Steel Yourself, a primer

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Brian.Evans

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In an effort to rejoin the community and provide some value, I have decided to cross post the series I'm writing on my Facebook page to this forum. I'm just as bad, if not worse, at telling new knifemakers to read the stickies, instead of teaching. This series is going to be very basic. It's meant to inform the rank newbie and hopefully whet their appetite for more knowledge. That said....

Steel Yourself, part 1

What is steel? It's what knives are made of, right? But what is steel, really? I typed that into Google and got this:

noun: a hard, strong, gray or bluish-gray alloy of iron with carbon and usually other elements, used extensively as a structural and fabricating material.

Ok, well, that helps a little. Kind of like asking what's a car and someone telling you, "it's a thing with four wheels and a steering wheel and it goes really fast." Lots of words, not a lot of explaining.

Steel is like a cake. There are a lot of different elements that go into the mix and when it's done we have a bar or sheet of hard-ish, magnetic metal.

The secret to steel is carbon. Carbon takes plain iron and turns it into something special. Something we can use to make almost anything. The springs in your ball point pen, or hinges on a door, our a man hole cover, or nails, or.......You get the idea. Steel is everywhere, but especially in our pockets our on or belts as knives.

Knives are one of Man's oldest tools. Archeologists recently found a1.4 million year old flint knife at Sima del Elefante, Spain. Tomorrow, I'll talk about what separates knife steel from all the other types of steel.

Teaser, the difference is in the details, in less than 2% of the total product. Tomorrow, in Steel Yourself, part 2.
 
:thumbup: I'm Looking forward to this , Still trying to figure all of this crazy stuff out!
 
Brian,

I'll be watching with interest. Thank you for your past and future contributions. The problem here is that every day there is a new crop of newbies looking for answers. As time goes by your posts will drop off the page and out of sight. You can't repeat yourself in the same detail for every batch of noobs. So eventually you or somebody else will refer the new makers to this series or to the stickies. And even if this series is made a sticky we are back to square one. I'm looking forward to reading what you have to share because I can't get enough of steel talk no matter how many times or ways it is offered. I just wish my brain could absorb it all as fast as I read it.
 
Brian.Evans said:
Steel is like a cake. There are a lot of different elements that go into the mix and when it's done we have a bar or sheet of hard-ish, magnetic metal.
Click to expand...

Before anything is added, iron is already magnetic coming out of the ground as a single element.
 
Another point worth considering in the discussion is that the % of elements is by weight.
1% of carbon may appear as a little thing VS the huge effect it has upon the steel, but 1% in weight of a steel stock is made by a lot of carbon! :)
 
Karl B. Andersen said:
Before anything is added, iron is already magnetic coming out of the ground as a single element.
Click to expand...
Karl, you are absolutely correct! Thank you for adding that. That's what I get for typing and trying to think that early. I will have to reword that line. It didn't quite present the way it sounded in my head.
 
stezann said:
Another point worth considering in the discussion is that the % of elements is by weight.
1% of carbon may appear as a little thing VS the huge effect it has upon the steel, but 1% in weight of a steel stock is made by a lot of carbon! :)
Click to expand...

Good point. Iron is 4.5 times as heavy as carbon. So by volume ( which is not how it is done), it is a 4.5% carbon/steel mix. Since that carbon is slowly added to the iron from a lot of wood and charcoal, it takes hundreds of pounds of carbon source material to add only an ounce of carbon to the 5 or 6 pounds of iron in a smelt.
 
Steel Yourself, Part II,
An ongoing blog series geared towards the new knifemaker or knife lover who wants to know why, rather than just how.

I had hoped to open this post with slightly funny pun using the word alloy, but frankly, I couldn’t come up with any. If anyone can think of something, that would be great.

A quick note before we jump into the fun part of this post. Alloying elements and percentages are in by weight, not volume. Iron is 4 ½ times heavier than carbon. Interesting to note, and something I only recently learned myself. I never thought of asking that particular question before. Thank you Stacy and Stezann!

