The properties of cast iron can be improved by adding some alloying elements to its composition, so can the properties of plain carbon steels be improved tremendously by addition of alloying elements. In fact, in the case of steels, the effect of alloying is much more marked.
The main object of alloying in steels are:
- Alloy steels can be hardened by heat treatment processes to greater depth and with less distortion and less chance of cracking.
- Alloying develops corrosion resisting property as in stainless steels.
- Alloying develops the property of red hardness as in cutting tool.
- Alloying develops the strength and toughness of steels as in high strength low alloy (HSLA) steels.
- Some alloy steel show a marked resistance to grain growth and oxidation at high temperatures etc.
Main alloying elements used are chromium, nickel, tungsten, molybdenum, vanadium, cobalt, manganese and silicon. Alloy steels are available in a great variety, each one has been developed for a specific purpose.
Different Types of Alloy Steel are
- Stainless steels
- Ferritic stainless steel
- Martensitic stainless steel
- Austenitic stainless steels
- Tool steels
- Special Alloy Steels
- Manganese steels
- Nickel steels
- Chromium steels
- Silicon steels