Constitutive Equations for Flow Behavior of Powder-forged Fe-0.5C-2Cu Steel under Hot Compression

To investigate the hot deformation behavior of powder-forged (P/F) Fc-0. 5C-2Cu steel, the hot compression tests were conducted at temperatures ranging from 900 to 1000 °C and strain rates from 0.1 to 10 s−1 using Gleeble-1500 thermal simulator. The true stress-true strain curves at different temperatures and strain rates of P/F steel were obtained. It is found that dynamic recovery only occurs as strain rate is 10 s−1 at 900 °C, and the dynamic recrystallization is the main softening mechanism. The flow stress increases with decreasing temperature and increasing strain rate. The experimental data are employed to develop constitutive equations on the basis of the Arrhenius-type equation by introducing the strain with nonlinear fitting. The flow stresses predicted by the proposed constitutive equations arc in good agreement with the experimental values, and the correlation coefficient (R2) and the average absolute relative error (AARE) arc 0.99525 and 3.07% respectively. These results indicate the proposed constitutive equations can effectively describe the hot deformation behavior of the material.