衝撃捩り試驗に依る燒入燒戻工具鋼の粘り強さの研究

抄録

The newly designed impact torsion tester which has the capacity of 30kg-m by the initial striking speed of 1, 000 rev/min is sbown in Figs. 1 and 2, Using this tester, the impact torsion tests of three carbon tool steels were made and the results are shown in Figs. 4 to 14. Two maxima of the impact torsion value occurred at drawing temperatures of 200° and 350° and two minima at 270° and 400° Drawing up to the first maximum point is very desirable for these carbon tool steels. The fact that the impact and static torsion tests are the best method to study toughness of hard and brittle materials, is shown by the experiment (Figs. 16 to 20), and explained theoretically using the Sunatani's law of failure.