Alloy Steel

Alloy steel contains, in addition to the iron and carbon that compose carbon steel, one or more alloying elements in varying amounts in order to modify or improve one or several properties of the steel, notably through a series of thermal or thermo-mechanical treatments, to better meet industrial and construction requirements. These properties include strength, hardness, toughness, wear resistance, creep strength, corrosion resistance, etc. The alloying elements include manganese (Mn), silicon (Si), chromium (Cr), nickel (Ni), molybdenum (Mo), vanadium (V) and tungsten (W).

Alloy steels can be grouped into two general categories, low-alloy steels and high-alloy steels.

The first category, where the content of any alloying element is limited to 5% (weight) maximum, contains innumerable grades, including the following :

  • grades AISI/SAE 4130, 4340, 8620 for mechanical parts like shafts, gears, molds; AISI 52100 grade for ball bearings, etc.;
  • high-strength low-alloy steels (HSLA) such as ASTM A242/A588 and low carbon quenched and tempered alloy steels like ASTM A514 that are mainly used in a variety of applications including bridges, construction, rail cars, transmission towers, shipbuilding, mobile cranes, mines, etc.

The second category, high-alloy steels, has at least one alloying element at a concentration of 5% or more (weight) in its chemical composition. This category includes certain types of tool steels, stainless steels, manganese steels, creep-resistant steels, cryogenic steel, etc.

Contact our metallurgists, to get the right alloy for your welding project.