ABSTRACT
Manganese contributes strength and moderately improves hardenability, which means it enhances the depth of hardness penetration after quenching. Manganese is generally beneficial to surface quality, however, high manganese content adversely affects ductility and weldability. Copper, when present in amounts exceeding 0.20%, enhances resistance to atmospheric corrosion. Nickel is a particularly valuable alloying element. It prOVides strength, improves toughness at low temperatures, benefits corrosion resistance, and adds a pacifying quality to the heat treatment process to assure more consistent and fool proof results. Chromium increases hardenability, improves wear and abrasion resistance, adds to corrosion resistance, and helps retain strength at high temperatures. Molybdenum helps control hardenability, has a powerful effect on increasing high temperature tensile and creep strengths, and reduces the susceptability of the steel to temper brittleness. Boron enhances hardenability and is most helpful in providing a predictable heat treatment response to low carbon steels. The combination of two or more alloying elements gives the steel the characteristic properties of each. In particular, the combined effect on hardenability is considerably greater than the sum of the same elements used individually.
