Development Of Energy Saving Heat Treatment Technology Of Heavy Cylinder

With the rapid development of economy and the continuous progress of science level of our country, to further improve the performance of the workpiece in the manufacturing industry is a must. Therefore, the proportion of the heat treatment of workpiece increases. Since the beginning of the 21 st century, the energy consumption of heat treatment increase in the total energy consumption proportion. With the understanding of the sustainable development strategy for energy saving and environmental protection, all the countries in the world are exploring an energy saving heat treatment technology. Heavy cylinder is the key component of a hydrogenation reactor. Due to its long period of heat treatment and large energy consumption, this paper attempt to find a heat treatment process which is not only to improve the microstructure and mechanical properties, but also to reduce the energy consumption.First of all, in order to improve the cooling rate of large cylinder and reduce the quenching heat stress and residual stress, this paper established mathematical models of spray cooling and air cooling. The CCT and TTT curve of large cylinder material were established by Jmat Pro software and experimental date. A mathematical model of organizational change was established.Secondly, the rolling rate and rolling time in different thickness of heavy cylinder were simulated by the DEFORM-2D software, which prepared for the later thermal simulation compression experiment. A heat treatment process of heavy cylinder after rolling was simulated by the software of DEFORM-HT model. Through the simulation of temperature field, stress field and microstructure field under different cooling conditions, paving the way for making the best heat treatment method. For making the temperature of critical region normalizing, the austenite content corresponding to different temperature in the heating process of normalizing was simulated.Thirdly, a residual heat treatment method of heavy cylinder after rolling was put forward. The method of spray-air combined cooling can not only decrease the thermal stress and residual stress of the heavy cylinder in the cooling process, but also increase the cooling rate and reduce the structure heresity in the subsequent heat treatment process.Finally, the lift type critical region normalizing and step type critical region normalizing heat treatment process were put forward as the center part of heavy cylinder was prone to mixed grain and coarse grain structure, long period of heat treatment, large energy consumption and other problems after rolling. The microstructure and mechanical properties of heavy cylinder material after the lift type critical region normalizing and step type critical region normalizing heat treatment process were studied through the heat treatment and mechanical properties experiments. Then, the feasibility of the proposed heat treatment process method was verified through contrasting with the isotherm type austenite region normalizing process.