GB703193A - Improvements in or relating to hardness testing machines - Google Patents

Abstract

703,193. Testing physical qualities of materials. NAPIER & SON, Ltd., D. Aug. 20, 1952 [July 27, 1951], No. 17813/51. Class 106 (2) An apparatus for subjecting the internal surfaces of tubes 10, Fig. 3, to a hardness test comprises a support 4 extending into the bore to be tested, and external pressure applying means for hydraulically or otherwise forcing an indentor 5 on the support 4 into engagement with the tube 10. Viewing means 45 are mounted on the support 4 so that the indentation formed in the surface of the tube by the indentor can be viewed through means such as a microscope 48 when the indentation is moved under the microscope. For this purpose, the tube 10 may be mounted on a movable trolley 53. The external pressure applying means may comprise a weight 22, Fig. 4, movable to various positions along a lever arm 21, the arm acting on a hydraulic pressure creating device 18 connected to the indentor 5. The indentor 5 may be included in an electric circuit wherein a system of lamps is adapted to indicate (a) when the indentor has penetrated to a required depth in the tube and (c) when the indentor has been at the required depth for a given time interval. The pressure exerted by the indentor is determined by means of the weight 22 and arm 21 or by connecting a pressure gauge in the hydraulic circuit. The support 4 includes means for illuminating the indentation.