Analysis on SH-CCT curves of HD15Ni1MnMoNbCu steel for nuclear power station

The microstructural evolution and Vickers hardness measurement in the welding heat-affected zone（HAZ） of HD15Ni1 MnMoNbCu steel for nuclear power station were investigated by Gleeble-3180 thermal mechanical simulator,and the simulated HAZ continuous cooling transformation curves（SH-CCT） were measured simultaneously.With t_8/5 increasing from3.75 s to 15 000 s,the product was obtained martensite,bainite,ferrite and pearlite,successively.The result of microstructure and Vickers hardness in the heat-affected zone was in good agreement with those measured by SH-CCT diagram with the heat input 16.2 kJ/cm as an example to weld the HD15Ni1 MnMoNbCu steel pipe using TIG/SMAW/SAW welding methods.