Dynamical Reliability of Four-high Rolling Mill under Stochastic Strip Characteristics Excitation

It has great significance to research the dynamical reliability probability of rolling mill rolls system for improving its stochastic dynamical reliability and products quality rolled. The fifth-octave vertical vibration stochastic dynamical model of rolls system was established, and the pseudo-excitation method was used to obtain the power spectral density and the variance variation characteristics with the rolling speed and time under stationary rolling force stochastic excitation, and the stochastic dynamical reliability of rolls system was analyzed by using the first-passage failure criterion. The results show that rolls system reliability has strong relationship with stochastic excitation intensity and thickness tolerance of rolled strip and damping of the roll gap, among them, the stochastic excitation intensity and thickness tolerance of rolled strip have greater influence on the dynamical reliability of rolls system than other parameters, and rolls system stochastic dynamical reliability can be improved by mainly controlling the rolled plate/strip accuracy and roll gap damping, thus improving the quality of rolled strip in rolling operation.