旁路耦合三丝间接电弧增材制造成形特性

Forming characteristics of bypass coupling triple-wire gas indirect arc additive manufacturing

采用旁路耦合三丝间接电弧焊(bypass coupling triple-wire gas indirect arc welding,BCTW-GIA焊)进行Q345低碳钢增材制造.利用高速成像设备研究了旁路电流变化对电弧特性的影响,并观察了对应的焊缝成形特性.结果表明,随着旁路电流的增加,间接电弧占比逐渐减少,而直接电弧占比逐渐增加,焊接热输入逐步提升,焊缝的接触角逐渐减小.当旁路电流为155 A时,可在表面成形良好的前提下得到铺展性最优的单道焊缝.采用此参数进行单道多层增材得到了直壁墙体,沉积速率高达13.3 kg/h.该增材制造方法具有较高的熔敷效率和较低的热输入,有利于改善增材试样的显微组织,并提高试样的平均硬度.试样底部、中部及顶部区域的平均硬度分别为186.80,172.44,176.04 HV.

The additive manufacturing of Q345 low carbon steel using bypass coupling triple-wire gas indirect arc welding(BCTW-GIA) is reported. The influence of bypass current variation on arc characteristics is studied by using high-speed imaging equipment, and the corresponding formimg characteristics of beads are observed. The results show that with the increase of bypass current, the gradual increases happen to the proportion of direct arc and the welding heat input, however the gradual decreases happen to the proportion of indirect arc and the contact angle of the beads. When the bypass current is 155 A, a single-pass welding bead with the best spreadability can be obtained under the premise of good forming surface.Based on this set of parameters, the straight wall can be acquired by single pass and multi-layer additive manufacturing with a deposition rate as high as 13.3 kg/h. The high cladding efficiency and low heat input of the additive manufacturing method are conducive to improving the microstructure of the additive samples and increasing the average hardness. The average hardnesses of the bottom, middle and top areas of the sample are 186.80, 172.44 and 176.04 HV, respectively.