Analysis And Research On Organizational Field And Mechanical Properties Of Hot-rolled H-beam In The Controlled Cooling Process

With the improvement of the modern architecture level, the mechanical properties of section steel products are increasingly demanded. Although the controlled rolling can effectively improve the properties of steel, it brings about the coarse tissue grain of steel and results in a decline in the mechanical properties of steel because of the thermal deformation. Therefore the effect of controlled rolling is limited. Practice has proved that the controlled cooling technology after steel rolling can realize the organization refinement of the steel material to improve the composite mechanical properties and has become a key development technology in the iron and steel enterprises at home and abroad. Therefore, the paper mainly studies the controlled cooling after rolling of hot-rolled Q235 H-beam to improve the material microstructure organization further and enhance its composite mechanical properties.Based on the basic theories of heat transfer and finite element analysis,the paper mainly studies simulation analyses in the controlled cooling process of hot-rolled H-beam. Through accessing to the domestic and foreign information of controlled cooling and combining with the actual production status, the paper determines the initial conditions and thermal boundary conditions more reasonably and utilizes the finite element ANSYS to complete a simulation of hot-rolled H-beam in the controlled cooling process,and it obtains the transient temperature field, the stress / strain field and the distributions of the corresponding time history curves at the same time so as to get the key cooling parameters which impacts the controlled cooling process of hot-rolled. In order to make the controlled cooling effect of H-beam meet the process requirements more accurately, the paper uses ANSYS optimization method to optimize the cooling parameters in the temperature field of the controlled cooling process in order to make surface and the internal temperature difference of H-beam achieve to the most reasonable minimum while the back red temperature lies in 640℃~700℃. And at the same time the paper is able to get the corresponding reduction in thermal stress and deformation when the temperature difference is smaller. The paper verifies that the theoretical simulation values are basically consistent with the measured values through the hot-rolled H-beam controlled cooling experiments. On the basis of this experiment the metallographic microstructure at room temperature is analyzed using scanning electron microscopy and at the same time the mechanical properties of the controlled cooling H-beam is examined. To do these so is to obtain the variation in metal organization microstructure and the composite mechanical properties under the different controlled cooling parameters. These analyses not only provide a theoretical basis to develop a reasonable cooling process but also have a certain practical reference value to further improve the mechanical properties of hot-rolled H-beam in the controlled cooling process.