Читать книгу Welding For Dummies - Steven Robert Farnsworth - Страница 29

Steel is an extremely common metal. It’s all around you — chances are, you’re probably not more than a few feet away from something made of steel. For that reason alone, it’s a very important metal for welding.

Steel is an alloy that’s made up primarily of iron, along with less than 2 percent of another material. That material is usually carbon, and the amount of carbon present in the steel is an important feature. Here’s a quick look at the three different levels of carbon steel:

 Low carbon or mild steel has less than .2 percent carbon. This category of steel is extremely easy to work with; you can cut and form low carbon or mild steel a lot easier than many other metals. Lots of objects, including screws, bolts, nuts, and washers, for starters, are made of low carbon steel. Sheets of low carbon or mild steel are often used to make automobile bodies and other familiar products.

 Medium carbon steel has .25 percent to .55 percent carbon, and it’s more difficult to work with and form than low carbon steel. You can find medium carbon steel in some of the same products made of low carbon steel, but the medium carbon versions are stronger. Machine parts (gears, axles, levers, and so on) are also often made out of medium carbon steel because of its strength and durability.

 High carbon steel is the really tough stuff. More precisely, it contains between .55 percent and 2 percent carbon. It’s the hardest and strongest type of steel, but it can be a real pain to cut and form. Manufacturers use high carbon steel to make things like cutting tools, files, and hammers because those items need to be strong enough to keep their shapes and integrity through years of heavy abuse.