CAT 538-6777 SLEEVE-SEM

CAT 538-6777 SEM is a Caterpillar SEM series steel positioning sleeve, suitable for pin positioning, bushing support, and other parts of excavators, loaders, and other construction machinery. It is used for fixing, guiding, and bearing radial loads. The following is raw data and does not include replacement parts information.

Core Technical Parameters (Raw Data)

Item Details
Basic Attributes Model 538-6777 SEM, Type: Steel Positioning Sleeve, Material: 42CrMo Alloy Steel, Single Weight: 1.26 kg, Working Temperature: -40℃ to +150℃, Applicable Radial Load: ≤180 kN, Applicable Shaft Diameter: 75 mm, Fit Tolerance: h6, Corrosion Resistance: ≥144 hours Salt Spray, Surface Treatment: Blackening + Oxidation, Hardness: HRC 38-42, Tensile Strength: ≥1080 MPa, Yield Strength: ≥930 MPa, Fitting Clearance: 0.010-0.025 mm

Key Dimensions (Metric/Imperial): Inner Diameter: 75 mm (2.953 in), Outer Diameter: 95 mm (3.740 in), Total Length: 60 mm (2.362 in), Wall Thickness: 10 mm, Chamfer: C1.5 mm, Flatness: ≤0.02 mm, Surface Roughness: Ra≤0.8 μm, Inner diameter tolerance +0.005/-0.00 mm, Outer diameter tolerance +0.010/-0.01 mm, Length tolerance +0.10/-0.05 mm, Roundness≤0.015 mm

Performance Parameters: Impact toughness ≥60 J/cm², Elastic modulus 206 GPa, Poisson’s ratio 0.27, Coefficient of thermal expansion 12.5×10^-6/℃, Compressive strength ≥1800 MPa, Shear strength ≥620 MPa, Fatigue limit ≥520 MPa (10^7 cycles), Assembly interference 0.012-0.022 mm

Structure and Adaptability Characteristics: High-strength structure: Integral forging of 42CrMo alloy steel, heat-treated with quenching and tempering, possessing high hardness, high toughness, and fatigue resistance, suitable for heavy loads and impact conditions, effectively preventing deformation and fracture, and ensuring positioning accuracy.

Positioning and Guiding Function: The straight-tube, stepless structure facilitates coaxial positioning of pins and bushings, reducing assembly deviations, improving component operational stability, and lowering the risk of abnormal wear due to inaccurate positioning.

Universal Compatibility: Compatible with the boom pin and stick pin positioning of Caterpillar 329D and 330D excavators and 980M loaders, as well as the bushing support of the swing mechanism. Suitable for frequent swinging and heavy-duty operations, and easy to install.

Compatible Models and Application Scenarios:

Excavators: For models such as 329D, 330D, and 336D, providing boom pin positioning, stick pin support, and bucket pin guidance to ensure precise positioning and stable operation of the working device. Suitable for heavy-duty operations in mining, infrastructure, etc.

Loaders: For models such as 980M and 982M, providing boom articulation pin positioning and rocker arm bushing support to accommodate frequent lifting, lowering, and turning conditions during material loading and unloading, improving operational efficiency.

Other: Compatible with the working device pin positioning parts of some Caterpillar bulldozers and graders, meeting the high-strength positioning requirements under harsh working conditions.

Installation and Maintenance Points (Original Data)

Installation: Clean the sleeve and mounting base, ensuring they are free of oil stains and metal shavings. Inspect the sleeve for cracks, deformation, and surface damage.

Cold press installation (pressing force ≤120 kN). Do not hammer or strike. Ensure an interference fit (interference 0.012-0.022 mm). After installation, the coaxiality should be ≤0.02 mm.

After installation, check the inner diameter and roundness. Apply anti-rust oil and run for 50 minutes, monitoring for abnormal heating and noise.

Maintenance: Check the sleeve wear and positioning condition every 800 hours. Replace immediately if wear exceeds 0.3 mm or positioning deviation exceeds 0.05 mm.

Regularly check the mounting base tightness. Use a dedicated pulling tool for disassembly to avoid prying, which could deform or damage the sleeve.