METHOD AND APPARATUS FOR TESTING THE HARDNESS OF A WORKPIECE BY THE PENETRATION METHOD

摘要

A method of testing the hardness of a workpiece having a continuously curved outer surface, in particular a pipe or rod, by the penetration method, includes (a) holding the workpiece in a horizontally and vertically fixed position; (b) arranging a machine tool and a hardness testing instrument having a penetration body above the workpiece for movement with respect to the workpiece; (c) linearly scanning a predetermined area of the curved surface of the workpiece for determining the distance between a distance sensor and the curved surface, the region lying in the horizontal path of the machine tool; (d) determining the summit point of the scanned curved surface area from the scanning operation of step (c); (e) selecting the scanned curved area as the test location for the horizontal positioning of the hardness testing instrument; (f) selecting a locus along the scanned curved area of the workpiece as the reference point for the vertical positioning of the machining tool; (g) machining a region into the surface of the workpiece; (f) pressing the penetration body with a defined force into the machined region to generate an impression surface into the machined region of the workpiece; and (i) determining the hardness of the workpiece from the surface of the depression. An apparatus for performing the method is also disclosed.