Manganese is essential to iron and steel production by virtue of its Sulphurfixing, deoxidizing, and alloying properties, Steelmaking, including its ironmaking component, has accounted for most manganese demand, presently in the range of 85% to 90% of the total demand. Manganese is a key component of low-cost stainless steel. Often ferromanganese (usually about 80% manganese) is the intermediate in modern processes. Small amounts of manganese improve the workability of steel at high temperatures by forming a high-melting sulphide and preventing the formation of a liquid iron sulphide at the grain boundaries. If the manganese content reaches 4%, the embrittlement of the steel becomes a dominant feature. The embrittlement decreases at higher manganese concentrations and reaches an acceptable level at 8%. Steel containing 8 to 15% of manganese has a high tensile strength of up to 863 MPa. The second largest application for manganese is in aluminum alloys. Aluminum with roughly 1.5% manganese has increased resistance to corrosion through grains that absorb impurities which would lead to galvanic corrosion. The corrosion-resistant aluminum alloys 3004 and 3104 (0.8 to 1.5% manganese) are used for most beverage cans. Si-Mn is a ferroalloy composed principally of Mn, Si, and Fe (iron), and normally contains much smaller proportions of minor elements, such as C, phosphorus (P), and Sulphur (S). The ferroalloy is also sometimes referred to as ferro-silicon-manganese. Both Mn and Si play an important role in the manufacturing of steel as deoxidizing, desulphurizing, and alloying agents. Si is the primary and more powerful deoxidizer. Mn is a milder deoxidizer than Si but enhances the effectiveness of the latter due to the formation of stable manganese silicates and aluminates. It also serves as desulphurizer. Mn is used as an alloying element in almost all types of steel.