mild steel

[vern six]

will mild steel make a good knife, and harden up ok?:confused::confused::confused:

[JohnW]

No, according to what I read you have to have at least 30 points carbon, such as 1030, for the steel to harden enough to hold an edge. But mild steel makes a good letter opener. You can forge it, shape it, and shine it up and make a mighty fine looking letter opener.

[EdCaffreyMS]

What is generally referred to as "mild steel" now a days, is a product called A-36 hot roll. Several years ago I picked up a batch of "mild steel" from an outfit where I had always purchased it, got it home and started to work. I quickly noticed that the steel was not consistent feeling under the hammer, and that when cooled in the slack tub exhibited hard and soft spots throughout. I went back to the store and asked for a spec sheet on the steel. I was told that they did not have one, which I found odd. I started calling around, and after talking with engineers at a couple of different steel plants, I learned that A-36 was the replacement for "mild steel" to be totally honest, its nothing more than "junk" steel. Heres how its made.... After all of the specific steels are produced, anything that is left over is all dumped into one crucible, and then melted, rolled. The only specification on A-36 is that it have a tensile strength of 36,000 psi. It can contain any number of things from titanium to aluminum. Its intended for structural use, where the only concern is the tensile strength. What we would call "mild steel" is rare these days, and more often than not requires a special order on the buyers part.

This stuff is inconsistent, unpredictable, and is definitely not something to use for a knife blade.

[yesteryearforge]

I have allways known mild steel to be cold rolled as in 1018
A36 was just refered to as hot rolled or just black iron
Allthough you can get pretty much any alloy cold rolled or hot rolled
Hot rolled or cold rolled just specifies the finish on
and or the tolerances of the product not so much whats in it

Mike Tanner

[Don A]

A lot of these guys, especially the beginners, are buying steel off the rack at Home Depot, Lowes, Tractor Supply, etc. Everything I'm seeing in these racks is A-36 hot-rolled.

If I go to our local steel supply and ask for a load of "mild steel", they'll give me A-36... unless I specify 1018 or "cold rolled".

You can usually tell the difference by the outward appearance. A-36 hot-rolled will have black mill scale on the surface. 1018 cold rolled will have a clean steel appearance, maybe a little rust.

Neither one is intended to be used as a blade. You can try a lot of different methods of trying to force some degree of hardenability into mild steel, but it is much, much easier to start with a good mid to high carbon steel.

My $.02

Don

[EdCaffreyMS]

yes, "hot" or "cold" rolled only refers to the methodology used to bring the bars to a specific size. Hot roll will be covered in mill scale, and generally is nominal in size, where as cold rolled is clean and will be very close to the specified size.
Check closely! Even most cold rolled now a days is A-36! Its not safe to assume anything with steel, until you check it out. Even the "standards" for well know steels such as the 10XX series have been "stretched" recently. This is all due to the fact that there is very little, if any "new" steel being produced in this country. The vast majority of the steel today is recycled. Which means they try to segregate scrap as well as they can, then throw it into a crucible, melt it down, and then test it to see what it comes closest to matching. That is over simplified, but you see what I mean.
I have data sheets on steel from 15-20 years ago, and when compared to recent data sheets for the same type of steel, most of the elemental specifications have widened by as much as 10-25 points. Thats significant! And it can cause a lot of problems with heat treating. We as Blacksmiths/Bladesmiths are such a small percentage of steel buyers that most of the steel companies consider us insignificant, and therefore don't pay much attention to our needs/wants. (don't laugh, thats almost a word for word quote that I got when discussing this very thing with a couple of steel company sales reps.)

Sorry, I got a little off subject there, but its something that folks need to be aware of.
The best thing that any beginner can do, is to educate themselves on steel. The types, the uses, and finally if your going to forge, it is very helpful if you understand the elements that steels can contain, and what those elements impart alone, and in conjunction with other elements to the given steel.
I have a chart on my site that lists elements, and how they effect steel. Your more than welcome to look at it, and/or copy it for your own use.

[vern six]

Tanks guys!

i'm glad to have smarter people than me to relay on
vern

[ThomasPowers]

Note that 30 point steel is the low end of medium carbon steel and so is not a good knife steel even if it will harden a bit. Old car coil or leaf springs are usually around 60 point and make a better blade. Files will generally be 95-100 point steel and so hold a better edge but may be more brittle.

