Are CPM ( Powder Steels ) More prone to chipping?

[Gator97]

CPM S30V was seriously misunderstood by makers, and HT was incorrect, resulting in chipping or soft, low durability edges. Properly done S30V is pretty good, not my favorite, but perfectly workable.

Well, I've heard that story, too!!!

Never gets dull but easy to sharpen!

Doesn't make sense at all, does it? Ah, but it CAN make sense when we cross over into the supernatural.

Not really, you don't need to get into super natural, just the term "sharpens" is applied different types of work, minor touchups and serious edge grinding. Most of the useres, including BF members, unless they invest serious time in learning sharpening, do get by just by light sharpening and that's easy for quality steels. Some seriously argue their trusty Buck 110(or insert any other knife) never needed any sharpening even though it was used for decades... it all depends what you call sharp and sharpening.
Think of the inverse. Ceramics is a real biatch to sharpen. Takes considerably longer time compared to any steel I have sharpened(CPM 125V, CPM 110V, ZDp-189 etc, all 64-66HRC ish)... Yet the edge it produces will not last as long as the steel edges do. Just because something is hard to sharpen, doesn't mean it'll hold a good edge, and vice versa to some extent.

 

[sodak]

Seems to be a lot of ill-will towards powdered steels. I've done some minor informal testing, and this is what I've found.

1. CPM D2 has about 10% more wear resistance than D2.

2. CPM S30V is my least favorite steel. I jumped on it when it first came out, it did NOT EVER chip on me, but I must have had knives with poor heat treating, because it took a lousy edge and didn't hold it worth beans. I won't ever buy it again.

3. CPM 3V is one of my favorite steels. I've got it from 3 different makers, and for outdoor knives, it's fantastic. Takes a tremendous beating with no damage, and sharpens up VERY easily on a DMT blue/red. I put it right up there with INFI and 52100 as my favorite outdoors/large chopper steels. I consider these 3 roughly equivalent in edge holding and ease of sharpening when used in the woods.

4. CPM 10V (from Phil Wilson) beats just about anything out there (at least in my humble knife collection) in terms of wear resistance. And not by a little bit either, it's probably an order of magnitude, when I do my informal tests. As for a CPM steel at 64.5 HRC being hard to sharpen, I can take this knife from safe-to-drag-across-your-wrist-dull to hair popping sharp in under a minute, easy. The knife geometry is perfectly optimized to take advantage of the steels properties - strength, so it's extremely thin behind the edge. It's my best edge-holder, and one of the easiest to sharpen, an apparent contradiction.

CPM 10V and 3V easily live up to the hype, IMO. This is based on my personal experience, not what other people say. I did have Ankerson confirm my CPM 10V results, and he agreed with me, although the difference for him might be less, as he has more exotic steels than I do to compare it to.

I still like lots of "regular" or "ingot" steels, I don't buy only CPM steels, but there's certainly room for them in my collection.

 

[CrimsonTideShooter]

Seems to be a lot of ill-will towards powdered steels. I've done some minor informal testing, and this is what I've found.

1. CPM D2 has about 10% more wear resistance than D2.

2. CPM S30V is my least favorite steel. I jumped on it when it first came out, it did NOT EVER chip on me, but I must have had knives with poor heat treating, because it took a lousy edge and didn't hold it worth beans. I won't ever buy it again.

3. CPM 3V is one of my favorite steels. I've got it from 3 different makers, and for outdoor knives, it's fantastic. Takes a tremendous beating with no damage, and sharpens up VERY easily on a DMT blue/red. I put it right up there with INFI and 52100 as my favorite outdoors/large chopper steels. I consider these 3 roughly equivalent in edge holding and ease of sharpening when used in the woods.

4. CPM 10V (from Phil Wilson) beats just about anything out there (at least in my humble knife collection) in terms of wear resistance. And not by a little bit either, it's probably an order of magnitude, when I do my informal tests. As for a CPM steel at 64.5 HRC being hard to sharpen, I can take this knife from safe-to-drag-across-your-wrist-dull to hair popping sharp in under a minute, easy. The knife geometry is perfectly optimized to take advantage of the steels properties - strength, so it's extremely thin behind the edge. It's my best edge-holder, and one of the easiest to sharpen, an apparent contradiction.

