Effect of Different Tempering Temperature on the Microstructure and Properties of G115 Steel Weld

Evolution of microstructure and room-temperature strength of G115 deposited metal after different tempering at 760°C,800°C and 820°C have been experimentally investigated using metallographic microscope, field emission scanning electron microscopy (SEM) and tensile test, charpy impact test. The results show that after tempering at 800 °C, the G115 deposited metal has the best mechanical properties and can obtain obvious tempered martensite structure of lath bundle. Tempering at 760-800°C, the M 23 C 6 precipitates has a tendency to grow up. The main mechanism that produces the above results is the recovery of martensite and the precipitation of carbon during high temperature tempering. Spherical oxide inclusions formed by welding metallurgy were found in the dimples of the impact fracture of the deposited metal and its influence on the high-temperature durability of the deposited metal needs further study.