Prediction of tensile strength and elongation of high alloy steels during solidification

Abstract

Phase dependence of tensile strength of high alloy steel during solidification has been studied by a technique for high temperature tensile testing. The experimental technique enabled a sample to melt and solidify without a crucible, and the measurement of a minute load in a solidification temperature range became possible. A numerical model for the analysis of phase transformation during solidification was developed with the assumption that local equilibrium holds at liquid/solid interface or δ/γ phase interface. The zero strength temperature was in agreement with zero ductility temperature, and both of these temperatures appeared at the fraction solid of 0.8. Both the tensile strength and elongation of high alloy steel were dependent on the phase state but not on chromium and nickel contents. The tensile strength in (liquid+δ), (liquid+γ), (liquid+δ+γ) and (δ+γ) coexisting state could be predicted using the experimental results. These estimated values are in good agreement with experimental results. © 2006 ISIJ.