脉冲电流对超薄316L板微流道成形精度的影响

目的 研究在金属双极板脉冲电流辅助冲压工艺中，将脉冲电流单独作用于保压阶段、冲压阶段以及作用于整个冲压过程(冲压阶段+保压阶段)3种通电方式对极板流道深度及壁厚分布的影响。方法 以316L不锈钢薄板作为实验材料，调节流经样品的电流参数，分别为0、10、20、30 A，分析脉冲电流参数和通电方式对极板流道深度及壁厚分布的影响规律。结果 在高电参数下，当采用在冲压阶段通电、在保压阶段断电的方式2时，在保压阶段可促进应力松弛，具有最佳的回弹抑制效果，其成形深度回弹可减小73.88%。在不同电参数下，3种成形方式对双极板流道壁厚分布具有相似的影响。槽顶和槽底的壁厚减薄相对较小，减薄量为原板材厚度的2%~6%;流道直壁壁厚减薄为原板厚度的9%~15%;而外圆角和内圆角区域的壁厚减薄较大，达到27%~30%。结论 在金属双极板脉冲电流辅助冲压工艺中，以不同方式施加脉冲电流，均可以显著提升流道深度，对壁厚影响并无明显差别。特别地，采用在冲压阶段通电、在保压阶段断电的方式2可以显著提升对流道回弹的抑制效果。

Effect of Pulse Current on the Forming Accuracy of Microchannels in Ultra-thin 316L Plates

The work aims to investigate the effects of three energization methods of applying pulse current to holding stage, stamping stage and entire stamping process (stamping stage + holding stage) on the depth and thickness distribution of flow channels in metal bipolar plates in pulse current-assisted stamping processes. With 316L stainless steel sheet as the experimental material, the current parameters passing through the sample were adjusted to 0, 10, 20, and 30 A, respectively. The effects of pulse current parameters and energization methods on the depth and wall thickness distribution of the flow channels in the bipolar plate were analyzed. Under high electrical parameters, Method 2 composed of energization during the stamping stage and de-energization during the holding stage, promoted stress relaxation and exhibited the best rebound suppression effect, reducing depth rebound by 73.88%. Furthermore, under different electrical parameters, all three forming methods showed similar effects on the thickness distribution of flow channels in bipolar plates. Thinning of the top and bottom of the groove was relatively small, ranging from 2% to 6% of the original plate thickness, while thinning of the straight wall of the flow channel was 9% to 15%. Notably, the thinning of the outer and inner corner regions was more significant, reaching 27% to 30%. Overall, in pulse current-assisted stamping processes for metal bipolar plates, applying pulse current in different ways significantly enhances flow channel depth with no significant difference in wall thickness impact. Particularly, Method 2 involving energization during the stamping stage exhibits a significant increasing trend in flow channel rebound suppression.