耐候桥梁钢的不预热焊接试验  

Non-preheated Welding Test of Atmospheric Corrosion Resisting Steel for Bridge

作　　者：彭宁琦[1] 邱福祥[1] 罗松云[1] 范明[1] PENG Ningqi;QIU Fuxiang;LUO Songyun;FAN Ming(Hunan Valin Xiangtan Iron and Steel Co.,Ltd.,Xiangtan 411101,China)

机构地区：[1]湖南华菱湘潭钢铁有限公司,湖南湘潭411101

出　　处：《金属材料与冶金工程》2020年第5期48-55,64,共9页Metal Materials and Metallurgy Engineering

基　　金：长株潭国家自主创新示范区专项(2018XK2301);湘潭市科技计划项目(CG(GX)-ZD20172028)。

摘　　要：按照相关标准,对开发的Q345qENH和Q420qENH耐候桥梁钢进行焊接热影响区最高硬度试验、斜Y坡口焊接裂纹试验、焊接工艺评定试验。结果表明,试验钢的焊接热影响区最高硬度在HV240以下,其具有良好的可焊性,即使对50 mm厚度、不预热焊接后也未出现裂纹;当采用常规的坡口形式和焊接方式,热输入量为15~35 kJ/cm时,焊接接头HZA粗晶区以板条贝氏体组织为主,组织硬度高于母材,冲击韧性有所降低,而接头的拉伸强度影响不大、未出现明显的软化区。开发的Q345qENH和Q420qENH耐候桥梁钢可实现不预热焊接,且具有良好的焊接性能。According to relevant standards,some experiments for Q345qENH and Q420qENH bridge steels with weather resistance were carried out that include maximum hardness test in weld heat affected zone,Y-groove cracking test,and welding procedure qualification test.Results show that the maximum hardness of the welding heat affected zone of the two experimental steels are below HV240 respectively,that indicates they have good weldability,and for 50 mm thick steel plate,there is also no crack after Y-groove cracking test even without preheating.And when using conventional groove forms and welding methods with heat input from 15 kJ/cm to 35 kJ/cm,the microstructure in coarse-grained HZA of welded joint is mainly lath bainite,whose hardness is higher than that of base metal but impact toughness is reduced,at the same tim e,tensile strength of the joint has little influence and no obvious softening zone.So the atmospheric corrosion resisting bridge structural steel of Q345qENH and Q420qENH under development can successfully be welded without preheating,and have good welding performance.

关 键 词：Q345qENH Q420qENH 耐大气腐蚀 预热温度 热影响区 

分 类 号：TG142.4[一般工业技术—材料科学与工程]