Drive for Uptime

More then 19 years ago, Gerdau Ameristeel Whitby, one of the largest steel mini-mills in Canada, decided to switch to new speed reduces and gearmotors in order to keep its plant runing 24/7. The acility’s hearsh evnironment had been causingfrequent failures on the previous euipment.

The former Co-Steel Lasco plant, located in Whiby, Ont., produces a wide range of commodity-grade steel products sch as rebar, structural angles and channels, as well as round and flat bars.

The plant, which began operations in 1964, includes an electric arc furnace with a ladle arc refining unit, a five-strand continuous caster, an 18-stand bar mill with continuous cut-to-length finishing, and a 15-stand structural mill. Annual melting capacity is 1.0 million tons and rolling capacity is 1.2 million tons.

Until 1984, the Whitby mill had used double reduction worm gear drives on its continuous caster’s straightener drive. The intensity of this steel mill application — heavy shock, backlash and reversing action — caused the worm gear reducers to fail as often as every six to eight weeks.

As a result, they had to be disassembled, rebuilt and reinstalled. It was this continuous process of maintenance and downtime that led the mill to choose SM-Cyclo’s speed reducers and gearmotors.

“In one case,” says Casey Bakker, mechnical designer at Gerdeau Ameristeel, “the gears of one of the previous drives flew out of the casing when shock pounded the worm right through it.” Over time, the mill replaced failed drives with Cyclo reducers, which they determined could tolerate the mill’s harsh demands of rapid reversal, shock loads, water, dirt and heat.

Today, it has over 300 Cyclos in operation, and has also applied them to replace worm gears in its affiliate recycling operations.

Cyclo’s unique principle of operation is responsible for its long-life and exceptionally high torque densities. Unlike helical and worm gear drives, the Cyclo has a cycloidal disk input that provides high overload capability and reliability over long periods of operation. The cycloidal design, enhanced by all-steel reduction parts, produces the strength and reliability required in continuous steel operations. Double output sealing keeps lubricants in and dirt out — a major concern in the hostile mill environment.

Stelco’s Hilton Works in Hamilton, Ont., had similar problems with maintenance and downtime on its caster runout tables. The parallel shaft helical gears that were driving the runout tables were failing at a rate of approximately one drive every four to six weeks.

While the operation could continue with a few drives down, the failed units caused uneven wear and accelerated maintenance needs on the overall runout table operation. After replacing the helical gears with Cyclos, Stelco is now in its ninth year with no failures and has been impressed with the minimal maintenance required as well as the performance.

“For steel mills like Stelco that want to drive toward 18-month continuous casting campaigns, the Cyclo’s ‘no downtime’ reliability is essential,” said Fergus Reid of the Stelco Maintenance Group. “We simply keep an eye on lubricant levels, and that’s really all the maintenance that’s required.” MRO

Donald Brownrigg is president of SM-Cyclo Canada, Mississauga, Ont. For more information, visit www.smcyclo.com.