1984 Volume 70 Issue 15 Pages 2057-2064
Transmission KOSSEL(TK) technique has been applied in an attempt to elucidate the origin of the potential nuclei of the celebrated (110) [001] secondary grains in hot-rolled sheets of high induction grain oriented silicon steel with or without a small amount of Mo. In the microstructure in the vicinity of the surface of the hot-rolled sheets, the development of the recrystallized grains is much more noticeably retarded and the polygonized {110} <001> grains elongated to the rolling direction are more preferentially formed in Mo added steel than in that of free from Mo. By TK measurement, two kinds of polygonized {110} <001> grains are found at the 1/10 depth ; large polygonized (110) [001] grains containing the highly oriented (110) [001] areas with sharpened TK patterns and small polygonized {110} <001> grains with all the diffused TK patterns. The potential nuclei of (110) [001] secondary grains can be inherited by the structure memory from the highly oriented (110) [001] areas within the former large polygonized (110) [001] grain. The frequency of generation and the rate of occupation of (110) [001] secondary nuclei of the hot-rolled sheet containing a small amount of Mo are approximately three times larger than those of free from Mo. It is considered that grain oriented silicon steel containing a small amount of Mo is more effective in the development of (110) [001] secondary grains having small grain sizes.