The Value of the Right Slewing Bearings in Metalworking

The life of slewing 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. Slew 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.

Also known as slewing rings or turntable bearings, they are an integral component in various industries and machinery, facilitating rotational movement in heavy-duty applications. Their design and functionality allow for the smooth and controlled movement of loads, making them essential in electric arc furnaces and ladle turrets.

Slewing bearings, at their core, are large-diameter bearings designed to handle heavy axial, radial, and moment loads while enabling smooth and controlled rotation. Their primary function is to support and facilitate the movement of heavy machinery or equipment, reducing friction and distributing the loads evenly.

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 bearings are counted upon to rotate thousands of tons of molten steel. NSK slewing bearings come optimized for the application, maintaining stability and precision under high temperatures, heavy loads, and low speeds. Lubrication features – designed to accommodate customers’ systems – facilitate grease replenishment to reduce friction and wear with a clean supply of lubricant. Seal and shield options promote long-life reliability, an essential prerequisite in these applications. That is of vital importance because any unscheduled downtime can cost a lot of money in lost work.

Design features

Slew bearings typically have a triple-row roller bearing design with a segmented steel cage. They can be configured with internal, external, or no integrated gearing, and a variety of standard or custom seal/shield options are available. Lubrication features are designed to customer specification, and outer diameters range from 1 to 6 meters. Ball bearing and combined ball/roller bearing slewing rings are also available.

Maintaining slewing bearings

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 rings can be impacted with corrosion damage, challenging their suitability for operation and presenting the prospect of extended downtime for costly bearing reconditioning. Proper storage and maintenance includes:

• Disassembly and tank storage of all components
• Ongoing condition monitoring with visual inspection and oil sampling
• Assembly and installation
• Anticipation of end of life and timely replacement

Proper maintenance can save mills hundreds of thousands of dollars from reduced downtime. For instance, the bolts of caster turret bearings can sometimes become elongated. In cases like this, a specialist can re-torque the bolts and inspect wear on the bearings. The proper care of slew bearings can improve productivity and efficiency, while the right design can reduce the number of times the bearings need maintenance over their life span. That adds up to a lot of cost savings considering that the bearings can last for five to 10 years in an electric arc furnace and for 20 to 30 years in caster turrets.

Steel mills and ironworks have a lot invested in making sure operations run smoothly. The last thing they need is a faulty bearing jamming up the works and halting production. The right bearings, paired with right maintenance specialists, can make all the difference.

For instance, the bolts of caster turret bearings can sometimes become elongated. In cases like this, a specialist can re-torque the bolts and inspect wear on the bearings. The right design can reduce the number of times the bearings need maintenance over their life span. That adds up to a lot of cost savings considering that the bearings can last for five to 10 years in an electric arc furnace and for 20 to 30 years in caster turrets.

Steel mills and ironworks have a lot invested in making sure operations run smoothly. The last thing they need is a faulty bearing jamming up the works and halting production. The right bearings, paired with right maintenance specialists, can make all the difference.