Couplings keep European steel mill rolling

Budapest – A large steel mill near Budapest has used nearly 350 individual couplings for the installation of a hot strip runout table to transport extremely hot metal around the plant.

The couplings were required to be able to withstand the high temperatures and contaminants that are present in metal working applications. Due to the number required, they also had to be easy to install and maintain in order to keep running costs down.

The Hungarian mill was undergoing a period of expansion to increase its productivity. Part of the expansion included a new 505ft hot-strip runout table for transporting the heated steel across the production plant.

The runout table was to be equipped with 337 six-foot wide, 12-inch diameter, stainless steel rollers, driven by 7.5kW motors at 900rpm. The new table would help the steel mill to increase its throughput from 1.8 million tonnes to 3 million tonnes each year.

Each roller needed to be fitted with a coupling that would continue to transfer the power from the motors efficiently despite the high temperatures, chemical contaminants and possibility of small degrees of misalignment.

The steel mill needed to be able to fit the couplings confident that they would require little maintenance or repair work. Having investigated its options, it was decided that DuraFlex coupling from TB Wood, part of Altra Industrial Motion’s industrial couplings division, would be the perfectly suited to the application.

David Proud, sales director for Altra Industrial Couplings, explains: “We were approached by the steel mill and asked if we could recommend a product that would function reliably at the heart of its production site. Steel mills are a notoriously harsh environment for any component.

“The runout table was to be responsible for transferring over 8,000 tons of steel everyday; a failure would create a bottle neck throughout the whole site which would slow production and prove very costly.”

DuraFlex couplings use a polyetherurethane material to transfer power to a driven shaft while accommodating misalignment and minimising vibration to prevent damage to the connected equipment.

The coupling is designed to reduce stress at the bonding point with the shoe which prevents failure at the bonding point. The unique material is resistant to water and other chemicals and suitable for operation in high temperatures.

The couplings are said to be quick to install due to the use of a simpler radial mounting, rather than axial mounting, design.

A ‘split-in-half’ element design allows for easy element installation and replacement without moving connected equipment or disturbing the shaft connection.