日本金属学会誌

J. Japan Inst. Metals, Vol. 45, No. 4 (1981),
pp. 388-394

On the Knife Scratching on the Surface of Grain Oriented Silicon Steel

K\=ohei Fukawa1

1Process Technology R & D Laboratories, Nippon Steel Corporation, Kitakyushu

Abstract:

We measured the wattlosses and observed the domain structures of knife-scratched grain oriented silicon steel single crystals, comparing to those of ball-scratching, and discussed the distribution of stresses caused by the scratching, and the reasons why the watt-loss decreases by the scratching and after stress-relief annealing.
The results obtained are as follows: (1) The distribution of residual internal stress caused by the knife-scratching is the same as that of ball-scratching, that is, the tensions perpendicular to the surface exist in the neighlourhood of top surface and bottom surface just beneath the scratch line, but the region of the stresses caused by the knife scratching is narrower than that by the ball scratching. (2) Degree of the deformation caused by the knife-scratching is much larger than that of the ball scratching. On annealing at 1073 K, the specimens with knife-scratching have recrystallized grains along the scratch-line and still have some residual stresses in it. On the other hand, the specimens with ball-scratching recovered to its original state. (3) In the case of knife-scratching, the decrease of wattloss is caused mainly by the internal stress, and the effect of the shape of groove is small. (4) In the case of knife-scratching, wattloss does not recover to the initial value on annealing at 1073 K. This is due to the shape of knife-scratching grooves, recrystallized grains along the grooves and residual internal stress. The effect of the former is much smaller than the sum of the latter two.


(Received 1980/09/27)

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