The Processing Method of Tungsten Cerium Alloy Wire

Adding a certain amount of rare earth elements in tungsten can change the properties of tungsten wire, such as adding cerium or thorium in tungsten can improve the electronic emission and ablative ability of the tungsten, and improve the processing properties of tungsten. The tungsten alloy wire and products produced by these characteristics are mainly used for electron tube hot wire, argon arc welding electrode and pulse tube heating wire.

Although a certain number of rare earth elements have been added, the tungsten wire and its products of various uses can be produced, but the tungsten cerium alloy (tungsten thorium alloy and tungsten rhenium alloy) produced in China can not be processed to the specifications of the specifications below 0.8mm (especially the specifications for below 0.3mm). The main reason is that the production process of the alloy billet is backward, the impurity content of the billet produced is too high, the additive distribution is uneven and the density is not consistent.

An enterprise uses a tungsten cerium alloy wire processing method, the following steps are as follows: (1) The ammonium para tungstate is melted into blue tungsten oxide, and then K₂SiO₃ solution and Al (NO₃)₃ liquid and mixture are doped; the content of potassium should be controlled in 50-80PPm. (2) The above raw materials are first reduced between 600℃ and 650℃, and the second reduction is performed between 800℃ and 850℃; (3) The reduced raw materials are pickled for 30 hours; (deionized water washes Multiple times so that the pH value = 7 vacuum drying 80 ℃ -120 ℃). (4) Adding cerium nitrate solution in the raw material after pickling at 300 ℃ -500 ℃ after sieving mixture and reducing it between 750 ℃ and -800 ℃ for the first time and reducing it between 900 ℃ and -950 ℃; (5) Over sifting mixture; (6) After pressing into billet, low temperature prefiring (1100 degrees ℃); (7) Two vertical melting and sintering, the first vertical melting and sintering temperature to 1500-1600, heat preservation for 12-15 minutes, fusing current 80-90%, second vertical melting and sintering temperature to 1700-1900, 12-15 minutes heat preservation, fuse current 80-90%, so that the density of tungsten strip is 17.4 to 17.9g/cm³;

Through the process, the axial alignment of tungsten grain boundaries is ensured, and the grains will not grow too long, which ensures the reasonable dislocation and ideal grain number of grain boundaries. In the process of doping, many kinds of additives (potassium carbonate, silica, alumina) can be grown rapidly and rapidly. These additives make the crystal grow rapidly and rapidly, forming a large interlocking grain with many grain boundaries arranged in the axial direction. The thermal stability and high temperature creep strength of this structure are good. . At the same time, after adding cerium or thorium or rhenium after pickling, the particles of these oxide particles enter the grain boundary of tungsten, which can prevent the grain boundary slipping, restrict the grain growth, improve the recrystallization temperature of tungsten, and maintain the fineness of recrystallized grain, thus improving the anti deformation and dislocation properties of tungsten cerium alloy wires.

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