Creep constitutive equations for cold-drawn 304L stainless steel

In this paper, two different forms of constitutive equations: Norton-Power Law and Prandtl Law (sine hyperbolic) have been proposed to study the creep behaviour of cold-drawn 304L stainless steel. For this purpose, the material and physical parameters for the creep constitutive equations have been determined using experimental data. The creep behaviour and properties for this material were examined by conducting uni-axial creep tests. Test samples have been obtained from cold-drawn bars and the material conforms to ASTM A276-05a specifications. Constant temperature and constant load uni-axial creep tests have been carried out at three temperatures of 680,700 and 720 °C, subjected to initial stresses of 200, 250, 320, 340 and 360 MPa. The experimental data have been used to obtain the creep constitutive parameters for two forms of equations using numerical optimization techniques. Also, the temperature and stress dependency of the creep properties for this alloy have been investigated using Larson-Miller and Monkman-Grant parameters. The results show that the constitutive equations in the form of Norton-Power law provide better agreement with experimental data.