超高压输电铁塔用Q460钢气保焊接头组织和性能研究  

Study on Microstructure and Mechanical Properties of GMAW Welded Joints of Q460 Steel for Transition Tower

作　　者：庞晓芬[1] 

机构地区：[1]内蒙古交通职业技术学院,内蒙古赤峰024005

出　　处：《热加工工艺》2016年第7期240-243,共4页Hot Working Technology

基　　金：内蒙古自治区高等学校科学研究项目(NJ10106)

摘　　要：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 gas metal arc welding method, the strong, medium and weak welding specifications were used for the butt welding of Q460 steel for transmission tower. The microstructure of the welded joints was observed, and the tensile, bending, impact and hardness mechanical properties were tested. The results show that, the main microstructure of the weld metal is proeutectoid ferrite ,granular ferrite and acicular ferrite, the CGHAZ microstructure is ferrite ＋ granular bainite, a small amount of martensite appears in the low heat input weld, the FGHAZ microstructure is uniform ferrite ＋ pearlite; with the increase of heat input. The ferrite content increases in weld metal. The microstructure in CGHAZ coarsens gradually. The microstructure of FGHAZ almost unchanges. The tensile strength of the welded joints with three heat input levels is not less than the strength of the base material. The bending properties is qualified which shows that the joint has high plasticity. With the increase of heat input, the weld metal impact toughness decreases gradually. The impact toughness of CGHAZ increases firstly and then decreases. The hardness of heat affected zone reduces gradually, while the heat input has little effect on the hardness in weld metal.

关 键 词：Q460钢 熔化极气体保护焊 显微组织 力学性能 

分 类 号：TG457.11[金属学及工艺—焊接] TG115.62