Molybdenum heating wire: The resilient wire under high temperature
Molybdenum heating element wires are a crucial material indispensable in modern industry. With a melting point of up to 2620℃, they maintain excellent strength and stable resistivity even at high temperatures, making them the core heating components in high-temperature furnaces, vacuum sintering equipment, and semiconductor manufacturing fields. The production process of these wires is a meticulous forging journey from powder to tough wire.
Production begins with high-purity molybdenum raw materials. Typically, molybdenum powder produced by the Fe-Sa method is used, with a purity of over 99.95%. These fine molybdenum powders need to undergo strict sieving and mixing to ensure uniform particle size, and trace amounts of rare earth oxides (such as lanthanum oxide, yttrium oxide) or aluminum oxide and other dopants are added to significantly enhance the high-temperature creep resistance and recrystallization temperature of the final product. This is the first crucial step in ensuring the long-term stability of the heating wire.
Uniform molybdenum powder is loaded into a flexible mold. Through cold isostatic pressing technology, it is pressed into a dense rod billet under ultra-high pressure. This process initially shapes the powder and gives it a certain strength. Subsequently, the rod billet is sent to a high-temperature sintering furnace, where it undergoes pre-sintering in a hydrogen atmosphere at 1800°C - 2200°C. This step removes the gases and impurities from the billet, and the particles initially combine through atomic diffusion, forming a "molybdenum electrode" with certain strength and conductivity.
The sintered molybdenum rods remain brittle and hard. To obtain a dense fibrous structure, thermal processing is necessary. The molybdenum rods are heated above the recrystallization temperature (approximately 1500°C) and repeatedly forged on a hydraulic press to initially refine the grains. Then, the crucial spinning forging process is carried out: the rod material undergoes radial high-frequency hammering in a rotating die, with the diameter gradually decreasing and the length extending. This process significantly enhances the density and ductility of the material, laying the organizational foundation for the subsequent drawing process.
After the spinning forging process, the molybdenum rods enter the drawing stage. They need to go through dozens or even hundreds of passes, being gradually drawn into the target wire diameter through successively smaller diamond or hard alloy drawing dies. Due to the hardness and brittleness of molybdenum at room temperature, after each pass of drawing, intermediate annealing is necessary. The annealing is carried out under hydrogen protection, with the temperature precisely controlled between 900℃ and 1400℃, to eliminate work hardening, restore the material's plasticity, and ensure the smooth progress of the subsequent drawing process.
When the filament reaches the specified size (common diameters ranging from 0.1mm to several millimeters), final annealing is required. This is not only to relieve stress but also to precisely control its microstructure and performance. By adjusting the annealing temperature and time, engineers can control the degree of recrystallization, thereby tailoring its resistivity, high-temperature strength and toughness to perfectly fit specific high-temperature application scenarios.
The finished molybdenum heating wire must undergo a series of rigorous tests, including diameter tolerance, surface finish, resistance uniformity and high-temperature lifespan testing, etc. Qualified products can be processed into various shapes (such as spiral or wave patterns), coated on the surface (such as siliconization to prevent oxidation), or assembled by welding, ultimately becoming reliable electrical heating elements that can work persistently in extreme environments, providing a stable "heart" for modern technology's high-temperature processes.
Molybdenum wire are demanded in various parts of the world, such as: USA, Canada, Chile, Brazil, Argentina, Colombia, Germany, France, United Kingdom, Italy, Sweden, Austria, Netherlands, Belgium, Switzerland, Spain, Czech Republic, Poland.
As professional Chinese manufacturer, Mosten Alloy can produce and supply molybdenum electrode, molybdenum strip, molybdenum sheet, molybdenum pellet, molybdenum block, molybdenum tube, molybdenum rod, molybdenum wire, molybdenum processing workpiece according to customer demand.
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