高速度衝撃による金属の変形と破壊(2)
1956 年 25 巻 3 号 p. 108-110
詳細
1956 年 25 巻 3 号 p. 108-110
Report is made on the propagation of fractures in mild steel plates caused by impact of high speed bullets with observations on twinning of ferrite grains and distortion of twin lines. (1) On the propagation of fracture
For as-rolled plates, resistance to fracture is larger in the direction of the rolling than in the direction perpendicular to it. This difference is lost by annealing.
In annealed plates, the crack is apt to take its path along pearlite grains. In as-rolled plates, crack with bifurcation is observed.
(2) On the deformation after twinning Micro-photographs show that the twinning is completed at the moment of impact followed by intense distortion of twin lines with the flow of ferrite grains. From this fact, it is denied that the twinning would proceed simultaneously with the brittle-type fracture.
