Rehashing Joe Talmadge's Steel Info

O

omniphile

Joined
Jun 17, 2006
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Hello to all.

I've tried to read all of Joe's excellent sticky in this forum several times but (not being that sharpest knife in the draw) I get confused easily.

So I'm trying to tabulate all his excellent research and info into something that my mind can get around, and refer to when needed. At the moment I'm just concentrating on his Stainless Steel section, and would welcome any corrections or criticisms of my interpretation so far.

If anyone would find it easier to correct this draft directly, I've made it available in PDF format (http://www.phile.com.au/SSteel.pdf) and in Excel spreadsheet format (http://www.phile.com.au/SSteel.xls).

Once I've incorporated any corrections, and got the OK for the revised draft, I am very happy to make it available to anyone who thinks it might be of some use.

Cheers and thank you
Phil (omni@phile.com.au)

SSteel.jpg
 
Welcome! I think this is a good idea and I'm waiting to see some input from others. A chart like this would have helped me out in the beginning.:thumbup:
 
General comment: As interesting as are these generalizations of production steels are to read, I don't think they are of much use. For the main production pieces, I think steel is one of the last thing you have to worry about after price/grind/handle...

Specific comment: Are you saying this is purely your intrepretation of the the writing of Joe Talmadge as seen in his Steel FAQ?
 
Hi kel_aa

Thanks for commenting. I really appreciate anyone that has a great deal of experience and knowledge helping a newb (me) to understand the intricacies of steel as it used, and useful, in knives.

Understandably even by me, is that this will be at best a generalisation since there will be many factors that are likely to differentiate the same type of steel used and how it performs. One of the things I am trying to achieve is to get some sort of feel for the different steels and how they perform in the real world - and then backtrack and see how it all fits into the "theory" of metallurgy. For example, I might find a relatively inexpensive knife on eBay, do a bit of looking into what steel may have been used, and then decide whether it is worthwhile to make a bid or not.

I have to admit, though, I hadn't even considered the type of grind. That's now another feature I will have to make sure I keep in mind. Not being in a position to spend much money (and not having sufficient judgement yet either), I'm "pretending" to ignore things like the type of handle. As long as it is reasonably functional, it'll do me for the moment and if I get into a suitably financial place in the future, I'll be able to worry about aesthetics/collectibility then.

In terms of your specific comment, yes. I'm probably wrong, but it is only my interpretation of Joe's research and experience in his FAQ. So any parts that are incorrect, are purely my responsibility.

Thanks again for posing your comments/questions, and allowing me to clarify what I was trying to accomplish.

Cheers
Phil
 
Neat idea, Omniphile!

I think that not mentioning how the steel is sharpened; what is dulling the steel when it was tested for edge retention; and what sort of comparisons were used to guage 'toughness' make the graph a bit misleading. None of the steels listed as 'very tough' deserve that listing when compared to many other knife steels.

S30V, S90V, and BG-42 are as close to perfect for a stainless steel for an every-day carry blade or hunting knife or fillet knife as a stainless steel can be (as are most all of the others listed and H1, too), but their lack of toughness won't come into play for most of those uses (hardness, wear-resistance, and sometimes corrosion resistance will, though).
 
Are you considering general production folders and fixed blades or custom pieces for youself? So are you getting into collection, verses general usage?

It doesn't sound like you have any specific needs in mind. Without a specific need, you'll only be evaluating the steel based on it's intrinsic properties, not as a whole tool system.

Forum member Cliff Stamp has used a lot of materials often in multiple implimentations. His take on different knife materials:

http://www.physics.mun.ca/~sstamp/knives/blade_materials.html
 
thombrogan: Thanks mate. That's exactly the kind of feedback I was hoping to hear, so I can correct it for both my use, AND to make it more generally useful for any other people that might be able to use it.

kel_aa: Excellent reference. I had a brief look and this is also just the ticket for me. I'll read this carefully too, and try to incorporate it. Thank you, thank you, thank you.

Cheerio
Phil

Edit added: kel_aa, I didn't have a specific type of blade or type in mind. And since it will only be a general guide (at least initially) I know it will be of limited use. But, I'd like to start somewhere in order to try to get both my brain cells around it :)
 
While I can understand your viewpoint, I would caution against using those specific catagories as they bring you down a path of misconception. It took me quite a while to dig out of it because it is the most common way people view steels, but it is heavily flawed and it leads to severe problems if you really want to understand why steels work the way they do. For example the performance ratio for steels can actually invert if you rank them in regards to edge retention slicing ropes vs push cutting. What I would suggest you look at first is hardness and primary carbide fraction. These are critical to almost all aspects of performance and this outlook at steels gives you a much clearer viewpoint of how they will perform. You refine this with the types of carbides (critical to wear resistance) and corrosion resistance.

