The process of manufacturing Nb-Ti single-core titanium alloy bars generally uses hot forging, cold rolling, and cold swaging of alloy ingots. However, flashing or other defects often occur during cold rolling or cold forging, and surface repairs are required, which is time-consuming and labour-intensive, which is very unreasonable. The process of the Nb-Ti rod is to stretch the extruded rod to a diameter of 12.6 mm, and after annealing at 800°C, to a diameter of 3.2 mm. This can ensure the surface finish and the roundness of the titanium alloy bar. During stretching, an emulsion of molybdenum disulfide, graphite fine powder, agar, trichloroethylene and water is mixed and coated on the surface of the titanium alloy bar, and then stretched after drying to achieve better results.
The cold drawing process of Nb25—70%Zr (weight) alloy physical examination was studied. The relationship between the drawing die angle, the coefficient of friction and the drawing force was measured, and a suitable lubricant was also selected. Nb-Zr and Nb-Ti have co-extensive properties, which are completely suitable for the stretching of dry Nb-Ti rods.
Experiments have proved that the choice of lubricant is the key to the success or failure of stretching. Add graphite powder and molybdenum disulfide into the water and a volatile solution to make emulsion liquid, and apply it on the surface of the titanium alloy bar. After drying, a dense film is formed on the surface of the titanium alloy bar. It has a large pressure and is not easy to fall off. The die angle of the drawing die is 12-16°, but the angle of 18-20° is better.
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