Rethinking S30V

[Cliff Stamp]

Alot of what happens with S30V seems to depend on the heat treat.

As with everything, but S30V's responce to heat treat was supposed to be one of its advantages.

Of course, I am really looking forward to the new CPM154.

Why, it is just ATS-34 with a new name. Yes a CPM process will lower carbide segregation, however this would mainly be felt in raising machinability and a slight gain in wear resistance. It should not put it over S30V based on the initial promotion of S30V by Crucible.

-Cliff

 

[Habeas Corpus]

I always thought that the general consensus was that powered steels performed better when laminated making the powdered steel the central core but I guess new techniques or improvements have made that school of though obsolete with some of them.

I'm not sure about that. The other possible explanation is that laminated blades are harder and thus more costly to manufacture. And some manufacturers do use powdered steel in laminated blades, Faellkniven for instance in the U2. There's also the upcoming sprint run of the Spyderco Delica and Calypso Jr., they will have laminated blades with ZDP-189 as the core.

Hans

 

[thombrogan]

I've begged Phil Wilson to reharden some of my production blades (he's a custom maker with extensive experience involving S60V, S90V, 10V, S30V - if Crucible makes it and it has a v; he's heat-treated it) and was lucky that he did. Before his treatment, they scoped at RC58 for most and RC59 for one and then most came back at RC61 (one came back at RC60.5-61).

Their edge retention jumped past their previous levels and, while they'll still chip when I do something stupid, they're less likely to chip than the edge of my currently un-Wilsonized Manix.

Of course, there's more to chip-resistance than hardness. An S30V blade hardened to RC60 and not tempered will likely chip more easily than one hardened to RC63 and tempered down to RC61 or RC59.5 (the magic RC numbers for S30V heat-treatments of Wilson and Bos respectively).

 

[STR]

Why, it is just ATS-34 with a new name.

I read a post not long ago from Sal saying that there is a difference between the original and the newer 154 steel which kind of indicates to me a question mark on your comment here. Not sure where the difference lies but there must be something better about the newer mix over the older. Sal's comments are here: http://www.bladeforums.com/forums/showthread.php?t=345427&page=1&highlight=cpm154

Personally I've had more trouble getting ATS34 and 154CM sharp than any other steel. Well, it gets sharp but it has never seemed to get to the point where I'm really all that pleased with it if that makes sense. Certainly not in the same league as VG10 or S30V and for sure way outclassed and out cut by D2.

 

[FitzSimmons]

woo hoo! first post here but I've lurked for a while.

I think this is a really interesting thread. I've also been enamoured with S30V but I keep reading everywhere about chipped blades and brittleness. I don't know how everyone else falls out on this, but blade strength is generally more important to me than edge retention. I've found more than one occasion to use a knife as a crowbar, and in a real pinch, I can sharpen an edge on a rock if need be.

The main lesson I take away from this thread is that my survival knife needs to be my edc knife. It needs regular stress testing to insure it will perform as advertised in a pinch. Even the best manufacturer can get a bad lot of steel, and not every steel measures up to its hype.

I'm leaning toward getting a D2 now and trying that for a while instead of an S30V. (I really like the looks of the Thorn Dozier but that skinny blade looks too tactical and kind of fragile.)

 

[STR]

Welcome to the forum.

You'll find that a lot of the Dozier grinds on D2 are particularly thin profiled. For the most part the D2 is a pretty tough steel. Not quite up there with A2 by any means but it keeps an edge better so to me the pay off is pretty good besides D2 is way more stain resistant than any other non stainless. I have reprofiled some tips on D2 knives though so yes, they can and do snap if taken to their limits. Cliff did some tests on a couple various brands in D2. Swamp Rat I think makes a good tough one but you can't really go wrong with a Dozier. No one, IMO makes better use of D2 than Bob. He has built his rep on that steel and knows it's limits.

As for the Thorn. I have two of those and like them both. Honestly they stay sharp longer than anything else I carry and the blades are just a spear point with a false edge that is quite useful. Only thing I didn't care for much is the top wing on the spine part. I took that off on my silver one because it is right where I want to put my thumb when using it.

Oh, and I know a guy that can really doll up a black Ka-Bar Dozier Thorn for you if you want to make it even more unique and beautiful. If you note on this one both the top and bottom wing have been removed. I left my silver one with the bottom one though.

 

[mschwoeb]

I have heard that CPM154 looks to be inbetween BG-42 and S30V in its attributes.

 

[Blop]

If you want to get in touch with CPM 154, take a blade of RWL 34.

 

[Blop]

I don´t know what is meant by tough, but D2 is not tough in terms of toughness considered with blades and edges.

