分析了选用不同激光能量密度对HT300进行表面强化处理时,材料表面呈现的四种状况:未相变硬化、相变硬化、表面微熔及表面熔凝的金相组织.根据工艺要求,选取相变硬化方法对轴端沟槽底表面进行处理.分析了工件激光处理方法并通过试验研究,寻找轴端沟槽底部激光强化工艺参数:激光功率(P)、光斑直径(D)及扫描速度(V)的优化组合.硬度测试及耐磨性能试验表明:激光相变处理和激光熔凝处理后轴端沟槽底部表面较表面感应淬火硬度分别提高7%和34%,绝对磨损体积分别下降了13%和25%.实?な?对轴端沟槽底部激光相变硬化处理方法较其他表面处理方法工艺简单,加工工件符合技术要求,试验结果对零件表面处理提供了可靠依据.

Analysis on inoculated cast iron HT300 surface layer microstrutures of non-transformation hardening, laser transformation hardening (LTH), laser shallow melting (LSM) and melting are presented by selecting different laser energy densities during laser strengthening treatment. And the processing for slot bottom of shaft end with laser transformation hardening are also discussed. The results show that laser transformation hardening treatment is satisfied the processing requirement. The optimization of laser processing parameters: laser power( P ), laser processing speck diameter( D ), and laser scanning velocity( V ) are obtained by taking a lot of experiments. The comparative results of hardness and abrasive resistance measurement show that hardness and absolute weared volume of HT300 samples processed by LTH/LSM are increased by 7%, 34% and decreased by 13%, 25% respectively than those of surface induction quenching. Practically LTH is simpler than other processing methods and the experimental results provide a reliable basis for processing the slot bottom surface of shaft end.