Universal stationary hardness testers are devices used to determine the hardness of various materials. Such hardness testers can carry out measurements using several hardness testing methods. Universal hardness testers are mainly classified according to the implemented methods of hardness testing and the scales used to display the obtained data.
Measurements are carried out according to Brinell in compliance with the standards EN ISO 6506, ASTM E-10, GOST 8.062-85 and GOST 9012-59, according to Rockwell and Super Rockwell in compliance with the standards EN ISO 6508, ASTM E-18, GOST 8.064-94, GOST 9013-59, GOST 22975-78, and according to Vickers in compliance with the standards EN ISO 6507, ASTM E-92, ASTM E-384, GOST 8.063-2007, GOST 9450-76, GOST R ISO 6507-1-2007.
According to Brinell.
The method is based on pressing a ball with a diameter of 1, 2.5, 5 and 10 mm with a defined test load and measuring the indent diameter after withdrawing the test force. The price of Brinell or Vickers hardness testers varies greatly depending on the indent measurement method: automatic mode measurement or using a separate microscope, such as a Brinell lens. In this case, the ball can be made either of steel or carbide, and the hardness scale will be designated as HB or HBW, respectively. The limit of hardness measurement for a steel ball indenter (anvil) is 450 units, and for a carbide ball indenter — up to 650 units. The results of measurements performed with a steel ball and with a carbide ball, with the same load and other parameters, will correlate, but there may be discrepancies which, in general, makes it incorrect to compare such measurement results with each other.
According to Vickers.
Currently, the Vickers hardness testing is regulated by a new standard that prescribes the load range of 1 gf-100 kgf (0.0098-980.7N). However, modern stationary Vickers hardness testers can operate in nano ranges starting from 0.25 gf, which is essential for scientific research.
In order to determine the hardness, a pyramid-shaped diamond indenter with interfacial angle of 136° is pressed into the specimen surface with a constant test load. This hardness testing method is an optical method and includes calculating the average value of the two indent diagonals. The price of a Vickers hardness tester depends on the mechanization degree, the availability of the automatic indent measurement function and the automatic load application function.
According to Rockwell.
In this method, either a diamond indenter with interfacial angle of 120° or a steel ball with a diameter of 1.588 mm is pressed into the surface. The hardness tester either has a special indicator that shows the hardness number of the inspected material, or performs the measurement in a fully automatic mode — depending on the device class and, therefore, on the price of the Rockwell hardness tester. Below you will find the standard EMCO-TEST hardness tester models used to measure the hardness of all types of articles.
