The scope of the Shape Rolling Study

The scope of this study was to identify the extent to which Finite Element Analysis is able to assist in the roll pass design of large European Standard Beams.

The study was carried out using Transvalor Forge, with the assumption that a rigid die would be used in production. The actual IPE profile studied is produced in seven roll passes. The first three passes were omitted from this study, since they introduce only small deformations in the initial shape. Two approaches were taken for the FEA of passes 4 to 7. First, they were simulated individually and later they were simulated in a more complex setup that included all four passes in a single simulation.

Individual Simulations for each Shape Rolling Pass

Starting from the standard hot forging template, the die designs were exported from the company’s 3D CAD system to the .step file format in Forge. All relevant boundary conditions such as the correct start position of the rolling guides; the correct temperature, friction and thermal exchange coefficients were then added to the template. Since the velocity and deformation within the rolls is uniform, the starting billet was reduced from 1200mm to 400mm in length in order to shorten the calculation time and processors needed to run the computation. The billet:

• was meshed using the standard Forge 3D tetrahedral mesher, resulting in a mesh of 10,000 elements. A dynamic re-meshing scheme sensitive to curvature and strain was set up to take place during the calculation
• material was set to Fe360 using the Hansel-Spittel polynomial law able to model the steel deformation in the temperature range between 844 and 1250°C. A strain rate between 0.01 and 500 1/s was also accounted for
• initial temperature was set to 1050°C
• actual production kinematics were used setting a roll velocity of  22.8rpm

Shape Rolling Complete Mill Simulation

Starting from the same hot forging template a more complex scenario was set up in which the actual billet length of 12000mm was used and where all the same 4 roll passes which had been simulated individually were simulated sequentially with each roll pass inheriting its starting part from the previous roll pass.
Re-meshing needed to be carried out and this resulted in 25000 elements and the computations which took about 8 hours to complete, were carried out on a 16 core processor cluster.
The findings of this study confirmed that FEA can prove to be very useful in the design phase of the shape rolling of beams.

The Shape Rolling Simulation Results

The comparison of the simulation results with the actual shape rolling production process showed agreement in the shape prediction, velocity of the bar, rolls wear and total loads, implying that similar simulations of other types of beams including the American Standard Beams would yield equally useful results.

Shape profile after the 5th roll pass including the bar temperature and total load on the rolls (top); the 6th roll pass (vertical) setup and the 7th (vertical) (bottom)