Transmission Kossel study of the formation of (110) [001] grains after an intermediate annealing in grain oriented silicon steel containing a small amount of Mo

Abstract

The transmission Kossel (TK) technique was applied in an attempt to elucidate the formation of (110) [001] grains in the recrystallized texture of high induction and low core loss grain oriented silicon steel containing a small amount of Mo after an intermediate annealing. Prior to the detailed TK examination, the etch pit technique was also used for seeking the representative areas of (110) [001] grains. The average matrix grain size of an intermediate annealed steel containing a small amount of Mo is slightly smaller than that with no Mo. The formation of (110) [001] grains in the vicinity of the steel surface is also strengthened due to the addition of Mo. The diameters of single (110) [001] grains are comparable to or slightly larger than those of other matrix grains, but those of the colonized (110) [001] grains occupy extremely large areas (about 40 pet at the maximum area). The areal fraction of (110) [001] grains of the intermediate annealed sheets containing a small amount of Mo is approximately 1 to 5 times as large as that with the conventional inhibitors such as MnSe and Sb. The colonies of (110) [001] grains formed during an intermediate annealing are compatible with the volume fraction inherited from small and well-defined (110) [001] areas with the sharpened TK patterns in the hotrolled sheet containing a small amount of Mo. It is believed that the preferential formation of (110) [001] grains during an intermediate annealing is inherited by the structure memory from the original hot-rolled texture, and it is noticeably strengthened with the addition of Mo.