? about S-30V Steel....

[Slaytanic]

I have a question about S-30V steel.
I recall coming across articles/chat etc.. that talk about grain structure being more important than Rockwell hardness in general with blade steels, I'd like to test that theory out particulary with S-30V.
Now... obviously I'm not a metallurgist and do not have tons of experience with exotic steels, so my knowledge base is somewhat limited. The 1st is a buddy of mine who has a Spyderco Military in S-30V, and he personally wasn't impressed at all with it! He's a field adjuster for an INS. Co. and uses his knives daily, cutting paper/molding/fabric/plastic etc... He said he personally didn't really see any difference in performance between his CRKT M-13 tanto & spear points in AUS-8 in terms of edge holding/toughness than the Spydee in S-30V? My Boss has a Microtech Amphibian in 154cm and used to have an LCC in S-30V(my old one) He basically feels the same, He said he thought his LCC went duller much quicker in S-30V than the Amphibian in 154cm, which he says he can't seem to dull? So.... to sum up my rambling post when You get into the higher quality steels like VG-10/154cm/ATS-34/S-30V etc.. do You think the the degree of the edge grind, and a high rockwell 60+ means more than grain structure??? And does S-30V only seem to live up to the hype when it's at 60+ rockwell?? Also, does anyone know the rockwell hardness of the 2 S-30V knives listed above??


Thanks,
Darrell................




Keep Supporting real Metal!!

 

[SIFU1A]

i know that i havent seen a lot of diff in cutting ability between M2/D2/ATS134/154CM/S30V/VG10 imho the grind might make at least as much diff, sure the better stuff wears a LITTLE better, and is a LITTLE harder to sharpen, but its not that much diff imho, lol when folks worry about sharpening them, isnt a biggie imho, also have a talonite maxx from d ralph, it too is a LITTLE harder than the D2/M2/S30V, but only a little.

imho all of the better steels are pretty good.

 

[dsvirsky]

Over on another forum, Jerry Hossom has talked about his observation that S30V is not as tolerant of a coarse edge as other steels; i.e., it will dull quickly unless you put a polished edge on the knife. If your friend and your boss like a "toothy" edge, it may well account for the performance that they're obtaining.

 

[guy g]

I gotta go check that out! My Small Sebby doesnt hold an edge very well. I sharpen it to a sharp utility edge on my Sharpmaker medium stones. This has worked on all of my other knives including my BG42 CRs. Good lead.

 

[thombrogan]

Slaytanic,

Your name keeps bringing up beautiful songs from my childhood... Never thought I'd feel wistful while "Die By the Sword" plays in my head. Anyways...

If you compare two different steels at the same RC, other factors will come into play. For knives with blades 4" or less, like most of us use for our EDC folders, hardness is one of the most important parts of edge retention and is more important than wear-resistance and toughness. The S30V in my Benchmade and some of my Spydies was at RC58. Okay sharpening, okay edge-retention; had nothing on my knives in M2, D2, and SGPS. Sent them to Phil Wilson to be rehardened to RC 61. Now, their edge-retention is remarkable compared to their former selves and, when the dreaded spectre, Dullness, comes to roost, they resharpen quicker than when they were softer.

If your uses require more toughness than hardness, choose a different steel. If you experiment with having Phil Wilson or Paul Bos reharden your blades to RC 61, your knives with seemingly over-rated steels will live up to the hype. Most knifeknuts will tell you the steel will be too brittle, but it outperform its former self even during uses which you may think require toughness over hardness, so brittle schmittle!

Also, take Jerry Hossom's advice and put as polished of an edge on your knives as you can. If they lose cutting ability, take SIFU1A's advice and adjust the blade grind.

 

[Slaytanic]

Thanks Guy's! this is interesting.. "My Small Sebby doesnt hold an edge very well. I sharpen it to a sharp utility edge on my Sharpmaker medium stones. This has worked on all of my other knives including my BG42 CRs." Ya know I had a SOG auto clip in BG-42 and could not for the life of me get that thing sharp after it lost the factory edge :grumpy: ??

-Polished edge on S-30V performs better than "toothy edge" I would have thought the other way around? hmmm......

- Thom Brogan, so... I was a little on the right track with the higher Rockwell, and so basically You really could have some S30-V at a lower rockwell that might only perform as well as a good batch of AUS-8??
(Your name keeps bringing up beautiful songs from my childhood... Never thought I'd feel wistful while "Die By the Sword" plays in my head.) NICE! still a slayer fan??

Thanks Guy's!
Darrell.......................

 

[Cliff Stamp]

-Polished edge on S-30V performs better than "toothy edge" I would have thought the other way around? hmmm......

It depends on what you are doing. If you are slicing you want a more aggressive edge, for push cuts an aggressive edge will go dull fast. It has nothing to do with S30V, if S30V was unresponsive to more aggressive edge finishes then this would mean the grain structure is poor, not fine.

