钛合金球形头骨钉镦锻加工工艺流程及性能研究

研究了国际上先进的医用骨钉的镦锻加工工艺。采用不等径活阴模技术,克服了球形头骨钉头部镦锻成形时冲头脱模困难的问题,成形了骨钉驱动槽和头部基本轮廓,然后采用专用机床进行头部轮廓修整和尾部螺纹引导加工,最后进行螺纹成形等工序。与采用传统棒料直接进行车制工艺相比,采用镦锻加工工艺可使材料利用率提高1倍以上,生产效率提升2倍以上。对镦锻成形的Ti6Al4V ELI和Ti6Al7Nb材料骨钉进行了金相组织、硬度和扭转性能检测,其试件的金相组织和硬度均满足相应标准的要求,最大扭矩和断裂扭转角与车制加工骨钉基本相当,因此证明了镦锻工艺可替代现有棒料的直接车制工艺。

Study on upsetting process and property for titanium alloy spherical bone screws

An advanced upsetting process for spherical bone screws was studied, and the difficulty to strip the punch was solved by the unequal diameter die, so the drive groove and the head primary profile of the bone screw were formed. Then, the head contour was amen-ded, and the tail thread was processed by special machine. Finally, the threat forming was conducted. Comparing with the traditional turning process, the material utilization ratio was increased by double, and the production efficiency was increased by two times. Further-more, the bone screws formed by upsetting for Ti6Al4V ELI and Ti6Al7Nb were tested microstructure, hardness and torsion properties. The microstructure and hardness met the standard requirements. The maximum torque and fracture torsion angle of the developed screws were es-sentially consistent with those made by turning process. Therefore, the upsetting process can substitute for the traditional turning process.