摘要
以一种新型中碳吉帕级δ-TRIP钢为研究对象,进行了加载频率为20 Hz、循环应力比R_(s)为-1的疲劳试验,获得了材料在不同存活率下的P-S-N曲线,并分析了材料断口形貌及裂纹扩展路径,深入研究了残余奥氏体在疲劳工况下的转变以及预应变量对δ-TRIP钢疲劳性能的影响。结果表明:δ-TRIP试验钢的疲劳极限强度约为361 MPa;其疲劳裂纹起源于平行段与圆弧交界处,在裂纹源和扩展区表现为韧性断裂特征,在瞬断区表现为脆性断裂特征;组织中大部分残余奥氏体在外力作用下发生TRIP效应,少量保留下来的残余奥氏体有利于提高δ-TRIP试验钢的疲劳性能;预变形对δ-TRIP钢的疲劳性能会产生不同程度的影响,预应变量越大,疲劳性能的下降程度越大。
For a new type of GPa-grade medium carbon δ-TRIP steel,the fatigue tests with a loading frequency of 20 Hz and a cyclic stress ratio R_(s) of-1 were carried out,and P-S-N curves of the material were obtained at different survival rates.Then,the fracture morphology and crack extension paths of the material were analyzed,and the transformation of residual austenite under the fatigue condition as well as the influence of pre-strain amount on the fatigue properties of δ-TRIP steel were investigated in depth.The results show that the fatigue ultimate strength of the test δ-TRIP steel is about 361 MPa,and its fatigue crack source starts at the junction of parallel section and circular arc,the ductile fracture characteristics in the crack source and expansion area as well as brittle fracture characteristics in the instantaneous fracture area were exhibited.The majority of the residual austenite in the organization undergoes the TRIP effect under the action of external force,a small amount of residual austenite is conducive to improving the fatigue performance of the δ-TRIP test steel,and the pre-deformation affects the fatigue properties of δ-TRIP steel in different degrees.Thus,the larger the decline amount of pre-strain,the larger the degree of fatigue performance.
作者
徐鑫
芦延鹏
王姝
郭金宇
梁笑
苏洪英
Xu Xin;Lu Yanpeng;Wang Shu;Guo Jinyu;Liang Xiao;Su Hongying(State Key Laboratory of Metal Material for Marine Equipment and Application,Anshan 114009,China;Ansteel Iron&Steel Research Institute,Anshan 114009,China;Automotive Steel Marketing and Service Center of Angang Steel Company Limited,Anshan 114009,China)
出处
《锻压技术》
CAS
CSCD
北大核心
2024年第9期213-219,共7页
Forging & Stamping Technology
