Steel: General information

When I grew up between two knife makers I remember them telling me that to properly temper a blade it had to be brought up to that purple color which was said to be about 500 degrees plus. Of course this was long before stainless steels were being used much for cutlery.

I distinctly remember an old 'temper color chart' on the wall of my one neighbor, Ray. It had the color, the equalivalent temp that the color was associtated with and the tool that each color was optimal for.

I don't remember the whole chart but I do remember that scissors were brown, that axes and wood chisels and what not were brown/purple and that knives and things like cold chisels were always purple. Oh and if it got black it got too hot and you had to retreat it.

Purple was like the fourth hottest color I think blue and dark blue were hotter if I recall correctly.

Anyway, that is as technical as I get. It was done by color for centuries and it seemed to werk just fine..
 
I think the topic of this thread refered to general steel information. This information will serve some of the forum member well in making decisions in thier knife purchases. Most folks have to borrow or buy to test the piece in consideration. I would recommend to anyone to read Cliff's evaluations in making a purchasing decision. When you are looking a a new knife catalog and want to get an idea of what the add is explaining, in particular about steel and you are ready to 1800VISA I'd like to see the buyer have this information, in their brain. I believe that Bladeforum members have come here to get more information and probably represent the more informed of the endline use. If I hadn't of seen the questions I wouldn't have posted the thread.

The cost of certain steels mandates a higher level of commitment and attention to all processes following. That doesn't garantee a better product, but it insures it with the reputation of the company you are dealing.

I don't share the view of makers and users being at odds about steel, its working, or its function. On the contrary I see more consistancy than I every have. I feel honored to participate in trying to improve modern cutlery, it lets me associate with wall to wall committed passionate people. Custom makers and commercial cutlers work for the endline user, and try very hard to please the ELU.

I doubt if there have ever in the history of mankind so many informed people chasing their excalibur. This is alot of people pushing the envelop, in and out of the box, that might give us repeat proven methods for making steel better. There is more and better information more cheaply available today than in the history of steel.

Metallugists of today have an economic assignment to produce the least cost material to do the job. Knifemakers have a whole different set of criteria. Many are trying to make it better, and the cost ratio doesn't matter. For those very differences both will learn from each other.

I have a personal posting policy. If I see repeated questions I try and post a reasonable thread and cover that information.

I didn't mean to stray from a topic that I started, I apologise. I felt some comments needed another point of view...Ed
 
My point was that you didn't have to know all that technical psycho babble that came up earlier. Not knowing that info didn't keep people from making a great knife. Not that things haven't improved in many ways since those days but just that like everything else involving technology we seem to lose an art form or skill that worked for many generations once again to computers and the digital age.

Ray and my other neighbor Dan both won cutting contests all the time with their blades but I would bet that they'd give you one long weird stare if you mentioned carbides and diffusing them to allow the alloys to sufficiently nucleate in the matrix all the while wondering what planet you are from. :confused:
 
I appreciate both technical and non-technical info. Anything that helps me to know more about how steel is made into blades is good as far as I am concerned. It seems though that the goal of this thread was to keep things easy to understand for the layman.

If someone wants to start a thread that delves much more deeply into the technical aspects of steel as it pertains to knifemaking, I sure wouldn't object.
 
I have an old sword, probably 1590's that is probably better than most made today. And they probably had a very different way of describing what they were doing. It is an emmense challenge not to go into techno babble when talking about the stuff. That is the challenge I laid out; How do we simply talk about steel? I think there is a way for people to gain usable important knowledge that will serve them in cutlery decisions...Ed
 
Cliff Stamp said:
You temper martensite as it is highly unstable and overstressed. This changes the actual crystal structure from one orientation to another, and can also cause the formation of additional carbides as the primary ones dissolve and the secondary ones like Vanadium form. As the secondary carbides are much harder, this can induce a hardness bump in tempering and the hardness rises, as does the wear resistance and toughness.

There are many heat treatments that do not involve tempering because they don't form martensite and are age and precipitation hardening steels. Bainite heat treatment for example involves holding the steel during the quench at a point above where martensite will form and letting it transform from austenite to bainite.If steels don't have enough carbon to form martensite and instead form pearlite then then don't need to be tempered either.

-Cliff
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Well, so much for general information.:grumpy:

I was hoping a thread would develop that did NOT require a damn PHD to understand.

Thanks for the great start Ed!!

Maybe you can keep it understandable for us "Laymen"
 
wolfmann601 said:
Well, so much for general information.:grumpy:

I was hoping a thread would develop that did NOT require a damn PHD to understand.

