基于内根焊的X80钢管道全自动焊接接头组织与性能  

Microstructure and properties of fully automatic welded joints of X80 steel pipes based on inner root welding

作　　者：汪宏辉 钱建康 文学 李熙岩 张亮 王晨[2] 雷正龙 Wang Honghui;Qian Jiankang;Wen Xue;Li Xiyan;Zhang Liang;Wang Chen;Lei Zhenglong(Sinopec Jiangsu Oil Construction Engineering Co.,Ltd.,Jiangsu 225009,China;National Key Laboratory of Precision Welding&Joining of Materials and Structures,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]中石化江苏油建工程有限公司,江苏扬州225009 [2]哈尔滨工业大学,材料结构精密焊接与连接全国重点实验室,哈尔滨150001

出　　处：《焊接》2024年第7期67-73,80,共8页Welding & Joining

摘　　要：【目的】在X80钢管道全自动焊接过程中,改变预热温度对焊接接头的组织与力学性能具有一定影响。该文系统地研究了严寒条件(-30℃)、预热80℃及预热120℃对X80钢管道内根焊全自动焊接接头的组织和力学性能的影响规律。【方法】通过光学显微镜(OM)及扫描电子显微镜(SEM)对接头的显微组织进行观察,并从拉伸试验、冲击试验、弯曲试验及硬度测试等方面对不同预热条件下的焊缝进行了力学性能的表征。【结果】结果表明,焊接接头显微组织主要由柱状晶组成,还有少量的等轴晶,预热温度的提高减小了显微组织中柱状晶的尺寸,强度和冲击韧性差异较小,不同预热温度下进行拉伸的试样均在母材处断裂;弯曲试验中预热80℃下局部出现最大为0.6 mm的裂纹,预热120℃的试样均未出现裂纹和其他缺陷。【结论】接头的硬度随着预热温度的提高呈现减小趋势;在低温环境下,预热是获得综合性能良好的焊接接头有效措施,在120℃预热条件下接头性能最佳。[Objective]In the process of fully automatic welding of X80 steel pipes,change of preheating temperature has a certain effect on microstructure and mechanical properties of welded joints.Effects of cold conditions(−30℃),preheating at 80℃and preheating at 120℃on microstructure and mechanical properties of fully automatic welded joints of X80 steel pipes were systematically studied in the paper.[Methods]Microstructure of welded joints was observed by optical microscope(OM)and scanning electron microscope(SEM),and mechanical properties of the welds under different preheating conditions were characterized in terms of tensile tests,impact tests,bending tests and hardness tests.[Results]The results showed that microstructure of welded joints was mainly composed of columnar crystals and a small number of equiaxed crystals.Increase of preheating temperature decreased the size of columnar crystals in microstructure,and difference of strength and impact toughness was small.Tensile samples under different preheating temperature fractured at base material.In bending test,local cracks up to 0.6 mm appeared at preheating 80℃,while no cracks or other defects appeared at preheating 120℃.[Conclusion]Hardness of welded joints showed a decreasing trend with the increase of preheating temperature.In cold environment,preheating was an effective measure to obtain good overall performance of welded joints,and best performance of welded joints under the condition of preheating 120℃.

关 键 词：X80管线钢 全自动焊 预热 显微组织 力学性能 

分 类 号：TG406[金属学及工艺—焊接]