CPM 10V and 3V easily live up to the hype, IMO. This is based on my personal experience, not what other people say. I did have Ankerson confirm my CPM 10V results, and he agreed with me, although the difference for him might be less, as he has more exotic steels than I do to compare it to.

I still like lots of "regular" or "ingot" steels, I don't buy only CPM steels, but there's certainly room for them in my collection.

The part in red:

A LOT of people confuse "ease of sharpening" with "ease of honing." When most people say they are "sharpening" their knives, they are actually just honing the edge. (steeling, using the sharpmaker, ceramic rods, etc.)

Many of the high performance steels I own are very easy to hone, but when it comes to an actual sharpening they are MUCH harder to work with. Especially with a knife ground as thin as the PW, the edge will be extremely easy to hone since there is a minute amount of steel to remove to get the edge back. I would imagine that your views would change if you had to reprofile the edge. Just my .02

 

[hardheart]

These steels are not hard to sharpen when you have corresponding equipment. With very high carbide fraction, you want very hard and durable abrasives. Diamond and ceramic work well. It can take more strokes to remove enough metal, but this is not hard, just more time consuming. If you can hold a consistent angle, it doesn't matter.

 

[CrimsonTideShooter]

These steels are not hard to sharpen when you have corresponding equipment. With very high carbide fraction, you want very hard and durable abrasives. Diamond and ceramic work well. It can take more strokes to remove enough metal, but this is not hard, just more time consuming. If you can hold a consistent angle, it doesn't matter.

I agree, I've never had a problem sharpening any steel I own. A lot of people say ZDP is a beast to sharpen, but for me it acted like most other high performance steels I've sharpened.

My point was that just honing an edge can't give you a good idea of how a steel sharpens. I have yet to run across a steel that couldn't go from butter knife dull to nearly hair whittling with a few masterfully placed strokes on a ceramic rod or the like.

 

[sodak]

I would imagine that your views would change if you had to reprofile the edge. Just my .02

I don't think so. I've reprofiled quite a few knives in various steels, including CPM 3V, S30V and D2. With an aggressive stone (and my edge pro), I've always found that the amount of metal that I have to remove matters much more than the type of steel that I'm removing. The longest sessions I've spent are with large knives that have a thick primary grind, and when I'm done with them, I have a very large and shiny edge bevel...

My point with the PW was that because the knife is well made, honing the edge is exactly the same as resetting the edge bevel! Good stuff!

 

[CrimsonTideShooter]

I don't think so. I've reprofiled quite a few knives in various steels, including CPM 3V, S30V and D2. With an aggressive stone (and my edge pro), I've always found that the amount of metal that I have to remove matters much more than the type of steel that I'm removing. The longest sessions I've spent are with large knives that have a thick primary grind, and when I'm done with them, I have a very large and shiny edge bevel...

My point with the PW was that because the knife is well made, honing the edge is exactly the same as resetting the edge bevel! Good stuff!

That was my exact point, although I probably didn't articulate it correctly. I wasn't meaning that the steels you mentioned would be ridiculously hard to sharpen, I just meant that it will be a lot tougher to actually recreate the bevel than it will to just hone an existing edge.

 

[BG42EDGE]

It's my best edge-holder, and one of the easiest to sharpen, an apparent contradiction.

Well, truth is, it not only APPEARS to be a contradiction......it's an obvious and glaring contradiction.

Where did this voodoo metallurgy concept come from in the first place?

Could it have been..................SATAN?????!!!!!!!!!???????



Naw, just steel and knife manufacturers trying to make a good living.

(And doing it!)

 

[sodak]

That was my exact point, although I probably didn't articulate it correctly. I wasn't meaning that the steels you mentioned would be ridiculously hard to sharpen, I just meant that it will be a lot tougher to actually recreate the bevel than it will to just hone an existing edge.

Sorry if I didn't read you quite clear enough, sounds like we are both saying the same thing.

Well, truth is, it not only APPEARS to be a contradiction......it's an obvious and glaring contradiction.

