Ultralow-aluminum non-oriented silicon steel inclusion control method

Abstract

The invention provides an ultralow-aluminum non-oriented silicon steel inclusion control method. Chemical components of the steel type comprise, by mass percent, not larger than 0.005% of C, 0.25%-1.50% of Si, 0.15%-0.55% of Mn, 0.02%-0.06% of P, not larger than 0.005% of S, not larger than 0.005% of Als and the balance Fe and inevitable impurities. The technological process comprises the steps of KR, BOF, RH and continuous casting. The slag amount is strictly controlled during converter tapping, and lime and a slag surface deoxidizer are added to adjust slag after tapping is finished; and after RH decarburization is finished, low-carbon and low-sulfur ferrosilicon, metal aluminum or an aluminum-calcium-iron alloy are firstly added for complex deoxidation, finally metal manganese and ferrophosphorus are added for alloying, then clean circulation is carried out for 6-10 min, and vacuum breaking and tapping are carried out to continuous casting pouring. Obtained molten steel mainly contains SiO2-Al2O3 series inclusions, so that the situation that low-melting-point SiO2-MnO series inclusions are generated, rolling extension and lengthening are caused, and grain growth is affected is avoided; and meanwhile, refractory material corrosion caused by generation of acidic inclusions of high SiO2 components is also avoided. The types of non-metallic inclusions in steel can be remarkably improved, the performance of non-oriented silicon steel is improved, and the pouring performance of the molten steel is improved.

Description

technical field [0001] The invention belongs to the technical field of iron and steel smelting, and in particular relates to a method for controlling inclusions in ultra-low aluminum non-oriented silicon steel. Background technique [0002] Ultra-low aluminum non-oriented silicon steel belongs to cold-rolled non-oriented silicon-manganese static electricity steel, such as W1300 and so on. Because of its simple manufacturing process, low manufacturing cost, wide range of uses, and large market demand, it is widely used in the production of household motors and micro motors, small motors, ballasts and transformers, etc. It is a national power, electronics and military industry. Indispensable soft magnetic alloy. [0003] At present, the smelting process of non-oriented silicon steel is relatively mature, and its conventional production process is: KR desulfurization→converter smelting→RH vacuum refining→continuous casting. Ultra-low aluminum non-oriented silicon steel is sil...

AI Technical Summary

Problems solved by technology

On the one hand, low melting point SiO 2 -MnO series inclusions will extend and become longer during the rolling process, affecting grain growth, resulting in high iron loss, which seriously affects the magnetic properties of non-oriented silicon steel; on the other hand, the generated high SiO 2 Such acidic inclusions seriously corrode the refractory material of smelting RH dipping pipes. The service life of W800 and W600 non-oriented silicon steel RH dipping pipes is about 110 furnaces, while the service life of W1300 non-oriented silicon steel RH dipping pipes is only 50-60 furnaces, which seriously affects molten steel. Quality and normal production

[0004] Patent CN108660294B provides a method for controlling inclusions in silicomanganese-killed non-oriented silicon steel, using synthetic slag and lime slag, and calcium carbide to deoxidize the slag through converter tapping, so that the oxygen potential of the molten steel and slag entering the station is stable and the RH is reduced. Oxidation of the metal after deoxidation alloying to control the composition of the inclusions, but the inclusions in this patented technical solution are mainly high SiO 2 Acidic inclusions, which seriously corrode the refractory materials of the ladle and RH dipping pipe, are not conducive to improving the cleanliness of molten steel

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