Hardness Testing

Southern Valve has 4 different methods to test hardness of materials


The UCI method (Ultrasonic Contact Impedance), or modified Vickers method, has been in use in the metal-processing industry for more than 50 years. In the past, the preferred areas of application were generally heavy and/or unmovable parts where traditional, standardised testing methods could not be used, or only with great difficulty. However, the reliability, speed of application, excellent selectivity and simple operation of modern UCI hardness testing devices has made this test method not only feasible but preferred in many valve repair applications


The Leeb hardness testing, otherwise called as Leeb Rebound Hardness Test (LRHT), is a type of non-destructive testing used to inspect large sized workpieces weighing above 1 kg. It also measures the coefficient of restitution. In the Leeb hardness testing method, the hardness value can be calculated from the energy loss of an impact body after impacting upon a metal. This Leeb quotient is equivalent to the measure of that energy loss due to deformation. The impact body rebounds faster from harder samples than the softer ones, resulting in a larger value 1000* vr / vi which is quoted as the Leeb rebound hardness unit HL. Unlike other stationary traditional methods including Rockwell, Brinell, and Vickers which were implemented only in the laboratories or testing areas, the Leeb method proves to be portable by achieving high testing rates at a reduced cost.


The Rockwell test is generally easier to perform, and more accurate than other types of hardness testing methods. The Rockwell test method is used on all metals, except in condition where the test metal structure or surface conditions would introduce too much variations; where the indentations would be too large for the application; or where the sample size or sample shape prohibits its use.

The Rockwell method measures the permanent depth of indentation produced by a force/load on an indenter. First, a preliminary test force (commonly referred to as preload or minor load) is applied to a sample using a diamond or ball indenter. This preload breaks through the surface to reduce the effects of surface finish. After holding the preliminary test force for a specified dwell time, the baseline depth of indentation is measured.


Telebrineller hardness measurements are a direct comparison to a known physical reference and therefore, measurements are not subject to inaccuracies due to; alloy, thickness, geometry, position, etc., that are common with many other portable testers.