Tungsten molybdenum ferroalloy for steelmaking
Tungsten-molybdenum-ferro alloy can be simply understood as an alloy composed of tungsten, molybdenum and iron. It is widely used in iron and steel industry because of its excellent physical and chemical properties.
When tungsten and molybdenum are used as steel-making additives, most of the tungsten and molybdenum alloy steel smelting are using tungsten and iron molybdenum as alloy additives, that is, tungsten is added in the form of FeW (tungsten and iron alloy or tungsten iron), and molybdenum is added in the form of FeMo (ferromolybdenum alloy or ferro molybdenum). Tungsten and molybdenum alloy steel is usually hydrometallurgical. First, tungsten and molybdenum associated ore is separated into tungsten concentrate and molybdenum concentrate by dressing method, tungsten concentrate is smelted into FeW, molybdenum concentrate generates MoO3 and then smelted into FeMo, and then FeW and FeMo are added for smelting during steelmaking.
The advantages of using tungsten and molybdenum as steel additives are as follows:
(1) Tungsten is an element that can generate carbides. Adding tungsten to steel can improve the toughness of steel. Due to the finer particle size and higher hardness of tungsten carbide, the hardness and wear resistance of steel can be greatly improved.
(2) Tungsten can enhance the tempering stability, redness and thermal strength of steel, and also increase the self-diffusion starting energy of iron, so as to significantly improve the recrystallization temperature of steel. In addition, the creep resistance of steel can be significantly optimized.
(3) Molybdenum mainly exists in the form of solid solution and carbide in steel, which can significantly improve the hardenability and thermal strength of steel, and thus prevent the temper brittleness of steel.
(4) Molybdenum can not only improve the remanence and coercivity of steel, but also improve the corrosion resistance of steel in some media.
In a word, to join tungsten, molybdenum in steel are two kinds of rare element, can significantly improve the properties of steel, steel grain refinement, with uniform microcrystalline structure, reduce the decomposition of eutectic temperature of steel, thus expanding the scope of the steel quenching and tempering, increase the strength of the steel, elastic limit, resistance to abrasion and impact strength, and give necessary hot hardness alloy steel, improve the efficiency of heat cutting.
In recent years, with the continuous development of chemical technology, tungsten and ferro-molybdenum alloy has gradually replaced tungsten and ferro-molybdenum as additives in steelmaking. This is mainly because the wMO alloy can be added at one time, the operation is relatively simple, to a certain extent, can shorten the process, reduce energy consumption.
