Inspection Method Of Ball Grinding And Cast Iron

The hardness is tested by Brinell hardness, and it shall be noted that:
(1) Thickness and width (or diameter) of the sample: the thickness of the sample shall not be less than 10 times of the indentation depth, to avoid the deformation area of the indentation through the bottom surface and affect the accuracy of the test. The width or diameter of the sample should ensure that the distance from the edge is at least 2.5 times the distance of the indentation diameter. To ensure the accuracy of the test, the diameter or side length of the sample should be 15-50mm.
(2) Hardness test load selection: using Brinell hardness test, according to the sample size of 2.5,5 and 10mm pressure head can be used, the load is 187.5,750 and 3000kg respectively. There are two materials of brinell hardness head, quenching steel ball and carbide, quenching steel ball head can only be used for hardness measurement below 450 HB, the measurement results of the two heads below 350 HB are the same, more than 350 HB, the steel ball will produce deformation, the measurement result is lower than the measurement result of carbide head, the test result needs to be corrected and compensated.
(3) Measurement of indentation: the diameter of indentation can be measured on the special indentation measuring device attached to the durometer, but zero calibration; when using gold microscope measurement, scale calibration to compensate and correct the deviation.