What precautions should be taken when measuring with a Vickers hardness tester?

Taiwan Nakazawa Co., Ltd. answers for you: When replacing the indenter or the anvil, ensure that the contact areas are wiped clean. After replacement, test several times using a steel sample of a certain hardness until the hardness values obtained twice in succession are the same. The purpose is to ensure that the contact parts of the indenter or anvil and the testing machine are tightly pressed and in good contact, so as not to affect the accuracy of the test results.
Whenever the specimen allows, generally select at least three different positions to test the hardness values and take the average value; take the average value as the hardness value of the specimen. For specimens with complex shapes, support blocks of corresponding shapes must be used, and testing can only be conducted after they are fixed. Circular specimens should generally be tested in a V-shaped groove. Before loading, check whether the loading handle is placed in the unloading position. When loading, the movement should be light and steady; do not use excessive force. After loading is completed, the loading handle should be placed in the unloading position to prevent the instrument from being under load for a long time, which could cause plastic deformation and affect measurement precision.