Thanks for the great start Ed!!

Maybe you can keep it understandable for us "Laymen"
Click to expand...

Ed,

Just another example of good intentions leading down the road to Hades. Why, oh, why did you mention Chemical Sensitizer?

Best Regards,

STeven Garsson
 
You try to explain some metallurgy and bam, the mad physicist paraphrases you, calls you out on references to refute the internet fluff, and gets Schempp and Bybee all down on the thread. I concede. I should have known better than to jump in and try to clarify the almighty one.
Please forgive me.
 
STR said:
My point was that you didn't have to know all that technical ...
Click to expand...
It doesn't hurt though, Alvin Johnson for example did a tremendous amount of research into ASM reference works when he wanted to start making knives which had superior edge holding performance. This allowed him to select the right steels and heat treatments, and his knives are essentially the extreme endpoint of low stress cutting and edge retention. They are also extensively field tested of course. Now he could have done it all without the knowledge, it just eliminates a lot of the guesswork. He is also looking at new materials based on projections of how they should perform based on what he knows.

As for my statement on contention in the industry, I don't mean to portray it as a scene where everyone is in opposition about every aspects of steels, however there are a number of areas which are fairly large and it is easy to find makers with extremly different viewpoints. Even something very simple for example such as what makes for good edge retention has widely different answers depending on who you ask, some will note that all it takes is high wear resistance and hardness can almost be ignored, others will argue that tougheness can be the most important, others will note high hardness is of critical value and some will describe all of those as being important depending on what is being cut.

-Cliff
 
It isn't that the people that do things the 'old way' have no knowledge of what they are doing. They simply go about meeting the same end result by different means or 'different knowledge'. A knife either works for what it was intended or it doesn't.

The accumulated knowledge of the craft and what worked and why it works that was handed down both verbally and in apprentice training was all they needed to learn or know. All the 'microscopic analysis' stuff was not even necessary or thought about until the advent of technology that allowed us to do so.

I doubt Bill Scagel spent a lot of time thinking about the microscopic structure of the steel he was using. He knew he could make what he worked with do the job from his past experiences and mistakes too no doubt. That isn't to suggest that he didn't look at a magnified view of an edge now and then. I'm just saying in general the stuff that came up earlier while probably quite true, was not really even known in that kind of detail until pretty much our life time or a little before.

Another good example is the guy that made that sword Ed mentioned earlier surely wasn't thinking on those lines or on that level of "PHD" thinking when he made that great blade. That sword and many other great blades from the past show us that while it may be good to know this "PHD" stuff, it isn't really necessary to make a blade that will in some cases outperform even a modern made one by someone that knows all of that and more.

The neighbors I spoke of when growing up are also good examples of this. Here are some old blacksmiths that could pretty much tear it up with everything they make and I doubt they even managed their own check books for lack of math skills when they were alive but they could and did make a great knife.
 
I should probably add that for the layman and middle of the road guys that know some stuff but leave the PHD stuff to the guys with PHDs in metallurgy: All we need is to keep with general terms and info. Believe me, we all like knowing more. But all most really need to know are the simpler terms and reasoning behind the use of certain steels.

For example: 5160 AKA O.C.S (old Chevy spring) makes a great leaf spring, but also a great blade that is very tough and quite good for heavy duty chopping tools including but not limited to swords. If you want to make it with a bit more attitude and better edge holding add some alloy and carbon to improve it and make it harder and you now have 52100. And so on and so on.
 
STR said:
The accumulated knowledge of the craft and what worked and why it works that was handed down both verbally and in apprentice training was all they needed to learn or know.
Click to expand...
You don't need to know anything behind why something works if you just simply copy how someone else does something exactly. Even if you want to improve a product, you don't need to know anything about the details of why what works actually works, if you have enough time, you just try something new and see if it makes it better or worse. The more you know the easier it is to see what roads are worth exploring. Talk to someone like R.J. Martin about his approach to steels and heat treating to see how having a background in engineering is an influence. Kevin Cashen is another guy who has all kinds of talent as a knifemaker, but has a tremendous wealth of materials knowledge.

-Cliff
 
Found the page I was looking for, this covers the process of heat treating in detail with both a very simple physical model
[*] while at the same time providing the details and the materials info for those who desire the knowledge :

http://swordforum.com/metallurgy/ites.html

-Cliff


[*] Fish in a bowl, no I am not kidding, really fish in a bowl, seriously, you know the pets you buy which cost like $0.25 and then you spend $500 for their on room and board, yeah that's the ones.
 
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