How to Select Ball Bearing Turntable / Slewing Bearing for Trailers

In the trailer slewing bearing market, two primary options are available: “slewing bearings” made of 50Mn material with hardened raceways (e.g., KDL900-3， KDL900-4 series, available with or without holes, featuring black phosphating surface treatment), and “turntables” made of Q355B material with unhardened raceways. Each has distinct advantages and disadvantages, suited for different scenarios.

50Mn Slewing Bearings (Quenched Raceway)

Their core advantage lies in exceptional wear resistance and fatigue strength. 50Mn steel undergoes quenching and tempering to achieve excellent comprehensive mechanical properties. The core raceway surface quenching process significantly enhances contact hardness and wear resistance, enabling them to handle heavy loads, frequent rotation, and harsh operating conditions with ease. Although its more complex material and heat treatment processes result in higher costs, the extended service life and enhanced reliability it delivers make it the optimal choice for heavy-duty, high-frequency use, or applications with extremely high safety requirements.

Q355B Turntable (Non-Hardened Raceway)

Its primary advantage lies in cost-effectiveness. As a high-strength low-alloy structural steel, Q355B offers decent strength. However, its raceways undergo no quenching treatment, resulting in significantly lower surface hardness and wear resistance compared to the former. This inherent limitation in load-bearing capacity, wear resistance, and fatigue performance makes it prone to indentation, wear, increased clearance, or even failure under prolonged heavy-duty use. Therefore, it is more suitable for light to medium loads, infrequent use, and cost-sensitive applications.

For customers prioritizing long-term reliability and optimal value, selecting slewing bearings made of 50Mn with hardened raceways represents a wiser and more economical long-term investment. Although the initial cost is slightly higher, it significantly reduces failure risks and maintenance expenses.