Profitable pass schedule design concepts for reversible hot rolling

Purpose and goal

The focus in the ProfRoll project has been to reduce process losses, increase process predictability and improve product quality in reversible hot rolling processes. This is mainly about yield losses caused by typical defects that appear on strips and plates. The goal has been to develop guidelines for new pass schedules.

Expected results and effects

FEM simulations indicated and industrial trials verified that pass schedules may be changed by decreasing the draft in vertical rolling. This gives a slight decrease in edge cracks but, most importantly, the possibility to do a more flexible rolling. Chamfered edges in the head and tail end of the original plate decrease the length which has to be cut off from the final plate. The yield gain is up to 2.4 % in the tests that were done. FEM simulations according to experimental design have been used to develop a model that can predict the influence of the work roll bending on the plate crown.

Planned approach and implementation

Material data for selected steel grades have been produced by tests and used for material modelling. Reversible hot rolling has been simulated using thermo-mechanical finite element models. Verifying simulations have been made using a pilot plant rolling mill. FEM simulations of rolling have been made for specific problems in the industry.