Abstract：In order to study the constitutive characteristics of the surface-modified layers of 18CrNiMo7-6 alloy steel under cyclic loading,18CrNiMo7-6 alloy steel was carburized and heat treated. Round bar samples with different surface modified layer thickness were obtained through chemical corrosion. Monotonic tensile test and cyclic loading test were carried out respectively to analyze the differences of mechanical properties,hysteretic properties,energy consumption capacity and microstructure. The skeleton curve under cyclic loading was fitted,and the difference between its mechanical properties and that under monotonic tension was studied. The cyclic constitutive parameters of the surface-modified layers under cyclic loading were calibrated based on the Chaboche cyclic constitutive model,the simulation were verified by the finite element software ABAQUS. The results showed that the hardness, yield strength and tensile strength of the sample increase with the increase of the thickness of the surface modified layer under monotonic tension. Under the same strain amplitude loading,the thicker the surface metamorphic layer was,the greater the response stress was,the lower the energy dissipation coefficient was,and the weaker the energy dissipation capacity of the material was. Ramberg-Osgood model can better fit the cyclic skeleton curve of surface-modified layers under cyclic loading. The main component of 18CrNiMo7-6 alloy steel was lath martensitewith the increase of surface modification layer thickness,the higher the dislocation density was. The matrix material of 18CrNiMo7-6 alloy steel showed the characteristics of cyclic hardening under cyclic loading,and the sample gradually showed the characteristics of cyclic softening with the increase of the thickness of the surface-modified layers. Chaboche cyclic constitutive model can accurately fit the mechanical response of samples with different surface-modified layers under cyclic loading.
王刚, 路留成, 张悦, 王书艳, 崔超. 18CrNiMo7-6合金钢表面变质层循环特性[J]. 钢铁, 2022, 57(9): 156-165.
WANG Gang, LU Liu-cheng, ZHANG Yue, WANG Shu-yan, CUI Chao. Cyclic characteristics of surface-modified layers of 18CrNiMo7-6 alloy steel[J]. Iron and Steel, 2022, 57(9): 156-165.
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