Gear drives are one of the most critical mechanical systems in the overall operation of, a steel hot strip rolling mill,
Typically, these systems use large through hardened gears, often of cast construction, meshing with solid on shaft
pinions of only slightly greaterhardness. While these gears performed adequately when the typical forty or fty year old
mill was placed in service, increasing loads and throughput have resulted in high maintenance activity and unexpected
failures. Since gear manufacturing is a relatively long lead time operation, and spare gear sets are not generally
available, improving the performance of a gear system is key to improving the overall performance of the mill itself.
This paper describes the initiation and progress of a program which addresses very large gears (approaching 200 inches
in diameter) and a number of pinion configurations ranging from long, integral, solid on shaft designs to multiple shell
pinion designs, most of which are carburized and hard finished, all of which meet or exceed AGMA Quality Class 10.
The general design procedures and overall implementation of the design and manufacturing program as well as a
description of the results in terms of improved mill gear system experience are also presented.