And for the new folks 100 points equals 1% small quantities can make big differences!

[kbaknife]

Thanks, so much, for your contributions to these threads, Ed.

[Quenchcrack]

Ed, I think you are laboring under a misconception regarding steel. Yes, the vast majority is recycled scrap. Air quality laws make it very difficult to run a blast furnace in the USA so most of those are off-shore. However, the steel company I work for, as well as most others, do not just dump any old piece of scrap into a crucible and melt it, then see what it can be used for. We order selected scrap from certain industries, we run compositional checks on random pieces of scrap, we put it all through a radiation detector so you won't glow in the dark, we blend it and melt it, check the melt chemistry, add slagging agents, blow oxygen into it to adjust the carbon and add various alloys to adust the chemistry to what is desired. If ordered, we can produce steel with no detectable sulfur or phosporus. We can vacuum degas it to reduce the nitrogen, oxygen and hydrogen to a few parts per million. This means we don't have to add much silicon, calcium or aluminum to deoxidize it and the inclusion count is almost nil. Obviously, we cannot make 150 tons of specialty steel so you can order 20 pounds. Making steel is difficult and expensive. The laws of economics apply in spades when you talk steel making. The biggest problem is not domestic steelmakers making junk. The big problem is our government is letting China and every other third world nation dump cheap steel on our ecomomy so that our domestic manufacturers and wholesalers can buy cheap steel to be competitive!!!! I agree with what you said about beginners educating themselves. Go find a source of good quality tool steel and forget about making a sword out of A36 or rebar. But don't complain about the quality of A36 if it doesn't meet your needs. ASTM is the industry group that writes the specifications. This group is dominated by USERS, not steelmakers. We only make what they say they want and what they want is a cheap structural grade like A36. If you want 1018, then order and be prepared to pay for 1018.

[gerald]

Quenchcrack, thanks for the run-down. It's good to hear from someone who is (and has been for a while) actually in the production end of the steel business.

[Snark]

Relying on a non-industry specific source is buying a pig in a poke. Specialty steel suppliers are the only reliable source of non scrap material. Local hardware stores, big box stores, etc, have no source of either documentation or traceability of the materials they sell. You're as well off (or better off) obtaining scrap that has already been used for specific manufacturing purposes - springs, blades, or the like - to make experimental or personal items. If you want to actually make tools, blades or anything else for specific purposes, then buying from a steel specialty supplier is a must. The manufacturing capability is better than it has ever been. It's the distribution that makes it tough to get what you expect.

[Glenn]

Snark
go to the top of the forum page and click on userCP
click on edit profile
go to the bottom of the page and enter your location, then save.

We would like to know where in the world your located.

[cats pa]

The biggest problem is not domestic steelmakers making junk. The big problem is our government is letting China and every other third world nation dump cheap steel on our ecomomy so that our domestic manufacturers and wholesalers can buy cheap steel to be competitive!!!!

I've used my fair share of rebar in residential construction work, but I must admit it never occurred to me to make a knife out of it. Leaf spring, chain saw bar, files, planer blades, yes. Rebar, no.

Correct me if I'm wrong, but even with cheap steel, I don't see our domestic manufacturers being competitive in price with imported products. They've just got too steep a hill to climb, too many costs that offshore mfgrs don't have.

Also, they're dealing with a market where a lot of consumers consider price as their primary criteria. "Why is this one 100 bucks and that one is only 20?" Too often, there's no one to tell them that it's mostly because this one will last longer or perform better or not fail at a crucial moment. So they buy the cheap one and complain when it turns out to be a POS. Hopefully, they go back and get the good one and learn their lesson, but not always.

The cost of potential failure is a variable that doesn't enter many people's economic equations, but should be considered. Would you fill your truck with gas at $1.50/gallon if you knew there was a 30% chance it would destroy your engine? Course not. The risk isn't worth the savings. A deal is only a deal if the product performs the function. How does a consumer decide if the product can perform the desired function? In many cases, the function is complicated and the available info is sparse, so it's kind of a crap shoot. No foolproof method, but - there are smart and foolish ways to play the game.

