In 1907, Ludwik published the proposal to use the depth of penetration of a diamond cone to assess the hardness of a material. Furthermore, the influence of the sample surface should be eliminated by applying a preliminary test force. It was not until 1922 that the American Rockwell, building on Ludwik’s idea, succeeded in developing a useful hardness testing method. Because of the simplicity of the method, Rockwell hardness testing quickly found its way into industry.
INDENTER FOR ROCKWELL HARDNESS TESTING
A diamond cone with a point angle of 120° or two hardened steel balls (diameter 1/16 inch = 1.5875 mm or 1/8 inch = 3.175 mm) are used as indenters in the Rockwell test. The steel balls may only be used if this is explicitly required in the product specification or is agreed separately. If required or agreed, carbide balls of 6.356 or 12.70 mm may also be used.
THE 3 STEPS OF ROCKWELL HARDNESS TESTING
t0 = indentation depth through test preload F0
RESULTS OF A ROCKWELL HARDNESS TEST
The result of a Rockwell hardness test is determined as follows:
According to DIN EN IS 6508-1 the result of a Rockwell hardness test is depicted as follows:
60 HRC W ⇒ Rockwell hardness value
60 HRC W ⇒ Generic marker for "Hardness Rockwell"
60 HRC W ⇒ Label for the hardness scale
60 HRC W ⇒ Label for the material of the indenter in case a ball is used (not shown for diamond cone)
Stránka 1 z 1 - 1 položek celkem