Brinell hardness (HB)
The steel ball diameter, load size and action time for Brinell hardness measurement should be selected according to Table 6-5 according to the expected hardness of the sample. The indentation diameter after the test should be within the range of 0.25D<d<0.6D, otherwise the test result is invalid. In addition, the minimum thickness of the sample shall not be less than 10 times the depth of the indentation.
Rockwell Hardness (HR)
Rockwell hardness is suitable for hardness testing of specimens whose surface hardness is greater than 450HBW. Ordinary Rockwell Hardness Tester can be used for the melt-sprayed layer; surface Rockwell Hardness Tester should be used for the sprayed layer. The principle is the same as that of the ordinary Rockwell Hardness Tester, but the load is smaller.
When measuring the hardness, the thickness of the coating is extremely important. The minimum thickness required for the coating is listed in Table 6-6, and the thickness values are all values after processing.
This method is applicable to the determination of metal spray coatings, ceramic coatings and brush lock coatings can also be used by the surface Rockwell hardness method.
