Design of utility tools and their application for testing mechanical properties of metallic materials

Abstract

This paper deals with the design of a series of tools which could assist the preparation of samples, the positioning and the measurement to resolve the problems that exist in mechanical properties testing. In order to decrease the operational difficulty and improve the quality of preparation, two kinds of fixtures are made to clamp the hardness sample and be used to grind or polish by the grinder. For the measurement of percentage elongation after fracture and percent reduction of area, a special device is assembled to quickly splice the fractured test pieces. By applying a single transverse fastening force, the efficiency of splicing of the test pieces can be increased substantially and it provides enough operation space for the vernier caliper. To raise the placing efficiency and avoid the dragging of Charpy impact test piece, a special gripping plier is designed to ensure the coincidence of the plane of symmetry of the notch and the swing plane of the striker. By using the supports of testing machine and separating the function of alignment and fixation, the new structure resolves the matters of existing method as unsatisfied placing effect or dragging of the test piece. In order to accurately install the fixtures of electro-hydraulic servo fatigue test system, a set of positioning brackets and plate tool are made to adjust the location of the large base and check the deflection between the fixtures.