Structured Manufacturing Data (2026)

Slewing Ring

Based on aggregated insights from structured factory profiles within the CNFX directory, the standard Slewing Ring used in the Machinery and Equipment Manufacturing sector typically supports operational capacities ranging from standard industrial configurations to heavy-duty production requirements.

Technical Definition & Core Assembly

A canonical Slewing Ring is characterized by the integration of Inner Ring and Outer Ring. In industrial production environments, manufacturers listed on CNFX commonly emphasize Alloy Steel (e.g., 42CrMo, 50Mn) construction to support stable, high-cycle operation across diverse manufacturing scenarios.

A large-diameter bearing that enables rotational movement between the crane's upper structure (slewing platform) and the fixed base or undercarriage.

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Product Specifications

Technical details and manufacturing context for Slewing Ring

Definition
In a Luffing Jib Crane, the slewing ring is a critical load-bearing component that connects the crane's rotating superstructure (including the operator's cab, machinery house, and luffing jib) to the stationary base or undercarriage. It allows the entire upper assembly to rotate 360 degrees horizontally, enabling precise positioning of the load. The slewing ring must withstand significant axial, radial, and moment loads from the jib, counterweights, and lifted materials while maintaining smooth, controlled rotation.
Working Principle
The slewing ring operates as a large rolling-element bearing. It consists of an inner ring (typically attached to the fixed base), an outer ring (attached to the rotating superstructure), and rolling elements (balls or rollers) in raceways between the rings. When hydraulic or electric drive motors engage with a gear ring (internal or external) on the slewing ring, torque is applied, causing the outer ring and attached upper structure to rotate relative to the stationary inner ring and base. The rolling elements reduce friction and distribute the immense loads.
Common Materials
Alloy Steel (e.g., 42CrMo, 50Mn), Case-Hardened Steel
Technical Parameters
  • Bore diameter (inner diameter) and outside diameter, defining the ring's size and load capacity. (mm) Per Request
Components / BOM
  • Inner Ring Part
    The stationary ring typically bolted to the crane's fixed base or undercarriage. Contains one raceway for the rolling elements.
    Material: Alloy Steel
  • Outer Ring
    The rotating ring bolted to the crane's superstructure (slewing platform). Contains the opposing raceway and often includes the gear teeth for drive engagement.
    Material: Alloy Steel
  • Rolling Elements Part
    Balls or rollers that circulate in the raceways between the inner and outer rings, enabling smooth rotation while carrying loads.
    Material: High-Carbon Chrome Steel (e.g., GCr15)
  • Seals Part
    Rubber or polymer seals installed in grooves to retain lubricant (grease) within the bearing and exclude contaminants like dust and water.
    Material: Nitrile Rubber (NBR) or Polyurethane
  • Gear Ring Part
    Integral or attached gear teeth (internal or external) machined onto one of the rings, which meshes with the drive pinion from the crane's slewing motor to transmit rotational force.
    Material: Case-Hardened Steel

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Slewing Ring.

Slewing Bearing Turntable Bearing large diameter slewing ring bearing crane slewing platform bearing alloy steel slewing ring heavy machinery rotational bearing slewing ring with gear teeth

Applied To / Applications

This component is essential for the following industrial systems and equipment:

Luffing Jib Crane
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Crawler Crane
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All-Terrain Crane
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Lattice Boom Crane
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Offshore Crane
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Upper structure
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Superstructure
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House (Upper Structure)
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Azimuth Thruster
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Industrial Ecosystem & Supply Chain Structure

Complementary Systems
Downstream Applications
Specialized Tooling

Application Fit & Sizing Matrix

Operational Limits
pressure: Dynamic load capacity: 50 kN to 50,000 kN, Static load capacity: 100 kN to 100,000 kN
other spec: Rotational speed: 0.1 to 10 RPM (typical), Sealing: IP65/IP67 standard, Lubrication: Grease or oil bath
temperature: -40°C to +80°C (standard), -60°C to +120°C (specialized)
Media Compatibility
✓ Heavy machinery applications (cranes, excavators) ✓ Wind turbine yaw/pitch systems ✓ Military/defense turret systems
Unsuitable: High-speed continuous rotation applications (>100 RPM)
Sizing Data Required
  • Maximum axial load (kN)
  • Maximum radial load (kN)
  • Required rotational torque (Nm)

Reliability & Engineering Risk Analysis

Failure Mode & Root Cause
Fatigue spalling
Cause: Cyclic loading exceeding material endurance limit, often due to improper preload, misalignment, or shock loads during operation.
Corrosion and fretting wear
Cause: Moisture ingress, inadequate sealing, or micro-movements between raceways and rolling elements leading to surface degradation and pitting.
Maintenance Indicators
  • Audible grinding or clicking noises during rotation indicating damaged rolling elements or raceways
  • Excessive backlash or wobble in the ring rotation suggesting bearing clearance issues or structural deformation
Engineering Tips
  • Implement regular lubrication with manufacturer-specified grease, ensuring proper sealing integrity to prevent contamination and moisture ingress
  • Establish periodic alignment checks and preload verification using torque monitoring to maintain optimal contact patterns and load distribution

Compliance & Manufacturing Standards

Reference Standards
ISO 1132-1:2000 - Rolling bearings - Tolerances - Part 1: Terms and definitions DIN 628-1:2017 - Rolling bearings - Part 1: Tolerances CE Marking - Machinery Directive 2006/42/EC for safety and performance
Manufacturing Precision
  • Bore diameter tolerance: +/-0.02mm (IT6 grade)
  • Raceway runout tolerance: 0.05mm maximum
Quality Inspection
  • Hardness testing (Rockwell C scale) of raceways and rolling elements
  • Ultrasonic testing for internal defects in critical components

Factories Producing Slewing Ring

Manufacturer profiles with relevant production capability in China

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Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

Technical documentation
4/5
Manufacturing capability
4/5
Inspection readiness
5/5
Supplier transparency
3/5

These scores are example evaluation dimensions, not real customer ratings, country-specific buyer feedback, or live inquiry activity.

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Frequently Asked Questions

What materials are used in manufacturing slewing rings?

Slewing rings are typically manufactured from high-strength alloy steels such as 42CrMo or 50Mn, often case-hardened for enhanced durability and load-bearing capacity in demanding industrial applications.

What are the main components of a slewing ring assembly?

A complete slewing ring assembly consists of an inner ring, outer ring, rolling elements (balls or rollers), seals to protect against contaminants, and an integrated gear ring for rotational drive mechanisms.

How do slewing rings enable crane movement?

Slewing rings provide the rotational interface between a crane's upper structure (slewing platform) and its fixed base, allowing 360-degree rotation while supporting heavy loads and transmitting torque through the gear ring.

Can I contact factories directly on CNFX?

CNFX is an open directory, not a transaction platform. Each factory profile provides direct contact information and production details to help you initiate direct inquiries with Chinese suppliers.

Data basis: CNFX manufacturer profiles, technical classification, publicly available product information, and ongoing plausibility checks for Machinery and Equipment Manufacturing.

Data Basis

CNFX manufacturer profiles, technical classification, publicly available product information, and ongoing plausibility checks.

Preliminary Technical Classification
This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

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