Creep properties of simulated heat-affected zone of HR3C austenitic steel

Tensile creep tests on austenitic stainless HR3C steel pipe in an as-received state and after heat affected zone (HAZ) thermal cycle simulation by means of the GLEEBLE 3800 physical simulator were carried out at 923 and 1023 K and an applied stress range between 100 and 350 MPa to evaluate the effect of welding on its creep properties and behaviour. It was found that creep testing was conducted in a power-law creep regime. The results show a clear detrimental influence of the HAZ simulation on creep properties of HR3C steel at 923 K and for very short creep exposure. However, with increasing time to fracture, the effect of weld simulation becomes less significant. By contrast, no such deterioration of creep properties was detected at 1023 K. The evaluated similar values of the stress exponents of the minimum creep rate and the time to fracture are explained using the assumption that both creep deformation and the fracture process are controlled by the same mechanism. The main creep fracture mode was intergranular brittle fracture due to grain boundary creep damage.