# ISO 6507-1:2018 pdf free

**ISO 6507-1**:2018 pdf free.Metalic materials – Vickers hardness test

The minimum distance between adjacent indentations and the minimum distance between an indentation and the edge of the test piece are shown in Figure 2.

The distance between the centre of any indentation and the edge of the test piece shall be at least 2,5 times the mean diagonal length of the indentation in the case of steel, copper and copper alloys and at least three times the mean diagonal length of the indentation in the case of light metals, lead and tin and their alloys.

The distance between the centres of two adjacent indentations shall be at least three times the mean diagonal length of the indentation in the case of steel, copper and copper alloys and at least six times the mean diagonal length in the case of light metals, lead and tin and their alloys. If two adjacent indentations differ in size, the spacing shall be based on the mean diagonal length of the larger indentation.

The lengths of the two diagonals shall be measured. The arithmetical mean of the two readings shall be taken for the calculation of the Vickers hardness. For all tests, the perimeter of the indentation shall be clearly defined in the field of view of the microscope.

Magnifications should be selected so that the diagonal can be enlarged to greater than 25 %, but less than 75 % of the maximum possible optical field of view; see 6.3.

NOTE 1 In general, decreasing the test force increases the scatter of results of the measurements. This is particularly true for low-force Vickers hardness tests and Vickers microhardness tests, where the principal limitation will arise in the measurement of the diagonals of the indentation. For Vickers microhardness, the accuracy of determination of the mean diagonal length is unlikely to be better than ± 0,001 mm when using an optical microscope (see References [6] to [9]).

NOTE 2 A helpful technique for adjusting optical systems that have Kohler illumination is given in Annex G. For flat surfaces, the difference between the lengths of the diagonals should not be greater than 5 %. If the difference is greater, this shall be stated in the test report.ISO 6507-1 pdf download.