Iron and Steel Technology December 2005 Table of Contents

December 2005

A Statistically Based Approach to Developing a Condition Monitoring Program
Ove Aspoy, reliability technician, USS-POSCO Industries, Pittsburg, Calif. (oaspoy@ussposco.com)

This project won the AIST Maintenance Processes Operating Committee’s Gold Reliability Achievement Award, which recognizes iron and steel producing companies for reliability improvements and achievements.

A condition monitoring program at USS-POSCO significantly reduced maintenance costs, collected fewer data points and utilized fewer resources compared to previous programs.

Diagnosing Cold Mill Chatter Through Mill Stand Hydraulic Monitoring and Roll Shop Grinder Testing
Derek Vines, reliability engineer, USS-POSCO Industries, Pittsburg, Calif. (dvines@ussposco.com)

This project won the AIST Maintenance Processes Operating Committee’s Silver Reliability Achievement Award, which recognizes iron and steel producing companies for reliability improvements and achievements.

USS-POSCO’s tandem cold mill had begun to experience an increased number of roll changes due to mill chatter. Through several innovative means, root causes were identified and chatter was reduced by 50 percent.

Types of Failures of Backup Roll Assemblies
Richard C. Schrama, senior specialist — equipment reliability services, Manufacturing Services Business Unit, Dofasco Inc., Hamilton, Ont., Canada (rick_schrama@dofasco.ca)

Oil film bearing backup roll assemblies used in steel rolling mills can develop many types of failures. This article deals with those failures and how to prevent them. Troubleshooting and maintenance of the oil film bearing employed in the assemblies are also discussed.

Sustaining Maintenance Improvement Initiatives
Mike McGee, senior director, Fluor Corp., Greenville, S.C. (mike.mcgee@fluor.com)

When the market relaxes or new management takes over, many companies allow maintenance practices to go by the wayside. Solutions are presented to ensure long-term success with a maintenance improvement initiative.

Relubrication-free Continuous Caster Guide Rolls
Warren E. Doerner, metals industry specialist, SKF-USA Service Division, Schwenksville, Pa. (warren.e.doerner@skf.com), and John Melanson, manager — application engineering, SKF Canada Ltd., Scarborough, Ont., Canada (john.melanson@skf.com)
Previous trials with the relubrication-free method of lubricating the bearings of slab caster rolls have sometimes been unsuccessful. However, improved caster control, increased emphasis on predictive maintenance, design changes and greater expertise have made this option more attractive. Examples of successful installations are provided.

Development and Advantages of a “Smart” Turret Bearing Technology
William S. Stan (left), president, PRES Inc., Westlake, Ohio (info@pres-inc.com); Jeff Blankenship, NSK Corp., Chapin, S.C. (blankej@nsk-corp.com); and Walter J. Kusnier (right), project manager — heavy industry, NSK Corp., Ann Arbor, Mich. (kusniew@nsk-corp.com)

Turret bearings, though designed for long life, can be impacted by a number of catastrophic events common to mill operation. Utilizing state-of-the-art sensor technology, the integrity of the turret bearing can be ensured, leading to increased reliability and more readily available operating information.

Plate Mill Backup Roll Bearings — Techniques to Maximize Life and Reduce Outage Time
Robert Appleby (left), maintenance and roll shop supervisor, Oregon Steel Mills, Portland, Ore. (applebr@osm.com), and Ted Vasiliw (right), senior application engineer, Castrol Industrial North America Inc., Industrial Lubricants & Services, Naperville, Ill. (ted.vasiliw@castrol.com)

The service life of the backup roll bearings on Oregon Steel Mills’ 4-high reversing plate mill was extended far beyond the initial expectations. The multiple changes employed to achieve these results, as well as the benefits realized, are discussed.

Running Steel “Lean”
Jack Harrison, senior partner, The Hands-On Group, Gotha, Fla. (jbharrison@handsongroup.com)

The philosophy of lean manufacturing is contrary to traditional steelmaking operating practices. Results prove, however, that the concept works. The application of lean manufacturing techniques to steelmaking is presented, with case studies revealing successful implementation.

Recycling of LD Slag and Sludge Through Sintermaking
U.S. Yadav, V.M. Koranne and B.K. Das, Tata Steel, Jamshedpur, India

Steel plant wastes contain iron, flux and fuel values. Dumping of wastes costs money, indicates improper utilization of natural resources and causes deterioration of the environment. Among various wastes, LD slag and LD sludge figure predominantly for their bulk, mineral value and cost-saving potential on recycling. The high lime and iron contents of these materials make them ideal replacements for limestone and iron ore. Experiments at a pot grate sinter unit have shown an improvement in plant productivity due to absence of loss on ignition (LOI) in these materials. The tumbler and reduction degradation strength of sinter deteriorate due to difficulties in the melt formation. This paper outlines the influences of LD slag and sludge on the sintering process and the quality of sinter produced.