A method for adding bismuth in the smelting of bismuth-containing high magnetic induction oriented silicon steel

Abstract

The invention provides a method for adding bismuth during smelting of bismuth-containing high-magnetic-inductivity oriented silicon steel. The method comprises the steps: (1) conducting converter smelting and steel tapping; (2) conducting vacuum treatment, specifically, placing a bismuth block container containing bismuth blocks into molten steel directly in the part, added with an alloy material, of a vacuum tube in the descending process of a steel ladle after the molten steel is subjected to vacuum treatment; argon is blown in from the bottom of the steel ladle while the bismuth block container is placed into the molten steel; and (3) carrying out protective casting and the subsequent process. The bismuth block container is composed of a conical barrel, a barrel cover connected to the upper end of the conical barrel and diffusion holes, wherein the diffusion holes are formed in the barrel cover and the conical barrel, and the hole diameter of the diffusion holes is smaller than 10 mm. According to the method, bismuth is easy to add, and the yield of the bismuth is more than 40%; the deviation of the bismuth contents of different parts of a casting blank in the length direction or the thickness direction is + / -10 ppm or so; the bismuth-containing high-magnetic-inductivity oriented silicon steel with the B800 value greater than 1.95 T can be obtained; equipment transformation is not involved, and production of other types of steel is not affected.

Description

technical field [0001] The invention relates to a production method of oriented silicon steel, in particular to a method of adding bismuth in the smelting of bismuth-containing high magnetic induction oriented silicon steel. Background technique [0002] Bismuth is a metal with a low melting point and high vapor pressure. Its melting point is about 271°C, its boiling point is about 1560°C, and its solubility in molten steel is about 20ppm. Similar to Sn, As, Sb, etc., it is a grain boundary segregation element. Taking advantage of this feature, adding bismuth to some alloy steels, especially grain-oriented silicon steel, can significantly improve certain properties. [0003] Taking AlN+MnS inhibitor system as the main high magnetic induction grain-oriented silicon steel as an example, bismuth precipitates along the grain boundaries of primary recrystallization, which hinders the movement of grain boundaries during high temperature annealing. Moreover, when bismuth coexists...

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Problems solved by technology

In this document, in order to prevent the oxidation of molten steel, the aperture of the alloy feeding pipe is small. After a period of use, the feeding pipe is easily blocked by steel slag, and in order to facilitate feeding, its length is generally more than 2 meters, which is not conducive to handling and storage.

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