碳钢旁路热丝PAW增材制造成形及组织和性能调控

为了解决电弧增材制造过程中电弧热输入过大导致成形较差、晶粒粗大等问题，以H08Mn2Si碳钢为增材材料，进行了旁路热丝等离子弧(PAW)增材制造成形及组织优化. 首先在单层单道沉积试验中，研究了主/旁路电流比对熔敷成形和热输入的影响；然后进行多层单道沉积试验，分析了不同层间温度下碳钢的成形、微观组织以及硬度；最后对成形良好的增材样件进行了拉伸性能测试. 结果表明，当主/旁路电流比较小时，可以获得表面均匀光滑的熔覆层、母材稀释率可减小至10%；当控制层间温度为较低的温度100 ℃时，增材成形表面质量较好，试样中间稳定区域处的微观组织晶粒尺寸细小，珠光体占比增加，平均硬度最高可达到294 HV；拉伸试验表明其强度性能以及塑性性能在各方向上均匀一致，断裂形式为韧性断裂.

Carbon steel bypass-current wire-heating PAW additive manufacturing forming and tissue performance modulation

In order to solve the problems of poor forming and coarse grain size caused by excessive arc heat input in the wire-arc additive manufacturing process, this paper conducted a study on forming and tissue optimization of bypass-current wire-heating plasma arc welding (PAW) additive manufacturing with H08Mn2Si carbon steel as the additive material. The effect of main/bypass current ratio on the fusion forming and heat input was investigated in a single-layer single-pass deposition test; then a multi-layer single-pass deposition test was conducted to analyze the forming, microstructure and hardness of carbon steel at different interlayer temperatures; finally, the tensile properties of the well-formed additive samples were tested. The results show that when the main/bypass current ratio is small, a uniform and smooth surface can be obtained, and the dilution rate of the base material can be reduced to 10%; when the interlayer temperature is controlled at a lower temperature of 100 °C, the surface quality of the formed additive is good, and the microstructure in the middle stable area of the specimen has a small grain size and an increased percentage of pearlite, and the highest average hardness can reach 294 HV. The tensile test shows that the strength and plastic properties are uniform in all directions, and the fracture form is ductile fracture.