316L不锈钢电弧增材制造工艺研究

目的 研究电弧增材制造过程中焊接速度和层间冷却时间对成形件精度和力学性能的影响。方法 使用316L不锈钢焊丝在钢板上进行20层往复式堆积试验，设置了不同的焊枪运行速度和层间冷却时间，完成了4个金属薄壁墙体的制备，对沉积样品的形貌外观、显微组织、硬度和拉伸性能进行了研究。结果 4组试样的制备过程都比较稳定，表面成形良好，层与层结合较为平滑，层间分明，无裂纹、塌陷等缺陷出现。当层间冷却时间达到一定值时，熔池凝固，样品的成形精度和高度较为稳定。单位时间内加入熔池的金属质量和热输入均随着焊接速度的增大而减小，不同焊接速度下沉积样品的层高和层宽不同。由于焊接速度增大、热输入减小，试样的硬度略微增大，拉伸性能增强。沿薄壁件的构建方向，4组试样的维氏硬度曲线呈波浪形，从每个熔合层的底部到顶部逐渐降低。结论 增材制造工艺参数对产品的成形质量、显微组织和力学性能都有影响，在保证成形过程稳定的前提下，提高焊枪堆积速度能提高产品的力学性能。

Wire and Arc Additive Manufacturing Technology of 316L Stainless Steel

The work aims to study the effects of welding speed and interlayer cooling time during wire and arc additive manufacturing (WAAM) on the accuracy and mechanical properties of formed parts. Here, deposition speed and cooling time between layers were examined and arc welding was used to conduct 20-layer reciprocating deposition experiments on 316L stainless steel. Four thin-walled metal walls were prepared. The morphology, microstructure, and hardness and tensile property of the deposited specimens were researched. The results showed that the preparation process of the 4 groups of specimens were relatively stable, the surface forming was good, the bonding between layers was smooth with clear stratification and without cracks, collapse and other defects. When the cooling time between layers reached a certain value, the molten pool would solidify, the forming width and height stability of the specimens were stable and the amount of molten metal per unit time added to the molten pool decreased as the deposition speed increased. The layer height and layer width of deposited specimens varied at different welding speeds. The hardness and tensile properties of the specimens increased slightly due to the increase of welding speed and the decrease of heat input. The Vickers hardness value curves of four groups of specimens exhibited a wave shape, gradually decreasing from the bottom to the top of each fused layer. Additive manufacturing process parameters have an effect on the forming quality, microstructure and mechanical properties of the product. Under the premise of ensuring the stability of the forming process, increasing the welding torch stacking speed can improve the mechanical properties of the product.