The Different Varieties of Ferrous Metal Parts

    The way in which the metal you are going to be welding has been prepared by the manufacturer will also have an impact on how you weld it. There are many different methods for readying iron and steel for use, and each of these has some impact on how the pieces go together when you are welding them.

    This is due to the fact that the fit between pieces is altered by how they were fashioned – some manufacturing is very precise, while other methods create rough metal pieces which are not as suitable for fine welding.

    Some of the more common manufacturing methods of ferrous metal that you are likely to encounter include:

•    Hot rolled steel (which is also known as HRS) is basic manufactured steel, rolled out while hot, creating a distinct grain which flows in the direction of rolling. If you bend hot rolled steel across the grain, it is unlikely to break, whereas the metal can split fairly easily if bend along the grain. This type of steel is fairly rough and has a slightly irregular shape, so only large, straightforward welds can be successfully made with it. Hot rolled steel is always fairly thick, and can be identified by burn marks or “mill scale” on its exterior.
•    Cold rolled steel is what all sheet metal is, as well as many other types of sheets, plates, and bars. It is a further refinement of hot rolled steel and has a smooth surface as well as precise shapes that can easily accept complex welds. Cold rolled steel, which goes by the abbreviation CRS also, is more costly than its hot-rolled counterparts, since it has been processed more (including “pickling” to remove mill scale).
•    Forged steel is steel that has actually been hammered into the proper shape through one of several different means. A smith can hand-forge steel in this way, but the more usual method nowadays is to forge the steel using industrial forging presses. Forged steel is used where exceptionally hard, strong, tough parts are needed – such as in vehicle axles. It’s fairly easy to weld this steel, but the weld is usually weaker than the steel itself and there may be safety issues with repairs because of this.
•    Cast steel is melted, then poured into a mold, which determines the final shape and surface quality of the piece. Cast steel is welded just like steel of the appropriate type.
 •    Wrought iron is the forged form of iron, similar to forged steel in the process by which it’s made. It is mostly used for decorative purposes now, though not always.
•    Cast iron can be welded in its grey, malleable, nodular, and alloy forms. White cast iron can’t be welded, but is very rare and you are unlikely to encounter it. Care must be taken not to overheat cast iron while welding it, or it will split.