BEST EDGE, Carbon vs. Stainless

Looking thru my Russell/Harrington catalog of industrial knives I see very few made of stainless, and as has been mentioned more than a few times by several people in this forum stainless doesn't seem to be used that often as a tool steel. The reason is that as was mentioned cross section is often used as a means to offset lower toughness or impact resistance, and that for a given level of toughness you can usually do better with carbon or tool steels. A woodworking chisel is a good example of a tool that needs to be sharp and tough, and very few are stainless. Most seem to be simpler tool steels or plain high carbon steel, hardened to RC59 thru RC64 per some tests of chisels that I've read. The conclusion that one can draw is that for a given level of toughness the typically higher hardness levels that can be achieved with carbon/tool steels will result in better edge holding and performance, which again is why the common tool steels aren't stainless.
 
The topic is "BEST EDGE" with the qualification that you are willing to maintain the edge. To me this implies that you are willing to oil, steel, and/or hone the edge. If you are willing to maintain the edge to this extent the wear resistance of the edge becomes a bit less critical and I start looking at how sharp I can get the edge and how much trouble it is to keep sharp. I find Sandvic 12C27, AUS-8, AUS-10, VG-10, and BG42 alloys take edges that rival your carbon steels. I don't think I trade off edge quality if I go to one of these stainless alloys. The only thing I figure on sacrificing is some toughness.
 
Merely 'trading off toughness' indicates that one isn't comparing similar possible edge conditions, as at a similar toughness level the tool/carbon steels will usually do better. I'll guess that a W2 or blue steel wood working chisel at RC62 or even a bit harder is a lot more similar in toughness to VG-10 at RC59 than Carbon V at the same hardness, and is the hardness range that one should possibly be doing the comparison in the recent discussion of how well the Fallkniven F1 performs. A fine grained steel like W2 at hardness levels in the lower 60s produces an amazing edge, one that is still pretty durable considering that we're talking about a chisel.
 
Hello folks,

Where have we seen this before? threads like this show up every two months. nevertheless, I like 'm.
biggrin.gif


Stainless vs carbon use to be a tradeoff between rusting VS poor edgeholding.
I don't think that any stainless steel can beat a properly treathed carbon steel blade (5160, 52100, W2, A2). Even VG10 is not so good in edgeholding compared to Ed Fowlers 52100. And definetely not in the toughness departement. A stainless good blade, being tough and so on, is usually 6 - 7 mm thick.
That is not gonna bend in normal use, way too much steel. A carbon steel blade can be 4-5 mm thick, and bend a couple degrees, but the reduced thickness makes it a better cutter. And, off course the smaller grainsize.
But....it rusts. And so does VG-10, don't worry. leave a drop of lemonjuice on it for a few minutes and you'll see. It just rusts less fast. Knifemakers should try and find the golden middleway between carbon and stainless steels, and I agree with Ed Caffrey, that'll be 5160 and 52100.

Then some dude invented the advanced sintering procedure, which results in powdermettallurgical steel. Radical new approach, but also radical prices compared to the price off 52100 or 5160 (broken leaf-springs).
I dare anyone to make a knife off any steel at choice, for the same money, 1 or more carbonsteel knives will still outcut it.
It's like an opinel and a benchmade. The benchmade costs 20 x an opinel. Does the Benchmade cuts 20 x better? No way.

so now it is :

Rusting x Bad edgeholding x High price.

And some other factors like toughness, impactresistance, flexibility, grainsize, availability....

greetz, Bart

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"If the world wouldn't SUCK, we'd all fall off !"

member of the BKS
http://www.expage.com/belgianknives
 
BARTStudent; thank you for your as usual, informative and opinionated post.

However, would you mind consulting the reference I gave in my post above, wherein 52100 and 5160 were roughly equal to traditional ingot tool and stainless steels, but clearly inferior in edge holding to the CPM440-V and Stellite 6K? This information seems quite contrary to the opinions you expressed.

Should you be able to provide factual information to back up your opinions, this would be greatly valued.

Thanks in advance, Walt
 
You guys are really a wealth of information.

From what I can gather, please disagree with me if I got this wrong, most carbon steels are better for most of the tough stuff we do with knives. My experience with carbon vs. SS bears this out. Most carbon steels hold an edge better and sharpen easier/better. Unless you spend much money, Stainless steels, do not match carbon in these areas.

With that said, is some time with fresh water and oil/Tuff Cloth, etcetera worth it? Unless you are in situations where it is not possible or prasctical, why not go with carbons steels (I like A-2 and 52100) and just keep them clean and oiled?
 
