This part of GB/T 4340 specifies the principles, symbols and descriptions, test equipment, samples, test procedures, uncertainty of results and test reports of metal Vickers hardness tests. This part specifies the method for determining the Vickers hardness of metals according to three test force ranges. This part specifies that the length of the diagonal of the Vickers hardness indentation ranges from 0.020mm to 1.400mm. The Vickers hardness test for special materials or products should be specified in relevant standards.