AE法による鉱車連結用リンクの低温脆性に関する研究
1986 年 102 巻 1185 号 p. 789-794
詳細
1986 年 102 巻 1185 号 p. 789-794
The problem of cold shortness of mine tub couplers, arose in winter at a coal mine in Hokkaido, Japan. Regarding this problem, the acoustic emission method was applied to the tensile test of the stud link and the fracture toughness test of same material at a low temperature.
Some stud links were tested under tention at a temperature of -30-20°C. The positions of fracture were classified as follows:(1) the loading part, (2) the corner and (3) the smallest section of link as shown in Photo. 1. Two of them broke brittlely and it was possible to locate defects by the method of acoustic emission. The results of fracture toughness test were concluded as follows: Forged carbon steel containing a fatigue crack breakes brittlely below a temperature of -10°C. Fracture toughness and crack growth factor reduce and the acoustic emission becomes active as the temperature declines The method of acoustic emission generally gives us low values of fracture toughness because it detects the acoustic signals caused by the void growth prior to the slow crack growth.
