edge holding and toughness on...

K

KLOW

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I'm curious from a performance standpoint, out of 1095, 1084, O-1 and 52100 (all properly heat treated and tempered) how would you rate these four steels from toughest to least tough, from the most edge retention to the least?
 
I've checked a number of sources regarding Blade steels, including Cashen's site, but I have yet to truly find any information comparing these steels against one another in terms of edge retention and toughness. I know they are all quite similar, I'm just wondering from a maker's standpoint how they compare to each other, on paper and in real life use. Any info or anecdotes would be greatly appreciated.
 
This is totally anecdotal, so take it for what it is worth. I have a 1080 scandi ground knife that will hold an edge far longer than a softer tempered flat ground 1095. I also have flat ground 1095 knives tempered harder that keep an edge well, without any durability issues so far.

On a theoretical level, the 1095 would have additional wear resistance over 1080, but less resistance to breaking due to the larger carbides in the steel. If I am wrong on this...I am sure someone will correct me.
 
Each maker will have a favorite in this selection and all will perform very well if Heat Treated properly. You can add to the list 1084 and 5160 at least. For ease of HT I would recommend 1080. It will hold up well if Ht'd the specific use designed. O-1 is a great steel but is a bit more difficult to work. Properly heat treated some phenomenal results can be had. 52100 is probably one of the most discussed steels out there. There are 2 diametrically apposed opinions of this steel. I have used it and it works quite well. There are others that have done more performance research as far as number of cuts thru rope etc. IMHO, It is more about your comfort level and getting the HT dialed in than what steel is used.
 
Chuck,
I think you are right in that a maker will have his own favorite steel. Mine is 52100. I have used the simple carbon steels and the others as well. As you know, edge holding and toughness depends a lot on grain size. I feel that the smaller grain size is more easily reduced in 52100 so I think it will probably be the best. O1 would be a very close second and it has a lot of the same alloys as 52100, just different percentages.
5160 makes a very good blade and can be heat treated for most applications of use. I know it seems to work like butter after working on some 52100.
For a knife that is tough and holds a very good edge, L6 would be another good choice, especially if any cold weather applications apply.
I guess that is why I like 52100. I figure if it is tough to work, it must be tough on all the other fronts too. :)
 
The thing is, edge holding is going to be SIGNIFICANTLY effected by edge geometry. So it's very hard to say.

For the rest, I haven't used 52100 but the other three are all (I'm going to get my butt kicked for saying this) more or less in the same "class" - excellent hard wearing knife steels, but not hugely different like D2, L6, 5160, or 15N20 would be. And all of those have some pretty major differences, I'm not lumping them together.

My personal experience is that 1095 is a bit more tweaky to HT, and gives cooler quenching lines, than 1084. 1084 is a rock solid simple to work steel that can be made to do a lot of things (I have made throwers out of it, even). O1 is a very good steel for a regular working knife that just needs to cut all day.

Caveat: I'm NOT an expert in any way. I make and mess around with knives and test them on pells and stumps and animals and such. No real chemistry or metallurgy in my answer.
 
Klow I am surprised that one of the experts have not really jumped on this. You have asked a very common question that probaly most have thought or asked themselves. But the answer is really not that easy. There are way to many variables with a knife than just say holding an edge. Edge geometry is one, what you are cutting is another and there are lots of others. One could work well but the other not so much. It took me awhile to start to understand this. So it is not that no one really wants to answer your question, it is just that your question can not really be answered. I guess one way to look at it is if that question could be answered then there would not be so many different steels in knife making, we would all be using the same thing, not really but it is the best analogy I could think of. Good luck.
 
Maybe I'm wrong but if we are talking about the same edge geometry and perfect hardening, perfect finish and at the same hardness it is pretty simple theoretically speaking of course: More carbon, more edge holding, with more carbides more abrasive resistance, with vanadium or cadmium etc inside more edge holding. I don't know exact scientific values but that's got to be not so hard to tell for a metallurgist which is tougher or which has more durable edge at same variables of geometry and hardness I hope :rolleyes:. OK I'm pretty sure I'm dead wrong but there got to be some relative values at a given instance...:confused:
 
Actually, there would probably be very few makers that could answer this question. As most of us try a few different steels and then settle on the one that "we" have gotten the best results, we work to get the most from that one. I really don't know of any makers that would have spent the time to develope the heat treat necessary to get the ultimate performance from each one.
There were a few people that tested knives for their own personal information and have shared it with the rest of the internet. Cliff Stamp comes to mind but I haven't seen him post on any forums in a long time. He did not pull punches and would test to destruction with all sorts of cutting and sharpening techniques.
He did a test on some knives I sent him that were heat treated "exactly the same way" and they performed quite differently. This is mainly because the different steels "do not" heat treat the same way to produce the same results. If they had been heat treated to obtain the best performance from each of the steels, they would have had closer results. This is what I gained from his testing on those knives.
The ABS cutting contests of the past led to a tweaking of heat treats by a lot of makers that competed. Myself being one of those and it was a very good learning experience. There were several of the steels represented by the different makers that you are asking about. Most did quite well and as it was a contest of knives and man, sometimes man didn't have enough technique or understanding of the cuts to come out on top. The edge geometry was of paramount importance in being about to complete the cuts. The technique required was made by the maker.
There really are too many variables in deciding which of the steels are the toughest, sharpest, etc. Even the same class of steels have variables when made in differen batches. The list goes on. It is good to search for the best but our lifetimes are way too short to find out "All" the answers. :)
Have a Great Day and Enjoy the Journey.
 
