Research On Large Cylinder Joint Heat Treatment Process Based On Induction Heating And Spray Cooling

The heavy cylinder is the key part of the equipment of nuclear power,petrochemical hydrogenation reactor and coal liquefaction.With the development of the energy industry structure to the direction of low-carbon economy and clean energy,the quality requirements of nuclear power,petrochemical,aerospace and other areas for heavy cylinder is more and more strict.The heat treatment process of large cylinder is divided into two processes of heating and cooling.In order to improve the heat treatment efficiency and heat treatment effect of large cylinder,the rapid heat treatment process of large cylinder is studied based on induction heating and spray cooling.The austenite growth law of 2.25Cr1Mo0.25 V steel is studied.The austenitizing thermal expansion curves at different heating rates is measured by experiments,and the starting temperature and finish temperature of the austenite transformation of the steel at different heating rates are obtained,which provides theoretical guidance for the optimization of the subsequent induction heating route.The large cylinder induction heating resistor insulation device is optimized.A large cylinder induction heating electromagnetic-thermal-force coupling model based on resistance insulation is established.The effects of resistance insulation and induction heating are analyzed by simulation.It shows that the resistance insulation can effectively improve the insulation effect of large cylinder and avoid surface burning.The Curie point effect in the induction heating process is studied,the inductive heating process route of large cylinder is optimized,and the traditional induction heating process and the optimized induction heating process are simulated.The energy consumption of the traditional induction heating method and the optimized induction heating method are calculated,and the maximum equivalent stress of the large cylinder under the traditional induction heating method and the optimized induction heating method are analyzed.The rapid heat treatment route of the large cylinder is designed.Considering the existence of latent heat of phase change in the initial stage of cooling,the secondary holding time after induction heating of the large cylinder is reduced,and the large cylinder core can utilize the latent heat of phase change during cooling to homogenize the austenite.The numerical simulation of the cooling process of large cylinder air-cooling alternate cooling is carried out,and the stage of latent heat of phase change is divided into the pre-cooling stage,mainly cooling the surface of large cylinder.The stage after the end of the latent heat of phase change is divided into the late stage of cooling,which ensures that the core of the large barrel can be cooled quickly.The thermal stress during the cooling process of large cylinder air-spray alternating cooling is analyzed,and the inadequacies of the large cylinder spray cooling device are proposed.Finally,the rapid heat treatment process of the large cylinder is experimentally verified,and the grain size and mechanical properties of the core and surface of the large cylinder after rapid heat treatment are measured.The experimental results show that the grain size of the core and the surface can meet the heat treatment requirements and the mechanical properties of the large cylinder meet the requirements.