ZZ Slewing Bearing

Heavy-Duty Slew Ring for Offshore Crane – Engineered for Harsh Marine Conditions

Operating in offshore environments demands equipment that is not only powerful but also built to withstand extreme conditions. Therefore, a heavy-duty slew ring for offshore cranes must offer exceptional strength, corrosion resistance, and precise motion control — all of which ZZ delivers with our marine-grade slewing bearings.

Offshore cranes are subjected to intense loads, sudden dynamic movements, and long working hours. Consequently, the slewing bearing becomes one of the most critical components in ensuring safe and reliable lifting operations.

At ZZ, we manufacture slew rings for offshore cranes with advanced materials, specialized coatings, and high-precision assembly to guarantee performance in harsh environments.

Why Choose ZZ Slew Rings for Offshore Applications?

  • High load capacity, suitable for boom-type and knuckle boom offshore cranes
  • Corrosion-resistant coatings, such as zinc-nickel or marine epoxy options
  • Sealed and lubricated structure, preventing saltwater intrusion
  • Anti-fatigue raceway treatment, for long-term use under heavy duty cycles
  • Custom bolt patterns and gear modules, matched to your crane specs

Moreover, our bearings are designed to comply with relevant offshore standards (such as DNV, ABS, or API) where applicable. This ensures your project meets international safety and quality expectations.

Engineering & Support

We don’t just deliver a product — we deliver a solution. From the early design phase to final installation, ZZ provides:

  • Application-based bearing selection
  • 3D drawings and structural simulations
  • Coating and sealing recommendations based on your offshore location
  • Quick production and logistics support for urgent vessel or platform projects

Use Case Example

For instance, we recently delivered a 2100mm external gear slew ring to a Norwegian offshore crane manufacturer. Despite rough sea conditions and high tilting moments, the bearing performed flawlessly during extended load tests.

How to Get Started

To get a quote, send us your crane model or required specs (diameter, gear type, load direction). Additionally, we welcome engineering drawings or replacement part numbers for direct match production.

Frequently Asked Questions

Expert Insights and Reliable Solutions to Your Most Common Questions.

ZZ Slewing Bearing supplies a full range of slewing bearings to meet different industrial needs:

  • Single row four point contact slewing bearings Application: medium loads, precise rotation.
  • Double row ball bearings  Application: higher radial and axial loads.
  • Cross roller bearings –Application: high rigidity, suitable for robots and machining centers.
  • Three row roller bearings – Application: extreme loads in heavy equipment.
  • Ball combine roller bearings –Application:  precise rotational adjustment applications.
  • Customized bearings – tailored for specific equipment requirements.

Typical selection parameter for ZZ clients:

Load type: axial, radial, and tilting moment.

Rotation RPM: ensures long service life.

Installation space & mounting dimensions: inner/outer ring diameter, bolt circle.

Precision & rigidity requirements: critical for cranes, excavators, and robots.

ZZ engineers provide professional selection guidance according to your equipment and drawings.

ZZ Slewing Bearing selects materials for strength, wear resistance, and long-term durability:

Slewing ring: 42CrMo, 50Mn, C45N, 40CrNiMo, C48E.

Special forging spare parts: carburized/hardened steels for gear teeth (20CrMnTi, 18CrNiMo7‑6).

Corrosion resistant: SS 304, 316L, duplex stainless steel.

Surface treatments: heat treatment, quenching, carburizing, induction hardening, and surface coating(Four-Layer Packing, Strong Anti-Rust Oil, Black Oxide Treatment, Jet Black Paint Finish, Hot-Dip Galvanizing (CGL), Electro-Galvanizing (EGL), Hot-Dip Galvanizing + Paint Finish)

Correct installation with flat surfaces.

Proper lubrication using grease.

Avoid overloading or shock loads over capacity.

Monitor operating conditions regularly to prevent debris entry.

Typical factors observed by ZZ engineers:

  • Insufficient or incorrect lubrication.
  • (dust, metal particles) in raceways.
  • Rolling element or track damage.
  • Uneven mounting surfaces or misalignment.
  • Incorrect bolt torque(below grade 8.8) or preloading.

In-stock: 3–7 days.

Custom: 2–6 weeks depending on size, load, and precision.

Warranty: 1 year

Lifetime Free Spare Parts: Glue, seals, steel ball

Yes — ZZ Slewing Bearing offers:

Detailed installation manuals.

Online engineering support.

Guidance for lubrication, maintenance, and troubleshooting solution.

Full range of materials and heat treatments for various load conditions.

High precision and strict quality inspection standards.

Engineering support before and after delivery.

Customization to exact equipment requirements.

Proven performance in cranes, excavators, robotics, wind turbines, and heavy machinery etc.

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