Layered inversion method for dynamic constitutive model of the 18CrNiMo7-6 alloy steel surface-modified layer
XU Guangtao
LI Gong
CHANG Xiao'an
HAN Guangzhao
ZHAO Minghao
Abstract：To address the issue of characterizing static and dynamic mechanical behaviors of the surface-modified layer(SML)in 18CrNiMo7-6 alloy steel,a layered inversion method for the Johnson-Cook(J-C)constitutive model of SML was proposed.The SML was subjected to layered processing,and dynamic compression tests were conducted on cylindrical specimens with different SML thicknesses.Through progressive parameter inversion,the strain rate sensitivity coefficient C at each depth of the SML was determined.Combined with quasi-static thin plate tensile tests at different temperatures for each depth of the SML,the corresponding yield strength A,strain hardening coefficient B,strain hardening index n,and thermal softening exponent m were determined.Test results show that the SML of 18CrNiMo7-6 alloy steel exhibits significant strain hardening,strain rate strengthening,and temperature softening effects.Additionally,a correlation model between J-C constitutive parameters and dimensionless depth h/hb(distance to SML surface/SML effective depth)was established,providing support for subsequent composite strengthening simulations.
Keywords：Surface-modified layerJohnson-Cook constitutive modelCarburization18CrNiMo7-6 alloy steel
Publication Date：2025-09-15
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：8( 54-61 )