Slewing rings bearings and their importance to metalmaking

The life of slewing ring bearings is a challenging one. They must sit for long periods of time, waiting for their chance to spring into action. When that time comes, the bearings must pivot on an axis and rotate a heavy load very slowly, 90 or 180 degrees. Once they have completed this task, they wait a long while, 30 or 45 minutes typically, before being called upon once again. Slewing ring bearings do a lot of sitting around, yet they must respond every time, and they must do it reliably for years on end. So they have to be well-made.

Slewing ring bearings are large-diameter bearings designed to handle heavy axial, radial, and moment loads while enabling smooth and controlled rotation. They are an integral component in various industries and machinery, facilitating rotational movement in heavy-duty applications, such as electric arc furnaces and ladle turrets.

Timing is everything in metalmaking, and if the parts do not run in order with precision, messes get made. They are big, hot, expensive messes, so the parts need to be reliable. In an electric arc furnace, temperatures can reach 2,500 degrees Fahrenheit and slewing ring bearings are counted upon to rotate thousands of tons of molten steel.

NSK slewing ring bearings are optimized for the application, maintaining stability and precision under high temperatures, heavy loads, and low speeds. Lubrication features facilitate grease replenishment to reduce friction and wear, while seal and shield options promote long-life reliability. This is essential in steelmaking applications, where any unscheduled downtime can cost thousands of dollars an hour in lost work.

Design features

• High-capacity, triple-row roller bearing design (typical)
• With segmented steel cage (additional options available)
• With internal, external, or no integrated gearing
• Various standard or custom seal/shield options
• Lubrication features to customer specification
• Outer diameter range of 1 to 6 meters
• Ball bearing and combined ball/roller bearing slewing rings are also available

Proper maintenance is key

While inventory management to avoid untimely shortage of such important bearings is standard practice, proper handling goes well beyond simply keeping them in stock. Improperly stored slewing ring bearings can be impacted with corrosion damage, challenging their suitability for operation and presenting the prospect of extended downtime for costly bearing reconditioning.

Proper maintenance of bearings is essential to ensure long life and reliability. This includes disassembly and tank storage of all components, ongoing condition monitoring with visual inspection and oil sampling, assembly and installation, and anticipation of end of life and timely replacement.

Proper maintenance of bearings can save mills hundreds of thousands of dollars from reduced downtime. It can also improve productivity and efficiency and reduce the number of times the bearings need maintenance over their life span.

Overall, slewing ring bearings are critical components in heavy-duty applications, and their proper design, installation, and maintenance are essential to ensure reliable operation and extended service life.