Hardness is defined as the resistance of a material against dynamic or static forces to scratch, cut, friction or plastic deformation. Since the beginning of the twentieth century, the subject of hardness has been investigated and various tests have been carried out.
First of all, hardness tests were developed by Brinell at the beginning of 1900. In these tests, a ball made of hard material of a certain size was pressed onto the surface of the material to be tested with a certain load and for a certain time and the trace area formed on the surface was observed. Brinell, with his calculations, the surface area of the material opened, the diameter of the ball as a function of the depth of the track has determined.
Another researcher, Vickers, conducted a hardness test using a square-based diamond pyramid. In these tests, a diamond, square pyramid tip with 136 degree angle was immersed to the surface of the material to be tested with a certain force and for a certain time and the trace area formed after the load was removed. Vickers, in his calculations by measuring the diagonals of this track area, found that the hardness value of a material is the ratio of load to permissible surface area.
One of the hardness tests is the Rockwell hardness test. Here, too, Rockwell is applied to a material surface with a steel ball of a certain size or a conical diamond with a tip angle 120 grade and tip diameter 0,2 mm. First, a fixed small load was applied and the end of the trace formed by the tip on the surface of the material was taken, then the load was increased to a higher level and the increase in the second track depth compared to the first track was measured.
Hardness test results are an important factor in many quality control processes and research and development studies. The properties of a material such as strength, ductility and abrasion resistance are determined by hardness tests. It is determined whether the material to be used in this way is suitable for the product. In these tests, the resistance of one material to permanent deformation by penetrating another harder material is measured. Therefore, in a hardness test, the applied load is evaluated with a certain loading profile, a certain loading time and a certain indentation geometry.
A hardness test is carried out by printing a specially sized and loaded object on the surface of the material to be tested, as described in the test examples above. The hardness value is calculated by measuring the penetration depth of the recess or by measuring the dimensions of the trace formed on the surface of the material. To determine which test method to choose, the microstructure of the material should be examined. For example, the type of material, homogeneity, size and condition of the part are important here. When determining a hardness test method, it is also important whether compliance with a standard is required.
There are countless standards taken into account in the hardness tests. Here are a few of them:
- TS EN ISO 6506-1 Metallic materials - Brinell hardness test - Part 1: Test method
- TS EN ISO 6507-1 Metallic materials - Vickers hardness test - Part 1: Test method
- TS EN ISO 6508-1 Metallic materials - Rockwell hardness test - Part 1: Test method
- TS EN ISO 14577-1 Metallic materials - Instrument trace test for hardness and material parameters - Part 1: Test method
Our company also provides hardness testing services within the scope of other testing services. Thanks to these services, enterprises are able to produce more efficient, high performance and quality products in a safe, fast and uninterrupted manner.
Hardness testing services provided within the scope of other testing services are only one of the services provided by our organization in this respect. Many other testing services are also available.