Bierbaum pyramid

In hardness tests by scratch methods, apart from the previously mentioned diamond cones with included angle of 90° or 120°, trihedral pyramid-shaped points (Bierbaum pyramid and Berkovich pyramid) and Vickers tetrahedral pyramid (Fig. 4.3.3) are now widely used their main... 

The physical meaning of hardness determined by Bierbaum s method is exactly equal to load P divided by the projected contact surface of pyramid with material under test in the scratch process. It should be mentioned here that the result obtained under Bierbaum s method is roughly directly proportional to the hardness number obtained by the pyramid indenter method, and the relation has the form... 

Point, yield, 7 Poisson s ratio, 9 Pure scratch, 52 Pyramid, Berkovich, 52 Bierbaum, 52... 

For the hardness factor in the other methods discussed, we can take b l, b 2, P b 2 or other proportional quantities. Bierbaum s method, used chiefly in the United States, may serve as an example. The load on the trihedral pyramid is constant and equal to 29.4 mN. The scratch direction is with the edge to the front . The Bierbaum hardness number is given by the formula... 

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