Steelworking

[Optimist]

Steel is one of the basic materials of modern civilization. Since I have done gunsmithing for quite a few years, it is a material I have a more than passing familiarity with. Steel is a form of iron with a limited amount of carbon in it, between a tenth of a percent, and two percent. Iron with no carbon at all is a very soft, ductile material. Iron with more than two percent is a tougher material, and, beyond about 4 percent, it is a very hard and brittle one.

Alloying elements like chromium, nickel, vanadium, tungsten and even lead are used in making up modern steels, and these different materials, alone or in combination, produce some strong effects on the basic iron-carbon mix. If there is interest in this matter, I will continue posting.

[Sniper-T]

As a steel worker for the last 25+ years; I have somewhat of a vested interest in it. Always looking to learn more.

Carry on!

[The Stig]

Yes, please do. We like subject matter experts.

[realist]

Optimist, Realist here. Do those two attract or repel, oh well. Working with metal is high on my list. I am taking up welding and would appreciate additional posts. Thanks

[Optimist]

Okay, I'll put together a basic presentation on how the carbon content of steel works, and how the level of carbon in the steel acts to change temperatures at which heat treatment needs to be done, and I'll post that, and the diagram, next weekend. If any of you have ever heated and cooled steel, there are points you may be familiar with, and others you may not have noticed. Generally, when you have a piece of red-hot steel in your tongs, you are moving pretty fast to try to accomplish something before the metal cools down, so it is easy to miss some of the finer points in the rush.

First things first, steel at room temperature is a mass of crystals, and the kind of crystals they are depends on the amount of carbon that is mixed in with the iron. For pure iron, with no carbon at all, the crystal structure will be ferrite, a very soft and ductile material, of pretty low strength. It is very strongly magnetic. If you heat this pure iron to about 1450 degrees Fahrenheit, it will no longer attract a magnet. The ferrite crystals are changing into a crystal structure called austenite. At the point where the ferrite stops attracting a magnet, you keep on pumping in more heat, but the iron doesn't get any hotter by the temperature you're measuring. This continues until all the ferrite is converted, and then the temp begins rising again. This plateau is called the calesence point. That heat was bound up in changing the crystal state of the material. Remember it, because this heat will come back around again when we cool the metal down.

[Optimist]

Now we have a piece of red-hot metal. It's somewhere above 1400 degrees, where the ferrite has turned itself into another kind of crystal called austenite. Austenite is not attracted to a magnet. (For future reference, that is why some kinds of stainless steel don't attract a magnet either; they're stuck in a stage where they are made up of austenite crystals, even after they have cooled down.) If we let this metal cool down, it cools to a point a little below the place where it stopped heating when we were making it hotter, and then the temp begins going up again. That is the austenite changing back to ferrite, and, when it does, it gives off heat.

[sidewinder]

Melt shops are dirty. Welding is harmful to your health. It was my favorite thing. I miss welding.

Welded stainless, brass, copper, cast iron, common iron through galvanized, oil, grease, lead based paint, rust, water & dirt.

It's a cold profession in the winter and hot in the summer. Same with melt shops. Which are loud and dangerous.

Welded on & in hot metal ladles, water cooled ductwork, induction furnaces, continuous casters, arc furnaces, cupolas, BOF furnaces, AODs, hot metal cranes, strip mills, rolling mills, bloomers, coilers, shot blasters, acid tubs, conveyers, locomotives, trucks, fabrication and anything else you can find in a steel mill. Seen and fixed cut throughs, doubleups, structural failures, new construction, rebuilds, explosion & fire damage. Worked with pipe fitters, millwrights, hydraulics, bricklayers, electricians, machinists, riggers, carpenters, mechanics, repairman.

Had many fellow workers killed by huge vehicles, overhead cranes, burned, electrocuted, falling & crushed. When I first started it was common to see men with lost arms and fingers. Safety conditions have greatly improved.

Years ago for every steelworker laid off 14 people in related industries lost jobs. Over 100,000 steel workers jobs have been lost. That equals over 1 million related jobs lost.

Stainless steel is non magnetic depending on how much the nickel content is. Nickel is not magnetic. The most expensive and best stainless steel has a high nickel content. The same nickel that is in a nickel nickel.

[nepreneaux]

So I am thinking D2 or 01 for making a knife. Which one?

[Optimist]

Stainless steel is non magnetic depending on how much the nickel content is. Nickel is not magnetic. The most expensive and best stainless steel has a high nickel content. The same nickel that is in a nickel nickel.

Reason the high-nickel stainless steels ain't magnetic is that the nickel locks the crystal structure into an austenite structure, one that don't allow magnets to attract to the steel because the poles of the iron atoms aren't oriented the way they are in all the other structures. Now a steel nickel is 19 parts nickel (the old pre-1984 ones, anyhow) and one part copper. If you are melting up steel in a crucible, you could, feasibly, use nickels to add that metal to your melt. I'm getting the piece about alloys ready for you guys, and it should be ready next weekend.

Nepreneaux, it depends on what you want to do with the knife, and how good your heat treat plant is. Most knives and other hand tools I make up from 1095, or W1, which is pretty close. They have to be kept oiled, or they rust. O1 is a tougher steel, and if I was to make a blade for batonning, it would be one I would consider. D2 is one of the steels I'd consider putting back in annealed form for making things that absolutely had to be unbustable, like firing pins and such. It's too expensive a material for me to use for a knife....

[Sniper-T]

Opt...

You a metalugist? What's your background?

Great info, thanks for taking the time to post!