Electrical resistance hardness tester for metallic materials
OwnerAlfred Ernstinventor
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Abstract
A conducting tip of a hardness tester for metals, alloys and similar conducting materials is set forth. The tester comprises a resistance measuring circuit for measuring the resistance between the indenting tip and the test specimen when a certain load is applied to the indenter, made of a substantially insulating material with a superficial conducting film, the conductivity of which decreases toward the tip vertex. This contains the error induced by differences in temperature affecting the resistivity of the conducting superficial film. A tip of conical form with an angle which does not exceed 110 degrees increases precision, as compared with indenters constructed to the Vickers pyramid standard or to the Rockwell 120 degree cone.
Claims6
A hardness tester for metals, metal alloys and similar conducting materials, comprising an indenter provided with an electrically conducting indenting tip and with means for measuring the resistance between said tip and a test specimen under a certain load applied to the indenter, said tip being made of a substantially insulating material having a conducting superficial film, the conductivity of which decreases towards the tip vertex.
Dependencies are inferred from the claim text.