Hot Rolling And Heat Treatment Technology Of 15CrMoR Pressure Vessel Steel

15CrMoR steel is low carbon and dilute-alloy pearlite steel which exhibits good integrated mechanical properties. Hot simulation and experimental rolling are used to simulate the real rolling technics of 15CrMoR pressure vessel steel. The main works are involved as follows:(1)When single press test is taken, the influence of the deforming temperature, deforming degree and deforming rate are researched, and the mathematical model of resistance of deformation is established. The behavior of dynamic softening of the steel in austenitic area is also researched. The activation energy of dynamic recrystallization is 346.9 kJ/mol.(2)The heat expansion method is taken to make the CCT curves under deformed and undeformed condition. The results show that deformation makes CCT curve move leftward and upward.(3)Based on the thermal simulation experiment, the rolling technology of the tested steel is researched by the hot rolling test in the laboratory. The experiment results show that the strength is increased with the decrease of finish rolling temperature. The results also indicate that the cooling rate after rolling can affect the properties.(4)The effect of the heat treatment on the micro structures and properties are analyzed. The results show that normalizing temperature has an evident influence on strength and toughness. When 940℃,15CrMoR steel has good strength plus good toughness. Normalizing cooling rate is also a crucial factor because it can change the microstructures of the steel. There is no temper brittleness within 15CrMoR steel. The relationship between the short time tensile strength and the long-term rupture strength is established. Working for 100,000 hours under the condition of 550℃high temperature, the long-term rupture strength of 15CrMoR steel is 71 MPa.(5)It is suggested that the appropriate industrial producing way is as follows:rough rolling temperature is 1100℃, finish rolling temperature is 860-850℃, normalizing temperature is 940℃, normalizing heating time is 2.5min/mm and temper temperature is 690℃.