Mn25Al7钢焊接接头的疲劳性能试验研究  

Fatigue performance tests of Mn25Al7 steel welded joints

作　　者：张宇[1] 李俊[1] 周俊[2] 陈威[1] 谌伟[1] 李晓彬[1] ZHANG Yu;LI Jun;ZHOU Jun;CHEN Wei;SHEN Wei;LI Xiao-bin(School of Naval Architecture,Ocean and Energy Power Engineering,Wuhan University of Technology,Wuhan 430063,China;China Ship Research and Design Center,Wuhan 430064,China)

机构地区：[1]武汉理工大学船海与能源动力工程学院,武汉430063 [2]中国舰船研究设计中心,武汉430064

出　　处：《船舶力学》2024年第7期1100-1110,共11页Journal of Ship Mechanics

基　　金：国家自然科学基金资助项目(51979213)。

摘　　要：Mn25Al7钢是一种新型的轻质高强船用钢,目前针对Mn25Al7钢的疲劳性能尚未开展相关试验研究。本文对Mn25Al7钢的母材、对接焊接接头及T型焊接接头等典型节点进行疲劳试验研究,分别基于名义应力方法和热点应力方法拟合得到典型节点疲劳等级曲线,并与现有规范的疲劳等级曲线进行对比分析。对三种试样的断口形貌进行观测,分析其裂纹扩展规律和断裂机理。试验结果表明:Mn25Al7钢母材疲劳寿命高于按规范设计的普通钢材;规范低估了母材和磨平焊趾的对接焊缝接头疲劳寿命,但能较好地评估T型焊缝接头的疲劳寿命。通过对比分析三种试件的损伤速率差别,进一步对断口形貌进行了系统分析,发现初始裂纹源和焊接残留物会造成疲劳强度的降低。本研究可为船用高强钢的疲劳寿命预测提供理论依据和试验支撑。Mn25Al7 steel is a new type of lightweight and high-strength marine steel,and the fatigue proper⁃ties of Mn25Al7 steel have not been studied in relevant experiments.In this paper,the fatigue tests of typical nodes such as base metal,butt welded joint and T-welded joint of Mn25Al7 steel were carried out,and the fa⁃tigue grade curve of the typical nodes was obtained based on the nominal stress method and the hot stress method,respectively,and compared with the fatigue grade curve of the existing standard.The fracture mor⁃phology of the three samples was observed,and the crack propagation law and fracture mechanism were ana⁃lyzed.The test results show that the fatigue life of Mn25Al7 steel base metal is higher than that of ordinary steel designed by the specification.The specification underestimates the fatigue life of butt weld joints of base metal and smoothed toes,but can accurately evaluate the fatigue life of T-weld joints.By comparing and analyzing the difference in damage rate of the three specimens,the fracture morphology was further systemati⁃cally analyzed.It is found that the initial crack source and welding residue will reduce the fatigue strength.This study can provide a theoretical basis and experimental support for the prediction of fatigue life of marine high-strength steel.

关 键 词：高强钢 疲劳评估 焊接接头 断口分析 疲劳试验 

分 类 号：U661.4[交通运输工程—船舶及航道工程]