Improvements in hardness testing, in particular in micro-hardness testing

摘要

651,800. Testing physical qualities of materials. GRODZINSKI, P. Jan. 27, 1948, No. 2400. [Class 106 (ii)] An indenter for testing hardness comprises a diamond or other hard material having a sharp, curved, indenting edge at which the " included angle " (defined in the Specification) is at least 120 degrees. As shown in Fig. 3, the circular indenting edge 5 of a diamond 2 is formed by the intersection of two conical surfaces 3, 4. The diamond is fixed in a sector-shaped member 8 mounted in a circular dovetail groove 7, Figs. 4a and 5, in a holder 6 which may be attached to testing apparatus (not shown). The member 8 can be adjusted, to bring a different point on the edge 5 into action, by a worm 11 engaging teeth 10, and is normally clamped by a fork-shaped block 18 and screw 19. A formula is given for calculating the hardness from the measured length of the impression made in the tested material. U.S.A. Specification 2,091,995 is referred to.