Processing method of tungsten alloy

Tungsten's high melting point, hard and brittle, difficult to process, but as long as there is a reasonable process, tungsten can be processed into material by powder metallurgy billet, extrusion, forging, rolling, spinning and drawing. The processing methods of tungsten alloy are as follows.

Spin forging is the production of tungsten billet and fine rod commonly used plastic processing methods, different sizes of rods in the hydrogen atmosphere heated to 1400 ~ 1600 ℃, in different types of spin forging machine for spin forging. The beginning of the deformation should not be too large, and then can be appropriate to increase the amount of deformation. Spin forging deformation process between the workpiece and die with graphite lubrication. Processed tungsten bar density of up to 18.8 ~ 19.2 g / cm 3. Due to the billet forging into a round billet, each part of the deformation is different, so that the organization is not uniform, at this time should be recrystallization annealing. Spin forging bar final diameter of about 3 mm.

Drawing billet can be used spin forging method of production, can also be used in the rolling method of production; rolling method of production of billet road deformation is large, the organization is more uniform, conducive to the processing of the future. Tungsten wire blanks drawn tungsten wire is used "warm drawing" method. First of all in the chain stretching machine to a diameter of 1.3 mm, and then, respectively, by the coarse pulling, pulling and fine pulling so that the diameter of 0.2, 0.06 and less than 0.06 millimeters.

There are also cutting operations. Tungsten is hard and notch-sensitive, cutting difficult, requiring the use of carbide tools. In order to prevent cutting cracks, the workpiece is often heated above the plastic-brittle transition temperature for cutting, and cutting procedures are strictly controlled. The grinding of tungsten requires light grinding with a specific type of grinding wheel and cooling, otherwise cracking will occur. Thickness of tungsten sheet above 0.2 mm should be pre-heated before stamping and shearing, more than a certain thickness of the plate, can not be sheared, often need to be cut with a grinding wheel.

Tungsten sheet rolling can be divided into hot rolling, warm rolling and cold rolling. Due to the large deformation resistance of tungsten, ordinary rolls can not fully meet the requirements of tungsten plate rolling, special material rolls should be used. When rolling, the roll should be preheated, according to different rolling conditions, the preheating temperature is 100～350℃. The relative density of the billet (the ratio of actual density to theoretical density) is greater than 90% before processing, billet density of 92 ~ 94% when processing performance is good.