軟鋼突合せ溶接継手の繰返衝撃引張試験について
1963 年 12 巻 113 号 p. 93-98
詳細
1963 年 12 巻 113 号 p. 93-98
In this experimental research, the authors carried out the repeated tension impact tests on butt welded joint connecting the plates of mild steels by using the universal repeated impact testing machine (Fujii type, capacity; 40∼5kg-cm, number of repetitions 600/min)
In these tests, four types of specimens in rolling direction were prepared, which were as follows: (A) Butt welded joint specimens, as-welded condition. (B) The same, reinforcement machined off. (C) The same, stress relief heat treatment. (D) Base metal specimens.
Some of the experimental results obtained are summarized as follows:
(1) The E-N curves, which show the results of the tests, plotted in normal-log scale, discontinuously change from upper curves to lower curves, without exception. The specimens fractured with large scale plastic deformation on upper curves, and with true fatigue fractured surface on lower curves.
(2) The fracture of all specimens on upper curves occurred at the parallel part of the base metal. On lower curves, the fracture of specimens at as-welded condition and of those machined off reinforcement occurred at the toe of the welded joint, while, the greater part of the heat treated specimens fractured at the fillet of the base metal, and the rest fractured at the toe of the joint.
(3) The values of impact fatigue strength at 105 and 5×105 cycles were estimated from the results of the tests as shown by Table 3.