So take for example 440A vs 440C which is an easy comparison as only one thing changes. As the carbon content increases this ties up more of the chromium and leave thus a greater amount of it left as primary carbides. This increases wear resistance and will also increase edge retention for quasi-static cutting, especially slicing, unless the edge angle is too low in which case it will reduce it. The higher primary carbide fraction also reduces impact toughness and flexibility and corrosion resistance. The extra carbon in 440C also raises the ability to harden the steel so gives it greater strength and resistance to deformation. 440C is also harder to grind than 440A due to the greater primary carbide fraction which means it needs to be made significantly harder to have similar ease of burr removal.

Yes this approach is much more involved and takes more time, but you only have to do it once, and there is no need to understand every steel instantly, plus many comparisons are similar once you get the basics. This viewpoint will give you an opposing viewpoint than is common because os the misconceptions. Note for example that 12C27 and 440C have a similar hardening responce and corrosion resistance as both can put similar amounts of C/Cr into austenite during hardening. The main difference is that 440C has a much higher primary carbide fraction. Thus the steels are similar in strength (from the hardness) with 440C having much higher wear resistance but having problems with carbide tear out at low angles. The higher primary carbide fraction also reduces toughness in resistance to impacts and bending. 12C27 is much easier to grind and in general has fewer burr issues.

One of the major things you also have to realize is that there is a large difference in how a steel can behave and how it is often used due to the manner in which it is heat treated. Reeve's S30V in his one piece line for example has little in common with Wilson't S30V because the heat treatment is so different. The choices a manufacturer makes are critical. Often times they use steels which are not really optimal, just well known, or easy to get and thus what you see isn't the best they could do but just attempts to shove a square peg in a wrong hole which degrades the steel and the knife. 440A for example is often used in very cheap knives but can actually be hardened to 60 HRC, which is above the hardness usually ran with S30V and is much harder than most S60V. However to get 440A at this hardness you need oil/cold and a high soak temperature and for those that use it, this isn't an option (or possibly even desired) so it runs much softer.

-Cliff
 
I think a table that showed the metals average RC swing would be pretty cool. An average of say 90% of the market so that a special case of too soft or too hard doesnt swing the scale out of reasonable proportion.
 
Good points made by all. I use the 50 pound sack of potatoes test. If I could peel and cutup a 50# sack without my hand cramping or the knife dulling then I have a good knife (system).

Here is a list of various steels with comparisons that is of interest. Again, so much depends on what the maker does with it that it is impossible to generalize except to say that reputable makers have spent years perfecting their craft and have jumped over all the hurdles involved in both production and custom knife making. It is well to learn from their experience.

http://www.ajh-knives.com/metals.html
 
As instructive as these list are in educating us in general materials properties of knife-making alloys, they really are of little value in solving the basic personal dilemma of, "Should I buy this knife or that knife?".

The variables of this dilemma might include:
- Scope of use (slicing, chopping, stabbing - of what materials?).
- Appropriate blade-thickness.
- Appropriate blade-grind.
- Appropriate edge-grind.
- Appropriate temper.
- Appropriate handle design.
- Ergonomics, such as finger-choils or guards.
- Oh yeah, let's not forget which steel alloy might be appropriate.


Another problem with these materials properties listings is the 'new wonder steel' problem. 'SuperSteel' is announced as the best knife alloy steel ever, but a year or so later we read user-reports indicating that it's just another contender - not really 'super'.

Close attention to knife reviews is much more helpful in resolving 'what to buy' than studying materials properties listings.
 
I agree that I think all of this information is nice to have, but from a practicality standpoint, it is only marginally useful. There are just too many different variables to factor in (not just from steel to steel, but also from maker to maker, both of which use the SAME steel, at least in name) to get a very accurate read on how a knife will perform.

I would love to hear how many people have taken a good quality knife and, in day to day use where they are not "testing" it's limits, dull it or break it and then say, "gee whiz, if only I had something made of _____, I would have had much better results." I think those cases are VERY rare.

Sure, stick an SAK blade an inch into some wood and start prying on it -- something WILL break or bend, whereas other knives won't. That's a no-brainer. But if you are actually so ignorant that you would use an SAK for something like that in the first place, then you may never be satisfied with a knife's performance, regardless of whichever one you have.

Not to flame the original poster here (seriously!), but some people are always in search of the perfect whatever. Girl, car, house, job, gun, knife, etc. My experience has been that those who do look for that stuff spend their lives doing it, and never really find it and are always unhappy (My ex-wife will be able to vouch for this in about 35 years :D ). Information is great, but too much information can lead to bad decisions. Rather than tormenting over which steel is better on a cloudy day with high humidity, its just better to get something you think you will like and use.