Sorry, I'm probly preaching to the choir here, but I get real tired of hearing ninnies complain about the results of their own bad choices. If a guy spends 40 hours painstakingly crafting a knife out of rebar, and it won't hold an edge, he has an opportunity to learn a valuable lesson. Next time, our hero will harden his mystery metal, and find out if it's knifeworthy before he polishes it to a high gloss. But, not a word of complaint will pass his lips, and later, he might tell the funny story on himself (but in my case it was kitchen knife steel, okay, not rebar).

On the subject of learning from the experience of others, is it true that chain saw bar is O-1? I read that somewhere, but didn't know for sure.

Parker

[EdCaffreyMS]

Quenchcrack,

I wasn't dogging you, or our steel companies, just trying to get the point across that everyone needs to be fully aware of what their buying as far as steel goes, and also to understand that if you walk into an establishment and ask for "mild steel" your gona get A-36. Most of the folks who have been around Blacksmithing/Blademsithing for a number of years can remember when "mild steel" meant 1018 without any question. When the change to A-36 took place it was something that was not made well known. Even the distributors that I deal/dealt with did not know of the change until customers started asking questions/complaining. Where it used to be safe to request "mild steel" and know you'd be getting 1018, it is now necessary to specifically request 1018 steel, and as you pointed out the cost is significantly higher. As for my comment about throwing scrap in and seeing what comes out, that was over simplified in hopes that everyone would get the idea of what I was talking about.
The main thing that frustrates me is the widening of the specs on various steels. The spec sheets I have from way back versus those I have from more recent times, as well as conversations with various contacts within the steel companies, proves that. I honestly did not think much of it prior to having some specific grades of steel, that I had used for many years, give some very abnormal results during/after forging and heat treating. When I eliminated all the variables in my shop, I started looking into the steels, and found what I wrote in my previous post.
I have no doubt that our production capabilities are the best in the world, but due to the import of substandard foreign steels, it has forced US steel makers to cut some corners in order to compete. Those are not my words, but those of Marketing VPs that I know from two different steel companies. Again, thats not dogging them or any steel company, its just something that we as end users have to realize and adapt to.

[Ice Czar]

for a slightly longer perspective
mild steel would be superior to the vast majority of edged weapons all throughout prehistory, ancient history, upto the 17th century (with exceptions) and a decent starting point (if the blister steel process is employed) into the 20th century

http://www.davistownmuseum.org/PDFs/Vol10_Appendix_A%20Guide%20to%20the%20Metallurgy%20of%20Edge%20Tools.pdf
The Davistown Museum (lots of cool info )

pointy and sharpenable :p

[gerald]

So, here's another question............. If A36 isn't considered "Air Hardening Tool Steel" (like A-2 for instance), how come it has the "A" designation. Obviously the 36 refers to its 36,000 pound tensile strength, but why the "A" if it ain't air hardening?

[Steve Sells]

Why should they? In one case it is a componant code the other is a construction term for loading stress. they are both using a different standards system.

It is like why do we have ounces in both volume and weight? depending on what system you use you will have a different amount, thay will both technically be an ounce. Soo many standards for various reasons.

[EdCaffreyMS]

Thats a question that I asked early on with the material. Nobody has ever given me what I consider a valid answer. I had a couple of pieces analyzed, and the list of elements it contained was long, including titanium, aluminum, chromium, and a number of others.
The reason I got interested in finding out what it contained was due to a project I was working on that required mild steel. I had forged a tenon on a piece, then cooled it in the slack tub so I could work on the other end. I noticed that the scale had blown off in several places, and upon examining the bar, the shapes of the hardened areas looked familiar.... a couple looked like screw shapes, and one looked like a coil spring. Thats when I decided to send it off for analysis. Talking with some of my contacts in the steel producing arena afterwards, I was told that the only spec on the steel was 36,000psi tensile strength, and that it could contain just about anything...which is what the analysis showed.

Over the past few years, many of the old concepts we as Blacksmiths/Bladesmiths have had about steel, have gone out the window. I've learned that even asking for a spec sheet with your steel order doesn't always mean anything, as I have been sent spec sheets that were photocopied out of books, and upon having samples tested, the spec sheets did not match the test results. One example is 1095, a steel that I used to trust and use a lot. A few years ago I noticed the specs started to creep wider and wider, and then I started getting emails and phone calls from newer Bladesmiths who could not get blades made of 1095 to harden. What I found was, due to the specs widening, the time/temp curve was a variable from batch to batch, depending on a specific element's content. In some cases the quench time was less than 1 second! Thats physically impossible in most small shops. Some still fight the battle, trying different techniques, and re-inventing their heat treating process with each new batch of steel, but for me it was a waste of time, material, and effort. I no longer use that particular grade of steel.

