Soft versus Hard Steel

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#1
Hi - I would like to learn about the different types of steel that knife makers use and the benefits/detriments of using softer steel. Here are a few questions I would appreciate feedback on:

1. Is there a type/s of steel that is considered the best or preferred to use?

2. What is lowest carbon content steel that is commonly worked with?

3. What are the potential problems that can emerge from working with softer carbon steel when making a knife?

4. Regardless of any potential downside in the performance of a knife made from softer steel, can a knife maker still make a knife from a piece of softer steel or is it somehow impossible or too problematic to do?

Thanks!
 

Doug Lester

Well-Known Member
#2
Hey, Daren. That's a wide open question. A lot will depend on how you intend to make knife blades. If you are intending to make blades strictly by stock removal and sending them out for heat treatment things open up as far as steel selection goes. If you are intending to forge blades then you are going to want to deal with simpler or moderately simple alloys.

Regardless, most of us start out with steel in a softened, also known as the pearletic state. That is steel with little carbon dissolved into the iron crystals but held in carbides, primarily iron carbide, form out blades then harden and temper them to make a usable knife blade. The advantage of working with steel in this form is that it is easier to cut, grind, and drill. There are some who might try to start out with an old file and grind it into a knife blade but they have to be careful that they don't draw the temper with grinding generated heat.

As far as carbon content goes, you are looking for at least 0.6% carbon though some might use high carbon railroad spikes (that is high carbon for railroad spikes) which come in ~0.4%. That means, no, you can't use a piece of flat bar from the hardware store. You won't be able to harden it enough to make something that will hold an edge.

A blade has to be hardened by heating it above where the atomic bonds between the iron molecules allow the crystals to reform so that they can absorb more carbon and then trap it in iron matrix by rapid cooling, be that in water, oil, or air, depending on the alloy. For that you are going to have to have a forge or a high temperature oven that can heat the steel to 1475°-1900° F, again the temperature is going to depend on the alloy.

Look on Amazon and see if you can find a copy of The Master Bladesmith by Jim Hrisoulas. There is one person there (at least he was there in the past) who thinks that his used copy is worth over $100. It's not. There should be others at a more normal price even if they're used. Another book, which is a bit more expensive, is Steel Metallurgy for the Non-Metallurgist by John Verhoeven. It explains what steel is and how we manipulate it with heat.

If you need more information or just feel lost shoot us a line and we'll put our heads together (which can be dangerous) and help you out.

Doug
 
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#3
Hey, Daren. That's a wide open question. A lot will depend on how you intend to make knife blades. If you are intending to make blades strictly by stock removal and sending them out for heat treatment things open up as far as steel selection goes. If you are intending to forge blades then you are going to want to deal with simpler or moderately simple alloys.

Regardless, most of us start out with steel in a softened, also known as the pearletic state. That is steel with little carbon dissolved into the iron crystals but held in carbides, primarily iron carbide, form out blades then harden and temper them to make a usable knife blade. The advantage of working with steel in this form is that it is easier to cut, grind, and drill. There are some who might try to start out with an old file and grind it into a knife blade but they have to be careful that they don't draw the temper with grinding generated heat.

As far as carbon content goes, you are looking for at least 0.06% carbon though some might use high carbon railroad spikes (that is high carbon for railroad spikes) which come in ~0.04%. That means, no, you can't use a piece of flat bar from the hardware store. You won't be able to harden it enough to make something that will hold an edge.

A blade has to be hardened by heating it above where the atomic bonds between the iron molecules allow the crystals to reform so that they can absorb more carbon and then trap it in iron matrix by rapid cooling, be that in water, oil, or air, depending on the alloy. For that you are going to have to have a forge or a high temperature oven that can heat the steel to 1475°-1900° F, again the temperature is going to depend on the alloy.

Look on Amazon and see if you can find a copy of The Master Bladesmith by Jim Hrisoulas. There is one person there (at least he was there in the past) who thinks that his used copy is worth over $100. It's not. There should be others at a more normal price even if they're used. Another book, which is a bit more expensive, is Steel Metallurgy for the Non-Metallurgist by John Verhoeven. It explains what steel is and how we manipulate it with heat.

If you need more information or just feel lost shoot us a line and we'll put our heads together (which can be dangerous) and help you out.

Doug
Hi Doug,

Thanks for the informative reply! Are those carbon figures accidentally off by a factor of 10?

Great info. I certainly need to read up more on steel and how heat affects it. What an interesting field of science. I will look into getting a copy of those books - thanks.

As a knife maker, what are your thoughts on the sense in making a knife from a knife-shaped piece of soft carbon steel?
 
#6
Thanks, Ed - much appreciated!
I've checked out your informative site - very helpful info. And wow - your knives are quite impressive. Some of the damascus ones are so creative.

Your site discourages using scrap steel. Under the hypothetical scenario where I propose hiring you to take a piece of scrap soft steel to make as best a knife as you can from it, would you be able to do that? Or is working with that type of material impossible due to reasons I don't understand?
 
