January 2008
Vol. 5, No. 1
Process Control and Automation

About the Cover

Several approaches for upgrading legacy level 2 computer systems are explored, including conversion tools, emulation software and complete rewrites. Project design, implementation, testing and commissioning are covered with cost/benefit comparisons and real-world project experience.

The injection-enhanced insulated gate bipolar transistor (IEGT) inverter is suitable for rolling mill main drives and other high-performance applications. This paper introduces the features of the IEGT inverter and recent applications in hot strip mills.

Previous tools to measure oil film thickness have been limited to off-line analysis in a laboratory or to handheld devices, causing oiling problems to be detected too late. A new system for measuring the oil layer on steel strips during production is presented.

Coil surface inspection systems are used to report or store defect information that can be utilized for real-time or off-line evaluation and decision-making. At ArcelorMittal Dofasco, they have also been used to successfully correlate continuous casting parameters to resulting defects on downstream coils.

By using an infrared radiation emitter, a radiative heat flux was applied to a copper mold covered with a solid slag disk to simulate the radiation component of the heat transfer phenomena that can be encountered during continuous casting. The solid slag disk was initially glass, and by application of high levels of incident radiation the glass disk would dynamically crystallize “in situ” during the experiment. This novel experiment allowed the progress of mold flux crystallization and its effect on radiation heat transfer rates to then be measured. In addition, it was also possible to melt the top surface of the sample and allow measurements to be made where there was a glass layer next to the mold wall, a crystallized layer and a liquid layer. In this manner, conditions similar to that found in a continuous caster can be simulated.