Temperature Control Technology by Finite Difference Scheme with Thickness Unequally Partitioned Method in Gradient Temperature Rolling Process

Abstract

In order to solve the problem of low the computational speed in gradient temperature rolling (GTR) process and guarantee the accuracy of temperature distribution in thickness direction, temperature control technology by finite difference scheme with thickness unequally partitioned method was investigated. The thickness partitioned method is adopted by means of equidistance logarithmic value for thickness, which causes the distance of two neighboring nodes to be larger as thickness increasing and gets the effect of more detailed grid on surface and rough grid in the core. Finite difference scheme was used to study the formation law of the temperature field which considers effect of oxide scale thickness in thickness direction, then temperature distributed regularity with different heat transfer coefficients in thickness direction of plate was obtained. The temperature distributions of gradient temperature rolling process is calculated while rolling procedure running, temperature gradient change rules over time with certain water jet pressure as well as temperature gradient change rules with different water jet pressures are studied. The industrial testing result illustrates that calculated rolling force reference and rolling torque reference are slightly larger than neighboring values by about 10% when gradient temperature rolling mode is used in pass 1, pass 3, pass 5 and pass 7. From comparison of measured temperature and calculated temperature, it indicates that prediction difference can be controlled with ±5°C when node number equals to 16 with half thickness and deviation of calculated force and measured force can be controlled with ± 4.0%.