That statement is nothing new from Hossom, he has been saying the same thing about aggressive edges in general long before S30V came out. It just depends on what the knife is being used for. If you are cutting rope then an aggressive edge on AUS-6A will outlast a polished edge on S30V all day long, and yes even if Bos heat treats the S30V.

If your friend is seeing poor edge retention in S30V I would look at the respective geometries of the blades in question, specifically check to see if the S30V blade is chipping and is the angle significantly different than the AUS-8A blade.

-Cliff

 

[STR]

I guess if you want to see a stark difference in the edge retention of two steels you would need to grab as sharp a bronze knife as you can find and start carving a piece of wood and then grab a steel one and do the same and compare. Then you'll notice. But from steel to steel. I don't see it as standing out all that much. To me a 150 year old steel like 1095 holds it's own against any of the new stainless steels for edge retention. The stainless just looks better longer.

The only significant difference I have seen in my own uses of the differing steels is that steels like D2, some of the S30V and M2 blades that are way harder usually than the other blades being made take a lot more strops or effort to get them back to the level of sharpness they were at when you first got them than the other steels do. It may be the hardness level of the blade or the grain density I'm not sure. They are harder to sharpen though.

To me it doesn't pan out to have a knife so hard that it makes it difficult to sharpen when you do need to touch it up so I tend to shy away from these steels now. I bought into the hype for a while though. However, the edge retention that was promoted by these harder blades and the people and/or companies making them just didn't pan out to me to end up making them worth having.

I get as much use and edge retention out of my Rockwell 56 high carbon blades as any of these new very expensive steels and they sharpen right back up in a hurry compared to these new so called "super steels". While you would be sitting there trying to get your super hard blade of D2 or M2 or S30V sharp again I'd be back up and running with mine after a few strops so to me its a no brainer.

 

[Cliff Stamp]

The stainless just looks better longer.

I like the look of an old patina on a 1095 blade personally.

They are harder to sharpen though.

You really have to take care when you grind knives from really hard and wear resistant steels, unless the edge geometry is near optimal and the steel really well suited to the work they are horrible to resharpen.

For a pure cutting blade, which is all those steels should be used for, the edge should have an edge bevel which is just barely visible and honed at an angle under the user sharpening angle and the primary grind relief very strong to prevent edge thickening.

These knives should also only be used where chipping and other forms of edge damage are not a concern. If any of these do not hold to be true, sharpening is really problematic.

-Cliff

 

[STR]

I like the look of an old patina on a 1095 blade personally.

I do too. Sometimes I soak them in warm vinegar after cleaning the blade up just to get that patina right away. I like the look of that 'blued' steel. I can relate to that completely Cliff.

 

[Cliff Stamp]

I think with me it is just that broken in look. Most blades also look better to me after I give them that full first sharpening even though the edges are no longer symmetrical, uniform and the flats are all scratched to hell.

-Cliff

 

[sodak]

Thombrogan,

How did you get hold of Mr. Wilson? I tried email a while back, with no luck. Maybe I'll try calling.

As for geometry and steel suitability, I've gotta put in a plug here. A couple of years ago, I got a Queen fixed blade (4180) in D2. A hunter blade. At first, just horrible. Came to me dull, couldn't get it sharp. since it cost under $40, I thought, what the heck. Put it on my Edgepro, and took the primary grind down to about 15 deg included. Total time invested, about a half an hour. Oh my....

It's now a different knife. The edge outlasts almost all of my other knives, I can strop/steel it back in about 30 seconds, and it still lasts a whole lot longer than many other knives that cost 5 - 10 times as much. Queen got the heat treat right on these.

I really scratched it up taking the grind down, very ugly, now I wouldn't trade this knife for the world.

 

[thombrogan]

STR,

Hardness doesn't always mean difficulty in resharpening. Reprofiling, sure, but that's different.

Sodak,

The only contact info I use is his email address: seamount@bigplanet.com He can be hard to reach at times. Patience is always good.

On a hardness of blade related note, Blade Magazine had an article on D2 last year and a Queen/Ontario said they ran their knives at RC 58 for easier sharpening and finishing.

Slaytanic,

They were the last live show I've attended (and with five days of tinitis, yep, that's the last!). Hearing "Raining Blood" as an encore was pure rapture. Now, my "Reign In Blood" cassette rides in my glove compartment for traffic jam stress relief. Yep, Slayer is a rock-n-roll combo in the tradition of Buddy Holly (drums, bass, guitars, singing and nothing else).

Back to steel:

Hardness isn't the only issue for edge-retention in light cutting, but it's one of the most important. More hardness means more martensite means more chance of carbide formation (assuming the steel has enough carbon and alloying elements). The harder you use your knives, the muddier the waters get, but for EDC use, hardness and thinness rule the roost.

Cliff Stamp,

I think you may retain cutting ability, but not the sharpness of the edge if it's toothier. I have knives with very thin edges which cut very well when smoothly polished, but when their edges degrade (through wear, deformation, or chipping) they still cut fairly well. They're related, but not identical. I think I learned that from you.

 

[Cliff Stamp]

I think you may retain cutting ability, but not the sharpness of the edge if it's toothier.

