Halting fracture of cast steel sleeves

This article describes how, to prevent the failure of steel sleeves, which are used to take up coiled aluminum as it emerges from a rolling mill, mandrel pressures were cut in half, the mandrel segments were machined to circular shape, and the sleeves from batches with suspect ductility were removed from service. When aluminum is rolled, steel sleeves are used to take up the coiled metal as it emerges from the rolling mill. The largest coil wound onto the sleeve is 86 inches (2.18 m) in diameter, weighs about 40,000 pounds (18 Mg), and rotates at 300 rpm. The sleeves are supported and driven by hydraulically expandable mandrels that are inserted in the sleeve ends. Because of the size and energy of the sleeve and coil, failure of a sleeve during the rolling process represents a significant danger. To date, two sleeve fractures have occurred at the ALCAN Rolled Products Co. plant in Terre Haute, Ind. The first involved a sleeve from the initial batch produced by the supplier. Since these were processed differently than subsequent batches, this failure was considered a special case. The second fracture prompted a deeper investigation.