compared to the latter with a higher HRC.

My thoughts.
 
Jerry Hossom :

"Very poor choice" would seem to rank it well below average, and I'm curious how can you say that?
Click to expand...

Blanket statements are often thrown around on the forums, and can be very misleading as they are judgements being made from viewpoints that are in no way standard. When these viewpoints are not clearly stated, the comments can lead to hype because different viewpoints can then get attached to the same judgements. It is like saying ATS-34 is a better steel than AISI 420. This suitability of the steel for a knife can only be evaluated if the desired charactersitics of the user and maker are defined. All materials are excellent choices for certain applications, and horrible choices for others.

As an example, I know a maker who uses mild steel for knives. The drawbacks for mild steel are many; low wear resistance, poor strength, little impact resistance, high rate of corrosion etc. . However at the sam time, it is really cheap, available, requires no heat treat, and is easy to grind with low tech equipment. It also has the two main necessary components for a knife material, as it can be shaped for high performance cutting, and high sharpness. Now it would be easy to break the knife if used for prying, as well as mangle it when chopping, however they are just used as light use cutters on fruit and flesh and they work well.

In regards to CPM-1V, I was recently asked to suggest a steel that could stand even highly corrosive enviroments without any visible rusting, even to the extent of a slight discoloration. For this case all the high end pseudo-stainless steels like ATS-34 are a horrible choice as not only will they take surface rusting, they will pit badly if left exposed to highly corrosive enviroments (extended salt water exposure). For that users perspective, CPM-1V would be a very poor choice. Also considering availability, cost, ease of working etc., could lead to it being a very poor choice. Or simply looking at low stress edge retention, if compared to something like CPM-10V at ~64 RC.

You also really can't restrict someones opinion to be as extreme as they want. If you browse rec.knives for example you will find people who prefer steels in the 64-66RC range, and they judge ~60RC steels as soft, and thus poor choices for blade materials, as they are harder to sharpen (burr formation), and don't hold an edge nearly as long on the types of cutting they do (low stress work). You could also find people of the exact opposite opinion who prefer steels in the ~52 or so RC range as they are easily filed, and that is the prefered method of sharpening.

INFI is a nitrided steel, a completely different chemistry than carbide forming steels.
Click to expand...

That was kind of the point.

-Cliff
 
So... does anyone know of someone who's yet tried to forge 1V?
If it's as tough as claimed it might make one hell of a tomahawk head in addition to the large knives and swords ya'll are talking about.

That pondering gets me in trouble all the time. ;)
 
I wonder what kind of a cold chisel CPM 1V would make? I know a lot of cold chisels are made from S5 and S7....Hmmmm might be a pretty pricy cold chisel in 1V.
:eek:
 
And then there's also stuff like Aermet 100 which is beginning to be used for punches and other tooling where extreme toughness and strengh is needed. There was another article which I can't find right now where it was written that Aermet 100 has the 2nd highest fracture toughness of any steel.
 
Among applications I wouldn't suggest for 1V is kitchen knives. It would corrode and be a pain to sharpen. On the other hand I'd love to have a hunting knife made of 1V that was as thin as a kitchen knife. That would really take advantage of the material's strengths to allow a high-performance thin blade. I like the combination of tungsten and vanadium in a blade.
 
Originally posted by Rob Simonich
Oh yeah Jerry? Well, the toughest steel i ever used was a D-10 Catapiller dozer I ran at a gold mine. You could tear the hell out of things with it! :D
Click to expand...

Bob Dozer makes knives out of D10? I thought he only worked in D2? ;)
 
Dozier may use D2, but Simonich uses D10 'cause he's such a high roller. ;) :D

I wouldn't use 1V in a normal sized knife quite honestly. CPM-3V is a much better knife steel, with more than adequate impact toughness and good wear resistance. S30V would be a great choice as well, much better for most knife applications than 1V.

I see CPM-1V as a potentially great sword steel and a very good steel for large field knives, hawks and hatchets that will take very hard use, such as military needs. If you want to chop a hole in the earth, 1V would be a good choice. What makes it so novel is that the toughness is associated with sufficient hardness at Rc58/59 to avoid excessive plastic deformation that is the other consequence of hard impacts, besides chipping. It is also hard enough and contains sufficient hard carbides to wear well enough, just not in the same league with other CPM's.
 
So, where can I purchase 1V in small quantities and find out how much it costs?
 
Well, I must congratulate you all on your accurate noses, when you sniff out a new material. And your persistence in looking for it.

1V is a new CPM grade for us, and we do have some limited stocks on hand. We have very little material available in flat sections under about 1" thick (we have a very small amount around 1/2"); we do have some smaller rounds that might be suitable for forging. You can call us at 800-365-1168, ask for Bruce Divita. Tell him ET sent you.

Frannkly we had not planned on much interest from the knife community for this grade; apparently we stand corrected. This grade will be less wear resistant than 3V, and the 3V toughness is so good (don't get me into the toughness debate!) that we did not think you would need higher. However, yes, the 1V has higher impact toughness than the 3V (roughly 50% higher by our testing, if I had to throw out a comparison.) While we have indeed found the toughness to be similar to S7, and in fact hardness-for-hardness perhaps a little better, we would not claim it to be twice the level of S7 (well, we are salesmen, so maybe we would CLAIM that....)

1V will not offer any significant corrosion resistance. It is not a high-chromium grade. We have intended it for indutrial tooling applications requiring high chipping resistance, combined with resistance to softening on exposure to heat, and a moderate level of wear resistance. Not as wear resistant as D2, but between A2 & D2 (probably closer to A2).

If that sounds like your axe, knife, sword, or chisel steel, give Bruce a call & see what we can do for you.

Oh, and for those of you interested in the applications we DID have in mind for this steel, we are looking at, among other applications:

For Hot (Warm) Work:
Hot and Warm Forming Dies
Hot Shear Dies
Hot Heading Dies
Extrusion Dies
Forging Dies and Punches
For Cold Work:
Cold Heading Dies
High Impact Blanking Dies
Punches
Thread Rolling Dies
 
ET, since I got my information off your data sheet, which clearly shows 1V superior to S7 in toughness, I'd suggest you might want to correct that if it's not true. Information I received earlier was even more dramatic.
 
Jerry:

You are correct about our toughness information for 1V. Depending on how we have heat treated it, and how we have heat treated the grades to which we have compared it, we have had some very different presentations of our own data. We have aimed the grade at such varied markets, and our standards of comparison have been different for each market. Our earliest data was more optimistic than what we are currently publishing because we were comparing it to higher hardness materials.

I think regardless of the numbers we have shown for a given situation, you are on the money in that it clearly has the highest toughness by far of any CPM grade we have offered. We'll eventually get our act sorted out, but until then, your own performance results on 1V used as a blade will probably be more meaningful than our lab test numbers anyway. Meanwhile we appreciate you letting us know when we get off track. We can use a little nudge once in a while to keep us on course!
 
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