Casting involves pouring molten metal into molds.
Because of advances in metallurgy numerous metals can be used in a wide range of applications. The most common are iron and steel. Although the chemical compound of the two metals is very similar, the slightest variation can change the properties widely, meaning that they are used in very different situations.
Iron
Iron is a metallic element mined in the form of iron ore. Smelting removes the iron from the ore. The smelting process takes place over a long period of time and is designed to remove not just the metal from the ore but also the impurities from the metal. Once that process is complete, what is left is pure iron.
Cast Iron
Cast iron is a follow-on from the smelting of pure iron. The smelting process is quicker than it is for iron ore and takes place at a higher temperature. It also involves the addition of carbon, usually about 1.5 percent of the weight of iron. In its molten state it is poured into molds, or casts, where it solidifies. When the mold is opened, the item comes out in one piece. It requires little additional work and is very durable.
Cast Steel
Steel is iron with carbon added to it, but in smaller quantities than with cast iron, usually less than 1 percent of the overall weight. Like cast iron, it is poured in its molten state into molds so the object comes out as one piece and requires little additional work.
Properties
The high carbon content in the cast iron makes the substance very brittle, or easily breakable, and less ductile, harder to make into shapes. It is very durable and very heavy. Cast steel is less brittle, easier to shape and lighter. It can also be mixed with other substances, for example with chromium to make stainless steel.
Applications
Cast iron is most commonly used for manhole and drain covers on the roads as the same mold can be used over and over again. Domestically it is most commonly used for cookware such as pots and pans, although this also has a lot to do with the metal's ability to conduct heat. Cast steel can be used more widely inasmuch as steel is a more useful material. Today few items are cast from steel because of modern processing techniques, but car panels, cutlery and other metal components were made from cast steel in the past. These days steel is rarely poured as molten metal but rather is press molded, meaning sheet steel is forced into place under pressure by large machines.
Tags: into molds, additional work, Cast Iron Cast, Cast steel, Cast Steel, comes piece