Where did this voodoo metallurgy concept come from in the first place?

Could it have been..................SATAN?????!!!!!!!!!???????



Naw, just steel and knife manufacturers trying to make a good living.

(And doing it!)

By the way, my Custom Shop 110 in BG42 is one of my favorite Buck knives! And a very good steel also, I wish I could replace all my S30V's with BG42....

 

[BG42EDGE]

Well, yes.......I DO like BG-42.

Nothing powder-puff about that steel.



I'm sure that some of the powder steels do a fine job......it's just that I haven't been convinced by the information that's out there thus far.

It's almost impossible to get unbiased information.

 

[Buck_110]

1. No
2. Because they have even carbide dispersion
3. Because it isn't about wear resistance, since the alloy composition and hardness are the same. It is about how much effort it takes to get the edge sharp.

1. Even carbide dispersion equates to even wear.
2. The fact that the carbides are dispersed evenly, and the possibility of clusters is eliminated, should result in greater wear resistance.
3. If more effort is needed to hog off steel, it has to be more wear resistant. Less effort would dictate less wear resistance. The very fact that the alloy compostion and hardness are the same, allows wear resistance between the two to be measured accurately. If the alloy composition and/or hardness differ, wear resistance data between the two wouldn't amount to a hill of beans; as more variables have to be factored into the equation.

With a higher quality microstructure, it is easier to form the edge. If the edge is not chipping, rolling, or burring while you are sharpening, then the edge forms faster and more cleanly.

This is true of ingot and powder steels.

Knife steels are compressed in non-molten form. The steel is not remelted to make a blade.

If powder steel were returned to molten form, the purpose of the production process would be negated.

 

[hardheart]

Well, truth is, it not only APPEARS to be a contradiction......it's an obvious and glaring contradiction.

No, it isn't. sodak quite clearly posted that the thin primary grind required less material removal for resharpening. A high hardness, high wear resistance steel ground to a thin edge, will cut well, and for a long time. That thin edge minimizes the amount of metal to remove when sharpening, so it is quick and easy. There is nothing contradictory about it. I don't think sodak is a shill for the steel makers, and I take him at his word.

 

[hardheart]

If this is the case, then powder steels are less wear resistant than their ingot steel counterparts; no?
1. No
1. Even carbide dispersion equates to even wear.

so, is even wear reduced wear?

Powder steels no doubt have even carbide dispersion, so why are they easier to sharpen?
2. Because they have even carbide dispersion
2. The fact that the carbides are dispersed evenly, and the possibility of clusters is eliminated, should result in greater wear resistance.

so why did you say that they have less wear resistance?

What else can it be due to except the fact that they are compressed in non-molten form?
3. Because it isn't about wear resistance, since the alloy composition and hardness are the same. It is about how much effort it takes to get the edge sharp. With a higher quality microstructure, it is easier to form the edge. If the edge is not chipping, rolling, or burring while you are sharpening, then the edge forms faster and more cleanly.
3. If more effort is needed to hog off steel, it has to be more wear resistant. Less effort would dictate less wear resistance. The very fact that the alloy compostion and hardness are the same, allows wear resistance between the two to be measured accurately. If the alloy composition and/or hardness differ, wear resistance data between the two wouldn't amount to a hill of beans; as more variables have to be factored into the equation.

Effort to hog off steel is not the only consideration in shapening. If the steel deforms too easily or chips too reaily, then it will take more work to sharpen properly. Having high wear resistance only necessitates having better sharpening gear.

This is true of ingot and powder steels.

and PM steels have a better heat treat response and a more homogeneous microstructure compared to ingot versions

Knife steels are compressed in non-molten form. The steel is not remelted to make a blade.
If powder steel were returned to molten form, the purpose of the production process would be negated.

exactly, the purpose would be lost, and the purpose is to make better steel.