Any hard steels can hardly be called tough. It should be called hard, even though some may say tough but just mean hard.

D2 is a hard steel, considering its carbon content. Every steel with a carbon content over 1% is rated as a hard steel.

Even tempering D2 up to its secondary hardness level doesn´t make it tough, it nearly remains at its low level. It needs four times more forces to bend and finally break some carbon steels at same hardness than D2. There are steel grades less tough, but D2 is not what i would consider with toughness.

That´s what anybody would seriously tell you. D2 is taken for it´s wear resistance and ability to take high hardness.

Back to S30V:

For me the chips indicate, that the carbide distribution is not that perfect as promoted and that there are sections with more and sections with less carbides.

I had the chance to look at a picture of S60V where you could see how many carbides are there and how they are spread. I guess S30V is quiet similar, just less carbide but all in all and compared to other grades pretty much. The CPM steel grades are so crowded with carbides, that it is no surprise, that the edge chips from time to time.

If the carbides are not held enough by steel matrix, they tend to fall out. As Cliff has said oftenly, if the matrix is to soft, the tendency increases. If you resharpen the edge, you take away tha matrix and so micro chips may apear right after sharpening.

So, if S30V is wear resistant enough for your edc tasks and can handle the things without real blade damage (oposed to edge chiping) it may be ok.

If an edge is wanted, where are much less micro chips, try a different steel.

 

[Cliff Stamp]

Their edge retention jumped past their previous levels...

Have you noticed any difference in sharpening?

I read a post not long ago from Sal saying that there is a difference between the original and the newer 154 steel ...

The CPM process would improve wear resistance through lower carbide segregation as noted, which should improve a CATRA score, note however the Crucible clearly is promoting this as a step down from S30V, just a cheaper alternative, similar as S30V was for S90V. I have no doubt that this will quickly be forgotton as it was for S30V.

This is linked to in the thread you referenced :

http://www.bladeforums.com/forums/showpost.php?p=3048294&postcount=54

note specifically :

"CPMS30V does have one or two shortcomings. It is more difficult to finish than ATS34 and 154CM and it does cost more.

Because we do listen to custom knife makers, we are now offering CPM154. CPM154 is our attempt at offering a premium stainless knife blade steel that is more user friendly - easier to finish - easier to grind and polish."

Thus this is a step up from ATS-34 without going to the cost of S30V.

For the most part the D2 is a pretty tough steel.

In my review of the Agent you critized light tip work which broke the knife because in your words :

I simply feel D2 is a very brittle steel...

http://www.bladeforums.com/forums/showpost.php?p=3026670&postcount=67

Noting that just stabing D2 blades into wood will break the tips off.

-Cliff

 

[STR]

I still content that it does break at the tips Cliff as I have seen often enough as you know. But I think I clarified that here because the D2 blades are usually such a thin profile compared to other steels.

I don't remember where I put it here but I said something to the effect that a D2 blade the same thickness, shape and blade profile as say the Manix would, in my opinion be very strong and tough, but the truth is you hardly see guys that use D2 making a blade that thick with it. Most feel that the D2 steel is tough enough and strong enough to be taken to a thinner profile than other steels which is of course why it can break and appear to be brittle. Other than the Dozier Agent that you broke in your test I have never seen a D2 blade broken that bad. Just the tips are what I've seen snapped off.

If you remember, I also said that D2 was something I owned and used and that it kept an edge better than anything else I owned. I obviously am not diswayed by the tip breaking I see in this steel. I just know that I have repaired several and that was why I was surprised at your test when you broke that tip but I really don't want to rehash this out with you again and I'm sure you don't either.

You quote me correctly though. Practical experience has shown me that D2 like any other steel when ground too thin is brittle when thinned down and yes, prying or even stabbing it in wood has been what broke them as it was explained to me while I reprofiled them back to a point for the various owners. With my own Queen D2 whittler it broke a tip while carving pine. Just too thin once again. On the D2 knife I made for my Brother-in-law and had Bob Dozier harden for me the tip broke on a deer bone.

Since those posts many emails have been shared with you and several other knowledgeable folks over some of the things said there and from what I've experienced with regards to D2. The general education that occurred from these exchanges has led me to believe that the D2 steel from most makers is a tough hard steel but frequently taken to thinner profiles than say another steel would be taken to in the same size blade. This could easily lead one to believe or observe that there is a "brittleness" that may not actually be brittleness per say, but in fact pushing beyond the limits of the steels ability to remain intact by making for that thin of an edge or tip profile.

I concede that life is a learning and growing experience. I said D2 was a brittle steel based on practical observations, but as we know things are not always as they appear. It would have perhaps been more accurate to say 'D2 is a thin steel' in the cases I experienced as that would have more aptly explained what I have seen in the way of tip breaks with this steel.

