I'm not a metalurgist. I don't know jack other than what I can dredge up to read. I realize, though, that somehow I've gotten it in my head that S30V, CPM3V, D2, BG42 - just to name some - would all outperform ATS-34; each with its relative strengths and weaknesses, sure, but all preferable to ATS-34 on an overall basis. I've also noticed, however, that many fine custom makers seem to use it, and to say they know much more than I do about steel would be to understate it to the point of ridiculousness. Straighten me out here, would you, fellas?
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Bias against ATS-34...Please enlighten me
- Thread starter cloozoe
- Start date
No bias. You list a bunch of very different steels.
S30V is essentially in principle a direct upgrade from ATS-34. It is more stainless, more abrasion resistant and finer grained, but it is essentially in the same class. And we all know by now that there on occasion issues with it, which likely originate in the way the steel was treated. Also in the same class is BG-42. It is an ingot steel like ATS-34, and I don't know how fine grained it is, but it seems that it has greater edge holding, which at the common bladeangles speaks for higher abrasion resistance. D2 is a semi stainless steel, very coarsely grained, very abrasion resistant. Non of the above are overly tough. 3V is a totally different animal. Nonstainless steel also powdermetal, together with the low chromium content would make me assume that it should be much finer grained than any of the above. In principle it is a VERY tough steel.
Hope that helps.
S30V is essentially in principle a direct upgrade from ATS-34. It is more stainless, more abrasion resistant and finer grained, but it is essentially in the same class. And we all know by now that there on occasion issues with it, which likely originate in the way the steel was treated. Also in the same class is BG-42. It is an ingot steel like ATS-34, and I don't know how fine grained it is, but it seems that it has greater edge holding, which at the common bladeangles speaks for higher abrasion resistance. D2 is a semi stainless steel, very coarsely grained, very abrasion resistant. Non of the above are overly tough. 3V is a totally different animal. Nonstainless steel also powdermetal, together with the low chromium content would make me assume that it should be much finer grained than any of the above. In principle it is a VERY tough steel.
Hope that helps.
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I'm not a metallurgist either, but it seems to me that ATS-34 is a very good steel. My opinion is based solely upon the performance of the knives that I own that have ATS-34, and I have found them to take a fine edge and hold it very well. For me, that is all that matters.
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I think the reason ATS-34 has fallen out of favor has less to do with the performance of the steel than with the inconsistency of the steel being produced. I have heard/ read several reports that the quality of ATS-34 available now is not what it once was. This doesn't mean that there's anything wrong with knives made from the stuff before, it's just that it's hard to find good ATS-34 now.
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s30v was design to be a knife steel. ATS-34 was the Japanese answer to American 154. I do belive the 154cm steel design for jet turbine blades. ATS 34 became in favor due to some poor 154cm. Funny how table turns with ats-34. D2 is a tool steel with chromium a hair under the 13% to make it stainless. CPM3v is tool steel make similar to s30v...using powder and forming under high pressure. 3v is not stainless but many believe it toughness is very high. I will enjoy reading other input.
If you suggest one steel outperforms another, then you need to define the performance parameters. Toughness, abrasion resistance, hardness, cost of machining, corrosion resistance etc etc. are all performance parameters. That's why there are so many steels for so many purposes. It isn't a simple answer. There is no ladder with each steel inhabiting its own rung. If you want to talk about performance, you need to define the performance parameter.
All the steels you mention do some things well and other things not so well. It is the nature of things.
All the steels you mention do some things well and other things not so well. It is the nature of things.
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I'm not biased against ATS-34...
I think it's an excellent stainless.
Takes a great edge, holds for a good long time, has good toughness, and you can get a great finish on it too. Pretty easy to sharpen as well.
In fact I got two new ATS-34 knives just in the past few days.
(My all around favorite stainless, though, is BG42.)
I think it's an excellent stainless.
Takes a great edge, holds for a good long time, has good toughness, and you can get a great finish on it too. Pretty easy to sharpen as well.
In fact I got two new ATS-34 knives just in the past few days.
(My all around favorite stainless, though, is BG42.)
S7 is tough, for one example.
I think it depends on who is doing the heat treating and such. I think Dozier is the best with D2. Also, there is a modified D2 that is supposed to have more chromium in it. I just inquired about having a knife made of that. I really like D2. I have a ATS-34 fixed custom and love it. Holds an edge fairly well and is easy to sharpen.