#7
Here's a little something that might help you begin to understand steel. In it's most basic form, steel contains nothing more then Iron, Carbon, and Manganese. Other elements are added to give desired working qualities, or end use item characteristics.

http://www.caffreyknives.net/element_content.html
Everyone who does not know about alloys should read this, great info Ed it is easy to understand too.
 
#9
We'll assume the OP is asking a serious question, but based on the above statement it sure sounds like a troll.
Dude, I’m a nerdy scientist doing the best I can. I’m actually just conducting research relating to what knife makers can or cannot use to make knives from. My company produces scrap metal in the form of pipe shrapnel and many of the pieces look like they could be transformed into unique swords and knives.

I am learning there is an overall resistance to using new materials to make knives from and my primary objective is to find out if my existing scrap can be used. My second objective is to learn whether my process can use the steel that you guys use and, once consumed in my process, if it can still be used to make a viable knife from.

I’m not a troll, just a guy trying to learn from all of you and taking each next step based on stuff you all tell me. So if you all keep saying you can’t make a knife from my stuff, I am faced with the reason being either a technical limitation or an attitudinal one. I just want to make the most of my scrap steel and have always been impressed by the type of work most of you do.

Thanks for your comment. This has been an interesting journey.
 

EdCaffreyMS

Forum Owner - Moderator
#10
Your site discourages using scrap steel. Under the hypothetical scenario where I propose hiring you to take a piece of scrap soft steel to make as best a knife as you can from it, would you be able to do that?
The answer is beyond yes and no..... Yes, I could make as best a knife as I could from it. The other part of the answer is no, because I simply would not do it. Why? because I know I would be producing a substandard product, because I'd chosen to use a base material that that was/is unsuitable for the end product. Were I to agree to produce what I would call "a knife shaped object", and knowingly use materials unsuitable for the task, there goes 30+ years of building a good reputation, along with a good portion of my integrity.....right out the door.

I've been asked MANY times to compete on the TV shows, and was even interviewed to be a Judge on one of them....but turned it all down, because in my mind, it simply sends an entirely wrong message about a craft/skill I dearly love. That message being that anyone can dig up a piece of scrap, and turn it into a knife in 3 hours. And in the process of the time constraints, all semblance of quality and craftsmanship go right out the window.

Or is working with that type of material impossible due to reasons I don't understand?
Let's just say that once you educate yourself on steel, you'll understand those "reasons" you mention. When referring to steel as "hard" or "soft"....it's appearant your mind is thinking two different types of steel..... the truth is, any given steel can be "hard" or "soft" depending on it's current state. Look up, and educate yourself on the following terms as they relate to steel:
Hardening
Tempering
annealing
normalizing

Here's another link to some info on my website that helps educate on steel types, and their associated designations: http://www.caffreyknives.net/steel_id.html
 
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John Wilson

Well-Known Member
#11
Dude, I’m a nerdy scientist doing the best I can. I’m actually just conducting research relating to what knife makers can or cannot use to make knives from. My company produces scrap metal in the form of pipe shrapnel and many of the pieces look like they could be transformed into unique swords and knives.
I mean this respectfully, but if you detect some degree of frustration in my tone, you are correct.

Your research should have begun with metallurgy, not looking for customers and then challenging their professional expertise when they give you feedback.

I am learning there is an overall resistance to using new materials
No, that is what you keep taking away from it when the responses have been clearly to the contrary. You are not proposing new materials. We know exactly what you are proposing, which is mild steel. You have been told several times that is a non-starter yet you insist we are just resisting change. What we are telling you, very politely and over and over again, is that you do not understand the science of steel because you have not researched metallurgy. Nobody expects you to be a metals expert, but they do expect you to listen and learn - which you are refusing to do.

my primary objective is to find out if my existing scrap can be used. My second objective is to learn whether my process can use the steel that you guys use and, once consumed in my process, if it can still be used to make a viable knife from.
The answer has been given several times now, in great detail. Yet you keep going back to your notion that if we’d only be open minded we’d come around to see it your way. Under your breath you are insisting that we do what we do by aping convention rather than working from education and experience.

I’m not a troll..... I am faced with the reason being either a technical limitation or an attitudinal one.
And there you go again. Your challenges are indeed attitudinal, your own.
 
#12
The reason you sense attitude from the makers here is that you keep asking the same question which is answered politely and correctly several times by people who know their business yet you keep asking. You passively accuse them of being closed minded to your shrapnel too so what are they to think. You claim you are a scientist yet you retain no information these people are trying to tell you. The only logical conclusion one can draw from an exchange like this is trolling which has occurred here in the past. Your shrapnel will never be considered for many reasons by a knifemaker who knows steel the least of those reasons is that it does not contain enough carbon. No, it would not matter if you made pipes from 1084 which is my personal favorite I would not use it even if it were free because it has been blown up and likely is damaged. The resulting knife would likely fail under use, I would have to replace it under warranty and the consumer would assume I make junk. Not gonna happen. You have been told the steel is useable for decorative ironwork and I suggest you try over at I Forge Iron you may find some takers there. If you want to hang out and learn what you can please feel free. The guys here will help how they can. But if you ask about this topic again I for one will know you are trolling and I will report it as such.
 
#13
Hey everyone - thanks for your replies. I really appreciate everyone's time and patience with these inquiries.

