MULTI-AXIAL FATIGUE LIFE PREDICTION METHOD OF WORKING ROLL NECK BEARING SECTION BASED ON STRAIN ENERGY

The bearing section of the work roll neck often suffers burnout failure due to bearing seizure, and additive manufacturing is usually used in the field to repair it.Life prediction of the repaired roll neck is the key to predict the safe service of the work roll in the field production and carry out overhaul，but there is a lack of research on the related issues.In view of the above problems, the stress analysis and multi-axis life prediction of the working roll neck bearing section of the four-high mill were carried out.Based on the SIMS model and the influence function method, the rolling force and the stress between the rolls were calculated.The moment balance equation of the roll neck end was established in the bearing section, and the bending stress model of the roll neck bearing section was established.The deformation resistance was regarded as the plastic deformation energy per unit volume to calculate the rolling torque in the deformation zone, and the torsional shear stress model of the roll neck bearing section was established.Using the first strength theory, the equivalent stress was obtained by combining the bending stress and the torsional shear stress.On the basis of proving the calculation accuracy of the model, the multi-axis fatigue model was used to predict the fatigue life of the roll neck bearing section, and compared with the service life of the actual roll in the production line.The results show that the stress calculation model of the working roll neck bearing section of the four-high mill is in line with the actual stress state of the roll neck.The error between the expected service life predicted by the theoretical model and the actual service life is less than 20%, which meets the actual engineering error requirements.