Some main uses of molybdenum products
Molybdenum charge products：Stainless steels, alloy steels, tool steels and high speed steels are usually smelted in an electric arc furnace. The initial charge generally contains alloy steel scrap, pig iron and some form of molybdenum to obtain the appropriate composition. Recycled waste is an important part of the molten charge, which comes from internal waste, waste collected by steel processors, and remelting raw materials purchased from the recyclers. Molybdenum from recycled waste accounts for 10 to 50 percent, depending on the type of steel and the market. Industrial molybdenum oxide is generally added with the waste to achieve the specified molybdenum content.I f only a small amount of new molybdenum is required, then iron molybdenum (Femo) is usually added.
After melting, the liquid metal is usually transferred to an AOD furnace or a ladle furnace for further refining. Ferromolybdenum is added at this stage to regulate the composition to achieve the specified Mo content.
The exclusive source of molybdenum for cast iron is FeMo, while only molybdenum metal particles are used for superalloys, as alloys require high purity element additions and vacuum smelting.
Molybdenum metal scrap from rolling manufacturing is also used as alloying element additive.
Molybdenum particle：Pure molybdenum metals (Mo content minimum 99.9%) are used in the production of superalloys to avoid contamination by trace elements.
The molybdenum powder was pressed into particles and sintered in hydrogen, and the oxygen and oxide film adsorbed on the surface of the powder particles were reduced chemically to increase the density of the pressed particles and the strength of the particles. The sintering process minimizes the oxygen brought into the molten metal by the particle charge, making it easier to process the charge in the smelting workshop.
Molybdenum metal and molybdenum alloy
Molybdenum metal is usually produced by powder metallurgy, where the molybdenum powder is hydraulically pressed and sintered at a temperature of about 2100 ° C. Hot working in the temperature range of 870-1260°C.Molybdenum forms volatile oxides when heated in air at temperatures above 600℃, so its high-temperature applications are limited to non-oxidizing or vacuum environments.
Molybdenum alloys exhibit excellent strength and mechanical stability at high temperatures (up to 1900°C).Compared with ceramics, molybdenum alloys have greater resistance to defects and brittle fracture due to their high ductility and toughness.
The unique properties of molybdenum alloys are utilized in many applications:
High temperature heating element, radiation protection, extrusion parts, forging die, etc.
Rotary X-ray anode for clinical diagnosis;
Glass furnace electrodes and parts resistant to melting glass;
Heat sink for semiconductor chip packaging, thermal expansion coefficient and silicon matching;
Sputter layer for integrated circuit chip gates and interconnections, thickness of only a few angstroms (10-7mm);
Spray coating on automotive piston rings and machine parts to reduce friction and improve wear.
Molybdenum hot zone of high temperature furnace
Molybdenum is also alloyed with many other metals for a number of special applications:
Molybdenum-tungsten alloy has excellent corrosion resistance of molten zinc.
Molybdenum is copper clad to provide electronic circuit boards with low expansion and high conductivity;
Molybdenum-25%rhenium alloys are used in rocket engine components and liquid metal heat exchangers and must be well ductile at room temperature.
