Steel casting is a method of forming steel into specific shapes by pouring molten metal into forms and cooling it such that it takes the desired shape. Casting is followed by final finishing steps to create the required surface finish and remove excess metal left from the casting process. This method offers the advantage of very flexible component design due to its ability to conform easily to many different shapes.
The steel casting process begins with making upper and lower molds to design specifications. These molds are coated inside to improve the surface finish of the final product. The two halves of the mold are then assembled together to form a closed shell.
Molten metal is poured into this shell, and the assembled set of molds is allowed to cool. Separating the molds after the metal has cooled allows removal of the part. At this point, excess material is removed from areas where the metal was poured into the closed mold assembly. This finishes the part to its desired shape.
An inspector then examines the part for defects developed during or after the steel casting process. Defects that can be corrected may be sent for grinding, welding, or other repair work. If a part cannot be repaired, it can generally be recycled for use in other steel castings by being melted down along with other scrap steel.
Steel casting offers some advantages over another common metalworking process known as forging. In the forging process, metal is shaped under compressive forces while remaining in a solid state. Hammering, pressing, rolling, and other operations are among such compressive forces used in forging.
While some components can be made with either process, steel casting allows for much greater freedom in the sizes and shapes of components that can be produced. A steel part that has been cast is also usually lighter than a comparable forged part, which can be a critical factor in some weight-restricted applications. Reproducibility is often better in steel casting because standardized molds are used rather than the relatively less controlled metalworking done in some forging operations.
Castings are found in a wide variety of applications in many different industries. They may be used for heavy industry in such applications as construction equipment, mining machinery, and power generation equipment. Transportation applications include use in railroad cars and military and industrial trucks. Steel casting may also be used to produce valves, fittings, electrical components, and other parts that require precise geometric dimensions.