研究了由时效热处理18Ni(300)钢制作拉杆的显微组织,以及使用工况条件下拉杆的室温循环加载力学性能和断口形貌,分析了拉杆的断裂模式.结果表明:经过固溶处理的18Ni(300)钢呈现淬火马氏体组织,原奥氏体晶粒尺寸约为24 μm,残余奥氏体面积分数约为0.26%;时效处理后,原奥氏体晶粒尺寸约为26 μm,未观察到残余奥氏体;18Ni(300)钢马氏体发生回复,(Ni,Co,Fe)3Ti相在位错上析出.模拟安装使用工况条件下,室温循环加载后拉杆试样的循环断裂周次均大于480次,断裂部位主要分布在拉杆螺纹根部;断口由塑性变形区和脆性变形区组成,塑性变形区居中;断面以拉伸断裂特征为主,以疲劳断裂特征为辅,由此推断拉杆主要受轴向拉伸的作用.
The microstructure,room temperature cyclic loading mechanical properties and fracture morphology of the tie rod made of 18Ni(300)steel after aging heat treatment were studied,and the fracture mode of the pull rod was analyzed.The results show that the 18Ni(300)steel after solution treatment exhibited quenched martensite structure,the original austenite grain size was about 24 μm,and the area fraction of retained austenite was about 0.26%.After aging treatment,the original austenite grain size was about 26 μm,and no retained austenite was observed.Martensite recovery of 18Ni(300)steel occurred,the(Ni,Co,Fe)3Ti phase was precipitated on the dislocation.Under the condition of simulated installation and use,the number of cyclic fracture cycles of the tie rod sample after cyclic loading at room temperature was greater than 480 times.It was found that the fracture site was mainly distributed at the root of the tie rod thread.The fracture was composed of plastic deformation zone and brittle deformation zone,and the plastic deformation zone was in the middle.The fracture section was mainly characterized by tensile fracture and supplemented by fatigue fracture.It was concluded that the pull rod was mainly subjected to axial tension.
丁明;胡卉桦;刘攀;郝宪朝;马颖澈
中核武汉核电运行技术股份有限公司, 武汉 430223中国科学院核用材料与安全评价重点实验室(中国科学院金属研究所), 沈阳 110016
金属材料
拉杆;18Ni(300)钢;力学性能;显微组织;塑性变形
tie rod;18Ni(300)steel;mechanical property;microstructure;plastic deformation
《理化检验-物理分册》 2024 (002)
1-5 / 5
10.11973/lhjy-wl202402001
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