Effect of peak temperature and cooling rate in welding thermal cycle on microstructure and properties of CGHAZ inSA508-3 steel

Because the microhardness and absorbed energy change greatly after CGHAZ experienceing different peak temperature and cooling rate in welding thermal cycle, the CGHAZ in the SA508-3 steel joint is highly unstable. When the peak temperature in the second welding thermal cycle was 600-700℃, the CGHAZ could get a better match between hardness and toughness. The formation of hidden martensite near grain boundary and grain coarsening should be avoided after the CGHAZ experienced secondary welding thermal cycle which peak temperature was 750-950℃ and t_8/5 was 10 s.