Have you researched the search function?
Hello all, I know there have been many posts that start out much the same as this one, but please bear with me.
I have been researching and generally splitting hairs over knives for a few years now, and in all of that time, I find it odd that with all of the users out there, and nitpickers like myself, there is so little empirical data comparing common steels in a quantitative capacity. Even after years of my own searches for "CPM-XXX vs M-123", I still find little to go on besides opinion. Not that the end user experience isn't important. After all, it's the ultimate test, and the gap between paper specs and practical use is sometimes wide. However, I also think it would benefit everyone, especially those who depend on their knives, and those who spend exorbitant amounts in the pursuit of knives that cut longer, better, and are tougher, if there were a large resource of strictly qualitative comparisons on aspects like toughness, wear resistance, sharpen-ability, and corrosion resistance. There are a few resources that compare these things relatively, and still others that compare other aspects for knifemakers such as hardenability and HT effects, but I have yet to find a comprehensive (or nearly so) chart or database on these "user" qualities.
I understand that steels behave differently, sometimes completely so, with different treatments, edges, and makers, but with all of the time and money I see spent in the hobby, it seems there is 10x the amount of subjective opinion vs. objective comparisons. After all, the Spyderco Mules alone should give some solid comparisons, since as far as I know they're all the same, only with different steel. This resource would be even better applied if it were community driven. If two dozen forum members are wondering how their knives compare to the newest steels around, they might all pitch in and get a new blank tested scientifically. At least then, no-one would be relying solely on statements like "Well I had X, but then I got Y and WOW!" and the like. Knife pass-arounds could yield solid, unchanging data on how a particular knife, edge, and HT performed, so to be logged for all who come after. It's an interesting notion.
Of course, testing reliably is easier said than done, and equipment can be expensive. I was just mulling this over last night and was wondering what everyone around here thought!
That particular test is one I've relied on in the past, but isn't exactly what I was driving at. There are tests such as that one done, and it is very useful stuff, but what I was really referring to was a community-driven resource to give things like charpy numbers, so that comparisons wouldn't simply be "S30v is better than VG-10, but not as good as ELMAX". Though, this may be more than enough to go on, I was just musing on a more sizable scientific approach.
Again, I'm not knocking anyone's past test results, they're all certainly better than what I have done (nothing).
There are charts like that available. Comparing different steels in their respective categories ie. Stainless against stainless, high speed tool steels against others, molybdenum steels against other molybdenum steels.
Hard to find something comparing across the different groups.
Where to find it? In the library, usually steel or metallurgy section.
Not all the information can be found on public domains and a little groundwork needs to be done.
Yes Mastiff, that's very close to what I mean. (I have never seen this one before, it looks very helpful). This is typical though, in that it is relative rather than absolute. If I want to know how D2 compares to M4, I'm lost here. If it must be relative, so be it (after all, we're comparing pretty similar materials here, not like copper vs. tungsten carbide), but I was really looking for something with definite values for things like wear resistance, toughness, etc.
Marthinus, I'm studying Mechanical engineering currently, and I have some leads on general materials handbooks and the like, some of which are almost definately in my University library. I figured this would be the best place to start, as these would likely give a great reference for Charpy numbers, modulus of elasticity, ASTM wear tests, etc. I was just posting here to see if there would be a great interest in such a venture, as I think a combination of these rigorous numbers and user testing would be ideal to get both sides of the equation filled out as completely as possible.
I was also thinking, as an intermediate project, of combining the many relative charts which are easily found ( think like these here) from various resources, such as the crucible sheets and those of other manufacturers, ain order to construct a comprehensive relative chart. I figure by looking at all of these which are able to be found, and then averaging the results of each, then combining them into a single chart, a much more complete picture could be painted. This would also undoubtedly give results for multiple levels of hardness for a single alloy, another important aspect that is sometimes not present in the smaller, more limited comparisons. Again, I'm just wondering if there is any demand for such a thing around here. I know we've all gotten on fine without it for years.
