Niobium-titanium-nitrogen and titanium-nitrogen composite micro-alloyed HRB400E steel bar and production method thereof

Abstract

The invention provides a niobium-titanium-nitrogen and titanium-nitrogen composite micro-alloyed HRB400E steel bar and a production method thereof, and belongs to the technical field of iron and steelsmelting. The niobium-titanium-nitrogen and titanium-nitrogen composite micro-alloyed HRB400E steel bar comprises, by mass, 0.21-0.25% of C, 0.50-0.65% of Si, 1.40-1.55% of Mn, not greater than 0.045% of P, not greater than 0.045% of S, 0.015-0.025% of Ti, 0.010-0.020% of Nb, 0.0070-0.0110% of N, and the balance Fe and other impurities. In the production method, ferrosilicon, silicomanganese anda carburant are added at the time of 1/4 tapping, and all alloys are added at the time of 3/4 tapping; the titanium-nitrogen alloy is added at an argon blowing station, and the argon blowing time is greater than or equal to 6 minutes; and high-casting-speed casting powder is adopted for continuous casting, a billet is heated, rolled and fed onto a cooling bed, and finally, the finished product isobtained. According to the niobium-titanium-nitrogen and titanium-nitrogen composite micro-alloyed HRB400E steel bar and the production method thereof, by adding the titanium-nitrogen alloy at the molten steel exposure positon of the argon blowing station, the titanium yield is increased; by reducing the influence of the niobium and titanium content on the quality of the high-casting-speed continuous casting billet, the titanium inclusion in steel is reduced, and the castability of molten steel meets requirements; and by adopting the high-casting-speed continuous casting powder, the cast billet quality is improved.

Description

technical field [0001] The invention relates to the technical field of iron and steel smelting, in particular to a microalloyed HRB400E steel bar and a production method thereof. Background technique [0002] Niobium, vanadium, and titanium are all important microalloying elements. In the production process of HRB400E rebar, most steel mills use vanadium and niobium elements, and very few steel mills use titanium elements, mainly due to the active nature of titanium elements. , easily react with oxygen, sulfur, nitrogen and other elements in molten steel. [0003] However, vanadium alloys are much more expensive than titanium alloys. Since July 2018, the price of vanadium-nitrogen alloy has been rising continuously. Among the alloy market prices in October, vanadium-nitrogen was 798,000 yuan / ton, titanium nitrogen was 50,000 yuan / ton, and niobium-titanium-nitrogen alloy was 150,000 yuan / ton . If the titanium yield can be increased, the problem of titanium microalloying ca...

AI Technical Summary

Problems solved by technology

If a niobium-titanium-nitrogen composite alloy is added during the tapping process of the converter, the molten steel is not completely deoxidized and has strong oxidizing properties, a large amount of titanium will be oxidized, and the yield is extremely low

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