To throw in my .02,
I have found high end stainless steels (CPM steels, BG42 & VG10, INFI) to equal the performance of any carbon steel, albiet at a higher cost.
The main factors in a blade's performance are construction (ie edge profile and cutting geometery) and heat treatment, with steel choice a distant third.
It is the heat treatment that, in large, determines the relative toughness and abbrassion resistance of a knife (and these characteristics or atributes may be mutually exclusive) while edge geometry will, in large, determine cutting efficiency. The major advantage of modern alloys is their relative stain resistance. YMMV
Stay cool,
Chad

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"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf."
George Orwell
"Those who hold the thin blue line keep order, and insure that anarchy and chaos will not prevail." Chad (1992)
"He who lives by the sword dies by the sword. He who dies by the sword did not train hard enough" -Chad (1999)
chad234@email.com
 
Chad, I think you got to where I was looking to get. High end $tainless $teels probably can be as good (whatever that means for your uses) as carbon steels, but at a price.

With that said, is a little care to a carbon a way to buy more knives for the same money without sacraficing peformance? If so, cool!

Besides the heat treat, does the blade steel selection have a more significant role relative to flex, strength, britteleness and the like?
 
I cobbled together some Charpy impact resistance and RC hardness data that I could find to go along with Wayne Goddard's hardness and cutting test data. Unfortunately there is still a lot of missing data. The reason for the effort is to support the notion that it's not adequate to merely make the test knives the same dimensionally, as ideally one would also be able to harden the test knives to the same level of impact resistance. The reason for wanting to do so is to be able to make valid comparisons as impact resistance, assuming similar use, will determine the ability to optimize cutting performance with thin blades and thin edges.

Looking at the data the Stellite 6B has some pretty humble impact resistance, and it's also somewhat soft and prone to having turned edges. The Cruwear is similar to Vascowear, both are excellent steels and neither are stainless. CPM 440V has good cutting performance but it's toughness is low compared to the other CPM steels. Otherwise, as expected, the tool steels and the low chromium CPM steels tend to be tougher than the stainless steels and cobalt alloys. All that extra chromium doesn't seem to give ATS34 or 154CM better cutting performance than 52100 or 5160, and while I don't have Charpy data for 52100 or 5160 it's a good bet that they're also a fair amount tougher.

In general it seems that it is as others have often stated, the common concession with stainless steel is lower toughness, which means that a carbon or tool steel can usually be used for better blade and edge geometry, and hence performance.

 
I guess it's late...here's the data :^)


RC Charpy Cuts
S7 ......... 57 ... 125 ......
3V 58 85
9V 49 74
3V ....... 60-62 50-40 .....
9V 56 36-47
A2 60 40
M4, CPM..... 62 .... 32 ......
Cruwear 62 30
M4, CPM 64 28
9V ......... 57 .... 26 ......
440C, T 56-57 26
440C 56-57 26
10V ...... 59-61 26-23 .....
420V 55-56 22
D2 59-60 22-21 47
M4, CPM ... 65.5 ... 20 ......
M2 62 20
440V 55-56 18-16
420V ..... 58-59 18-16 .....
10V 63-64 16-15
ATS34 59-60 14-13 38
154CM .... 59-60 14-13 ... 38
440A 58 14
440V 58-59 13-12
440V ....... 61 .... 11 ......
440C Mod, 58 11
Stellite 6B 6

Stellite 6K 44 ............ 58
440V 58
Vascowear 61 56
D5 ......... 61 ............ 52
F8 45
O7 forged 61 44
M2 ......... 64 ............ 44
154CM-cryo 61 44
52100 forg 60 43
5160 forge . 60 ............ 43
D5 59 40
440C 58 33
440C ........................25

 
Look at the Charpy for 3V: 85!!! that is damn tough. It was said earlier that blade shape and heat treat are likely more important than steel selection. Well, the Charpy value of 3V helps support that. With such a high value you could grind a CS SRK out of it to the same dimensions as a Carbon V one and it would be EVEN TOUGHER!!! Or you can grind it THINNER, get the same impact toughness as a Carbon V version, but get IMPROVED SLICING ABILITIES with the thinner grind!!! That is definitely something you gotta look at when thinking carbon versus stainless!! In bigger blades ATS-34 isn't as advantageous as 3V!!!! My Benchmade Sentinel is never used for chopping so the idea of impact toughness at first seems as though 3V has no advantages in smaller blades either, but NO!!! You still can grind most blades with 3V thinner than you can with most other steels while retaining a great deal of toughness.

