There are a few reports that Cu sulfides precipitate with the addition of Cu in the grain-oriented silicon steel, but the precipitates of Cu sulfides have not yet been well observed Thus, the observation of the precipitation of Cu sulfides is performed and the metallurgical effects of Cu addition on the grain-oriented silicon steel are studied.
(1) With the addition of small amount of Cu, fine particles of (Cu, Mn) 1.8S (size 200500Å) precipitate and inhibition effects of normal grain-growth are enhanced. The distribution of Cu sulfides in hot rolled sheets provides beneficial geometrical situation to grow sharp Goss grains selectively during the secondary recrystallization.
(2) In the texture at the subsurface of hot rolled sheets, {110} (001) grains are increased, and after decarburization, {554} <225> and {110} <001> grainsare increased, on the other hand {100} <001> grains are decreased. These make secondary recrystallization easy.
(3) When small amount of Cu is added and cold rolling reduction is increased from 55% to 65%, there are improvements of magnetic properties of grain-oriented silicon steel.
