| "AUTOMATION
OF THE NATIONAL STEEL COLD MILL" Modern tandem cold rolling mills can achieve throughputs of up to 2
million tonnes per year and their efficient and reliable operation is critical to the
profitability of the production process. While many automation upgrades are motivated
primarily by the increasing unreliability of ageing automation equipment and access to
spares, such upgrades provide an opportunity to take advantage of recent technical
developments in automation and the improvements which can be realised through these. The
National Steel Corporation (NSC), Iligan 5-stand mill is a 1976 Blaw Knox mill with
hydraulic rollgap actuators on stand one and electric screwdowns on the remaining stands.
The mill has 23MW of rated drive power and a maximum speed of 1980 m/min. Products rolled
range in width from 600 to 1245mm and in exit thickness from 0.18 to 1.6mm. End uses of
the steel include tinplate, galvanized roofing, canning line feed, drumstock, fabrications
and electrical appliances. The mill was previously commissioned in 1985. The major
objective of the recent upgrade was to reduce production delays caused by failures due to
the ageing Honeywell 4400 and GE Directomatic II computer equipment.
The new system was supplied by Industrial
Automation Services of Australia with installation and commissioning support from NSC
engineering staff. The system includes dynamic controls, performance reporting and an
extensive graphical operator interface. Of particular interest are the novel adaptive
setup algorithms which generate speed dependent actuator references and control system
gains. These compensate for speed effects, thus reducing disturbances to the dynamic
controls. This in turn decreases strip breaks and other threading problems and
off-specification head and tail end lengths. mailto:hatchias_info@hatch.ca
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