Experimental study and prediction of deformation behavior of low carbon steel at low strain rate and high temperature

Abstract

Various types of carbon steel have been used extensively in construction and manufacturing. In this paper, axial deformation tests of 20# low carbon steel using either constant strain rate or suddenly jumping strain rates were carried out in a high pressure, high temperature Paterson-type gas apparatus. The test pressures, temperatures and strain rates ranged from 100 to 300 MPa, 700 to 900°C, and 10-5 to 10-3 s-1 , respectively. The stress-strain curves from the experiments were used to obtain the deformation constitutive equation. The functions relating the parameters in the constitutive equation and the strain are similar at both low and high strain rates. The predicted flow stress calculated from the constitutive equation fits the experimental data from the constant strain rate tests well, but only roughly fits the data from the strain rate jump tests. Regardless of whether the steel is ferritic or austenitic, the deformation behavior of 20# low carbon steel at low strain rate can be described by the same constitutive equation; however the parameter lnA in the equation needs to be corrected when deformation is carried out at temperatures where a phase change is occurring.