A single-stand, 4-high temper (skinpass) mill is used to develop the appropriate properties for a variety of products, including carbon steels, and high-strength low-alloy material. The mill provides reductions/elongations between 0.2 and 2.0%, and can process strip 36–72 inches wide in coil weights up to 88,000 pounds. The temper mill has an annual rated capacity of 600,000 tons with a production rate of 101 tons/hour.
Line equipment includes an entry payoff reel with a 4-segment mandrel that shifts for strip centering correction; the single mill stand; an electrostatic oiler, and an exit tension reel with another 4-segment mandrel. The entire unit has an overall length of 34 feet from the payoff reel centerline to the centerline of the exit downcoiler. Coil handling capabilities include walking beam entry and exit conveyors with coil cars, and cradle rollers for coil unbending at the entry end.
The mill which operates with a 2.9 million pound work force is equipped with two sets of forged steel work rolls, cast steel backup rolls, and tapered roller bearings on both work and backup rolls. Work rolls changes are dependent on the product lineup. Backup rolls currently change every month. Roll screwdown is achieved with two hydraulic gap control cylinders located between the bottom housing yoke and the bottom backup chock.
The mill is powered by a 1,285-hp motor that provides a roll rotational speed of 391 rpm; maximum strip exit speed is 2,300 fpm. The mill is equipped with work roll bending (positive force up to 146,000 pound and negative force up to 101,000 pounds), and has a thickness gauge to provide cross-profile measurement.
Mill operation is supported by a stand-alone test station at the delivery end of the mill, equipped with hardness and surface roughness testers. A 12,000 sq. ft. storage area is located at the entry and delivery end of the mill.
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