Patent ID: 7785393
Filing Date: 2010-08-31
Classification: B22D,C21C

Abstract:
1. The method of making silicon-bearing steel having a carbon content between 0.003 and 0.5% by weight comprising the steps of: a) refining molten steel to make a silicon-bearing steel having a silicon content between 0.1% and 0.5% by weight by addition of a calcium-containing silicon additive, b) determining the amount of calcium content in the calcium-containing silicon additive, c) determining whether the amount of calcium in the calcium-containing silicon additive is more or less than the amount of calcium desired in the finished steel, d) when the amount of calcium in the calcium-containing silicon additive is more than the amount of calcium desired in the finished steel, adding the amount of calcium-containing silicon additive corresponding to the excess calcium early in the refining to combine with sulfur and other impurities in the steel during the refining; e) desulfurizing the molten steel; f) adding the calcium-containing silicon additive containing the total amount of calcium desired in the finished steel after desulfurization of the molten steel and before casting, and g) when the amount of calcium in the calcium-containing silicon additive does not provide the total amount of calcium desired in the finished steel, adding an additional amount of calcium after desulfurization of the molten steel and before casting to the molten steel during refining.