ATS-34 is a great knife steel. The problem is that in the last several years it has some quality problems that are probably more cosmetic than anything. The issue is this: knife makers got tired of the inclusions that popped up on a blade that you had several hours of work into. Inclusions are dark spots of junk/slag/who knows but they absolutely ruin the blade cosmetically. The other issue was/is that there were weird blotches showing up in the finish that would not buff or sand away. Again, a blade that is ruined cosmetically after several hours of work. This wasn't in every piece of steel but it was often enough to be a problem. I tried ATS34 from 3 different sources in both hot and cold rolled and had the problems across all three sources and finally gave up and moved to 154CM which does not have those issues.
Esav Benyamin
MidniteSuperMod
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As each new steel comes on line, it is valued by the experts for the peculiar strengths it brings to the mix, and valued by the masses for its novelty, and the hype surrounding its introduction.
With one new steel after another popping up, the best steels of a few years ago seem to fade in the masses' memory, but the experts having by now become familiar with them, manage to get excellent performance from them.
Some people will tell you that 440 steels are less than impressive and so 440C is yesterday. But 440C is one of the best stainless steels ever, for performance, corrosion-resistance, and polish.
But it's old!
Consider also that the differences in performance are often small, and the difference in heat treatment, blade geometry, and specific use of the blade are often much more important. How about making the blade of a gentleman's knife, designed to sit for months in a pocket, from the toughest steel available?
Why bother? It will never need that toughness. 440A might be better: cheaper, more easily worked, easier to resharpen if it ever does dull under the light use to which it might be subjected ...
To answer the original question directly, don't asssume any widespread bias against ATS-34 simply because few people discuss it anymore, and a few may speak from bad advice, not having personal experience to draw on.
With one new steel after another popping up, the best steels of a few years ago seem to fade in the masses' memory, but the experts having by now become familiar with them, manage to get excellent performance from them.
Some people will tell you that 440 steels are less than impressive and so 440C is yesterday. But 440C is one of the best stainless steels ever, for performance, corrosion-resistance, and polish.
But it's old!
Consider also that the differences in performance are often small, and the difference in heat treatment, blade geometry, and specific use of the blade are often much more important. How about making the blade of a gentleman's knife, designed to sit for months in a pocket, from the toughest steel available?
Why bother? It will never need that toughness. 440A might be better: cheaper, more easily worked, easier to resharpen if it ever does dull under the light use to which it might be subjected ...
To answer the original question directly, don't asssume any widespread bias against ATS-34 simply because few people discuss it anymore, and a few may speak from bad advice, not having personal experience to draw on.
...[E]xactly what is meant by 'toughness[?]
Toughness and strength are two different properties; strength is the ability of a material to resist being pulled apart, while toughness is the ability to resist crack growth in a material...
Toughness is an important property in material design because good toughness minimises the potential for catastrophic failure. A material with good toughness may bend and buckle as a result of an impact or overloading situation, but it will resist rupture minimising the damage that may otherwise occur.
...
Measuring Toughness
Numerous factors affect the toughness of steel. Principal among them are the chemical composition, microstructure grain size and level of impurities (or inclusions) in the steel. In terms of composition, increasing amounts of carbon will lower toughness while increasing amounts of manganese and silicon will tend to improve toughness. Micro-alloying elements, such as niobium, titanium, vanadium and aluminium, will also improve toughness principally by producing a smaller grain size in the steel. Other elements such as sulphur will tend to form elongated inclusions known as stringers which have a marked detrimental effect on toughness.
As mentioned previously, a finer grain size improves the toughness of steel. Several processes have been developed to reduce grain size, in particular normalising and controlled rolling.
Energy Absorption
As toughness is the ability of a material to resist the growth of a crack, the measurement of toughness involves quantifying the force required to propagate (or grow) a crack. Propagation of a crack in a given material requires a certain amount of energy which is characteristic of a particular material at a given temperature. A tough material will absorb a lot of energy before a crack will grow, while a brittle material absorbs very little energy. The measure of toughness of a material is in the energy it absorbs during testing.
...
http://www.bluescopesteel.com.au/index.cfm?objectID=F2066D3F-14FC-11D4-89F600C04FCF6B8F
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As each new steel comes on line, it is valued by the experts for the peculiar strengths it brings to the mix, and valued by the masses for its novelty, and the hype surrounding its introduction.
With one new steel after another popping up, the best steels of a few years ago seem to fade in the masses' memory, but the experts having by now become familiar with them, manage to get excellent performance from them.
