Step Washer Fits SANDVIK Crusher 442.8731-01

Sandvik CH660 Step Washer: 442.8731-01 Steel Replacement

The Step Washer (Part # 442.8731-01) is a critical thrust bearing component in the Sandvik CH660 (Svedala H6800) Hydrocone crusher. Located at the bottom of the Main Shaft, it forms part of the three-piece Step Bearing Assembly that supports the entire weight of the shaft and the dynamic crushing load (up to 450 tons). This specific part is the Hardened Steel Washer that interfaces with the sacrificial Bronze Step Washer.

We manufacture this component from SAE 52100 (GCr15) Bearing Steel. Unlike standard structural steel, this material is through-hardened to HRC 58-62 and precision-ground to a mirror finish (Ra 0.4μm). This extreme hardness and surface finish are essential to maintain the hydrodynamic oil wedge required to lift the main shaft during operation.

Technical Specifications

Engineering Analysis: Why Hardness Matters

[Engineer’s Note] The Step Washer operates in a “Hydroset” system where the shaft position changes constantly.

1. Friction Reduction: The mating Bronze washer is soft. If the Steel washer (442.8731-01) is not glass-smooth and hard, it will act like sandpaper, destroying the bronze washer in hours.

2. Load Distribution: At 450 tons of crushing force, any soft spot in the steel plate will depress, causing uneven oil film thickness and “hot spots” that lead to burnt bearings.

Field Diagnosis: When to Replace

Step bearing failure is the #1 cause of “Main Shaft Drop” in Hydrocone crushers. Inspect for:

1. Blueing (Overheating)
Upon disassembly, if the steel washer surface is blue or purple, the oil film failed. The steel has lost its temper (hardness) and must be replaced. Re-using a blued washer will destroy the new bronze plate immediately.

2. Scoring / Grooving
Run your fingernail across the face. If you feel any catch, the plate is scored. Deep scratches cut the oil film pressure, preventing the Hydroset system from lifting the shaft efficiently.

3. Wedge Wear
Measure the thickness at 4 points (90° apart). If there is >0.5mm difference, the shaft is bent or the piston bushing is worn. A wedged washer will cause severe vibration.

Installation Best Practices

1. Matched Set: Never install a new Steel Washer against an old, worn Bronze Washer. The surfaces will not mate, leading to point loading. Always replace the entire 3-piece set (Top Steel, Middle Bronze, Bottom Steel) together.
2. Cleanliness: This is a hydraulic component. Even a lint-free cloth can leave fibers that bridge the oil film. Wash thoroughly with clean oil before installation.
3. Pre-Lube: Coat all faces with ISO VG 150 oil during assembly. Do not start the crusher dry.

Workshops And Warehouses

Cross-Brand Compatibility Disclaimer

Our aftermarket crusher spares are engineered to be fully interchangeable with OEM components. All manufacturer names, part numbers (e.g., 442.8731-01), and descriptions are used for reference purposes only. NEWREG supplies independently manufactured replacement parts and is not affiliated with the OEM.