.1450 Mm, Hot Rolling Mill Simulation Study Of The Laminar Cooling Process

The microstructure of hot rolling strip is depended on controlling the temperature from finishing rolling to coiling. In order to gain appropriate coiling temperature and control microstructure of hot rolling strip to improve mechanical characters, adopting cooling process after hot rolling becomes a key process of gaining good characters which were lay on the microstructure of hot strip. In laminar cooling process, cooling is powerful and uniform, the cooling speed can be easily controlled. Besides the maintaining of equipment is quite simple. For all the advantage mentioned, laminar cooling is one of the most popular cooling mode in hot strip manufacture.The cooling process is quite complicated which include many diathermanous courses such as the quantity of heat between strip and water, the quantity of heat among the rollers, and the heating radiation in the whole process. So establish an accurate model to control the temperature decrease of strip in laminar cooling process is the key task.This paper take account of all factor which affected the diathermanous courses of strip, including the heating radiation among the strip, the quantity of heat between strip and water, and the quantity of heat inside the strip. The diathermanous courses of cooling process were analyzed by air cooling and water cooling temperature decrease. Then we got the model of the two cooling ways. In the air cooling model which considered the heat conduction in the strip, the heating radiation parameter of strip surface is linear to the thickness; in the water cooling model, the temperature decrease forced by the side was also considered, besides the heat flux consistency and the coefficient of heat flux consistency were introduced in the model. Based on the analysis of the thermal conduction, making use of the datas of worksite,we calculated the model parameters by regressive method to establish the model. The specific heat and heat conduction parameters of strip were change with composition and temperature of the steel. They were separated managed to ensure the precision of the model.Base on the laminar cooling model, the core calculating program was developed by FORTRAN POWER STATION. The results such as status of cooling aggregative ducts and the temperature decrease curve of the strip were outputted by STANFORD GRAPHICS when inputs steel kinds, finishing rolling temperature, coiling temperature, cooling speed and cooling type. The laminar cooling was emulated by the program. The results calculated by the program were accordant to the production data. The research was applied on the DP and the TRIP steel already. The laminar cooling processes of those steels were base on the program. This research was also applied on the temperature testing of PY402 which is optimizing the coiling temperature.