Pure manganese has a relatively high tensile strength, but is very brittle. It is used as an alloying agent in steel to deoxidize and desulfurize the metal. In metals other than steel, percentages of 1 to 15 percent will increase the toughness and the hardenability of the metal involved.
Uses. It is used mainly as an alloying agent in making steel to increase tensile strength. It is also added during the steel-making process to remove sulfur as a slag. Austenitic manganese steels are used for railroad track work, power shovel buckets, and rock crushers. Medium-carbon manganese steels are used to make car axles and gears.
Manganese is essential to the production of iron and steel because of its sulfur-fixing, deoxidizing, and alloying properties. Steelmaking, accounts for most manganese demand, presently in the range of 85% to 90% of the total demand.
Capabilities. It can be welded, machined, and cold-worked.
Limitations. Austenitic manganese steels are best machined with cemented carbide, cobalt, and high-speed steel cutters.
Properties. Pure manganese has tensile strength of 72,000 psi (496,440 kPa) (quenched) Brinell hardness number of 330; specific gravity of 7.43: a melting point of 2270°F (1243°C); and is brittle. Manganese alloy has a tensile strength of 110,000 psi (758,450 kPa). Generally, the metal is highly polishable and brittle.
Among a variety of other uses, manganese is a key component of low-cost stainless steel formulations.
Small amounts of manganese improve the workability of steel at high temperatures.
The second large application for manganese is as an alloying agent for aluminium. Aluminium with a manganese content of roughly 1.5% has an increased resistance against corrosion due to the formation of grains absorbing impurities which would lead to galvanic corrosion.