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Do the teeth of single-row or double-row slewing bearings used in truck-mounted aerial work platforms require Hardening treatment?

In our collaborations with aerial work platform manufacturers, we frequently encounter differing requirements regarding whether slewing bearing tooth need medium-frequency quenching. Some customers insist on quenching, while others believe no treatment is necessary, as the equipment functions normally in the short term. This inevitably raises the question: how should one make the right choice?

I. When is tooth hardening treatment required?

Medium-frequency hardening of the teeth is essential when aerial work platforms operate under any of the following conditions:

High-intensity, high-frequency operation: Such as large double-row ball slew bearings supporting heavy-tonnage vehicles, or equipment in rental fleets requiring frequent lifting and rotation. Hardening significantly enhances tooth surface wear resistance and extends service life.

Impact loads: Teeth endure shocks during operations in strong winds or on unstable chassis supports. The hardened layer provides high surface hardness and core toughness, effectively preventing tooth breakage.

Pursuit of exceptional reliability: For brands emphasizing high safety and longevity, hardened teeth are crucial for ensuring long-term stable operation of core components, significantly reducing failure rates.

II. When is quenching unnecessary?

For small-to-medium tonnage vehicles with low usage frequency and extremely mild operating conditions (typically employing single-row ball bearings), unquenched teeth can meet basic requirements. Their advantages include lower initial costs and superior root toughness in the unhardened state.

Our advise:

Considering safety and total lifecycle cost, we recommend medium-frequency hardening of the teeth for slewing bearings in aerial work platforms.

For single-row ball slew bearings, hardening serves as “insurance” against unexpected impacts; for double-row ball slew rings, it is the “standard configuration” for load-bearing capacity. This is not an unnecessary feature but a highly valuable investment. By incurring a modest cost increase, it fundamentally mitigates the two core risks of “wear” and “tooth breakage,” directly enhancing the product's safety margin and market competitiveness. When making a selection, decisions should be based on the vehicle's design positioning, operational intensity, and safety standards for long-term planning, rather than relying solely on short-term luck of avoiding failures.