Pressed-notch Charpy Testについて
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概要
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A marked tendency to put more and more the V-notch Charpy requirement in force on hull structural steel is seen lately, while it is not always practicable to carry out the test with accuracy.In particular, it is often difficult to prepare the test specimen with accurate V-notch in conformity to rigid requirements of machining tolerance.The paper shows an examination on the applicability of the pressed-notch Charpy test as a commercial test. And its relation to the V-notch Charpy test is also discussed. Main conclusions are asfollows : (1) Pressed-notch is very easy to be provided and its acuity cen be kept without difficulty.(2) Ordinary error in notch depth and a little wear of knife edge for pressing do not disturb the test data.(3) Effect of strain aging caused by pressing notch is also practically negligible.(4) Percentage of crystallinity is more easy to be recorded accurately in the case of pressed-notch than in the case of V-notch.(5) V-notch Charpy value at 0℃ is guaranteed more than 35ft-lb (6kg-m/cm^2), provided that the material shows cleavage depth not exceeding 5mm in the pressed-notch Charpy test at room temperature (about+20℃).(6) In due consideration on the fracture appearances and the load-deflection curves for the van der Veen tests with 3mm and 8mm deep notches, the author suggests that the resistance of the material to the propagation of brittle crack is well expressed by the pressed-notch Charpy data while the main meaning of the V-notch Charpy data is the resistance to the initiation of brittle crack.
- 社団法人日本船舶海洋工学会の論文