Study on residual stress by neutron diffraction in SM570-TMC welded by flux-cored wires containing different nickel

Abstract

Residual stresses developed during fusion welding operations may affect the fatigue life of the steel welded structures under dynamic loading conditions. This research aimed to investigate the residual stress distribution along the fusion welded joint. Neutron diffraction was used to measure internal stresses of flux-cored arc welded SM570-TMC steel plate, which fabricated using two different types of welding wire, E71 LT H4 (containing 0.4%Ni) and E81-Ni1 (containing 1%Ni). The longitudinal, normal, and transverse directions of residual stress were measured at the welded joint along lines 3 mm and 8 mm below the top surface. Neutron diffraction results show that residual stress in the longitudinal direction was higher than both normal and transverse directions. The residual stresses of weld using welding wire containing 1%Ni seem higher than 0.4%Ni. It may correspond to the formation of hard phases in the weld metal (WM) due to increasing nickel content.