Ok sorry for the rant. :)
 
Cliff Stamp said:
Reeve's S30V in his one piece line for example has little in common with Wilson's S30V because the heat treatment is so different.
-Cliff
Click to expand...
Cliff, which Wilson are you referring to? Phil?
 
on_the_edge said:
There are just too many different variables to factor in (not just from steel to steel, but also from maker to maker, both of which use the SAME steel, at least in name) to get a very accurate read on how a knife will perform.
Click to expand...

Yes, you need to combine the influence of geometry as well and this can easily be as much or more important than steel. Using a better steel allows in part a better geometry so they are not independent.

Gator97 said:
Cliff, which Wilson are you referring to? Phil?
Click to expand...

Yes.

gud4u said:
As instructive as these list are in educating us in general materials properties of knife-making alloys, they really are of little value in solving the basic personal dilemma of, "Should I buy this knife or that knife?".
Click to expand...

While I think too much can be read in to steel too little is again a danger. There are steel which would be immediately unsuitable in particular knives due to intrinsic characteristics, L6 in a salt water fillet blade for example, or 15V in a chopper. Steel is just a part of the performance and needs to be integrated with the rest of the information to understand the performance of the knife. I think there is use in grouping steels, just like grouping grinds or balance or other aspects of performance.

Another problem with these materials properties listings is the 'new wonder steel' problem. 'SuperSteel' is announced as the best knife alloy steel ever, but a year or so later we read user-reports indicating that it's just another contender - not really 'super'.
Click to expand...

That's hype, you always ignore that. It is also *extremely* easy to spot.

-Cliff
 
Wow, a lot of work! Looking at it makes me realize that a lot of the statements made in the FAQ need to be looked at in context ... I make comments about, for example, one stainless being tough in the context of other stainlesses, but the tough stainless might not be tough at all in the broader context of all steels. Also, some of the ratings in the table I dont' agree with, even though they apparently came directly from the FAQ, which again probably means they're out of context, though now I"m motivated to check more closely
 
OK, OK. I concede! In retrospect (and with the benefit of truly-appreciated input from the many experienced and very knowledgable posters in this thread), I can now see I have approached this incorrectly.

[Sarcasm="On"][Irony="On"] It is now obvious that everyone except me is dumb. It's almost if that no other members here could explain to me, like I'm a professor in astrophysics (in 25 words or less), the comparisons and contrasts between Albert Einstein's General and Specific Theories of Relativity with examples, and applying specific references to Chaos Theory and the Uncertainty Principle. [Sarcasm="Off"][Irony="Off"]

In other words, I was hoping someone could do the impossible task of creating a simple table that would be both relevant and reasonably accurate out of a very complex subject.

My apologies and thanks for putting me on the right path. Many people have suggested alternate ways of approaching this, and I certainly will adopt these approaches.

Cheers
Phil

Edit added: [Sarcasm="On" Strength="Extremely Strong"][Irony="Off" Strength="Extremely Strong"] Maybe I could tip some blowpipe darts with some of Indian George's fatally hot chilli and shoot them at some of these people that can't perform miracles! :) [Sarcasm="Off"][Irony="Off"]
 
Consider replacing the vague statements in the hardness column with actual Rockwell numbers for that particular steel. Describing a steel is soft, hard, medium, etc is not very informative (especially to this audience). We all go by Rockwell numbers.
 
D2 has a high wear resistance due to the high primary carbide fraction, with steels like S90/10V being extremely high. The primary carbide is mostly chromium rich and very segregated at well over 10 microns in size. The grain fracture size is 7.5, 440C is 6.5, most of the cutlery tool steels are 8.5-9.5. This is a nonlinear scale, even increase of one is actually a doubling. These properties give D2 a low sharpness and edge stablity at acute angles.

Corrosion resistance is low compared to even the high carbon stainless as the chroimum is mainly there for carbides. It tends to not form a patina with use but will pit heavily if exposed to salt water. General hardness is between 58-60 with some going 1-2 points softer or harder. It maximizes at 64/65 HRC which takes oil/cold and a low temper. I don't think any maker runs it that hard. Mel Sorg used to use 62 which is the hardest I have seen promoted.

-Cliff
 
Cliff, thanks for your explanation.

I've read several comparisions of S30V, VG10, and D2. My desire is a steel that I can sharpen at low angles (say, 20 degrees inclusive) but still have good edge retention. I'm not as concerned about sharpening difficulty as I am in with being able to put a durable low angle edge on it. I'm not planning on trying to cut through bricks or anything crazy like that. I'm just looking for something that will take the lowest angle and maintain that sharpness for a reasonable time under reasonable use.

In all that I've read, I came across several comments that suggest that S30V is grand, but that it is very difficult for a manufacturer to get it right. Taking all of that into consideration, it seems to me that VG-10 should deliver what I'm looking for.


Considering only these 3 steels, and my desired results, which is your preference?
 
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