The sharpness is higher for slicing when left rougher, but lower for push cuts, sharpness being defined by the amount of force necessary to make a cut in the limit of no wedging forces exerted on the blade, ie. a hypothetical blade with no thickness.

Note if S30V had lower performance on rougher finishes than other stainless steels, ie. there was something limiting about the steel in this aspect it would mean you are seeing carbide tear out, or ultra-brittle performance as the teeth break off. This really isn't an issue with any steel I have seen even for ones that are poor in that regard.

I have taken D2, which has a huge clumpy grain structure compared to S30V, down to nothing edge wide (edge grind is primary, so ~5 degrees per side), which a huge rough finish, 100 AO, and it caught hair above the skin, sliced 3/8" hemp readily with less than 10 lbs, and made over 2000 cuts before it took over 2000 lbs
[*].

[*]It should have been over 4000, but I was sloppy on the last 1000 and exerted too much pressure on the cuts, putting more than was necessary and it blunted prematurely based on the performance through the first 1000. One of these weeks when I have nothing better to do I'll repeat that work and confirm that hypothesis.

The work that I have seen Hossom use to promote his blades is that which does well with a smooth finish, irregardless of the steel, thus it makes sense for him to promote this finish. There is however lots of other work at which this finish is less than optimal, and some for which it is a downright horrible choice.

-Cliff

 

[JDBLADE]

Besides the proper heat-treatment as steel is only as good as its profile and the way it is sharpened. If you take a meatworkers boner eg which is normally made out of something like 440A and heat-treated to about 56hrc once the worker has finished the profile which will basically has no secondary edge at all it will be used all day with regular strokes on a smooth steel. That knife will probably last all week until it revisits the stone to be re-sharpened. No "miracle" steel has been used just good old knowledge of edge geometry and sharpening ability. Of course that boner will last about 6 weeks before it is thrown away and a new one broken in. What this does illustrate and has been mentioned above is that neither heat-treatment nor grain structure is the only element in a good blade but that the correct profile and edge are also vitally important.

One of the reasons we have steels such as D2, S30V & VG10 is that we want a knife that is going to last and cut well without the microscopic edge of the meatworker. Not many people would accept an EDC blade with the same steel and profile of the meatworkers boner just as the meatworker would not accept a blade of the same steel and profile of your best EDC. But still it comes back to any knife regardless of steel and heat treatment having the right profile and sharpened edge for the job at hand. I think in many cases we expect too much out of our EDC's whilst they can be multi-functional they can not carry out every cutting job we give them to the same highest level because different jobs require different profiles etc. That is why many people carry more than one folder and have a selection of knives because they no that one knife can not do everything you ask of it.

 

[thombrogan]

The sharpness is higher for slicing when left rougher, but lower for push cuts, sharpness being defined by the amount of force necessary to make a cut in the limit of no wedging forces exerted on the blade, ie. a hypothetical blade with no thickness.

I stand corrected. Thank you.

That is why many people carry more than one folder and have a selection of knives because they no that one knife can not do everything you ask of it.

I'd argue that is why we should carry more than one folder and have a large selection of blades. For almost everyone, it turns out that we do have several blades for several different purposes. Still, I bet most of us knifeknuts carry more than one folder because it just feels right.

 

[Cliff Stamp]

Besides the proper heat-treatment as steel is only as good as its profile and the way it is sharpened.

Geometry defines performance, steel sets limits on functional geometry.

If you take a meatworkers boner eg which is normally made out of something like 440A and heat-treated to about 56hrc once the worker has finished the profile which will basically has no secondary edge at all it will be used all day with regular strokes on a smooth steel.

Make the same knife out of 1095 or M2 at full hardness and he cuts all day long with no strokes on any steel.

-Cliff

 

[JDBLADE]

Make the same knife out of 1095 or M2 at full hardness and he cuts all day long with no strokes on any steel.

-Cliff

True - but firstly, government regulations would not allow the use of non-stainless steels. Secondly even if used steels such as S30V to their full capabilities you would have a hard time convincing the average meatworker to try it as one would be the expense involved and secondly would be the hardness for some reason (I expect if is sharpening and time involved) meatworkers do not like to use hard blades. We did some work with chicken boners using 154cm and whilst they liked using the blades produced they just could not agree with the costs, both time and money, involved.

 

[Cliff Stamp]

True - but firstly, government regulations would not allow the use of non-stainless steels.

BG-42 at 64 HRC then.

...convincing the average meatworker to try it as one would be the expense involved

There is this, the customs would run 10x the cost of the current models.

...and secondly would be the hardness for some reason (I expect if is sharpening and time involved) meatworkers do not like to use hard blades.

Alvin checked this, all the ones he tried fell in love with them, not just meat workers but lots of others as well.

Sharpening is trivial with the right geometry.

-Cliff

 

[sodak]

Who would be willing to make a custom blade out of either 1095 or M2 at these hardnesses? I'm tempted to try it, depending upon the $$$.