The Complete Process of LTZC Supplying Slewing Bearings to Italian Clients

LTZC received an order from an Italian construction machinery enterprise, requiring the supply of 3 sets of slewing bearings with specific specifications for the turntable rotation mechanism of its 25-ton off-road cranes. Through technical docking, manufacturing, client inspection, packaging, and delivery, the order was successfully fulfilled and recognized by the client.

Details of the Supplied Slewing Bearings

The slewing bearings supplied this time are the independently developed 013.60.2800 external gear four-point contact ball slewing bearings by LTZC, with the following parameters and structure:

• Model Specifications: 013.60.2800, nominal outer diameter 2,800 mm, inner diameter 2,000 mm, width 150 mm.

• Structural Composition: Composed of an inner ring, outer ring, 48 sets of silicon carbide ceramc rolling elements, and a polyamide cage. The outer side of the outer ring is machined with an external gear ring with a module of 10, and the tooth surface is carburized and quenched to a hardness of HRC 58-62. The inner and outer rings are made of 42CrMo alloy steel, overall tempered to a hardness of HB 220-250. The raceway surface roughness is Ra 0.02 μm, designed in an arc shape to withstand axial force, radial force, and overturning moment simultaneously. The rated dynamic axial load is 1,200 kN, the rated radial load is 500 kN, and the rated static moment is 8,000 kN·m.

Inspection Process by Italian Clients

• Dimensional Accuracy Inspection: Using a German MAHR length measuring instrument to measure key dimensions such as the outer diameter of the outer ring, inner diameter of the inner ring, and width, with errors controlled within ±0.03 mm, meeting the client's requirement of ±0.05 mm. A laser interferometer was used to scan the raceway surface, with the maximum shape error within 10 mm length being 2.5 μm, less than the client-specified 3 μm.

• Mechanical Performance Test: On LTZC's dynamic load test bench, the bearing rotated continuously for 5,000 cycles under 120% rated load (axial force 1,440 kN, radial force 600 kN). The entire process showed a temperature rise of 38°C, vibration acceleration stabilized at 0.08g, and gear meshing impact coefficient of 0.8, all exceeding industry average levels.

• Anti-corrosion Performance Test: A sample of the outer ring of one bearing was randomly selected for a salt spray test. After 72 hours of continuous spraying, the surface showed no rust traces, meeting the client's requirement of 600 hours without rust for the Mediterranean climate.

Packaging and Delivery

• Inner Layer Protection: The bearings were vacuum-wrapped with 0.12 mm thick PE film, and the vacuum degree was controlled at -0.09 MPa to ensure isolation from air and moisture.

• Middle Layer Cushioning: Customized polyurethane foam padding was cut to the shape of the bearing. The padding was 50 mm thick and had a density of 40 kg/m³, capable of withstanding impacts from 30° tilting during transportation.

• Outer Layer Packaging: A 25 mm thick larch solid wood box was used, with dimensions of 3,000 mm × 3,000 mm × 200 mm. Each corner was equipped with 10 mm thick steel corner protectors. The box was labeled in Italian with warnings such as "This Side Up" and "Stacking Limit 1 Layer", and included product certificates, copies of inspection reports, and installation manuals (in Chinese, English, and Italian).

 The client representative signed the acceptance form at the shipping site and stated that LTZC would be given priority for cooperation in subsequent projects.

IF you are looking for slewing bearing, please contact LTZC.