I haven't got a 3V blade myself to try but the experience of many a forumite demonstrates what I have said. But I don't intend this to be a commercial for 3V, but rather a commercial for learning a bit of chemistry to aid in understanding and shopping!!!!

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"Come What May..."
 
Even though I don't want to sound stupid, I will BE stupid if I don't ask this question.

Can someone explain Charpy ratings and how to read the information posted by "johno" for me?

I would hate to think that I am the only one that could use this insight. Thanks in advance.
 
Depending on which screen fonts you're using the table that I posted may either look like a table or gibberish. I'll post another attempt below that looks like it'll be readable with either type of fonts.

Yes 3V is very tough, which is the point that I was making, as neither 3V, nor 10V, 15V, or 9V are stainless. In the CPM steels 440V and 420V are stainless, and their better impact resistance values are obtained at moderately low hardness levels.
 
Looking at Fallkniven's website (fallkniven.com), there is a section on the independent tests of VG-10. Fallkniven claims that this is one of the strongest steels around. I don't know much about charpy indices or metallurgy, beyond what I read here and in magazines, but I do lknow that VG-10 works well for me.
 
The RC is hardness, Rockwell C scale, the Charpy is impact resistance per the notched Charpy test used with metals in ft/lbs, as I recall, and the Cuts are the edge holding results per Goddard's rope cutting tests. The stars indicate missing values. The top portion of the table is sorted by Charpy value and the lower portion with no Charpy values by edge holding. It'd be nice to get more Charpy data, and maybe also add another set of values for edge holding, maybe using the CPM abrasion resistance data.

Steel_______RC______Charpy________Cuts
S7__________57_________125__________**
3V__________58__________85__________**
9V__________49__________74__________**
3V________60-62_______50-40_________**
9V__________56________36-47_________**
A2__________60__________40__________**
M4,CPM______62__________32__________**
Cruwear_____62__________30__________**
M4,CPM______64__________28__________**
9V__________57__________26__________**
440C,T____56-57_________26__________**
440C______56-57_________26__________**
10V_______59-61_______26-23_________**
420V______55-56_________22__________**
D2________59-60_______22-21_________47
M4,CPM______66__________20__________**
M2__________62__________20__________**
440V______55-56_______18-16_________**
420V______58-59_______18-16_________**
10V_______63-64_______16-15_________**
ATS34_____59-60_______14-13_________38
154CM_____59-60_______14-13_________38
440A________58__________14__________**
440V______58-59_______13-12_________**
440V________61__________11__________**
440CMod_____58__________11__________**
Stellite6B__**___________6__________**

Stellite6K__44__________**__________58
440V________**__________**__________58
Vascowear___61__________**__________56
D5__________61__________**__________52
F8__________**__________**__________45
O7forged____61__________**__________44
M2__________64__________**__________44
154CM-cryo__61__________**__________44
52100forge__60__________**__________43
5160forged__60__________**__________43
D5__________59__________**__________40
440C________58__________**__________33
440C________**__________**__________25
 
Thanks johno.

Wonder where VG-10 would be.

[This message has been edited by Nimrod (edited 10-01-2000).]
 
I would guess that VG10 would be similar to the other RC59 stainless steels with 1% or so carbon, like ATS34, 154CM and 440C. People like the edge holding on VG10 but the Fallkniven knives seem to be either a bit thick to compensate for the somewhat lower toughness or moderately thick and kind of fragile like the 3/16 inch thick F1. It's a common and acceptable tradeoff for most people as edge holding is tested on a regular basis while few will test toughness limits, especally on a more expensive knife.
 
OK, call me ignorant, but why doesn't anyone make knives out of S7 or 3V ?

Now that we know the basics, how does heat treating affect the everyday usability of these steels?

[This message has been edited by Nimrod (edited 10-01-2000).]
 
3V is being used more often, for instance in the Whitewing (?) folders which are at the top of my wish list. Do a seach on 3V to check out other knives, such as the ones that Cliff Stamp has reviewed. L6 is a traditional steel that is used instead of S7, as is 5160 and some others. One viewpoint is that the heat treating and steel need to be chosen for a desired set of properties, something that the data above suggests as the properties can change dramatically.
 
As one of Bailey Bradshaw's Whitewing distributors, I can testify that this CPM3V is some good stuff! I have three of the Whitewing folders left, and its getting tougher to sell these. I really want to keep one for myself!

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Danbo, soul brother of Rambo
 
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