The working principle is the same as the Brinell one, but in this case it employs only one indenter, being a pyramidal diamond with square base having an angle of 136° between the opposite faces. After the indentation is made, the two diagonals will be measured and as these are almost never the same, the average value will be considered.
Advantages of the Vickers method
The main advantage of the Vickers method consists in employing only one scale, that can range from the lowest to the highest hardness. For this reason this method is fundamental for researching laboratories. Any deformation of the indentation may reveal structural characteristics of the test material. As for the Brinell test, the Vickers method is not sensitive to any deflection of the work piece. In comparison with the Rockwell and Brinell values, the Vickers hardness number has a proper meaning, as it represents a specific load on an indentation having always the same shape.
Limitations of the Vickers method
The limitation of the Vickers method is due to the low speed of operation, as the measurement of indentation has to be made optically (microscope or profile projector). The test area must be carefully prepared and polished. For this reason, perpendicularity of the indenter axis is a very important factor, as any inclination would give an irregular indentation. For these reasons, Vickers method is not recommended for testing in production lines. Finally, we can say that the Vickers method is more suitable for testing in laboratories than in workshops. In order to overcome the above limitations, we have realized for our hardness testers the possibility to detect the value of hardness in Vickers with faster and less laborious procedures.