Production Process of Tungsten Cemented Carbide Balls

The production process of tungsten cemented carbide balls primarily involves powder metallurgy combined with precision machining techniques. The following is an overview of the carbide ball production process:

1. Raw Material Preparation:

Material Selection: The primary raw material is tungsten carbide (WC) powder, with cobalt (Co) added as a binder. Small amounts of other carbides (such as TiC and TaC) may be added to improve performance.

Batching: The raw materials are accurately weighed according to a specific ratio (e.g., 90-94% WC, 6-10% Co) to ensure that the alloy's properties meet the requirements.

2. Powder Mixing:

Place tungsten carbide, cobalt, and other powders in a ball mill. Add an appropriate amount of alcohol or water as a wet grinding medium and mix thoroughly. The ball milling process typically lasts 24-72 hours to ensure a fine and evenly distributed powder. Sometimes, paraffin wax or polyethylene glycol is added as a molding agent to facilitate subsequent molding.

3. Drying and Granulation:

The mixed slurry is spray-dried or vacuum-dried to remove the liquid, forming a uniform granular powder suitable for compacting.

The granulation process ensures that the powder has good flowability, making it easier to fill the mold.

4. Compression Molding:

The dried powder is loaded into a mold and formed into a spherical billet (blank) through cold isostatic pressing (CIP) or mechanical pressing.

The pressing process requires controlled pressure to ensure uniform billet density and avoid internal defects.

5. Pre-Sintering (Optional):

The compacted billet is pre-sintered at a relatively low temperature to remove the molding agent and enhance its strength for subsequent processing.

6. Precision Molding and Processing:

The billet is initially formed into a spherical shape close to the final dimensions by turning, grinding, or rolling.

This step may require multiple passes to achieve high precision.

7. Sintering:

The finished blank is placed in a vacuum sintering furnace or hot isostatic pressing (HIP) furnace and sintered at high temperatures.

During the sintering process, the cobalt phase melts and bonds the tungsten carbide particles together. Simultaneously, the blank shrinks to its final density, significantly increasing its hardness.

8. Finishing and Grinding:

The sintered tungsten cemented carbide balls undergo precision grinding and polishing to achieve final dimensional accuracy and surface finish.

Grinding with diamond grinding tools ensures sphericity and surface quality.

9. Quality Inspection:

Tungsten cemented carbide balls undergo multiple inspections, including:

Dimensional Accuracy: Sphericity and diameter are checked using high-precision measuring equipment.

Surface Quality: Surface defects such as cracks and pores are inspected.

Performance Testing: Hardness (e.g., HRA 85-92), density, and compressive strength are measured.

Common inspection tools include microscopes, hardness testers, and roundness gauges.

10. Cleaning and Packaging:

Qualified tungsten cemented carbide balls undergo ultrasonic cleaning to remove surface residue.

Products are packaged according to customer requirements, usually using shockproof and moisture-proof packaging materials.

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