 

[Cliff Stamp]

Most feel that the D2 steel is tough enough and strong enough to be taken to a thinner profile than other steels ...

Toughness generally refers to the ability to take sudden loads, impacts. D2 does this poorly, it also has little ductility. D2 however has a high wear resistance, and is a fairly strong steel at the high hardness it is usually ran 61/62 HRC. It is a really nice steel in thin cutting knives as it is highly optomized for that type of use.

...D2 like any other steel when ground too thin is brittle when thinned down

Steels don't get more brittle as they are thinned down, they get more flexible. It takes less force to bend them of course, as they are weaker with the reduced cross section, but they will bend to a higher angle before they break.

If you take a steel like L6 and grind it really thin, it doesn't become brittle. The Barteax machetes in 1/16" and 1/8" stock can take a massive beating as the steel is inherently tough. They can of course flex readily, but are very ductile.

-Cliff

 

[STR]

I agree to some extent but that doesn't explain the easy tip breaks with very little 'bending' before it snapped really.

As I said this forum and others like it are a classroom to a large extent. The reason we all come here is just for this reason and to improve on our hobby and for some of us our craft. I know I stand here a better knife maker because of the impact and effect of input and knowledge from this forum and it's twin at KFs.

Now, as for your comments of D2 not taking sudden impacts well, it seems to me your test on that Swamp Rat says otherwise at least regarding the thicker parts of the blade, even if it did indent dramatically. http://www.physics.mun.ca/~sstamp/knives/safari_skinner.html As I recall that was one tough little knife that had the living $hit beat out of it and it took it and asked for more! If these pictures don't define tough then I don't know what it is. Don't toughness and flexibility and wear resistance all go hand in hand? http://www.bladeforums.com/forums/showthread.php?t=322561

It also would seem that some of the troops with one of Doziers tacticals would strongly disagree: as I know they have beaten their knives up also. I do agree that D2 is not as tough as an A2 or M2 steel based on other tests and what I've read but certainly D2 holds it's own compared to other stain resistant steels.

What I mean by that is that I put D2 in comparisons often with stainless even though it technically is a non stainless: as it performs much like stainless does in resisting color change and rust, perhaps better than some of the so called stainless steels do. My experience with ATS34/154CM and S30V is that they readily form rust particles just from daily carry if not watched carefully, particularly around the pivot.

Surely you would concurr that D2 is the most stainless of the 'non stainless' steels?

 

[Crushenator 500]

I think it's clear what the answer is here... INFI for the win!


-- Ignore this post please.. --

 

[Critter]

I have been a big fan of S30V, but I'm rethinking that position because two of my blades -- a Manix and a Ritter RSK -- have chipped from light chopping of small (less then pencil size) branches.

When I take my morning walk, I sometimes find a small branch growing over the drive, so I slip my knife out of my pocket and give the branch a quick trim. Nothing big, just alder branch/twigs and blackberry branches.

But both blades have developed tiny chips in the edge. I haven't had this problem with other steels, so what's with the S30V? Does it require a lower hardening treatment?

Twindog,

I apologize for the delay responding, but I've been somewhat under the weather. Whatever probelms some have had or think they have had with S30V, based on my personal experience abusing the crap out of the RSK MK1s, chipping generally shouldn't be a major issue, though most any steel will chip to one degree or another under the right circumstances, and certianly not from chopping small branches as you describe. Please contact Aeromedix for a replacement (I've advised them), I'd like to get this blade back to examine.

Thanks and again, I apologize for the delay and for this issue you've had.

 

[Cliff Stamp]

Whatever probelms some have had or think they have had with S30V ...

Doug, there have been many complaints about S30V in regards to durability by many different people, I don't think the "think they have had" is warrented, plus consider the effect this type of statement has on people who just want to share their experience about the knives. Though I agree with you the steel when hardened correctly should be able to take small brush without harm.

Don't toughness and flexibility and wear resistance all go hand in hand?

Impact toughness and ductility tend to increase together, wear resistance tends to be optomized along the opposite path as you need a high alloy content, though it can increase slightly with deep cryo, the CPM process and other methods which reduce carbide segregation.

D2 holds it's own compared to other stain resistant steels.

It stands similar with ATS-34, but not to 420HC, and similar.

As for Swamp Rat's D2, the work they did does indeed show decent toughness for that class of steel, however this would not compare well to for example the SR101 they use. They also don't claim otherwise and still promote the SR101 for the heavy use.

It is all about baselines, this is why you get people like the guys you mentioned with Dozier's tacticals. You get for example some people who will claim a knife is extremely tough because you can hit it with a piece of wood and it doesn't shatter. Take someone who has used, and I mean really used one of the tough spring steels and ask them to workout D2 and ask for their perspective.

