Founded in 1971, China Steel Corporation (CSC) is Taiwan’s largest steel producer with an annual production of more than 10 million tons of crude steel. CSC produces a range of products that includes plates, bars, wire rods, hot and cold rolled coils, electrogalvanized coils, electrical steel coils, hot-dip galvanized coils, and Ti/Ni-base alloys. The company sees itself as a strong innovator with corporate values such as “teamwork, entrepreneurial approach, down-to-earthness and pursuit of innovation”.
The shutdown of the mill and installation of the new equipment was executed in a short time frame – to the full satisfaction of CSC – to keep the period of no production as short as possible. The equipment comprised not only the Reducing & Sizing Block but also a complete new cooling process including water cooling lines, electrics and automation, as well as the overall process. The start-up phase was also implemented during the short shutdown period. The level 1 and 2 systems for process control, first developed by KOCKS, exceeded all expectations. Temperature variations in the roughing and intermediate mill were kept at ≤ 10°C at block and coiler entry respectively, which resulted in products of reliably constant technological final properties.
KOCKS water boxes are distinguished by features such as:
The required level of cooling is attainable within tightest tolerances. Maintenance costs are minimized, and constant and reliable functionality maintained despite highly unfavorable working conditions.
Besides the innovative mechanical design of the water cooling line, the automation of this product is of particular interest.
In order to achieve optimal and locally adjusted cooling for the rolled product, cooling water amounts have to be controlled in a very precise way. Based on the measured ingoing bar temperature profile, amounts of cooling water are automatically adapted to each position of the rolled product. This is necessary to equalize possible local temperature differences. In addition, a closed-loop of control, which is based on the exit temperature measurement, enables the system not only to adapt to temperature differences, but also to keep the entire cooling level within the tightest tolerances. Both measures are key features to reach exactly the desired material properties of the rolled product. Furthermore, due to an accurate bar tracking, the automation system makes it possible to skip cooling for defined lengths of the bar heads. Thanks to this feature, possible problems with split bar heads can be prevented.
The ergonomic user interface on the pulpit allows the operator to easily oversee the whole process, and a sophisticated cooling program management system makes it straightforward to maintain an overview of even large ranges of rolled products. The automation system works hand in hand with the process simulation software KOCKS Microstructure Simulator (KMS). With it, cooling programs can be simulated in advance concerning microstructure evolution and temperature development, which enables fast and efficient development or improvement of new high quality rolled products. KMS and the cooling line automation system are directly connected in order to make the application of newly developed cooling programs as easy as possible.