煤矿机械用Q690高强钢激光-MAG复合焊可行性分析

目的研究激光-MAG复合焊在采煤机Q690高强钢板上的加工工艺,以提高8.8 m高端采煤机电控箱结构焊接接头的加工效率和质量性能。方法对激光-MAG复合焊工艺试验进行试验设计与参数设计,观察接头的显微组织,对接头进行拉伸试验和冲击试验,观察断口形貌。结果焊缝区整体组织性能优于母材,保证采煤机电控箱隔爆性能要求,拉伸断口和冲击断口均表现为韧性断口形貌,但是在冲击断口上观察到明显的气孔。焊缝内存在微量气孔,导致焊接接头结合不紧密,拉伸试验出现了脆性断裂。结论避免焊接工艺设计中出现气孔是激光-MAG复合焊焊接接头满足Q690钢在煤矿机械中使用要求的关键技术。

Feasibility Analysis of Laser-MAG Hybrid Welding of Q690 High Strength Steel for Coal Mining Machinery

The paper aims to research the processing technology of laser MAG composite welding on Q690 high-strength steel plate of coal mining machine to improve the processing efficiency and quality performance of 8.8 m high-end coal mining electrical control box structure welding joint. In this paper, the microstructure of the joint was observed through design and test of parameters of the laser MAG hybrid welding process, and the tensile test and the impact test of the joint were carried out to observe the fracture morphology. The results showed that the overall structure and properties of the weld area were better than that of the base metal, which could ensure the flameproof performance of the control box of the coal mining machinery. The tensile fracture and impact fracture showed ductile fracture morphology; but obvious pores were observed on the impact fracture. There were micro pores in the weld, which lead to the joint not closely connected and brittle fracture in tensile test. It is the key technology to avoid porosity in the welding process design of laser MAG composite welding joint to meet the requirements of Q690 steel used in coal mining machinery.