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通过熔化极气体保护焊方法,分别采用强、中、弱三种规范对输电铁塔用Q460钢进行对接焊,对焊接接头显微组织进行了观察,并对接头拉伸、弯曲、冲击、硬度等力学性能进行了检测。结果表明,焊缝区主要组织为先共析铁素体+块状铁素体+针状铁素体,粗晶区主要组织为铁素体+粒状贝氏体,低热输入时还有少量马氏体,细晶区组织为均匀的铁素体+珠光体;随着热输入增加,焊缝组织中铁素体含量增多,热影响区组织逐渐粗化,细晶区组织几乎不变;三种热输入的接头抗拉强度均不低于母材强度,弯曲性能合格,接头具有较高的塑性;随着热输入的增加,焊缝金属冲击韧性逐渐降低,热影响区的冲击韧性则先升高后下降,热影响区硬度逐渐降低,热输入对焊缝区硬度影响不大。
Through welding gas arc welding method, we use the three kinds of norms of strong, medium and weak respectively to butt weld the Q460 steel of transmission tower, and observe the microstructure of the welded joint, and observe the tensile, bending, impact and hardness Mechanical properties were tested. The results show that the main microstructure of the weld zone is pro-eutectoid ferrite + massive ferrite + acicular ferrite, the main structure of coarse-grained zone is ferrite + granular bainite, and a small amount of horse The microstructure of the austenite and the fine-grained zone is uniform ferrite + pearlite. With the increase of heat input, the content of ferrite in the weld increases, the microstructure of the heat-affected zone gradually coarsens and the microstructure of the microstructure is almost unchanged. Tensile strength of hot-welded joints are not lower than the base metal strength, bending performance qualified, the joint has a high plasticity; With the increase of heat input, the weld metal impact toughness gradually decreased, heat-affected zone impact toughness first rose High and then decreased, heat affected zone hardness decreased gradually, heat input weld zone hardness is not affected.