Method for controlling nitrogen content of high-permeability-grade oriented electrical steel belt

Abstract

The invention relates to the technical field of steelmaking, in particular to a method for controlling the nitrogen content of a high-permeability-grade oriented electric steel belt. The method particularly includes following steps that molten steel is connected with bottom flushing nitrogen after reaching an RH (relative humidity) refining furnace, and nitrogen flushing treatment is performed for the molten steel; ultimate vacuum treatment is performed at the preliminary stage of RH refining treatment, RH ultimate vacuum degree is smaller than or equal to 200Pa, and nitrogen circulates in anRH vacuum chamber in the whole process; and after the ultimate vacuum treatment is performed for 12 minutes to 15 minutes, RH vacuum degree is reset according to the initial nitrogen content of the molten liquid, RH refining nitrogen adding treatment is performed, and the RH vacuum degree is reduced after a nitrogen adding target value is reached. By means of reasonably controlling nitrogen flow and the RH vacuum degree in an RH refining process, requirements on nitrogen content precision for production of the high-permeability-grade oriented electric steel belt are met. Besides, the method is simple, is high in applicability, and does not affect controlling to purity and H content of the high-permeability-grade oriented electric steel belt.

Description

technical field [0001] The invention relates to the technical field of steelmaking, in particular to a method for controlling the nitrogen content of a high-permeability grade oriented electrical steel strip. Background technique [0002] High magnetic permeability grade oriented electrical steel strip requires that the N content of molten steel should be controlled stably at ±5ppm. By stably controlling the N content and Als content of molten steel, quantitative and fine dispersed AlN will be formed in the hot rolling and normalized pickling process. As an inhibitor, AlN inhibits the growth of primary grains, forms Goss texture through secondary recrystallization during high temperature annealing, and produces oriented electrical steel strips with good magnetic properties. In order to meet the nitrogen content control requirements in the production of high-permeability grade grain-oriented electrical steel, the method of nitrogen increase control by adding nitrided alloys h...

AI Technical Summary

Problems solved by technology

In order to meet the nitrogen content control requirements in the production of high-permeability grade grain-oriented electrical steel, the method of nitrogen increase control by adding nitrided alloys has been adopted at home and abroad, but the nitrogen increase control of nitrided alloys has the situation that the nitrogen absorption rate of steel liquid is unstable. , it is difficult to meet the requirement of controlling the N content of molten steel within ±5ppm accuracy

At home and abroad, the RH refining process is also used to switch between N gas and Ar gas to control liquid steel nitrogen. This method requires equipment modification, and the cost of using Ar gas is also higher than that of N gas treatment throughout the process.

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