Microstructure and Properties of Novel Heat-Resistant HR3C/T92 Dissimilar Steel Welded Joint

HR3Csteel and T92steel were welded by handwork gas tungsten arc welding using Ni-based HIG- 370electrode as welding material.The microstructure and mechanical properties of T92/HR3Cdissimilar welded joint were investigated by means of optical microscopy,scanning electron microscopy,X-ray diffraction,tensile test,bending test,impact test and hardness test.The results show that the prepared T92/HR3Cdissimilar welded joint had superior strength,ductility and toughness,fractured at the base metal of T92steel.The matrix of the welded metal was composed of austenitic cellular dendrite.Precipitates of weld metal consisted of M23 C6 and NbC. The base metal of HR3Csteel as well as the heat affected zone close to HR3Csteel consisted of austenite and precipitates of Nb(C,N)and M23 C6.The microstructure of the base metal of T92steel and the heat affected zone close to T92steel was tempered martensite and M23 C6 precipitate.