三电极二氧化碳气体保护角焊组织与性能研究

Research on Microstructure and Properties of Triple-Electrode CO_2 Welding

三电极CO2保护焊可克服高速单电极焊时产生的咬边、驼峰等焊接缺陷,大大提高焊接效率。本文在对船用AB-A级钢板进行三电极焊接工艺研究的基础上,对比了单、双、三电极焊接接头组织与性能。结果表明,在焊接线能量相同情况下,三电极焊接组织中焊缝区先共析铁素体和珠光体的量比单、双电极焊接时的要少。且三电极焊接中冷却速度更快,类似于高温状态下的三层焊接,这样较高的第二层和第三层的层间温度使焊接接头的晶粒粗大,显微硬度比单、双电极的硬度略微高,但由于三种焊接方法的线能量相同,使得硬度差别并不大。

Triple-electrode welding technology was adopted to overcome weld defects such as undercutting and humping appeared at high peed welding by sing-electrode welding. Single-, twin- and triple-electrode fillet welding experiments were tested on AB-A steel plate at the same heat input. The microstructure and hardness of weld metals were analyzed separately by optical microscope and micro-hardness instrument. The results show that the amount of proeutoetoid ferrite and pearite by triple-electrode welding are less than that of single- and twin-electrode welding. In addition, the average of hardness measurements using the triple-electrode welding is higher than that using single- and twin-electrode welding due to the cooling rates, which seem to be faster, and the high interpass temperature in the second and third pass.The hardness differences are not large because of the same heat input.