Discussion of the Microstructure and Hardness of Welded Joints for Steel 15GrMoR

A welding experiment is conducted on the base steel 15CrMoR using electrodes A302 and R307,respectively.The microstructure of the metal in the welded joint and the metal in heat-affected zone is analyzed,and the hardness test of the welded joints is performed.The results show that the microstructure is made of ferrite,pearlite and some carbide,and the hardness of the metal in the welded joints is close to that of the base metal using electrode R307.Using electrode A302,the welded metal microstructure is comprised of the austenite and dendrite δ ferrite with intercrystalline segregation,and bainite is formed in the heat-affected zone,which leads to much higher hardness of the metal in heat-affected zone than that of the welded metal.