Measurement of chatter marks on the backup roll of a cold temper mill

Continuous tracking measurements were conducted for eliminating the chatter marks of a 1700 temper mill. The character of vibration and the interaction between vibration and chatter marks were found based on the study of inherent characteristics of the temper mill and the analysis of vibration signals in different periods. The primary vibration model was self-sustained vibration and the vibration frequency was 150 Hz in initial stage, but in steady stage the relative movement between the work roll and the backup roll induced chatter marks. In middle and final period the primary vibration model was a coexistence of forced vibration and self-sustained vibration, and the forming process of chatter marks was accelerated by forced vibration resulted from chatter marks. Based on the above studies some countermeasures are derived as follows:adding a roll to control vibration in the inlet side or changing the speed of temper rolling.