Titanium alloy is an ideal structural material due to its excellent mechanical properties such as high strength and high toughness. In order to achieve a good fixed connection effect, the material must have high tensile strength, and also need good plasticity and bending characteristics. The traditional method uses cold-drawn stainless steel wire, but the material is poor in plasticity, the elongation is less than 5%, and the bending characteristics are poor. Researchers use Ti-6Al-4V titanium alloy, through reasonable regulation of interstitial oxygen in the alloy, and hot drawing of rolled billets, to produce ultra-high-strength TC4 titanium alloy wires, and analyze different oxygen content and process control Influence on the mechanical properties of materials in order to obtain the best preparation method.
By studying the cold drawing process of titanium rods and wires, the effects of pretreatment process and die parameters before cold drawing of titanium rods and wires on the forming of blanks were analyzed. By selecting reasonable cold drawing processing parameters, The cold drawing production of titanium alloy at room temperature is realized. The composition inspection and microstructure analysis of the titanium rod blank produced by hot drawing showed that the grain structure of the titanium rod and the titanium wire was broken and incomplete recrystallization occurred after the hot drawing, and the grains were relatively fine and equiaxed. The rheological direction of the structure is not obvious. This structure provides favorable conditions for cold drawing deformation of titanium wire. The fracture of the titanium wire after hot drawing showed obvious plastic fracture characteristics. With the increase of the deformation, a large number of holes appeared at the bottom of the dimple. The overall performance of the billet was good after annealing at 760 ℃ for 1 hour. A uniform and dense light yellow oxide film was formed on the surface of the billet under the premise of ensuring the quality of the annealing.
After the titanium alloy bar stock was drawn through the surface pretreatment process, phosphate-lubricated coatings and oxalate-lubricated coatings were successfully prepared with thicknesses of 2 μm and 20 μm respectively. The adhesion of the agent provides a good carrier, and at the same time can play a role in isolating the direct contact between the blank and the mold. Through numerical analysis of cold drawing of titanium rods, the shape parameters of cold drawing dies for rods and wires in a certain size range were determined. When the working cone angle was 10-12 °, the deformation force was in a lower range. Through the cold drawing processing experiments of titanium rods, it was found that the effect of the oxalate lubricating coating is better, and the surface quality of the drawn blank is higher. After four consecutive draws, the total deformation of the blank reaches 45%, reaching mass production. Claim. After cold drawing of titanium rods, the strength increased and the elongation decreased, and a significant work hardening effect occurred. The plasticity of the billet was restored after the annealing treatment, which did not affect the next cold drawing process. The grain structure of titanium alloy rods is equiaxed after cold drawing and annealing. With the increase of deformation, the degree of equiaxedness increases.
