Estimation of reliability of the TPA 350 mill working stand housing after a long operation

Among the processes, taking place at the shells rolling at automatic mill, the least studied are a working stand housing behavior, which becomes apparent in the form of its dynamic shifting. It can be explained by the fact, that the shell interacting with the rollers and the mandrel is effected by rod mechanism of the mandrel holding at the rolling axis. The possibility of the non-controlled deformed state can be explained also by deviation from the regulation state of anchor bolts fastening system and various defects in the stand housing. It made a foundation to accomplish monitoring of the space state of the TPA 350 automatic mill stand, resulted in registration of the working stand housing stress-deformed state. Besides, it resulted in a task formulation for elaboration of the stand space model aimed at its application for the justification of the strategy of the TPA 350 mill further operation. Results of the study of stress-deformed state of the working stand housing of the TPA 350 automatic mill presented. The study was carried out by the method of finished elements at 3D models. Comprising of the obtained theoretical data with experiment studies of the housing tension confirmed the model adequateness. It was determined, that maximal stresses originate in the zones of the revealed cracks of the working stand housing. The locations of the maximal stresses concentration “migrate” at variation of fastening conditions and the stand housing loading. A function of risk obtained for the stage of a crack originating and for the stage of defect development in the housing. The automatic mill housing safety was exhausted after 50 years of operation. Currently the automatic mill housing operates in the zone of complete risk, accompanying by cracks formation. For the mixed mechanism of crushing, the periods of round defect development in the TPA 350 automatic mill housing determined.