电火花沉积工艺对点焊电极TiC沉积层硬度的影响

Influence of Electrospark Deposition Processes on Hardness of TiC Coating on Surface of Spot-welding Electrode

为了改善镀锌钢板点焊电极的寿命,在电极表面进行了电火花振动熔敷TiC的工艺试验。通过正交试验考察了沉积工艺参数(电容、基体电极转速、振动频率、沉积时间)对沉积层硬度的影响,并考察了对基体材料进行前、后处理对沉积层硬度的影响。结果表明,电容是影响电火花沉积层硬度的主要因素;振动频率、基体转速、沉积时间对沉积层硬度影响较小。试验条件下最佳的工艺参数为:电容量30000μF,基体转速1320Hz,振动频率A档,沉积时间120s。前处理改善界面,对沉积层硬度影响小;后处理促进元素扩散,降低沉积层硬度,但减少了过渡层的微孔和微裂纹。

In order to improve the lifespan of the spot-welding electrode for zinc-coated steel, electrospark deposition（ESD） processes are studied with TiC as coating material and CrZrCu as substrate. ESD parameters such as capacitance, deposition time, electrode rotate speed and vibratory frequency are investigated by means of the orthogonal experiment. The pre-treatment and post-treatment of the substrate are tested. The results indicate that the capacitance is the most important factor that influences the hardness of ESD coating while the vibratory frequency is less important, meanwhile the rotate speed of electrode and depositing time influence slightly. The optimized parameters under the test conditions are capacitance at 30000μF, electrode rotate speed at 1320Hz, vibratory frequency at grade A, and depositing time for 120s. The pre-treatment improves the interface with weak influence on the coating hardness. The posttreatment boosts the element diffusion and modifies the transition layer structure but decreases the hardness.