CAT 522-8217 BUSH-SEM

CAT 522-8217 is a Caterpillar genuine SEM series straight tube heavy-duty bushing (without flange), adapted for the pin supports of tracked construction machinery chassis, booms, and connecting rods, used to withstand radial heavy loads and reciprocating oscillating loads. The following is pure original data and does not include replacement parts information.

Core Technical Parameters (Raw Data)

Item Details
Basic Attributes
Model 522-8217 (SEM Series), Type: Straight Cylindrical Heavy-Duty Bushing (Flangeless), Material: Alloy Structural Steel (Temperature + Surface Hardening), Single Weight: 0.85 kg, Operating Temperature: -40℃ to +120℃, Rated Radial Load: ≤150 kN, Lubrication Method: Grease Lubrication (Requires Oil Nozzle), Fitting Tolerance: H8, Corrosion Resistance: ≥96 Hour Salt Spray, Suitable Pin Diameter: 50 mm, Non-Elastic Structure, Surface Treatment: Oxidation Blackening + Oil Immersion for Rust Prevention

Key Dimensions (Metric / Imperial)
Inner Diameter: 50 mm (1.969 in), Outer Diameter: 60 mm (2.362 in), Total Length: 90 mm (3.543 in), Wall Thickness: 5 mm, Chamfer: C2 mm, Flatness: ≤0.03 mm, Surface Roughness: Ra≤1.6 μm, Hole Diameter Tolerance: +0.03/-0.00 mm, outer diameter tolerance + 0.05/-0.02 mm, length tolerance + 0.15/-0.10 mm

Performance Parameters: Surface hardness HRC 54-58, core hardness HB 220-250, compressive strength ≥850 MPa, coefficient of friction ≤0.12 (lubricated state), coefficient of thermal expansion 11.5×10^-6/℃, suitable fastening torque 90-110 N・m, reusable ≤2 times, no axial positioning function

Structure and Adaptability Characteristics: Heavy-duty radial support: 5 mm thick wall + quenching and tempering treatment, suitable for high-frequency heavy-duty swinging parts such as track frames and booms, distributing pin load and preventing shaft hole wear and increased clearance.

Lubrication Adaptability Design: Lubrication grooves are reserved on the inner wall, suitable for radial grease injection, ensuring long-term lubrication, suitable for continuous operation in dusty outdoor conditions.

Precise Fit: Strict dimensional and tolerance control ensures a tight fit with the pins and seat holes after installation, reducing vibration and noise and improving the operational stability of the connection points.

Compatible Models and Application Scenarios

Crawler Bulldozers: Compatible with D6N and D7E series balance beam pins and track frame connecting rod pin supports.

Wheel Loaders: Compatible with 966K and 972K boom and stick connecting pins and rocker arm support.

Excavators: Compatible with 320GC and 330GC stick and boom connecting pins for radial support of heavy-duty swinging structures, distributing loads, reducing wear, and suitable for long-term high-intensity working conditions.

Installation and Maintenance Points (Original Data)

Installation: Clean the bearings, pins, and seat holes, ensuring they are free of oil stains and metal shavings. Inspect the bushing surface for cracks, deformation, or rust; replace if necessary.

Cold-press installation (pressing force ≤ 60 kN), do not hammer or strike. The bushing and seat hole should have an interference fit (interference 0.020-0.035 mm), ensuring proper installation without misalignment.

After installation, check axial movement ≤ 0.1 mm. Add NLGI 2 lithium-based grease and run for 20 minutes, monitoring temperature ≤ 70℃.

Maintenance: Replenish grease every 1000 hours. Check bushing clearance every 2000 hours. Replace immediately if clearance exceeds 0.2 mm.

Inspect simultaneously with the pin to avoid reducing fit accuracy and causing abnormal clearance due to separate replacement.