Some people will tell you that 440 steels are less than impressive and so 440C is yesterday. But 440C is one of the best stainless steels ever, for performance, corrosion-resistance, and polish.
But it's old!
Consider also that the differences in performance are often small, and the difference in heat treatment, blade geometry, and specific use of the blade are often much more important. How about making the blade of a gentleman's knife, designed to sit for months in a pocket, from the toughest steel available?
Why bother? It will never need that toughness. 440A might be better: cheaper, more easily worked, easier to resharpen if it ever does dull under the light use to which it might be subjected ...
To answer the original question directly, don't asssume any widespread bias against ATS-34 simply because few people discuss it anymore, and a few may speak from bad advice, not having personal experience to draw on.
I also perfer 440c over s30v, it is timed proven. S30v is a good steel, but reports are it is easy to chip, this is caused by heat treatment, I believe do others agree or disagree.
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440c is poor next to every steel listed in the OP imo. While the margin may not warrant a "junk" label, the fact is the others simply outpreform it. First off the RC of 440c will decide if it was HT'd for toughness or edge hardness while many of the newer stainless steels will find a better ballance of both. Also 440c will not hold the thinner angles that many of the new SS's will. Even amongst the new SS's there are obvious winners over other ones. I dont think anyone who has had both 154cm and cpm 154 wouldn't choose the cpm 154. 440c does not allow the best HT or geometry for the average high preformance knife at this time. This is why you will find very few custom makers using it, they can simply turn out a better blade. Maybe somone who doesnt use knives much wouldnt notice but as someone who cuts alot the 440c is easily outshined in every respect. Also I dont pay much attention to the claims against S30V. I have not only made knives out of it and had no issues but I have owned dozens of folders using the steel and have never had any chipping problems. I think 20cv will be one to watch.
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20cv please bigjimslade a little info. It is new to me
Guess I am a bit late to this party.
No D2 is not tough and even with the appropriate or best heat treat it still isn't. But then again, no stainless (with the exception of maybe H1, which I don't know enough about these PH steels are very diffent) is. All the really tough steels are non-stainless. It is a good edgeholder though. Yes, D2 is used for dies but that doesn't mean it has to be tough. The application doesn't necessarily require toughness but rather abrasion resistance and D2 is very good for that.
The king of the crop in toughness or near to it would be S7 that rifon2 already mentioned. It is a shocksteel, its what jackhammer bits are made of. Its on the order of 6 times as tough as D2. Even A2 is easily twice as tough as D2. On paper at least 3V is very tough. How well it holds in a knife seems still very much debated.
It is important to realize that there are several types of toughness: Impact toughness, tensional toughness, torsional toughness etc. When comparing impact toughness and tensional toughness not even the units are the same and the mechanism of failure is very different. However, as a rule of thumb, a steel that tends to have high tensional toughness has usually also a fairly high impact toughness and vice versa.
Impact toughness is simply how much impact energy a material can absorb without breaking. There are two fundamentally different types of failure, one is more a rupture, a tearing, the other is more a cleaving/cracking. Steels that fail by the former mechanism are usually tougher. Impact toughness essentially looks at microcrack propagation at sudden shock loads. A material will fail at MUCH lower energies under shock loads than under semi-static loads.
Tensional toughness is the ability to withstand tearing apart (semi-statically - read: slowly) which is relevant to some extend when bending steel (knife blade), because the outside of the bend gets pulled. When tearing steel, first it elongates but returns to true when you stop pulling. The force you can apply with no permanent deformation taking place is called the strength, the extention of the deformation times the strength is called the resiliance.
If you pull further at some point you will start to deform the material permanently. The largest force you can apply without the material deforming permanently is called the yield strength. When the material finally permanently deforms, it will deform for a while before rupturing. The maximum length by which you can permanently deform the material is called the ductility. If a material is very ductile you can pull for a long time before the material fully fails. Toughness is the measure of how ductile a material at a given force is. In otherwords, one material may be very ductile but it requires very little strength to deform and a different material may be deformed only very little but it might take a lot of force and both can have the same toughness. This is the wordy explanation of a stress-strain curve.
Even though the term toughness is used a lot in regards to knives. If you want a knife that is not easily bend and when it does bend will return to true afterwards, you are actually looking for yieldstrength and resiliance. However, often toughness is also important because, it is often helpful that you get a warning before a blade breaks. Steels with very low toughness my snap very suddenly. First they bend without taking a set and suddenly they break, because they have no ductility (very similar to glass). At the edge, toughness is quite important as well because in the thin cross sections at the edge, the yield strength is easily exceed especially on hard impacts and you often rather prefer the edge to roll rather than chip, but to some extent that then crosses into impact toughness where you would have to look at the micro crack propagation at the edge.
