GF98.00-U-9100-03A Hardness Test Procedures on Object (Surface Harness)

GF98.00-U-9100-03A Hardness test procedures on object (surface harness)

Introduction to subject

Surface hardness
The hardness of an object is the resistance it has to penetration of another object: For example when a tip, blade or ball is pressed into it.

Scratch hardness scale
The so-called "Moh's hardness scale" defines a series of materials which can be scratched by the subsequent materials:
1. Talcum
2. Gypsum
3. Calcite, lacquer
4. Fluorite
5. Apatite
6. Feldspar
7. Quartz (sand)
8. Topaz
9. Corundum
10. Diamond

Test procedure
The impression test ("Buchholz hardness test") according to DIN 53 153 or ISO 2815 is preferable, however, only possible on horizontal surfaces.

Testing principle
The test instrument is positioned on the painted surface and the impression mark then measured with a magnifying glass for evaluation of the hardness.

Note:
Since the hardness test on the object requires a certain amount of experience in handling the equipment, the tests should be performed only by trained personnel.
Moreover, the test conditions should be specified, if they differ from the DIN standard.