Deformation Control Mechanism And Application Of Extremely Thin Steel Plate In Roller Quenching Process

The traditional medium-thick steel plate quenching can not meet the heat treatment production and research and development needs of high-quality ultra-thin,ultra-wide and highstrength steel plates.The quenching process technology and equipment upgrading has become very urgent.As a hot research topic in this field,the existing results have further increased.The feasibility of successful implementation of the project.Therefore,this project takes ultra-thin high-strength steel plate as the research object,introduces the ultimate cold-speed instant quenching method and single-beam or multi-beam slit jet quenching technology,and carries out the high-level and orderly heat transfer of the whole plate surface in the quenching process.The basic research of straightness shape control is to develop the instantaneous synergistic control process of plate cross-section temperature,stress and phase change under large cooling speed conditions,and obtain high-quality plates with no difference in full-surface deformation displacement.The above related research has the theoretical and experimental basis,coupled with the demand for domestic high-thickness steel plate production enterprises for highperformance,low-cost,reduced heat treatment and industrial application of new quenching equipment,will certainly create a good application prospect for the project research results.The main conclusions are as follows:(1)Using computational fluid dynamics,based on Fluent software,simulations were carried out with different slit injection angles of 30°,45°,60° and different jet velocities of 20m/s,25m/s and 30m/s.Quenching,quantitative analysis of the velocity curve of different regions and the temperature profile of the quenched steel plate.The results of different process data show that the velocity curves in different regions under 30° and 25m/s processes and the ultimate cooling rate of steel plates after quenching are more excellent.(2)Based on the elastoplastic finite element principle,the residual stress in the quenching process of the steel plate was analyzed based on ANSYS software.The simulated quenching process was simulated under the premise of uneven quenching and the third type of boundary conditions.In order to study the influence of different upper and lower surface heat transfer coefficients on thermal stress,three different R values were set at 5%,7.5%,and 10%,respectively.Through the analysis of the quantitative thermal stress,when the R value is 5%,the uniformity of the residual stress inside the steel sheet and the surface layer is optimal.Summarize the different laws of quenching thermal stress in different periods.The metal of the surface layer is subjected to tensile stress at the initial stage of quenching,and becomes a compressive stress as the quenching progresses.The metal core is subjected to compressive stress at the initial stage of quenching,and is subjected to a change in tensile stress at the later stage of quenching.(3)Diferent quenching injection angles were studied by on-site quenching experiments.The hardness uniformity of steel plates under different processes was obtained by analyzing the hardness of steel plates.The quenching uniformity of the three different jet angle processes performed well,but the hardness deviation values were slightly different,1%,2%and 3%respectively.The data analysis can obtain the uniformity of the quenched steel plate obtained by the 30° quenching process.Optimal.The uniformity of the quenched steel sheets of different processes was studied by means of X-ray measurement of residual stress.The distribution of residual stress and shear stress in transverse,longitudinal and oblique directions was obtained.The data analysis showed that the quenched steel sheets obtained from the 30° jet inclination angle were obtained.The residual stress value distribution is more uniform and the value is smaller.(4)Through the adjustment of the process parameters of different quenching machines on the premise,under the premise that the roller speed is constant,the flatness of the steel plate is the best when the water ratio is 1.2.Under the premise of a certain water ratio,the straightness of the steel plate is optimal when the roll speed is 30 m·min-1.According to the analysis of the performance indexes and plate shape test results of the quenched plate,the performance and straightness of the plate after quenching are up to or better than the national and enterprise assessment standards,which meets the actual production needs.The research results of this paper have a strong practicability for the development of the ultimate thin gauge steel plate equipment and process technology.The equipment involved in research and development has been successfully applied to a steel mill in Hunan to meet the production needs of the site.