I don't have anything scientific to add (not that I have much science that y'all would trust anyways) but if there was 1 best steel what would we all argue and fight about? :confused:

Steel, techniques, processes... these are all doors that lead to paths that lead to the journey of the craft. How boring if there was only 1 door. :(
 
KLOW said:
I've checked a number of sources regarding Blade steels, including Cashen's site, but I have yet to truly find any information comparing these steels against one another in terms of edge retention and toughness. I know they are all quite similar, I'm just wondering from a maker's standpoint how they compare to each other, on paper and in real life use. Any info or anecdotes would be greatly appreciated.
Click to expand...

If you want those kind of numbers, you are going to have to go into the metallurgy world. Try Heat Treater's Guide or steel manufacturer web sites. I'm not thinking of more now, but the numbers are there.

If information from individuals will work for you, Kevin Cashen's information is as educated and experiential as you will find... like you could bank on it... and imagine that in this day and age...

Oh, in the industry numbers you are not likely to find data on 52100 as a cutting steel. It was, after all, a steel designed to roll... why any one would use a steel designed to roll as a steel to cut is beyond me...

Sam, can I come stay with you for a while 'til this blows over?

Mike
 
After messing around with O1, 5160 and 1075/80 early on, I settled on W2. The vanadium keeps the grain size small like Ray was talking about with 52100. One other thing that the vanadium does is actually retard massive grain growth until the steel get a fair bit hotter than some others. You can get a nasty edge on the stuff. It is also rather abrasion resistant, so it holds that edge for a while. My understanding is that it's impact resistance is not bad either. Not as tough as L6 or as resilient as 5160, but what other steels are? Now for the bad news. Nobody in the US really makes the stuff any more, so you have to scrounge it up like Don Hanson did and you have to be set up to heat treat it. Using Crisco or the dregs of your old car's transmission aren't going to harden it fully. VERY fast oil only. Now Ray may want to correct me on this, but it may also be a bit more forgiving on "do overs" in the heat treating process than 52100.
 
In case any of you guys don't know, raker is Ray Kirk, an ABS mastersmith. hint, click on his name and visit his homepage :)
 
Joe,
Haven't you heard of the "triple quench". If you mess up the quench on the 52100, just do it again. :) A good heat treat oven takes care of most of those problems. The temper temperature I use is 460 to 475. Depening on end use and size.
Most of the knife making carbon steels were all designed for something else. There are not enough forgers making knives to support a steel industry. That is why we can pick out the one we "like" to use to produce our knives. All the data in the engineering books are for idustrial purposes. I don't remember finding any on cutting applications either. But you can use them as a "guide" in developing the heat treat for your "batch" of steel.
In the last few years, Crucible has been making some steel especially for knives. They seem to be doing well with it. They do have some good makers that have been helping and testing it for them.
Will,
When they make one kind of car, they will use one steel for knives. I just don't think it will happen
 
My reticence in answering such a thread is that no matter how much objective testing and information to put behind it there are going to be at least half a dozen other answers diametrically oppose yet just as adamant on their performance views of each. While the folks who made the steels have no problem in laying out the strong points and short comings of each of them bladesmiths have a habit of disregarding anything those folks may say. First of all, everybody has their own definition of acceptable levels of performance, and totally different priorities in which of the properties is most desirable. The next huge problem is that the folks who made the steel assumed that the folks who would be using it would follow the recommendations they were kind enough to lay out after exhaustive R&D and testing. Industry standardized heat treatments so that they could be very repeatable and comparable; there is no standard heat treatment in bladesmithing. I could tell you that 1084 should be tougher than 1095 or O1 but I can guarantee there would be smiths reading it that would say I am full of it because they have done some unorthodox heat treatment that resulted in tougher (actually less hard) O1 or 1095. And of course there will always be the soft spine and hard edge thing that quite honestly industry would never include in a reasonable heat treat recommendation. And last, but not least, you have pet steels that have taken on an over-inflated reputation from all the P.R. around them such as 52100; trying to categorize any such steel objectively would not work with folks who feel that it may be the greatest in both edge holding and toughness, despite the fact that the two are often in opposition.

My advice is to go with the facts:

Industry uses and designed the following steels for abrasion prone applications:

O1- slitters and cutters
52100- bearings

As for 1095 and 1084, their abrasion resistance would be due to simple iron carbides, and 1084 would have scant few of them left over. Iron carbide (cementite) is hard stuff but chromium and especially tungsten or vanadium carbides are many times harder and more abrasion resistant. Thus if heat treated properly the two alloy steels will definitely have a natural advantage in edge holding and due to depth of hardening along with the common presence of tungsten and vanadium I would put O1 at the top (knowing that numbers of smiths who have done the hocus pocus, hokey pokey around the quench tank will think that is blasphemy);).

As for the toughness factor, we kind of need to eliminate any special heat treating considerations in order to look just at the innate ability of the steel itself, since many steels can be made tougher simply by not making it as hard. Thus it is too easy for any smith too simply lower edge holding expectations in order to get toughness.

Large complex carbides lowers toughness so of the group the one steel with the greatest natural potential to be tough would be 1084. It has just enough carbon to reach maximum hardness without any pesky leftover carbides. The other three really depend upon the previous thermal treatments and the final treatment. Those with alloying will tend to tie up the excess carbon and keep it out of your way, however if those carbides get out of hand you will have a real problem, while 1095 will have more movable carbides but they will be quicker to get in and out of trouble. I would put O1 at the bottom of the toughness heap with 52100 and 1095 rather closer to each other than the other two extremes.
 
You know, Kevin, as much as I struggle with metallurgy, sometimes you are just frikin' wonderful...

Mike
 
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