Original Date: 08/26/1996
Revision Date: 01/18/2007
Best Practice : Cold Roll
Weirton Steel Corporation (WSC) suffered a major production setback in April 1994 when its #9 Tandem Mill caught fire and burned out of control for several hours. This mill, Weirton’s fastest and highest quality, light-gauge, cold reduction mill, was producing about 60% of the coils needed for the company’s tinplating operations. As an immediate result of the loss, the company had to refocus and shift its product mix to offset the tinplating sales losses. The fire was fueled by hydraulic fluid and byproducts that had coated the interior of the structure. Extensive damage included destruction of all electrical controls and automation systems; severe damage to the various mechanical systems; and major structural deformation. The company turned this disaster into an opportunity by rebuilding the mill from the ground up, using the latest in advanced steelmaking technology.
In less than six months, the revamped facility was brought back on-line and began producing in October 1994. This massive $87 million effort was accomplished through an experienced management team which had recently completed a $300 million modernization project to upgrade the hot rolling operations. The new #9 Tandem Mill is a five-stand, four-high, automatic continuous tandem mill, featuring upgraded GE controls, five x-ray gauges, fireproof hydraulics, and automatic thickness controls. The mill generally accepts input coils of 0.095-inch and reduces them down to an average of 0.0104-inch.
Modernizations of the mill include improved safety features and advanced controls to produce better-quality, closer- tolerance coils of light-gauge steel products. The new system uses fire-resistant water glycol for its hydraulic systems, replacing the old mineral-based hydraulic fluids. WSC claims to be the only company in the world to use 100% water glycol. In a related-safety improvement, the fog exhaust system was upgraded and now is regularly cleaned with water flushes. Other features include replacing the old Buss gauges for size control with new, automated x-ray gauges. The old gauges required two people per gauge to adjust or calibrate the gauge, and turnaround time was 45 to 60 minutes. In the new system, the process is automated and takes about 15 minutes. The rolling coolant system has been upgraded from an emulsion system to a dispersion system.
Average yields produced on this new Tandem Mill are running at 98.9%.
For more information see the
Point of Contact for this survey.