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以工程机械用钢为研究对象,采用硬度、OM、TEM+EDS等手段,研究了不同焊接线能量和焊接速度下多层焊接接头的力学性能与显微组织,并对焊缝区域的第二相及其作用机理进行了分析。结果表明,热影响区中的粗晶区和细晶区的晶粒尺寸逐渐减小,粒状贝氏体含量降低。当焊接线线能量为7.5 k J/cm,焊接速度为1.25 m/min时焊缝组织主要为针状铁素体,冲击韧度最高。
Taking the steel of construction machinery as the research object, the mechanical properties and microstructure of multi-layer welded joints under different welding line energy and welding speed were studied by means of hardness, OM, TEM + EDS and so on. The second Phase and its mechanism of action were analyzed. The results show that the grain size of the coarse grain and fine grain in the heat affected zone decreases and the content of granular bainite decreases. When the welding wire energy is 7.5 kJ / cm and the welding speed is 1.25 m / min, the weld microstructure is mainly acicular ferrite with the highest impact toughness.