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采用ER50-6及SLD-70两种实芯焊丝分别对T750GJ高强钢进行焊接,并对焊接接头进行拉伸试验、弯曲试验、显微硬度试验及微观组织观察。试验结果表明,采用SLD-70焊丝焊接的接头强度高于ER50-6焊丝的,超过930MPa,断裂的位置在热影响区(HAZ);两种焊接接头的塑性均良好,弯曲试验后无裂纹;由于热循环作用的影响,HAZ晶粒急剧长大,同时铁素体呈板条状聚集,两种焊接接头均出现软化;SLD-70焊丝更适于T750GJ钢的焊接。
The ER50-6 and SLD-70 solid wires were respectively used to weld T750GJ high strength steel. The tensile test, bending test, microhardness test and microstructure observation of welded joints were carried out. The test results show that the strength of joints welded with SLD-70 wire is higher than that of ER50-6 wire, exceeding 930MPa, and the fracture location is in the heat-affected zone (HAZ). The plasticity of both welded joints is good and no crack after bending test. Due to the effect of thermal cycling, the HAZ grains grow sharply and the ferrite lamellae gather. Both welded joints soften. The SLD-70 wire is more suitable for the welding of T750GJ steel.