1955 Volume 41 Issue 7 Pages 762-770
The steel forging industry in Japan, which had suffered a tragic outcome due to downfall of heavy industries after the Great War- H, gradually has been recovering with rehabilitation. of industries. Nevertheless, from the perspective of quantity, the 1953 figure still lies at the stage of 38% of the 1940 statistics. In the field of techniques, however, rationalization of the equipment has proceeded and attained to an international level in many points owing to introduction of the heat control, the metallurgical control and the statistical quality control. The present paper described the progress in the modern forging technique with. reference to heavy rotorshafts. for generators, steam-turbine rotorshafts and others. The heat treatment after forging of these forged products has made so much progress and, by utilization of the S-curves, forgings have been less liable to suffer from occurrence of flakes. Also, the inspection of internal defects in these forged products by use of supersonic waves has been applied in practice, especially to the generator-rotorshafts.