Calibration is an essential first step in ensuring accurate and reliable results with a Vickers hardness tester. It includes assessing and modifying a number of the machine's functional features to make sure it satisfies requirements. This is a summary of the procedure:

1. See the handbook for instructions: Consult the detailed guidelines and instructions contained in the Vickers hardness tester model handbook.

2. Assemble the calibration tools: Certified reference blocks, such as tempered glass or annealed steel, composed of materials with known hardness values, must be used.

3. The surroundings: As directed by the handbook, make sure the temperature and humidity are under control as these can impact test results.     

4. Force of indentation: Measure the applied force against the reference block using a force gauge, and then compare the result to the given value. Make any necessary adjustments to the machine's settings to achieve the desired force.

5. Staying put: Use a stopwatch to measure the dwell time, or the amount of time the indenter is on the sample, and compare the result to the given value. Adjust the timings as necessary.

6. Measurement of indentation: Measure the Vickers indentation's diagonals on the reference block with a microscope fitted with a graticule or with specialized software. Examine the measured diagonals in relation to the reference material's expected values.

7. computations and modifications: To find the Vickers hardness (HV), use the following equation: HV can be expressed as 1.8544 × F / d², where d is the average diagonal length in micrometers and F is the applied force in kilograms. Compare the calculated HV to the known HV value of the reference block. If a noticeable difference appears, adjust the machine's settings or get more troubleshooting advice from the manufacturer.

8. Documentation: Ensure that all calibration data is kept on file, including measured values, calculations, reference block values, and any necessary adjustments. This document provides traceability and calibration evidence.

Remember that precise calibration of a Vickers hardness tester requires specific equipment and knowledge. If you are uncomfortable doing the treatment yourself, it is best to consult with a certified laboratory or licensed technician.