国产加钒钢焊接接头不同区域的蠕变裂纹扩展行为  

Creep Crack Propagation Behavior of Different Regions in Domestic Vanadium Steel Welded Joint

作　　者：顾腾飞 王宁[1,2] 许开源 曾熙婷 谈建平 涂善东[1,2] GU Tengfei;WANG Ning;XU Kaiyuan;ZENG Xiting;TAN Jianping;TU Shandong(Key Laboratory of Pressure System and Safety,Ministry of Education,East China University of Science and Technology,Shanghai 200237,China;Shanghai Institute of Aircraft Mechanics and Control,Shanghai 200092,China)

机构地区：[1]华东理工大学,承压系统与安全教育部重点实验室,上海200237 [2]上海飞行器力学与控制研究院,上海200092

出　　处：《机械工程材料》2024年第9期17-24,共8页Materials For Mechanical Engineering

基　　金：国家自然科学基金联合基金资助项目(U21B2077)。

摘　　要：以国产2.25Cr-1Mo-V加钒钢焊接接头为研究对象,在550℃和不同初始应力强度因子(19.04,17.57,16.40,14.64,13.47MPa·m^(0.5))下对母材、焊缝和热影响区进行蠕变裂纹扩展试验,研究了焊接接头不同区域的蠕变裂纹扩展行为,探究了应力强度因子和C^(*)参量表征蠕变裂纹扩展速率的适用性,并观察了断口形貌。结果表明:随着初始应力强度因子的增加,母材、焊缝和热影响区的蠕变断裂寿命缩短,归一化稳态蠕变裂纹扩展速率增大。在相同初始应力强度因子下,焊缝的蠕变断裂寿命最长、归一化稳态蠕变裂纹扩展速率最小,说明焊缝抵抗蠕变裂纹扩展的能力最强,蠕变性能最佳;热影响区的蠕变断裂寿命最短、归一化稳态蠕变裂纹扩展速率最大。接头不同区域的归一化蠕变裂纹扩展速率与应力强度因子的变化曲线都呈类似“V”字形状,对应蠕变裂纹的萌生、稳定扩展和加速扩展阶段;应力强度因子和归一化蠕变裂纹扩展速率的分布具有显著的分散性;C^(*)参量与归一化蠕变裂纹扩展速率具有更强线性关系,且C^(*)参量和归一化蠕变裂纹扩展速率的分布集中。随着初始应力强度因子的增加,母材、焊缝和热影响区的断裂模式由沿晶断裂或穿晶断裂向沿晶/穿晶混合断裂转变。Taking the domestically produced 2.25Cr-1Mo-V vanadium steel welded joint as the research object,creep crack propagation tests were conducted on the base metal,weld,and heat affected zone at 550℃and different initial stress intensity factors(19.04,17.57,16.40,14.64,13.47 MPa·m^(0.5)).The creep crack propagation behavior of different regions in the welded joint was studied,and the applicability of stress intensity factor and C^(*)parameter to characterize creep crack propagation rate was investigated.The fracture morphology was observed.The results show that as the initial stress intensity factor increased,the creep fracture lives of the base metal,weld,and heat affected zone were all shortened,and the normalized steady-state creep crack propagation rate increased.Under the same initial stress intensity factor,the creep fracture life of the weld was the longest and the normalized steady-state creep crack propagation rate was the smallest,indicating that the weld had the strongest resistance to creep crack propagation and the best creep performance;the creep fracture life of the heat affected zone was the shortest and the normalized steady-state creep crack propagation rate was the highest.The curves of normalized creep crack propagation rate and stress intensity factor of different regions in welded joint all showed a“V”shape,corresponding to the initiation,stable propagation,and accelerated propagation stages of creep cracks.The distribution of stress intensity factor and normalized creep crack propagation rate exhibited significant dispersion.The C^(*)parameter had a strong linear relationship with the normalized creep crack propagation rate,and the distribution of C^(*)parameter and normalized creep crack propagation rate was concentrated.With the increase of initial stress intensity factor,the fracture mode of base metal,weld and heat affected zone changed from intergranular or transgranular fracture to intergranular/transgranular mixed fracture.

关 键 词：2.25Cr-1Mo-V加钒钢 焊接接头 蠕变裂纹扩展行为 应力强度因子 

分 类 号：V216.45[航空宇航科学与技术—航空宇航推进理论与工程]