 

[Steel130]

From what I understand powder steels are not necessarily just better at wear resistance right? as Zknives puts it:

"On the internet, I'll often see someone posting about wanting to upgrade from their ATS-34 folder to one that has S30V, and then in a different post, declare that they sharpen all their knives at 20° per-side. Why spend all that extra money for S30V, just to get some marginal wear resistance advantages but no other performance advantages? If that same user would take advantage of S30V's superior toughness and drop the edge angle to 15° per-side, they would see a large leap in cutting performance, along with the extra wear resistance. Because of choosing the right sharpening angle, the more expensive S30V knife now gives an impressive return on investment. *Now* you can see what all the fuss is about!"

So it seems that powder steels performance can also be seen in being able to hold a thinner edge longer than other steels, not blanketing all steels, but as a goal. S30Vs toughness allows it to hold a stronger edge at say 30* inclusive versus a 440c edge at 30* inclusive. Wouldnt S30Vs increased toughness partially be to the finer grain structure?

Would 3Vs higher wear resistance than S7 be partly due to finer grain structure and an increased amount of carbon and chromium? I am trying to learn here. I dont really like whoever it is trolling that all powder steels are "magical". Simple logic may not help in steel as it doesnt for me. I dont fully understand how a blade can be stronger but not as tough. Seems like the two would coincide. Powder steels all also seem to aim for a more homogeneous structure or more uniform and without as many voids in the piece of steel right?

 

[Buck_110]

so, is even wear reduced wear?

No, it's just that, even. Powder steel, despite its evenly dispersed carbides, doesn't automatically provide greater wear resistance than ingot steel.

so why did you say that they have less wear resistance?

Because based on that fact alone, on paper, they should; but that's not the case, as proved by the ease required to sharpen powder steels as compared to their ingot counterparts. Wear resistance between the two is also goverened by each steel's production process.

Effort to hog off steel is not the only consideration in shapening. If the steel deforms too easily or chips too reaily, then it will take more work to sharpen properly. Having high wear resistance only necessitates having better sharpening gear.

Sharpening is all about hogging off steel; whether it be a little or a lot. If steel isn't moving(in one way or another), the edge isn't being sharpened.

and PM steels have a better heat treat response and a more homogeneous microstructure compared to ingot versions

This by itself can mean something. The finished product will be a testament to the heat treat imparted.

 

[hardheart]

No, it's just that, even. Powder steel, despite its evenly dispersed carbides, doesn't automatically provide greater wear resistance than ingot steel.

it doesn't provide it at all. Despite the claims of lies and hype, a check of comparison graphs shows, as a distinct example, that Crucible claims 154CM and CPM154 have the same level of wear resistance. The carbide volume is the same, the alloy content is the same

Sharpening is all about hogging off steel; whether it be a little or a lot. If steel isn't moving(in one way or another), the edge isn't being sharpened.

No, sharpening is all about reducing the radius of the edge apex, 'hogging' does not require that finesse and attention to detail. Any actions that are counter to this edge refinement extends the sharpening process. Any shortcomings in the blade makes those unwanted actions more likely to occur.

 

[Buck_110]

I dont fully understand how a blade can be stronger but not as tough. Seems like the two would coincide.

As a general rule of thumb, things that are tough are usally strong.
However, something can be strong, and lack toughness.

A two cubic foot block of ice is strong. It'll easily support quite a bit of weight without failing. Tap it with a hammer, and you'll see it isn't tough at all.
Substitute the ice with wood, granite, steel, etc. All will prove to be tougher than ice when tapped with the same hammer.

 

[Buck_110]

it doesn't provide it at all. Despite the claims of lies and hype,...

I agree.

No, sharpening is all about reducing the radius of the edge apex,...

But, this is done by removing steel.

'hogging' does not require that finesse and attention to detail.

Agreed. It's usually the result of too much tequilla, bad judgement, and the fact the bar is about to close.

 

[Longtrang]

I guess the s30v knives I have had were properly heat treated. My Zt0300 holds an edge better than most of my other blades. My Al Mar SERE was scary sharp and easy to hone. I have used both extensively, no chips yet.

 

[BG42EDGE]

My powder steel knife is so hard and holds an edge so well it practically never gets dull...... but it sharpens up real easy when it does get dull.

I drive faster to get better gas mileage.

I can have my cake and eat it too.

If I drink more......I get sober.

I have these shoes......and the more I walk, the newer they get.

Magic shoes.