大径厚比导管全位置焊接分区段组织结构与力学性能分析  

Microstructure and mechanical properties analysis of pipe full-position welding with a large diameter to thickness ratio

作　　者：刘婷 竺叶青 吴强 刘海 熊俊杰 Liu Ting;Zhu Yeqing;Wu Qiang;Liu Hai;Xiong Junjie(Shanghai Spaceflight Precision Machinery Institute,Shanghai 201600,China;Shanghai Shenjian Precision Machinery Technology Co.,Ltd.,Shanghai 201600,China;Shanghai Aerospace Equipment Manufacturer,Shanghai 201100,China)

机构地区：[1]上海航天精密机械研究所,上海201600 [2]上海神剑精密机械科技有限公司,上海201600 [3]上海航天设备制造总厂,上海201100

出　　处：《焊接》2024年第9期69-74,共6页Welding & Joining

基　　金：上海市优秀学术/技术带头人计划资助(22XD1344000)。

摘　　要：【目的】在大径厚比不锈钢导管全位置焊接工艺中,研究分区段焊缝的组织结构与力学性能的差异。【方法】对外径为52 mm、厚度为0.8 mm的不锈钢管材进行脉冲钨极氩弧(Tungsten inert gas,TIG)全位置焊接试验,采用分区段设置工艺参数的控制方法优化焊缝成形。通过分区段方法对焊缝宏观形貌、微观组织和抗拉强度进行分析,评定全位置焊接过程中熔池综合受力情况差异对焊缝宏观成形和力学性能的影响。【结果】结果表明,采用的分区段设置参数的焊接方法能够有效适用于大径厚比管材环缝焊接,得到的焊缝内外表面光泽度良好,无需进行打磨处理;焊缝内外表面凹陷均小于0.1 mm,分区段焊缝熔宽均匀度良好,上熔宽与下熔宽之比均在1.1左右;焊缝中心微观组织由细小柱状奥氏体枝晶和枝晶间铁素体组成,热影响区窄,在半熔化区域与柱状晶之间存在狭长的细小晶粒带;各区段抗拉强度差别较小,平均值为534 MPa,达到I级焊缝要求。【结论】分区段设置工艺参数对薄壁不锈钢管进行全位置焊接,外观成形和内部质量能够达到I级焊缝要求,可满足航天行业增压输送系统导管的生产要求。[Objective]In order to analyse the differences in microstructure and mechanical properties of segmented welds in the full position welding process of large diameter to thickness ratio stainless steel conduits.[Methods]The pulsed TIG full-position welding test was carried out on the stainless steel pipe with an outer diameter of 52 mm and a thickness of 0.8 mm.The control method of setting the process parameters in the segmented section was used to optimize the weld forming.The macro morphology,microstructure and tensile properties of the weld were studied by section method.The influence of different melted pool forces on the macroscopic forming and mechanical properties of the weld during the full-position welding process was evaluated.[Results]The results showed that setting parameters of the segments during fullposition welding process could be effectively applied to the pipe girth weld with a large diameter to thickness ratio.The inner and outer surfaces of the weld behaved good gloss,there was no need to polish.The surface depression in the inside and outside of the weld was less than 0.1 mm.The uniformity of segmented weld width was good,and the ratio of the upper welding width to the bottom was around 1.1.The microstructure of the weld center was composed of fine columnar austenite dendrites and interdendrite ferrite,with a narrow heat-affected zone and a narrow band of fine grains between the semi-melted region and the columnar crystals.The tensile strength of each section had little difference,the average value reached 534 MPa,up to the requirements of first-class welding standard.[Conclusion]Setting the process parameters in the segmented section of full position welding on thin-walled stainless steel pipes,the appearance and internal quality could up to the requirements of first-class welding standard,which could met the production requirements of pressurized conveying system pipes in the aerospace industry.

关 键 词：全位置焊接 微观组织 力学性能 表面凹陷 

分 类 号：TG442[金属学及工艺—焊接]