-Cliff

 

[STR]

This is true, I guess for the purposes that D2 is usually made for like skinning and pocket folders it is plenty tough. Some of the bigger fixed blades in it have a pretty good edge all the time so it is a compromise to some extent there I guess to get that edge keeping D2 is known for but not so much of a compromise at all in a folder or skinner. As I recall the thickest blade Bob makes is like a 3/16" thick and most are like 1/8 so when you compare what people are doing with the D2 knives with those thinner blades they seem pretty tough to me, especially when compared to a 1/4" leaf spring or a 5/16" one. What would the D2 be like at those thicknesses so it was and apples to apples comparison Cliff?

I made a knife once out of a 50 Chevy truck spring. It was a beast at between a 1/4" and 5/16" thick. What a monster that was. It was plenty tough come to think of it, but it could only be made to barely shave hair and was too thick to really do much with other than break cinder blocks or chop or hack down bushes and limbs.

I sold that one about 7 years ago after having it for nearly 12 years under the seat of my truck. Forgot all about it till you mentioned leaf springs. Had to dig for a few to find the pic of that one. It all came back to me after that. Nice elk antler handle and my first attempt at file work. Don't think I even signed it. I remember using a fishing lure brass shiner for the handle cap. LOL.

 

[Cliff Stamp]

It was plenty tough come to think of it, but it could only be made to barely shave hair and was too thick to really do much with ...

Yeah you really need to do a lot of grinding on thick stock to make a knife, otherwise its just a sharpened club.

-Cliff

 

[Critter]

Doug, there have been many complaints about S30V in regards to durability by many different people, I don't think the "think they have had" is warrented, plus consider the effect this type of statement has on people who just want to share their experience about the knives. Though I agree with you the steel when hardened correctly should be able to take small brush without harm.

Cliff,

I think, perhaps, we're a wee bit over-reacting to my comment. I didn't mean anything insulting by the comment twoards anyone in this thread, nor would I discourage anyone from sharing their personal perceptions of their experiences. That's one of the great values of forums such as these.

Every steel has had its share of issues in production at one time or another. Some folks notice them, some folks imagine them, some folks are blind to them and others just climb on the bandwagon, on both sides. That's no different than with any issue with any manufactured product. I do tend to be wary of broad negative statements that may or may not be relevant to any particular manufacturer's products as produced, whether it is knives or many other products. As a consumer advocate and product testing journalist for nearly two decades, I think I have a little insight into these sorts of issue. I think it's very important to be specific when you have concerns, so as not to otherwise impugn good products.

Certianly some steels are less forgiving than others towards production manufacturing, and S30V does have its peculiarities, but the example mentioned here WRT the RSK Mk1 is certianly an exception. I cannot, and care not to, comment WRT some other manufacturer's knives or production issues. If my personal experience was that S30V had such issues as a matter of course, even when handled correctly, I would not have spec'd it for the knives. I didn't choose it because it was the latest hot steel; I chose it because when treated properly it has some outstanding qualities that I appreciate. Other steels excel in other areas; all steels are compromises. I happen to like where S30V's compromises fall out when done right. Next year I may find a steel that I like even better and I won't hesistate to switch if I do.

The new RSK MkII/BK12 uses a very simple (and cheap) high carbon steel because of the value and performance it offers in that style of knife. While very much more forgiving of manufacturing variences, I've also seen knives made of such steels that exhibited serious issues, but you'll rarely see much written about them because it isn't the hot steel. We also intend to do a S30V version because some folks want a true stainless blade and of those available right now, IMHO, S30V offers the best overall performance. YMMV, but that's what makes this industry so vital, we don't all agree on everything. Be pretty darn boring if we did.

Hope that better explains my comments.

 

[Twindog]

Twindog,

I apologize for the delay responding, but I've been somewhat under the weather. Whatever probelms some have had or think they have had with S30V, based on my personal experience abusing the crap out of the RSK MK1s, chipping generally shouldn't be a major issue, though most any steel will chip to one degree or another under the right circumstances, and certianly not from chopping small branches as you describe. Please contact Aeromedix for a replacement (I've advised them), I'd like to get this blade back to examine.

Thanks and again, I apologize for the delay and for this issue you've had.

Thanks, Critter, but I was not angling for a new knife. Both the Manix and the Ritter RSK are great knives, but it just seems as those these small chips that develop along the edge are fairly common for S30V, although I haven't heard of complaints about the softer Sebenza blade. I'll reprofile both of these knives and see how it goes. If you would like a macro photo, I can email one to you.