Method for deciding change point of back up roll in rolling mill through accumulative fatigue control

摘要

The present invention is composed of a roll mill rolls from the replacement of reinforcement reinforcement to support the work roll and the work roll point relates to the determination method. The objective is the rolling load and fatigue destruction by calculating the cumulative fatigue and fatigue calculation receive a roll while taking into account the local stress concentration due to the wear of the roll to the actual number of revolutions of the approximation on the basis of the fluctuation in the load in real time, Before this occurs is to provide a way to replace a reinforcing role. ; to the present invention for achieving the object, ; Substitution of the reinforcing role of the reinforcing rolls for supporting the work rolls and the rolling mill composed of work rolls is in direct contact with the rolled material point determination In the method, ; obtaining a contact stress of the reinforcing rolls according to Formula 1, ; [Equation 1] ; Here, _c contacts stress, P is the rolling load, l is the reinforcement of the work roll and the width direction of the contact length rolls ; b Chapter caused by contact of Roll pyeonhyeong, ; contact stresses obtained in the above ( _c ) a step to obtain the actual contact stress by substituting the equation (3), ; [Equation 3] ; Here, _act is the actual contact stresses, Rc is the stress concentration factor, k is a constant, Wd is a wear depth ; In the substituting the actual contact stresses obtained in equation (4) by destroying the number of revolutions of the roll of reinforcement to occur (N _i ) obtained the following, the steps of measuring the actual rotational speed of the reinforcing roll (ni), ; [Equation 4] ; Here, a1, a2 are constants, _critical is the critical stress value ; ni Ni and obtained from the Equation 5 Substituting calculating fatigue (Fi) by, ; [Equation 5] ; periodically step to calculate the fatigue of the reinforcement roll to calculate the fatigue accumulated by substituting Equation 6, ; Equation 6] ; cumulative fatigue (F) is the critical fatigue (F _critical ) with the cumulative fatigue roll mill reinforcement control comprises a step of determining a replacement time of the reinforcement is greater than the roll obtained from the The way to determine the time for replacing the technical subject matter.