Abstract: The cooling rate in simulated HAZ continuous cooling transformation（SHCCT） diagram under traditional welding condition is constant, while the cooling in actual welding process is natural heat dissipation. The difference between the two processes causes that the SHCCT diagram cannot directly predict the microstructure and performance of the welding HAZ. Therefore, the simulated HAZ natural cooling transformation curve（SHNCT） of metal materials was proposed. During the drawing of the SHNCT diagram, the natural cooling curve duiring welding thermal simulation was used, which is closer to the thermal cycle curve of actual welding. The obtained HAZ structure and performance can be directly used for the guidance of welding production. The grain size, phase ratio, hardness and impact energy of TSZ410 stainless steel HAZ at different t_1300/250 were measured, and the SHNCT diagram was drawn.