Simulering av valsverk för att identifiera och förbättra lastfördelning

This master thesis was done at Swerim AB in cooperation with SSAB and the Technical University of Luleå in the purpose of preventing spalling problems in hot rolling mills. Spallings are a fatigue damage that occurs on the rolls due to extreme loads and unfavorable conditions between the rolls in a mill. This report describes how the roughing mill, which is the first of a series of hot rolling mills is modelled and simulated in order to compute and improve the load distribution between the rolls. The load distribution tells a lot where the spalling problems occurs. By computer aided design and simulations with the finite element method a parametric computational model was created and used to simulate the load distribution between the work roll and backup roll with worn andfresh rolls. These simulations showed what the load distribution looks like when using new rolls and that the load distribution is especially bad when the work roll is worn. The computational model was used to simulate how the load distribution changes with different geometries on the backup roll to provide valuable input and suggest new designs on the backup roll currently used by SSAB Borlänge