Method for heating directional silicon steel slab

Abstract

The invention discloses a method for heating a directional silicon steel slab. The method comprises the following steps: smelting components according to common directional silicon steel requirement; casting the components to a slab blank; cooling the slab blank to normal temperature, and carrying out surface treatment on the slab blank; and putting the slab blank in a heating furnace for heating. The method is characterized in that the slab blank adopts a sectional heating mode; and the temperature of the slab blank from surface to one eighth position is controlled to reach 1,300 to 1,350 DEG C for 10 to 20 minutes, so that enough second phase solid solution can be provided, and can be diffused and extracted from the subsurface of a hot rolled plate in a hot rolling or normalizing process to achieve the aims of inhibiting primary crystalline grains and promoting growth of secondary crystalline grains. The method can greatly reduce the high temperature heating time of the directional silicon steel slab in the furnace under the condition of not changing original components, not only can acquire better electromagnetic performance of products, but also can achieve the aims of remarkably reducing the production cost of hot rolling and improving the yield and the production efficiency.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, and relates to a method for producing silicon steel, in particular to a method for heating an oriented silicon steel billet. Background technique [0002] At present, there are two methods for heating oriented silicon steel slabs: one is the high-temperature heating method, which keeps the slab above 1350°C (1350°C-1370°C for GO; 1380°C-1400°C for Hi-B) for a long time (generally 4 to 5 hours) heating, so that the coarse second phase particles > 1um in the slab are solid-dissolved, and then the fine dispersed second phase particles ≤ 50nm are precipitated during the hot rolling or normalizing process, so as to ensure the secondary recrystallization Develop fully and acquire high magnetism. However, the slab heated at high temperature for a long time will cause the following disadvantages: 1) The burning loss due to overoxidation increases (3.5% to 6%), which is about 4 times...

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Problems solved by technology

[0006] The invention discloses a heating method between the slab high-temperature heating method and the low-temperature heating method. However, there is a problem that the post-process technology needs to be significantly adjusted. By controlling the heating temperature system of the slab, the temperature from the surface of the slab to the 1 / 8 layer is rapidly increased, and the temperature is kept for a certain period of time to ensure a certain amount of coarse second-phase particles in this area. Then, in the process of hot rolling or normalization, fine and dispersed precipitation occurs as the temperature decreases, so as to obtain a hot-rolled sheet with fine and dispersed distribution of second phase particles from the surface to 1 / 8 layer

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