How Sandvik Engineers Ensure High‑Reliability Upper Frame Assembly in CH&CS Series Cone Crushers

Introduction

In the mining and aggregates industry, Sandvik CH and CS series cone crushers have long been recognized for their high reliability.
Among the key structural components of these machines, the Upper Frame Assembly (also known as the Top Shell Assembly) is one of the primary load‑bearing structures in the crusher.

From an engineering perspective, the upper frame performs several critical functions:

• Supporting the crushing chamber
• Providing the installation base for the concave liner
• Supporting the upper bearing of the main shaft
• Transmitting dynamic crushing forces
• Working together with the hydraulic adjustment system to control the Closed Side Setting (CSS)

During operation, crushers are subjected to continuous impact loads and dynamic stresses generated by irregular ore.Therefore, the design and manufacturing quality of the Upper Frame directly affect structural stability, service life, and production efficiency of the crusher.

1. Structural Function of Upper Frame Assembly

In a typical cone crusher structure, the Upper Frame forms the upper portion of the machine and works together with the main shaft, liners, and crushing chamber as an integrated system.

Structural Support 
The Upper Frame provides structural rigidity for the entire crushing system, ensuring that the main shaft remains properly aligned during eccentric motion.

Crushing Force Distribution  
During crushing, impact forces generated between the mantle and concave are transmitted to the frame structure. The Upper Frame distributes these crushing forces across the structure to prevent localized structural damage.

Liner Installation Platform  
The Upper Frame includes the concave seating surface. This area must maintain high machining precision to ensure stable liner installation and maintain correct crushing chamber geometry.

2. Structural Design Philosophy

In modern cone crusher design, the Upper Frame is classified as a heavy‑duty structural casting.

Original equipment manufacturers typically consider several engineering factors during the design phase:

Load Path Design  
Crushing forces follow a load path from mantle → concave → frame. A well‑designed structure minimizes stress concentration and improves long‑term reliability.

Structural Stiffness  
Insufficient frame rigidity may lead to crushing chamber misalignment, uneven liner wear, and increased machine vibration.

Integrated Frame Concept  
Many cone crushers adopt a two‑part cast steel frame structure consisting of the top shell and bottom shell. This design ensures both structural strength and maintenance accessibility.

3. Material Engineering of Upper Frame

Material selection is one of the most critical factors affecting the reliability of large cone crusher structural components.

For heavy‑duty structural castings such as the Upper Frame Assembly, the industry commonly utilizes GS20Mn5N high‑strength cast steel (equivalent to GS200+N).

GS20Mn5N is an engineering cast steel specified in European EN standards and is widely used in heavy mining equipment structures, crusher frames, and other large load‑bearing mechanical components.
The material provides a balanced combination of strength, toughness, and fatigue resistance, making it suitable for structures subjected to dynamic crushing loads and cyclic impact loading.

Typical chemical composition includes:

This composition ensures high structural strength while maintaining sufficient toughness and fatigue resistance.

High Impact Toughness  
During ore crushing, the crushing chamber generates continuous high‑energy impact loads. GS20Mn5N possesses excellent impact toughness, enabling the structure to absorb impact energy and reduce the risk of brittle fracture.

Excellent Fatigue Resistance  
Mining equipment typically operates continuously. GS20Mn5N provides typical mechanical properties such as:
• Yield strength ≥200 MPa
• Tensile strength 450–650 MPa
• Elongation approximately 20%

This combination of strength and ductility allows the material to maintain stable performance under long‑term cyclic loading.

Manganese Strengthening Effect  
Approximately 1.0–1.5% manganese content improves the steel’s hardenability and structural strength, resulting in more stable mechanical properties after heat treatment.

Low Impurity Content for Structural Integrity  
Strict limits on phosphorus and sulfur help reduce inclusion defects and crack initiation risks, improving the structural integrity of large cast components.

Good Weldability for Heavy Equipment Structures  
With carbon content controlled below 0.23%, GS20Mn5N exhibits good weldability, which is important for repair welding or structural reinforcement during long‑term equipment operation.

As a result, GS20Mn5N is widely used in:
• Crusher upper frame assemblies
• Large mining equipment castings
• Heavy load‑bearing mechanical structures

In practice, material performance depends not only on chemical composition but also on casting quality, heat treatment control, and machining accuracy. Only when these factors are strictly controlled can the Upper Frame Assembly maintain long‑term reliability in demanding mining environments.

4. Casting and Heat Treatment Technology

The casting quality of large structural components directly determines the performance of the Upper Frame

Casting Process Control
• Proper gating system design
• Controlled solidification sequence
• Prevention of shrinkage cavities

Heat Treatment

Processes such as normalizing and tempering improve material strength, toughness, and fatigue resistance.

5. Precision Machining and Dimensional Control

Key regions of the Upper Frame require precision machining, including:
• Concave seating surface
• Threaded adjustment interface
• Main shaft bearing seat
• Bolt connection surfaces

Machining tolerances directly influence crushing chamber alignment and overall crusher vibration level.

High‑precision manufacturing is typically achieved using CNC machining centers and large horizontal boring machines.

6. Common Wear and Failure Situations

Frame Cracking – Long‑term impact loads or stress concentration may lead to structural cracks.

Thread Wear – Threads used for CSS adjustment may experience wear during frequent adjustments.

Bolt Hole Deformation – Connection areas may deform under high loads.

Concave Seat Wear – Improper installation or prolonged operation may cause wear at the liner seating surface.

Optimized structural design, proper material selection, and precision machining significantly reduce the risk of these failures.

7. Operation and Maintenance Recommendations

To extend the service life of the Upper Frame Assembly, the following practices are recommended:
• Regular inspection for frame cracks
• Verification of bolt torque conditions
• Proper lubrication maintenance
• Avoidance of overload operation

Conclusion

The Upper Frame Assembly is one of the most critical structural components of a cone crusher.

Its design and manufacturing quality directly influence crusher reliability, service life, and production efficiency.
Only through strict control of materials, manufacturing processes, and structural engineering can high‑reliability crusher structural components be achieved.

Hyton provides one-stop wear and spare parts solution for Sandvik cone crushers. Here are the specific part numbers for the CH&CS series upper frame assembly. Please refer to them：

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In the next article, we will take a closer look at the Head Assembly in cone crushers and explore how material selection, heat treatment, and assembly precision influence crusher reliability.