More along the lines of what you are looking for. These are steels common in cutlery circles. http://www.latrobesteel.com/assets/d...ade_Steels.pdf
14/4 CrMo is the same as 154cm. 20CV is very similar to M390/CTS 204P
A good book to start with is:
Steel Heat Treatment Handbook by George E. Totten, 2006, Portland State University, Portland, Oregon, USA. Published by Taylor and Francis Group.
However, even in Charpy you have different standards of samples. That can also influence the data. IMO, there are to many variables and steels in order to complete a comprehensive, accurate, data sheet comparing all the steels at the same time. I just think the graph will be to lopsided and hence the "relative" data is used.
There are many thesis done that focus on one steel and how different heat treatments can affect its performance.
Here are some good journals you can also get at university:
Good luck if you want to do it but please, if you post it in a public domain before it is published be warned, intellectual property means nothing then. Rather get it published and then make it available to the public. Then it has gone through pear reviews etc.
PS. I think what you might benefit from greatly is the following, it will cost you, but if you are really serious about it they have a massive database and keep it up to date:
Last edited by marthinus; 10-29-2012 at 03:37 AM.
The info just comes from the steel producers. You will notice that is where all the actual charts and numbers originate. There is rarely interest in these values, you will see it is the same small group of users who participate in the discussions. A lot is available online, I have a gig of pdfs and pictures in the knife folder on my desktop. Alloy is important, but most properties in the charts are unimportant to knives. We don't really need to reference red hardness or creep resistance.
Most will say that it depends on the heat treat, or that it doesn't matter what the steel is because the brand will determine how tough or how sharp the knife they make actually is. Most also don't care because they buy production knives, where the input in steel choice and working hardness is virtually nil in most cases. You have to buy the whole knife, not just your design of choice with steel of choice.
Geometry will overwhelm alloy in many knife comparisons. Size/shape/volume are kept constant in actual testing of steel properties, but very few want to try to equate this to any knife performance. Anecdotal evidence is weighted much higher since there is no standard knife shape and cross section. How you sharpen a knife has more influence than what it is made of when it comes down to testing actual knives.
"When the thunderclap comes, there is no time to cover the ears"
Okay guys, first of all, thanks for all of the info. I'm wading through this data and more right now trying to formulate something useful overall. Right now, I'm still trying to list all of the steels usually encountered in knifemaking these days, and research testing methods.
Marthinus, thank you for the links, I will likely go the route of buying a subscription to a large database or simply buy the best book I can find on the subject once I get a good feel for what's needed. That online resource seems to be the most promising lead so far. I understand that not all or even an appreciable amount of this info will just be sitting around on the net (Though I haven't searched exhaustively).
It's also interesting to hear about how edge geometry is so indicative of performance. This could be standardized too in the community, though it would require knifemaking skills and equipment to form say 1"x1/8"x3" bars and put a decided uniform grind onto them, and then test several of them using exactly the same methods. This would certainly be a lot of work, (like the great tests Ankerson did, only using exactly the same geometries and blade shapes), and would then only give very limited results for that one (unrealistic) blade. However, this test is not so much about knives but knife steels, and so at least we would have some absolute numbers to compare with confidence. Sort of how a tensile strength test is not used on actual parts, but only a standard size and shape of material to be tested (usually).
I agree in the extraneous factors on most charts, which I believe have been geared more towards large companies and those who actually work the metal, such as knifemakers. It seems there is little in the way of concrete data willingly supplied to smaller consumer and eventual users.
As for the charts coming from steel producers, that is one of the reasons I was hoping it would be feasible to do some independent testing, so that then it would be at once more geared toward the knife-using community and transparent.
This is quickly growing into a large, costly venture, I can see why it hasn’t been done so far.
Good luck. Many have tried. Much too expensive and time consuming for anyone who has to work for a living. Spyderco's Mule project was born for this very purpose.
"When the thunderclap comes, there is no time to cover the ears"
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