The harsh environmental conditions in steel mills place extreme requirements on components. The Quick Flex elastomeric couplings transmit torque to drive the roller tables in a hot rolling mill. The thermally stable couplings are low-wear, low-maintenance, and help minimise downtime.
In the steelmaking process, molten pig iron produced in the blast furnace is transformed into crude steel in converters. The crude steel is then cast into long strips called slabs in continuous casting lines. The slabs, up to 10m long and weighing as much as 25 tons, are rolled and shaped to form strip steel or steel wire rolls. Glowing from heat, these slabs are transported on roller tables. To avoid high heat damage to the conveying rollers, the slabs must move continuously on the rollers until they cool down or are ready to enter the next processing step.
Surrounding equipment component reliability is crucial: “If a roller table coupling fails, it may be possible to continue working until the next planned stoppage, but this risks damaging the roller,” says Detlef Peick, Business Development Manager for the couplings division at R+L Hydraulics in Werdohl. “This leads to longer downtimes for subsequent repairs, and high roller replacement costs. Stopping the roller table avoids damage to the roller, but creates a production bottleneck for the downstream line operations.”
Typically in the past, this application has used gear couplings that are good at handling shaft displacements that occur due to the regular temperature fluctuations. Simultaneously, gear couplings safely transmit high turning moments. “However, gear couplings have disadvantages,” says Detlef Peick. “They need frequent lubrication and must be opened regularly for inspection at high cost and inconvenience. When the coupling hubs or sleeve bodies need replacement, the gearbox must be removed from the drive shaft and possibly even the electric motor must be removed from its base first. After replacement, the gear mechanism and the electric motor must be realigned to ensure proper functioning. These activities take a lot of time – time which in steelmaking is very expensive.”