One of the most common questions aspiring bladesmiths ask is, “Why can’t I use this awesome, cheap steel I found at Home Depot/Lowes/ACE/True Value/etc., etc. to make my zombie slayer/survival/dragon hunter/ten inch chopper, of which I’ve always dreamed?” Setting aside the obviously problematic second half of this hypothetical question, why can’t our new friend make his dream knife from low carbon welding steel found at local hardware emporiums?

Carbon, dear Watson, carbon…..or rather a lack thereof.

As we established last time, steel is like a cake. A grey, hard to eat cake. The basic difference between steel and iron is the addition of the sixth element, carbon. In my next post I will explain the molecular change that results in steel being able to harden, but suffice it to say that carbon allows steel to harden. No carbon, no hardness.

Perhaps I am getting the cart in front of the horse, but this is supposed to be simple. Just as adding more of an ingredient into a recipe changes the outcome, so can steel manufacturers change the composition of steel in order to tailor it to a specific task.

Mild steel, or weld steel is likely named A36 or 1018. The 18 in 1018 refers to 0.18% carbon content. A36 usually has around 0.26% carbon content, with roughly similar manganese (Mn), phosphorus (P), and sulfur (S) contents.

A very good blade steel for beginners and experts alike is 1084. If you guessed that it has around 0.84% carbon content, you have been paying attention. This is a good low alloy steel (not much else in it but carbon and iron) that is easy to heat treat because 0.8% carbon happens to be at the eutectoid point of steel. Don’t worry about what that means. Just look at the word and remember it for later.

What else can iron be alloyed with other than carbon? I’m glad you asked, dear reader.

Lot’s o’ stuff. Next question.



Oh…..you wanted actual examples? Well then, that’s a different question. You have to learn to ask the question you actually want answered. How am I to know what question you actually wanted the answer?

I’m going to make a list, because frankly there is no other way. I’m listing basics here. There are other things these elements do, but they are beyond the scope of this post. Remember guys, there are entire careers built on this information. It’s folly to pretend that I could hit everything in this little post.

Manganese: Decreases the speed needed to drop the temperature of the steel during the hardening phase past the pearlite nose (another term you don’t need to know yet. Just take it in and keep reading.) Manganese makes the steel harden more efficiently.

Phosphorus: P is a balancing act. It increases hardness and strength, but it makes the steel less ductile and tough.

Sulphur: Sulphur improves the ability to machine a steel, which can be important in choosing a 300 series stainless steel. Ask a machinist friend how much fun it is to machine 304 stainless…….On a related note, if you do not currently have a machinist friend, get one as quickly as possible. Everyone needs more machinists in their life, plus their toys are really, REALLY cool.

Silicon: Used as a deoxidizer, which makes it more likely to not suffer internal defects. However, too much silicon can degrade surface finish in certain applications, mostly not related to knifemaking.

Vanadium: This is one of my favorite alloying elements. Holy cow, I’m a geek. I have a favorite alloying element…..I need to get out more. Anyway, V is used to refine grain size. Grain size directly affects strength and toughness of hardened steel. Over about 0.05% Vanadium forms carbides, another word that you just need to read and remember for later.

Chromium: Chromium is a very important alloying element. Why? Because I said so. Ok, that never worked with me either…..Chromium is the element that makes stainless steel, stainless. Above 14% a steel is considered stainless, or more accurately, stain resistant. Above 5% chromium content, steel becomes air hardening rather than oil or water hardening.

This is getting a bit long, so I’ll give you some homework. Other alloying elements could include, but are not limited to, nickel, molybdenum, and tungsten. You can look them up if you’d like more information.

Next time on Steel Yourself, we will look into austenization, why some steels get hard and how they do it, and how many Jane Austen puns I can make in one post. Until then, stay steely.
 
Vanadium doesn't refine grain, it assists in pinning grain boundaries, helping inhibit grain growth.
 
Is this all there is??
I've been wondering what the effects of different elements have on knife steel. So I can actually understand what I'm looking at when looking at materials.
 
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