High Alloy Steel - This group of expensive and specialized steels contain alloy levels in excess of 10%, giving them outstanding properties. Austenitic manganese steel contains high carbon and manganese levels, that give it two exceptional qualities, the ability to harden while undergoing cold work and great toughness. The term austenitic refers to the crystalline structure of these steels. Stainless steels are high alloy steels that have the ability to resist corrosion. This characteristic is mainly due to the high chromium content, i.e., 10% or greater. Nickel is also used in substantial quantities in some stainless steels. Tool steels are used for cutting and forming operations. They are high quality steels used in making tools, punches, forming dies, extruding dies, forgings and so forth. Depending upon their properties and usage, they are sometimes referred to as water hardening, shock resisting, oil hardening, air hardening, and hot work tool steel. Because of the high levels of alloying elements, special care and practices are required when welding high alloy steels.