Research On Variable Gauge Rolling Process Model For Ultra-heavy Plate

As an important steel product,ultra-heavy plate is widely used in all aspects of national economic construction.In order to solve the common problems of internal structure loosening,grain coarseness and segregation of ultra-heavy plate products,variable gauge rolling technology is proposed to apply to the production of ultra-heavy plate,in this paper.On the basis of not changing the existing process and equipment conditions,the deformation permeability can be improved by increasing single pass reduction in order to improve rolling conditions,dig out the potential of equipment and improve the quality of product core.In this paper,the process model of ultra-heavy plate with variable gauge rolling is studied.The main contents of this paper are as follows:(1)Aiming at the transient biting process of steel rolling,a multi-degree-of-freedom mechanical model of the main drive system is established based on the lumped mass method,and the dynamic parameters of the mechanical model are calculated.On this basis,a mathematical model of torsional vibration is established according to Lagrange’s theorem.The natural frequencies and main modes of the system are calculated by Matlab,and the torsional vibration response of the drive system is analyzed,which provides the basis for judging the weak links of the whole drive system and establishing the torque model of the impact stage in the variable gauge rolling of ultra-heavy plate.The rolling torque model of impact stage was fitted,and the influence of rolling process conditions on impact rolling torque was analyzed.(2)The similarities and differences between variable gauge rolling and conventional rolling are analyzed.Based on the geometry and mechanics theory,the parameters models of bite angle,length of deformation zone,neutral angle and forward slip in the thinning and flattening stages of rolling process are deduced according to the characteristics of the gauge changed at the exit of the rolled piece and the gauge changed at the entry of the rolled piece in the flattening stage.A prediction model for width and length of rolled piece suitable for variable gauge rolling process is established.Rolling force and rolling torque models are established on the basis of variable gauge rolling process parameters model.(3)Based on the integrated development environment of Visual Studio 2010,the calculation program of variable gauge rolling process model for ultra-heavy plate is designed.All function modules of the calculation program are developed by using C++programming language.The rolling torque calculation functions for head impact stage and the rolling load of thinning and flattening rolling stages are realized.The variation law of rolling load under the coupling conditions of different speed and different gauge variation curves is analyzed,and the optimal rolling speed and gauge variation curve are determined.(4)A practical application of variable gauge rolling technology in a domestic heavy plate mill was carried out.In order to verify the accuracy of variable gauge rolling model and the improvement effect of variable gauge rolling technology on rolling conditions,the process parameters were calculated and analyzed with variable gauge rolling model,and the calculated results were compared with the actual data.