电站锅炉用耐热钢激光焊接工艺

The laser welding technology of heat-resistant steels for power boiler

采用窄间隙激光填丝焊接技术,进行了电站锅炉用常规及新型耐热钢同质、异种接头的激光焊接工艺试验,研究了各种接头的激光焊接性及其在焊接过程中存在的问题和解决措施,获得了优化的焊接工艺参数。工艺试验结果显示:焊接过程中存在的主要问题是背面内凹、层间链状孔洞和火口裂纹。采用优化后的焊接工艺参数,可以获得正、背面成形良好的焊接接头,其焊缝结束处过渡饱满均匀,不存在火口裂纹,试样剖开后没有发现内凹与层间链状孔洞等缺陷。焊接接头经RT和PT检验,100%合格。

As a reliable and advanced joining technique, laser welding have more unique advantages than traditional arc welding due to the very low heat input, and considered one of the most promising joining technologies in power boiler manufacturing. In the paper, a slab CO2 laser with an output power of 3 500 W was applied and the narrow gap laser welding process was adopted with filler wire to weld general and new type of heat-resistant steel tubes. The weldability and the main problems which occurred in welding process were investigated. It was found that inside recess, holes located multiple passes and crater cracks were the main problems in laser welding. At last, the optimized process parameters were obtained. A sound joint which accepted with RT and PT tests can be obtained by optimized process parameters, and there was no flaw in weld joint.