A Downcoiler Simulator for High Performance Coiling in Hot Strip Mill Lines

The objective of this study is to develop a coiling process simulator that can be used to test suggested coiling control algorithms, and thereby improve overall coiling performance. To accomplish this, a thorough study, of the pinching and coiling mechanism of the downcoiler has been carried out, and then used to derive an appropriate mathematical model. An additional torque compensation algorithm is proposed to improve the shape of the strip to be coiled The simulation environment permits the coiling process to be estimated offline, using the actual system parameters necessary for successful coiling These parameters include strip tension, pinch roll force, and driving motor power for pinching and coiling. For effective coiling control, the additional compensated torque algorithm can be used to reduce the irregular shape of the loose coil that sometimes arises from insufficient coiling torque. In order to evaluate the performance and practicality of both the developed software and the proposed coiling control algorithm, experiments were conducted using the downcoiler in the No. 2 Hot Strip Mill at Pohang Works, where coiling operations are normally carried out at high strip tension compared to other downcoilers. The simulations and experimental results show that the set-up value for the unit tension can actually be lowered, which could lead to significant improvement in coiling strip quality, as well as reduced power consumption. In addition, a test coiling operation with the additional torque compensation algorithm resulted in even more effective coiling and a reduction in bad telescope quality of the coiled strip.