Applications of Tungsten and Molybdenum in Spot Welding Machine Electrodes!

Tungsten and molybdenum are commonly used refractory metals, serving as electrode materials in spot welders due to their high melting points, hardness, and resistance to adhesion. Manufacturers of tungsten and molybdenum products note that their electrical conductivity also exceeds that of metals like iron.

Tungsten lacks ductility at room temperature and is prone to fracturing. Electrodes made entirely of tungsten rods are only suitable for welding under low currents and pressures, such as in the welding of small copper alloy components in electronic products. When welding under high currents and pressures, tungsten rods or tungsten sheets are often embedded into the tip of copper alloy electrodes to form composite electrodes. This not only enhances the electrical conductivity of the electrode and improves the heat dissipation of the tungsten electrode but also prevents the tungsten electrode from breaking due to impact during welding.

Molybdenum, aside from having a lower melting point than tungsten, shares similar thermal conductivity, coefficient of thermal expansion, and electrical conductivity. It is harder than tungsten but boasts excellent toughness and is easy to machine. Molybdenum is used as an electrode just like tungsten, often combined with copper alloys to form inlaid composite electrodes.

Due to material size limitations, electrodes made of pure tungsten or molybdenum are generally not made too large, and there are also restrictions on the electrode shapes. Therefore, manufacturers of tungsten-molybdenum products indicate that copper-tungsten and silver-tungsten powder sintered materials are still more commonly used.

By blending copper or silver powder with a specific ratio of tungsten powder, and then compacting and sintering the mixture, a series of powder sintered materials with varying hardness and conductivity can be produced. These materials have a softening temperature close to the melting point of copper or silver, with their hardness and conductivity depending on the tungsten powder content, particle size, and distribution.

Copper-tungsten, commonly used as electrode material for spot welding machines, typically contains over 60% tungsten by weight. Common grades include Cu-W70 and Cu-W80.

Silver-tungsten has similar properties to copper-tungsten, but its conductivity and calming reaction performance are lower than copper-tungsten. Additionally, silver-tungsten has a lower anti-adhesive capability and is more expensive.

Copper-carbide tungsten is a sintered electrode material with strong thermal relief reaction properties at high temperatures. The copper-carbide tungsten electrodes exhibit stable contact resistance and good anti-adhesion properties, although carbide tungsten is hard and has poor machinability.

Powder sintered materials can be processed into electrodes of various shapes and sizes, such as cylindrical electrodes with diameters ranging from 10 to 85mm and heights from 10 to 50mm, whereas tungsten rods have a diameter of only 10mm.

That concludes the content shared by the tungsten and molybdenum products manufacturer this time. Feel free to inquire or place an order as needed.