METHOD OF DETERMINING CRYOGENIC FRACTURE TOUGHNESS VALUE AND APPARATUS FOR TESTING FRACTURE TOUGHNESS AT CRYOGENIC TEMPERATURE

摘要

PURPOSE:To facilitate the production of a small-sized punch test piece and to reduce the consumption of liquid helium by using a desk type tension tester having a load cell and applying load to the small-sized test piece by the projecting part thereof in the state of immersing the small-sized test piece which is grasped and held by a mounting means into a cryogenic cooling medium. CONSTITUTION:The small-sized punch test piece mounting means D is mounted in the hole part of a moving plate and a pulling rod 2 is raised by operating the desk type tension tester A having the load cell. A pulling plate 3 ascends together with the moving plate 6 and the mounting means D ascends as well. The front face of the punch 11 comes into contact with the projection 4a of a stationary plate supported by respective posts 5 and the load increases gradually until a steel ball 10 is pressed to the small-sized punch test piece 21 by the punch 11 at the cryogenic temp. of the liquid helium, by which the test piece 21 is bulged and broken. The production of the test piece is thus facilitated and the consumption of the liquid helium is reduced.