Understanding what the numbers mean and how they relate to material properties is required to interpret Vickers hardness test results. Here's a breakdown to help you:
Understanding the Format
- HV: The Vickers hardness scale is indicated.
- Hardness Number: This is a numerical value that represents the material's hardness. Greater hardness is indicated by higher numbers.
- Load (kgf): This is the test load used during the measurement. Micro-Vickers tests typically range from 10gf to 1kgf, while macro-Vickers tests range from 5kgf to 30kgf.
Interpreting the Hardness Number
- Comparison with reference values: Check to see if your material type has established hardness ranges. This allows you to see how your sample compares.
- Relative comparison within the sample: Hardness can be compared across different areas of the same sample or between samples under similar conditions.
- Consider the load: Due to material deformation, higher loads can result in slightly lower hardness values. The values, however, generally stabilize above 200gf.
Additional Factors
- Material microstructure: The grain size, phase presence, and phase distribution can all affect hardness.
- Test conditions: Ensure proper preparation, testing procedure, and calibration of equipment.
- Reporting format: Additional information, such as indentation size or conversion to other hardness scales, may be included in some reports.
