TP304H/T22异种钢焊接接头微观组织特性对焊缝失效的影响分析  

Analysis of the influence of microstructure characteristics of TP304H/T22 dissimilar steel welding joint on weld failure

作　　者：孙戬 潘晨阳 沈永鳌 张周博 林何 成小乐[1,2] SUN Jian;PAN Chen-yang;SHEN Yong-ao;ZHANG Zhou-bo;LIN He;CHENG Xiao-le(School of Mechanical and Electrical Engineering,Xi’an Polytechnic University,Xi’an 710048,China;Xi’an Key Laboratory of Modern Intelligent Textile Equipment,Xi’an 710048,China;China Aerospace Xi’an Power Control Technology Co.,Ltd.,Xi’an 710003,China;Xi’an Thermal Engineering Research Institute Co.,Ltd.,Xi’an 710054,China)

机构地区：[1]西安工程大学机电工程学院,陕西西安710048 [2]西安市现代智能纺织装备重点实验室,陕西西安710048 [3]中国航发西安动力控制科技有限公司,陕西西安710003 [4]西安热工研究院有限公司,陕西西安710054

出　　处：《重型机械》2023年第5期53-59,共7页Heavy Machinery

基　　金：国家自然科学基金青年科学基金项目(51805402);西安市现代智能纺织装备重点实验室建设项目(2019220614SYS021CG043)。

摘　　要：异种钢焊接接头在锅炉再热器与过热器中具有广泛的应用,但长期服役于高压高温等工况易萌生裂纹导致早期失效。通过对某运行已超过20万小时的TP304H/T22异种钢焊接接头的焊缝、母材与垫板交界区域,近熔合线侧的热影响区及远离焊缝的母材区域的微观组织及裂纹萌生与扩展进行研究,考察分析接头裂纹区域与非裂纹区域的组织特征对焊缝失效的影响。结果表明:焊缝、母材及垫板三者的交界处的微观晶粒分布密集呈无规则排列且随着服役时间的增长存在明显的粗化现象,导致该区域易萌生裂纹并扩展延伸;非裂纹区域的显微组织结构排列均匀有序并存有大量孪晶,钢材热稳定性提高,不易产生裂纹。本研究能够为开发高性能异种钢焊接接头工艺以及现有焊接接头性能检测和维护提供研究基础。Dissimilar steel welded joints are widely used in boiler reheaters and superheaters,but long-term service under high pressure and high temperature conditions is prone to crack initiation and early failure.Through the study of microstructure and crack initiation and propagation in the zone of the junction area between the base metal,weld seam,and the backing plate,the heat-affected zone on the near-fusion line side and the base metal region away from the weld seam of a certain TP304H/T22 dissimilar steel welded joint that has been operating for over 200 000 hours,this paper analyzed the influence of the microstructure characteristics of the crack and non-crack areas of the joint on the failure of the weld seam.The results show that the distribution of microscopic grains at the junction of the weld,the base metal,and the backing plate is dense and irregularly arranged,and there is an obvious coarsening phenomenon with the increase of service time,which leads to crack initiation and extension in this area,while the microstructure of the non-crack area is uniformly arranged and there are many twins to improve the thermal stability of the steel,and cracks are not easy to occur.This study can provide a research basis for the development of high-performance dissimilar steel welded joint technology and the performance detection and maintenance of existing welded joints.

关 键 词：焊接接头 异种钢 微观组织 焊缝失效 

分 类 号：TG142.1[一般工业技术—材料科学与工程]