AGICO Cement offers durable and precisely engineered ball mill trunnion (also called ball mill hollow shaft). As a professional ball mill trunnion manufacturer, we provide cast steel trunnions for cement mills, coal mills, SAG mills, and rod mills. Our ball mill spare parts are widely used in cement plants, mining industries, and power stations.
The ball mill trunnion is a critical component installed at both ends of the ball mill cylinder. It supports the entire rotating part of the mill, transmits torque, and provides the inlet and outlet passages for raw materials and ground products.
A typical ball mill has two trunnions:
- Feed trunnion – allows raw material and grinding media to enter the mill.
- Discharge trunnion – allows ground material to exit the mill.
Technical Specifications
Weight: 1 – 45 tons (customizable)
Diameter: 2 meters or above
Material: ZG230-450, ZG270-500, ASTM 1025, DIN CK25, alloy steel, carbon steel
Cast Steel Grades: ASTM A27/A148, DIN GS-45/GS-52, BS 410-420
Heat Treatment: Annealing, normalizing, quenching, tempering
NDT Methods: UT, MT, PT, X-ray inspection
Application: Cement ball mill, raw mill, coal mill, SAG mill, rod mill
Manufacturing Process of Ball Mill Trunnion/Hollow Shaft
1. Casting simulation (CAE) → 2. Wood pattern making → 3. Sand mold making → 4. Smelting → 5. Molten steel testing → 6. Pouring (low temp & fast) → 7. Sand cleaning → 8. Heat preservation → 9. Secondary cleaning → 10. Heat treatment → 11. CNC machining (roughing & finishing) → 12. Non-destructive testing (UT/MT/PT/X-ray) → 13. Packaging & delivery (seaworthy plywood)
Quality Control
AGICO has a complete quality management system. Each ball mill trunnion is inspected before shipment.
- Chemical composition analysis
- Mechanical property testing (tensile strength, hardness)
- Dimensional accuracy check
- Ultrasonic testing (UT)
- Magnetic particle testing (MT)
- Penetrant testing (PT)
- X-ray inspection (for critical areas)
- Surface finish inspection
All inspection reports are provided to customers for full traceability.
Advantages of AGICO Cement Ball Mill Trunnion
High Strength & Toughness
Made of high-strength cast steel (ZG230-450, ZG270-500, ASTM 1025, DIN CK25, etc.) with optimized heat treatment (annealing, normalizing, quenching, tempering). Our trunnions resist cracking under heavy loads and impact.
No Cracks at the Stress Point
The trunnion connects to the end cover at a sharp corner – this is where most cracks start. AGICO uses a larger fillet radius (rounded corner) and extra material thickness at this critical area. We also add smooth transition design to spread the load over a bigger area. Result: far fewer cracks than ordinary trunnions.
Smooth Bearing Surface
The trunnion sits on the main bearing. If the surface is rough or not round, the bearing overheats and fails. AGICO machines the surface with CNC lathes, then grinds it to a mirror finish. This keeps the bearing cool.
Handles Heavy Loads
The trunnion carries tens of tons of weight. When the mill starts, if the bearing lacks oil, metal rubs on metal. AGICO trunnions have the right surface hardness to handle this. We also recommend using a hydrostatic bearing oil system to lift the trunnion before starting.
Replaceable Inner Liner
AGICO supplies a trunnion liner (replaceable protective sleeve) that takes on all the wear. We also supply the custom trunnion liner and the bearing bottom liner – everything needed for a complete trunnion replacement.
Large Size, Factory Price
AGICO casts single-piece trunnions up to 45 tons. One solid piece means no weak weld joints and longer life. As a manufacturer, we offer a lower price for ball mill trunnions.
Applications of Ball Mill Hollow Shaft
The AGICO ball mill trunnion for sale is suitable for the following:
- Metallurgical industry – various grinding mills
- Cement plants – cement mill, raw meal mill, coal mill
- Mining industry – SAG mill, AG mill, rod mill
- Power stations – coal grinding mills
- Steel plants – slag ball mills
AGICO Factory
How to Choose the Right Ball Mill Trunnion (Buyer’s Guide)
When selecting a ball mill trunnion, consider the following:
- Size & Fit: The trunnion must match your ball mill’s flange diameter, length, and bore size. AGICO manufactures to your exact drawings.
- Material Grade: Choose cast steel or alloy steel based on your operating load and environment. AGICO offers ZG230-450, ZG270-500, ASTM 1025, and custom alloys.
- Load Capacity: Calculate the total weight of the mill cylinder, grinding media, and material. The trunnion must safely support this load without deformation.
- Operating Environment: High temperature, humidity, or corrosive conditions require special materials and seal design. AGICO can recommend suitable solutions.
- Machining Accuracy: The journal surface (contact with spherical bearing) must be ground to high smoothness. Poor surface finish causes rapid bearing wear and overheating.
- Manufacturer Capability: Choose a supplier with in-house casting, heat treatment, machining, and NDT. AGICO has all these capabilities under one roof.
Quick Comparison
| Factor | Requirement | AGICO Advantage |
|---|---|---|
| Weight | 1–15 tons | Customizable up to 45 tons |
| Material | High-strength cast steel | Full ASTM/DIN/BS grades |
| Hardness | 30% higher than average | Unique heat treatment |
| Defects | No blowholes, sand holes | CAE simulation + NDT |
| Delivery | 30–45 days | Fast production |
Frequently Asked Questions (FAQ)
Q1: What is the service life of AGICO ball mill trunnion?
A: With proper maintenance and lubrication, AGICO trunnions can last 8–12 years. Our heat treatment and material selection extend service life by approximately 50% compared to conventional products.
Q2: Why do ball mill trunnions crack?
A: Common causes include casting defects (shrinkage and slag inclusion), inadequate heat treatment (residual stress), poor lubrication (dry friction causing thermal stress), seal failure (dust/slurry intrusion), or misalignment during installation. AGICO’s CAE simulation and complete NDT eliminate casting defects.
Q3: Can AGICO produce trunnions according to my drawings?
A: Yes. AGICO accepts custom orders based on customer drawings, including special sizes, materials, and surface treatments. MOQ is negotiable.
Q4: What is the lead time for a ball mill trunnion?
A: Standard lead time is 30–45 days. For urgent replacement needs, please contact us to check expedited options.
Q5: How to maintain a ball mill trunnion?
A:
Q6: What is the difference between trunnion and hollow shaft?
A: They are the same part. Ball mill trunnion is the more technical term, while ball mill hollow shaft describes its shape.
Q7: Do you sell other ball mill spare parts?
A: Yes, we supply ball mill spare parts, including liners, diaphragms, girth gears, and bearings.
