柔性钛电极电火花表面强化模具钢Cr12试验研究

Study of Electric Discharge Surface Hardening Mold Steel Cr12 by Flexible Titanium Electrode

介绍了利用柔性钛电极对模具钢Cr12表面进行电火花表面强化的方法及特点,测试了强化层显微硬度、表面粗糙度值,分析了强化层微观形貌、强化层成分及放电波形等。结果表明:经电火花表面强化的模具钢Cr12表面相对于基体硬度提高1.5倍以上。EDS图像显示钛及其氧化物沉积扩散到试件表面,形成均匀强化膜,强化表面能保持较低的表面粗糙度值,放电波形呈现在短路和电弧放电状态之间跳转,分散了脉冲放电能量,同时柔性电极对强化表面有磨削涂覆作用,能有效改善和消除放电蚀坑及表面缺陷对强化表面质量的影响。对于表面粗糙度值大的表面,经柔性电极强化后,其值有所降低。

Methods and characteristics of electric discharge surface hardening mold steel Cr12 by flexible electrode were described, the microhardness and the surface roughness of the enhanced layer were texted , microscopic morphology and composition of the strengthening layer and the electric discharging waves were analysed in the text. It was shown that the handness of the strengthening layer of Cr12 was harder than the substrate by 1.5 times. EDS images showed that the titanium and its oxide deposited and diffused to the surface of the specimen and then formed homogeneous enhancement film, therefore, a lower surface roughness value could be maintained. Besides, the discharge waveform jumped between the short-circuit state and the arc discharge state, pulse discharge energy was disper- sed. At the same time, the flexible electrode could grind and coat on the enhanced surface, the influ- ence of the discharge pits and surface defects on the enhanced surface quality could be effectively eliminated. For rough surface, the surface roughness would be reduced with applying the method of flexible electrode enhancing.