Home >> Science & Nature >> Rocks & Minerals

Mechanical Properties of Cast Steel

Steel, in its most basic form, is a combination of iron and carbon. These elements are combined in specific ratios that affect the strength, ductility and hardness of the resulting compound. Other elements may be added to form alloys, such as stainless steel. Cast steel begins with molten material that is poured into a mold. According to Philip P. Stella, metallurgical engineer at M.S. Aerospace in Sylmar, California, the casting process was introduced to manufacture complex parts that maintain most of the strength of their forged counterparts in a cost-effective manner. He went on to describe the main characteristics of cast steel: strength, ductility and workability and explained that it is a very complex structure whose very character is dependent on the recipe and how it is cooked.

Strength
- Casting is ideal for complex shapes.
  
  Stella explains that strength is derived by closely controlling the mixture and properly managing the heating and cooling process. While the resulting part may not be as strong as a properly forged piece, it has strength in all directions rather than only one direction as in an extrusion. The mold can be engineered to withstand the stresses necessary for the part. Cast steel parts are also better suited to welding because they do not suffer the same molecular changes when re-heated.
Ductility
- Steel hasp that exceeded its ductile range.
  
  Ductility is the property of steel that allows a certain amount of stretch or deformity before catastrophic failure. A process known as hot isostatic pressing (HIP) is used to increase the strength of a casting by placing it under tremendous pressure and controlled heat to more tightly compact the molecular structure. Because steel for casting requires only melting components together, the alloy can be varied tremendously in the foundry whereas a mill can only accommodate a few recipes for their forgings.
Workability
- These cast parts required little final processing.
  
  Cast steel parts are nearly at finished dimension and shape when they cool. They often only need minor final shaping to be put into service. This workability saves countless hours of machining, forging and heat-treating used in other fabrication methods. Mold tolerances can be held tight enough to yield a finished part without further processing

Rocks & Minerals