A method for controlling inclusions in ultra-low aluminum non-oriented silicon steel

Abstract

The invention provides a method for controlling inclusions in ultra-low aluminum non-oriented silicon steel. The chemical composition mass percentage of the steel is C≤0.005%, Si: 0.25%‑1.50%, Mn: 0.15%‑0.55%, P: 0.02%‑0.06%, S≤0.005%, Als≤0.005%, and the balance is Fe and unavoidable impurities. The process flow is: KR→BOF→RH→continuous casting. Converter tapping strictly controls the amount of slag, adding lime and slag surface deoxidizer to adjust slag at the end of tapping; after RH decarburization, first add low-carbon and low-sulfur ferrosilicon, metal aluminum or aluminum-calcium-iron alloy compound deoxidation, and finally add metal manganese , ferrophosphorus for alloying, and then a net cycle of 6-10min, the steel is broken out and transported to continuous casting. The obtained molten steel is mainly SiO 2 ‑Al 2 o 3 System inclusions, avoiding the formation of low melting point SiO 2 ‑MnO-based inclusions make the rolling elongation longer and affect the grain growth; at the same time, it also avoids the formation of high SiO 2 The components are acidic inclusions, leading to corrosion of refractory materials. It can significantly improve the type of non-metallic inclusions in steel, improve the performance of non-oriented silicon steel, and improve the pouring performance of molten steel.

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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