Research On Laminar Cooling Control System Of Xinstell 1580 Hot Rolling Strip

The temperature of hot rolled strip has a great influence on the microstructure and properties of the final product. The main goal of laminar cooling control of hot rolled strip is to keep the coiling temperature as setting before. The main method to control the coiling temperature is as follow, first though pre-calculation, the preset valve settings can be obtained, then via online calculation, the new valve settings can be updated in time, last using the post-calculation the model parameters can be obtained. Because of the limit of detection device, it is very difficult to make accurate measurement temperature change of the strip on the production process. So it is very important to accurately predict the coiling temperature and the temperature distribution along the cooling section. This thesis, based on the current laminar cooling control system for 1580 mm HSM in Xinsteel, is aimed to absorb the laminar cooling model and control method and make some preliminary work for further development.This thesis mainly includes:(1) The mathematical models about Xinsteel HSM laminar cooling process control are extracted, which mainly include temperature model of strip, material model and heat transfer model with environment.(2) Based on Xinsteel HSM laminar cooling control system hardware and software. Analysis of pre-calculation and post-calculation methods for the model parameters has been done. The pre-calculation uses local study strategy to determine model parameters of the energy balance partial differential equation in cooling process, based on the plate physical parameters, process requirements and history cooling database. Due to the difference between the pre-calculation and the real values, we take use of post-calculation to modify the model parameters with the measurement of the final temperature after the cooling process, which can update the database continuously and increase the pre-calculation accuracy. This method can precisely indentify process models for every guage of plate with various influencing factors and large ranges of parameters changing, and automatically adapt to the environment. It also provides the basis for controller design the computer processes.(3) The basic framework of the laminar cooling software is studied. The main attention is paid to the sub-processes function of processes control system, operation and the relationship between the sub-processes, Which is provide a basis for HSM laminar cooling control system development and application's secondary development.(4) The strip to strip adaption and inner strip adaption modes, through which the modified model parameters are obtained, are summarized. Through the analysis of the existing production process data, we can conduct that Xinsteel HSM laminar cooling system owns a high precision which can meet the needs of current production.