Production process of high-quality ultra-low-carbon IF steel

Abstract

The invention discloses a production process of high-quality ultra-low-carbon IF steel. The production process includes the procedures of blast furnace molten iron, DeS pretreatment desulfurization, DeP dephosphorization, DeC decarbonization, RH vacuum treatment and CC conventional slab continuous casting. In the DeP dephosphorization procedure, the final temperature is not lower than 1330 DEG C, and the mass percent of final semi-steel components are controlled so that the mass percent of C can range from 3.40% to 3.60%, the mass percent of S cannot be higher than 0.010% and the mass percent of P cannot be higher than 0.040%. In the DeC decarbonization procedure, non-turning-down direct discharge is adopted, and the mass percent of final molten steel components are controlled so that the mass percent of C can range from 0.025% to 0.040%, the mass percent of S cannot be larger than 0.011% and the mass percent of P cannot be larger than 0.010%, and the final temperature ranges from 1680 DEG C to 1700 DEG C. In the RH vacuum treatment procedure, a vacuum mechanical pump is used for adjusting the vacuum degree. In the CC conventional slab continuous casting procedure, a tundish is made of non-carbon and non-magnesium refractory, and the draw speed is controlled to range from 1.1 m / min to 1.4 m / min. By means of the method, a continuous casting billet without any defect is produced, high-quality hot-rolled coiled plates are produced through hot rolling, and high-quality continuously-annealed and zinc-plated products are finally produced through cold rolling.

Description

technical field [0001] The invention belongs to the field of iron and steel smelting, in particular to a production process of high-quality ultra-low carbon IF steel. Background technique [0002] IF steel (Interstitial Free Steel), also known as interstitial free steel, has the characteristics of excellent deep drawing performance, ultra-low carbon, microalloying, and pure steel, as well as high plastic strain ratio and high elongation. , high hardening index, low yield ratio, and excellent non-aging performance, so it is known as the third generation of ultra-deep drawing steel, and is widely used in the automobile industry and home appliance industry. Its essence is to add Ti and Nb to steel to form nitrogen-containing compounds of Ti and Nb, so as to obtain clean ferritic steel without interstitial atoms, that is, ultra-low carbon interstitial atom-free steel. [0003] In recent years, with the rapid development of the automobile industry, the demand for IF steel has in...

AI Technical Summary

Problems solved by technology

Adopting the above-mentioned production process will bring about the following problems: First, the use of a 100t converter with a small capacity will cause a large rate of temperature drop during the production process, causing RH refining to increase the temperature by supplementing oxygen and increasing the probability of formation of molten steel inclusions; P is difficult, the production cycle is long, and the rhythm of the conventional slab continuous casting machine is asymmetrical, resulting in fluctuations in casting speed, large fluctuations in mold liquid level, prone to mold slag entrainment, and adverse effects on the surface quality of coils

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