Lobbying for better knife steel

butcher_block · Mar 9, 2006

maybe its just me but i sharpen all the high V carbide steels with DMT hones and dont seen to have any problems getting a good sharp edge
is that because V carbides have a hardness of 82-84 Rc and im not pushing the carbides around and realy grinding on them instead

chipping is something i had happen to my para but that was all my fault (welds on shopping cart baskets give bout the same time the para chipped i might have put more side load on it then i thought)
butch

Cliff Stamp · Mar 9, 2006

Crompal said:
As you increase corrosion resistance and edge retention you decrease toughness and ease of sharpening.

This isn't strictly true, edge retention doesn't equal wear resistance and ease of sharpening doesn't equal grindability. Edge retention can be strongly dependent on toughness for example (choppers) and thus if you decrease toughness you decrease edge retention. Ease of sharpening is more dependent on suitability of steel for the given application and optomization of geometry that grindability. I have for example lots of blades which have low grindability but sharpen very easily, M2 at 65 HRC, S30V at 60 HRC, O1 at 63.5 HRC, etc. .

-Cliff

JoHnYKwSt · Mar 9, 2006

SteelDriver said:
Keep in mind that the US steel industry does not revolve around the knives; far from it really. AFAIK S30V is the first American steel made specifically for knives. We're lucky Crucible took an interest and actually produced a steel per knifemakers requests. S90V and S125V were not made for cutlery applications in mind, so they don't have the properties many knife manufacturers look for.

SteelDriver, you are definitely right about this. I guess when I read others say that S125V is the answer to ZDP-189, the steel snob in me gets the better of me and I forget that the US steel industry is not competing with Hitachi's ZDP at all and could probably care less. We are definitely lucky to have a steel like S30V developed by Crucible. Thank you Mr Barber for not only developing the steel but also for posting so that we may all learn.

tristram · Mar 12, 2006

JoHnYKwSt said:
I, like others, have experienced improved performance after a couple of sharpenings with S30V.... My point is the direction in which the American steels are moving...
The Japanese push hardness in their steels, the US is in a race with vanadium carbides. I think the vanadium carbides route is reaching the end and its time to look push other things to create better knife steel.
BG42, is a steel that is most similar to the two japanese steels, VG10 and ZDP-189. It has vanadium carbides, but just enough to leave the chromium free for stain resistance. BG42 gets harder than S30V and because of that, edge holding is about equal in my experience, yet it is easier to sharpen. BG42 is for many people their favorite steel....
Everyone concentrates way too much on edge holding in my opinion, and the fact that they will have to sharpen it is pushed to the back of their mind. ....It may sound like I am bashing S30V but this is not the case....It is in fact right up there with VG10, although I do like VG10 better due to its ease of sharping...
I am no metallurgist, and any of the things I've said above may be completely wrong, there is surely more to it that I am missing, and if so please set me right because the above shows the impression I am getting which I hope to not be the case.

Thanks, that all makes a lot of sense to me, though also to me some of the professional talk here is above my comprehension.

psy-ops · Mar 12, 2006

When I first got into survival knives, I was looking for for an indestructible knife. Now as I have gotten older and wiser, I realize that there will be no perfect steel.

Yes, I am sure some will get mad at my comment. I will say, I support exploration in the development of perfect steel.

But I am not wasting my own time or knives in that process. I have adapted my knife usage intelligently. A knife is for cutting (period)! Get another tool when it is needed.

Frankly, I am happy with carbon steels. I have yet to see another steel that out does carbon in any area other than edge retention. My answer to that is I love sharpening. It is one of the most enjoying moments in my life.

I guess if one hates to sharpen then there the problem lies.

Cliff Stamp · Mar 12, 2006

chrisaloia said:
I have yet to see another steel that out does carbon in any area other than edge retention.

Tool steels in general can be stronger, tougher with more wear resistance than plain carbon steels. It isn't just a matter of less frequent sharpening, you can also lower the geometry on those steels and thus the knife cuts better for longer.

-Cliff

WadeF · Mar 12, 2006

As mentioned in past threads, and even this one, people have found that the factory edges on many knives, using various steels, often have problems like chipping, not holding an edge well, etc. However, once the knife had been resharpened a couple times, or enough to remove the steel that may have been damaged by factory shapening (belt sander, or whatever they use, that may generate to much heat and destroy the temper at the edge of the blade), the knives performed much better.

So to the steel experts out there, is there something in the properties of s30v that would make it more vunerable to having it's temper damaged from the way the factories sharpen their knives, compared to other steels?

Cliff Stamp · Mar 12, 2006

It is tempered at similar temperatures to other stainless steels such as ATS-34. However due to the very high vanadium content it takes longer to grind which may lead to more pressure and/or dull belts being used during sharpening unless changes are made from grinding other steels. However if you were grinding something like D2, then S30V isn't much of a change.

-Cliff

WadeF · Mar 12, 2006

Cliff Stamp said:
It is tempered at similar temperatures to other stainless steels such as ATS-34. However due to the very high vanadium content it takes longer to grind which may lead to more pressure and/or dull belts being used during sharpening unless changes are made from grinding other steels. However if you were grinding something like D2, then S30V isn't much of a change.

-Cliff

Okay, so let's say s30v knives and D2 knives take longer to grind, which would probably result in the edges getting hotter than a knife that would be quicker, and easier to grind. How is D2 tempered? Does D2 take a higher temperature to mess up the temper than s30v?

Cliff Stamp · Mar 13, 2006

Both are tempered close to 400F for most knives and thus there is no significant difference in heat resistance, both have secondary hardening responces but they are usually not used.

However everyone who uses D2 knows it is difficult to grind whereas this was promoted as one of the high points of S30V, along with the responce to heat treatment, Crucible has reversed both positions lately in responce to the chipping problems.

Ref :

http://www.crucibleservice.com/datash/S30Vvs440C3.pdf

This is comparing 440C and S30V and note the statements about heat treating being much better than 440C and in particular "excellent grindability".

-Cliff

HoB · Mar 13, 2006

I more and more get the feeling that the only bad thing that happened to S30V and that you can say about S30V is that it got unfortunate enough to become so popular that it is being used in every $100+ knife. Regardless of how it got initially promoted, it seems to me that it is a high-end bladesteel that might have been better off staying in high-end folders, were the additional cost of a careful small batch heattreat and the frequent change of grinding belts is financially sound.

There is no magic in steel treatment, so if Phil Wilson for example can make a knife in which S30V really shines then the potential is in the steel. Only the way others treat the steel is not developing the steel to its full potential. So calling for a better steel is not really solving the problem. Rather the opposite: by demanding a steel that is optimized for an even great range of different properties, it is likely going to be even more complex and even more difficult to treat properly and the likelyhood of something going wrong increases.

This is of course all while still obeying the limits of a steel. If somebody tries to compare a large combat blade made from S30V to one made from 5160 in the same style and stock thickness both tempered to their max toughness, has somehow read S30V's spec sheet wrong.