Effect of long-term stress relief annealing on properties of low-alloy weld deposit of covered electrodes for welding of thick-walled nuclear constructions

Abstract

Abstract The article discusses the results of tests on the impact of long-term stress relief annealing at 620–650°C and cooling at a rate of 10°C/h on the mechanical properties of low-alloy weld deposits of covered electrodes containing 1.5–3% Ni, 0–0.3% Mo and 0.01–0.03% P. The article also contains information on the most advantageous nickel content for obtaining the highest impact energy (KV) values in subzero temperatures. X-ray structural analysis revealed that such weld deposits contain solely Fe3C carbides, which prevents the impact of molybdenum carbides on the change of KV. The study also confirmed the adverse effect of phosphorus on the weld deposit impact energy after long-lasting heat treatment.