I hope that some of this may help and I hope that it is clear that the above is really just a rough outline. There are other people on this forum that I am sure can explain this better and in greater detail.
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Component Wt. %
C 1.9
Cr 20
Fe 71.9
Mn 0.3
Mo 1
Si 0.3
V 4
W 0.6
Material Notes:
DuraTech 20CV is a highly wear resistant, powder metallurgy stainless tool steel. The steel containes a large volume of extremely hard vanadium carbides, wich provide excellent wear resistance. DuraTech 20CV contains the highest amount of chromium of any high-vanadium stainless steel currently available. The chromium-rich matrix provides outstanding corrosion resistance. DuraTech 20CV is a versatile stainless tool steel with a unique combination of high wear resistance, high corrosion resistance, good impact toughness, and excellent polishability. This combination of properties is the result of the fine grain size, small carbides, and superior cleanliness of the powder metallurgy (PM) microstructure. DuraTech 20CV excels in applications, which require a combination of high wear resisatance. The unique combinations of properties makes DuraTech 20CV an excellent steel for plastic injection feed screws, barrel liners, screw tips, and mold cavities, especially for plastic resins which contain abrasive fillers. Other applications inlcude food processing equipement, pelletizer knives, granulator knives, and high-performance custom knives.
Information Provided by Timken Latrobe Steel.
Mechanical Properties
Hardness, Rockwell C 54 54 Oil Quenched from 1071°C; 540°C Temper Temperature
Hardness, Rockwell C 59 59 Oil Quenched from 1071°C; 410°C Temper Temperature
Hardness, Rockwell C 60 60 Oil Quenched from 1071°C; As Quenched
Modulus of Elasticity 214 GPa 31000 ksi
Machinability 35 - 40 % 35 - 40 % 1% Carbon Steel
Rick Hinderer shared his thoughts on the steel and is now making his amazing XM-18 in the steel. I know Kirby Lambert did a limited edition knife in it as well. I think you will see more makers working with it soon.
http://www.bladeforums.com/forums/showthread.php?t=457335&highlight=20cv
This link defines steel characteristics well and runs through quite a few of them with a short overview for those wanting more clarity on specific terms.
http://www.bladeforums.com/forums/showthread.php?t=368828
C 1.9
Cr 20
Fe 71.9
Mn 0.3
Mo 1
Si 0.3
V 4
W 0.6
Material Notes:
DuraTech 20CV is a highly wear resistant, powder metallurgy stainless tool steel. The steel containes a large volume of extremely hard vanadium carbides, wich provide excellent wear resistance. DuraTech 20CV contains the highest amount of chromium of any high-vanadium stainless steel currently available. The chromium-rich matrix provides outstanding corrosion resistance. DuraTech 20CV is a versatile stainless tool steel with a unique combination of high wear resistance, high corrosion resistance, good impact toughness, and excellent polishability. This combination of properties is the result of the fine grain size, small carbides, and superior cleanliness of the powder metallurgy (PM) microstructure. DuraTech 20CV excels in applications, which require a combination of high wear resisatance. The unique combinations of properties makes DuraTech 20CV an excellent steel for plastic injection feed screws, barrel liners, screw tips, and mold cavities, especially for plastic resins which contain abrasive fillers. Other applications inlcude food processing equipement, pelletizer knives, granulator knives, and high-performance custom knives.
Information Provided by Timken Latrobe Steel.
Mechanical Properties
Hardness, Rockwell C 54 54 Oil Quenched from 1071°C; 540°C Temper Temperature
Hardness, Rockwell C 59 59 Oil Quenched from 1071°C; 410°C Temper Temperature
Hardness, Rockwell C 60 60 Oil Quenched from 1071°C; As Quenched
Modulus of Elasticity 214 GPa 31000 ksi
Machinability 35 - 40 % 35 - 40 % 1% Carbon Steel
Rick Hinderer shared his thoughts on the steel and is now making his amazing XM-18 in the steel. I know Kirby Lambert did a limited edition knife in it as well. I think you will see more makers working with it soon.
http://www.bladeforums.com/forums/showthread.php?t=457335&highlight=20cv
This link defines steel characteristics well and runs through quite a few of them with a short overview for those wanting more clarity on specific terms.
http://www.bladeforums.com/forums/showthread.php?t=368828