Another example is that one NW steel supplier advertised 52100 in flat stock. Now unless someone purchases 52100, then rolls/forges it flat, your not going to get it in that configuration. (52100 is only produced in round stock)
I purchased one 36" length, and when it arrived I started forging. I've forge a good amount of 52100, and this stuff was totally different under the hammer. I forged two "test" blades, heat treated as I would 52100, and then began testing it. As a general rule, I can make a 52100 blade flex to 90 degrees without cracking/breaking. These blades literally shattered at about 30 degrees of flex. I sent samples off for testing, and they came back as O-1! When I called the dealer where I had purchased the steel and confronted them about it, I was told "Its close enough that we can call it 52100." WHAT???? Needless to say, I no longer do business with that distributor.

The whole point is that many of the things we knew/trusted, and took for granted with steels, may no longer valid. Competition from foreign steel sources (who sometimes introduce substandard products) have forced the US steel industry to change in order to compete. That, in turn has a trickle down effect on the small end user. Its not that big of a deal with making ornamental items, but it has a huge impact on those who must heat treat their products. Its just something that we need to be aware of, and that we will have to deal with. My only intent posting this information is to make those who might not be aware, that these circumstances do exist, and to hopefully help avoid them.

[gerald]

Why should they? In one case it is a componant code the other is a construction term for loading stress. they are both using a different standards system.

It is like why do we have ounces in both volume and weight? depending on what system you use you will have a different amount, thay will both technically be an ounce. Soo many standards for various reasons.

So, what the heck DOES the "A" stand for in A-36????

[gerald]

OK, I got it. Since "the community" wouldn't spoon feed it to me, I actually did some looking up on my own. Here's my (very) quick and dirty explanation of why the "A" in A36.

To paraphrase what Steve Sells said earlier: there are component codes and construction terms....which still doesn't tell us what the "A" in A-36 stands for (A is for aardvark, etc).

So, here's what I found out after sorting out what Steve tried to tell me:

When it comes to steel (and other metalic products) there are generally two outfits that establish "standards": ASTM International and AISI.

AISI is the outfit that gives us one set of number/letter codes for steel products: "S" for shock resisting, "A" for air hardening, "10XX for carbon steels, etc.

ASTM gives us standards for all sorts of materials (rubber, plastic, iron and steel, copper, etc). It turns out that the section of their codes that deal with iron and steel products is the "A" section and all codes that fall under that section have an "A" prefix. A-36 is the spec for Carbon Structural Steel. Specs in the "B" section, for instance, apply to non-ferrous metals and alloys.

SO - the bottom line to all this is that the "A" in A-36 just stands for the section of the ASTM standards that deals with Carbon Structural Steel.

As Steve Sells alluded, we still can't mix apples and oranges when we talk about steel codes.

[Quenchcrack]

Ed, Your points are well made. I hope I didn't come off too crabby. The steel industry is in a state of flux and most of the US production will be controlled by foreigners soon. Just wait until the Russians or East Indians decide what goes into A36!!! I find it strange that the tolerances for alloy elements are getting wider while our ability to control them is getting better. The melt practices at my company allow us to hold a carbon spread of .03 Max. That's +/- .0015%C from heat to heat. Other elements are similarly well controlled. By reducing the variability of the chemistry, we can control downstream processes more closely and produce more prime tons without rejects messing up the economics. However, we cannot control the distributors!
Let me add another bit of information. There are organizations all over the world that write steel specifications. Just in the USA we have American Society for Testing and Materials, Society of Automotive Engineers, American Society of Mechanical Engineers, American Petroleum Institute, American Iron and Steel Institute, Association of Iron and Steel Engineers, and on and on. Each one is focused on different industries. It is common for a customer to call us and ask us to triple stencil his pipe as meeting three different specifications. This means he doesn't have to carry three similar products. Since we have to produce the product to meet three specs, the actual product has to fit into the tiny area where all three specs overlap. This means we hold the spec to roughly 1/3 the tolerance. We do it regularly and that is called control. Don't ask your distributor to sell you any Chinese triple stencil product, though.