Ed - thank you so much for that fantastic reply and steel references. So the knife can be made and the crux of hesitation is that the material has to be suited to the purpose for making the knife, according to the purpose you have aligned with, which is to make a knife that functions as a knife (rather than appears knife-like). And this gives rise to the apprehension regarding unknown materials and soft steel (can't make a good edge).

It also seems that there is perceived reputational damage that can come from working with material that delivers a substandard result. And so when someone asks you to work with a new material, your reply suggests it may sound like you're being asked to change your standard and potentially risk your reputation and so you decline. Thank you - all of that makes perfect sense and I really appreciate the honesty.

If I was to make my detonation assemblies from any of the metals you listed, what are your thoughts on making a knife from a piece of that type of shrapnel? Or would that still seem too risky? I can reanneal the steel after detonation if that is necessary. Thanks tons.
 
#14
Dude, I’m a nerdy scientist doing the best I can.
I think most of us went there Daren...lol. we operate from a more practical less imaginative/theoretical postition...so meshing "what ifs" to our "been there/done that" mindset doesn't always work. When I first started reading some of this stuff I thought, "Just because you like blowin' stuff up doesn't mean we have to help re-purpose the results...lol"

I like doing stock removal knives...using fairly pure steel...so I know my thinking on not wanting any impurities in my steel are biasing me against the process you are "feeling" your way through...

good luck...who knows what you may end up with eventually...maybe something really different and cool?!
 
#15
Thanks, John, for your reply.

I am not looking for customers as I have nothing to sell. I am sorry to hear that dealing with me trying to understand your group is frustrating you. Beginning with metallurgy would not have helped, because the issue isn't with the material being soft or hard steel, it's like what Ed said about substandard materials, reputation and such. And that was what I meant by attitudinal btw, not a negative attitude or resistant attitude - I meant an attitude like a mindset or mental filter that demands the art of knifemaking to be executed a particular way or not at all.

I have not said that knifemakers are resistant to change, I said I am sensing there is a resistance using new materials. That's the truth. That's why there are charts of materials to use and recommendations on what not to use.

I see my material as new because of the peculiar conditions it goes through to arrive in the shrapnel state I'm talking about. Soft steel is a no-go, ok, that's fine. Now I know - but not due to metallurgical science. What if I use the types of steel that you might use to make a knife from? If we're just talking material and turning a blind eye to the detonation process, it should potentially be fine if it was reannealed. Or would it be? How would we know for sure?

You said: "The answer has been given several times now, in great detail. Yet you keep going back to your notion that if we’d only be open minded we’d come around to see it your way. Under your breath you are insisting that we do what we do by aping convention rather than working from education and experience. "

These things aren't accurate. I am not trying to persuade anyone to use my shrapnel, I am trying to understand whether you can work with it. If technical objections are brought up by one of your experts, the engineer in me looks for technical solutions. If I present a solution I'm not trying to change anyone's mind or disrespect anyone's education or experience, I'm merely overcoming a technical objection.
 
#17
Hi Chris - I think the root of any misunderstanding comes from how you and most other knifemakers have a standard for your craft that I was previously not aware of. That's all.

I'm not passively accusing anyone of anything. I'm just trying to learn, and the truth is I did not see why making a knife from shrapnel would be a problem, even with the "wrong" steel, unless there was a technical reason I didn't understand.

When you say you wouldn't use 1080 pipe shrapnel because it it likely damaged, this is a great example. The objection you give is "likely damaged", which implies you would use it if you knew for certain that is was not damaged.

If I said I can have the piece subjected to a test to determine the presence of any inner microfractures through X-Ray, and give you a piece of undamaged 1080 shrapnel, and a certificate of analysis, I'm not giving you the gears or trolling or whatever else. I'm just having a conversation to see if you can work with my shrapnel and working with the stuff you tell me.

That's why I keep asking questions. I am most certainly not trying to do anything other than learn. Thanks for your patience.
 

KenH

Well-Known Member
#18
Darin, if you can provide a piece of shrapnel steel of 1080 or similar decent knife making steel (for example anywhere from 1070 to 1095) and assurance it's not full of microfractures from the explosion, I'm sure there are several here who'd be willing to make a knife from it. I know I'd be happy to make a knife from shrapnel you sent to me with assurance of no microfractures.

Before when I mentioned it sounded like a troll thread I didn't know all your information.

Ken H>
 

J. Doyle

Dealer - Purveyor
#19
Dude...........WHY? Why would any of us want to use pipe shrapnel from an explosion?

***EVEN IF*** it was suitable knife steel scrap, ITS STILL SCRAP! Its like 5 steps backwards before we can go forward......who does that?

That would be a lot of extra work for REALLY COOL highly significant scrap, which yours isn't.

Your proposing blowing up something to make scraps of knife steel that would then need to be tested and analyzed and then subjected to several thermal/forging/shaping/more thermal treatments to make a knife from........that isn't even cool or interesting.

NO ONE IN THEIR RIGHT MIND WOULD BE INTERESTED IN THAT!!!!!

This is not typical trolling.....but its like passive aggressive trolling.
 
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