The effect of melt carbon content on the grain growth behavior and induction of boron silicon-iron

Carbon is usually considered to be an unavoidable impurity rather than an alloying element in conventional grain oriented silicon-iron. In the laboratory, this alloy can be readily made from heats with very low initial carbon content, However, carbon has been found to serve a necessary function in high permeability boron silicon-iron, and may be necessary in high permeability silicon-iron alloys generally. Laboratory heats of boron silicon-iron were found to require, with 3.1% silicon, a melt carbon content of not less than about 0.02% in order for secondary recrystallization to occur in the final anneal. This minimum carbon content is the amount required to begin to form austenite at the hot rolling temperature. Only 0.010% carbon is required for complete secondary recrystallization if 1.1% nickel, also an austenite former, is present. In the absence of austenite during hot rolling, during the final anneal there is less restraint on the normal grain growth and fewer potential