Transactions . no matter how high thetemperature of anneal was carried, short of the actual melting point, thegrains always formed with their longest dimension in the direction inwhich the original sheet had been rolled. This is quite remarkable inthat the large grains do not grow under 1,050° C, and it is difficult tounderstand how any strain could persist after the piece had been annealedto 800° C. Repeated experiments, however, have demonstrated beyondquestion that the effect of rolling does persist, very much like the latentimage on a photographic plate. This fact, coupled with the facts n
Transactions . no matter how high thetemperature of anneal was carried, short of the actual melting point, thegrains always formed with their longest dimension in the direction inwhich the original sheet had been rolled. This is quite remarkable inthat the large grains do not grow under 1,050° C, and it is difficult tounderstand how any strain could persist after the piece had been annealedto 800° C. Repeated experiments, however, have demonstrated beyondquestion that the effect of rolling does persist, very much like the latentimage on a photographic plate. This fact, coupled with the facts notedin the preceding paragraph, gave rise to a closer investigation of theeffect of mechanical working. 576 GRAIN GROWTH IN SILICON STEEL. The two samples shown in Fig. 8 were rolled along the edges a, so thatthe samples were reduced in thickness for only about one-third of thewidth. After annealing at 1,050° C. for an hour they developed thestructure shown. The deformed areas have small grains, while those. Fig. 8.—Showing the Effect of Strain upon the Structure of Silicon were Rolled along the Edges a. Actual Size. areaswhich were put under strain without any actual deformation developedgrains of considerable coarseness, which have grown in the direction ofstrain. Samples hammered with a ball hammer showed the same effect,, a small fine-grained circular area surrounded by a fringe of largegrains extending into the surrounding unaltered portion. GRAIN GROWTH IN SILICON STEEL. 577 Several large-grained samples were then hammered lightly in differentportions of the grains, and these worked areas, after annealing above900° C, were found to be broken up into smaller grains. In this case,
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
