Hardness testing of tungsten carbide parts

Hardness testing is a critical quality control measure for tungsten carbide parts, which are renowned for their high hardness and durability. Given the stringent demands placed on these components, particularly in high-stress applications like hardware molds and precision tooling, ensuring the hardness meets specified requirements is paramount. Here’s a detailed guide to understanding and executing hardness testing for tungsten carbide parts:

Understanding Hardness Requirements

Customers may specify hardness in several ways:

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1. Explicit Requirements: Customers may specify the grade of tungsten carbide, such as K10, YG8, or C2. These specifications often come without a designated manufacturer, relying on universally recognized standards for these grades.
2. General Requirements: Typical for less critical applications where the manufacturer’s expertise can guide the selection based on the intended use, such as hardware molds or die components.
3. Specific Manufacturer and Grade: Some customers specify both the manufacturer and grade of tungsten carbide, expecting the processor to supply material certifications confirming the composition and hardness.
4. Hardness Data Requirements: For instance, demanding a hardness greater than 92 HRA for certain parts, which sets a clear benchmark for quality control.
5. Specific Hardness Tolerances: Requests like a hardness of 92 HRA with a tolerance of ±1 HRA are common in precision applications, necessitating exacting manufacturing and testing protocols.

Hardness Testing Protocol

The process of hardness testing typically follows these steps:

1. Preparation of Specimen:
   • Ensure the surface of the tungsten carbide part is smooth and free from significant machining marks.
   • Verify the thickness of the specimen is appropriate (typically less than 1.6mm for certain tests).
2. Testing Procedure:
   • Conduct the hardness test following the Rockwell Hardness Test method, specifically using the HRA scale suitable for tungsten carbide.
   • Position the indentations correctly: centers of adjacent indentations should be within 2mm, and the center of an indentation must be no less than 1mm from any edge.
3. Calibration and Measurement:
   • Use calibrated hardness blocks close in hardness to the tungsten carbide to ensure the accuracy of the hardness tester.
   • Perform three measurements and calculate the average to determine the final hardness value.
4. Adjustment and Verification:
   • If deviations occur (more than ±0.5 HRA from the standard), recalibrate the hardness tester.
   • For minor deviations (±0.3-0.5 HRA), adjust the measured value as needed.
5. Communication and Standardization:
   • Communicate with the customer about the measurement method and establish a unified standard to compare trial samples.
   • Label the measurement locations clearly on the part to ensure consistency in testing and re-testing.

Conclusion

By adhering to stringent testing protocols and maintaining open communication with clients regarding specifications and outcomes, manufacturers can ensure that tungsten carbide parts meet the high-performance standards required. Our facility is equipped with the latest technology and expertise to handle all aspects of precision carbide part processing and testing, ensuring that each component delivers on strength and durability. For more information or to discuss your specific needs, please feel free to contact us.