Niobium titanium microalloyed HRB500E screw-thread steel and preparation method thereof

Abstract

The invention discloses a niobium titanium microalloyed HRB500E screw-thread steel and a preparation method thereof. The HRB500E screw-thread steel comprises the following chemical components of, in percentage by mass, 0.22% to 0.25% of C, 0.30% to 0.50% of Si, 1.2% to 1.5% of Mn, 0.020% to 0.025% of Nb, 0.015% to 0.022% of Ti, 0.011%-0.015% of N, less than or equal to 0.025% of P, less than or equal to 0.018% of S, and the balance Fe and inevitable impurities. The screw-thread steel is prepared through the metallurgy process of 150t combined blown converter smelting-LF refining-7 machine 7 strand billet continuous casting; and through the optimization of an alloy system, Nb + Ti composite microalloying replaces V microalloying, the alloying cost is obviously reduced, the metallurgy process is controllable, and the low-cost stable batch production of HRB500E is realized.

Description

technical field [0001] The invention relates to the technical field of iron and steel materials, in particular to niobium-titanium microalloyed HRB500E threaded steel and a preparation method thereof. Background technique [0002] In the current and future period of time, China's infrastructure construction is still very active, and rebar will continue to occupy an important position and a considerable proportion in steel consumption. Therefore, for a period of time, rebar will still be the single steel series with the largest production and sales volume in China. The production and sales rate in recent years has been measured in hundreds of millions of tons. One of the most important production varieties. [0003] In order to realize the product upgrade of rebar, the new standard GB / T 1499.2-2018 for rebar was released, and it was enforced on November 1, 2018. The new standard cancels the 335MPa grade steel bars and adds 600MPa grade steel bars, which actually meets the n...

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Problems solved by technology

[0009] The present invention mainly aims at the problem that in the current production process of HRB500E threaded steel, vanadium alloy is mainly added to achieve alloy strengthening, but the price of vanadium alloy is high, which makes it difficult to control the cost for production enterprises and users, and provides a niobium-titanium micro-alloyed HRB500E Rebar and its preparation method; the method of the present invention is based on the production of HRB500E rebar by 150-ton double blowing converter smelting-LF refining-7-machine 7-strand billet continuous casting metallurgical process, and realizes low-cost and stable batch production of HRB500E by optimizing the alloy system

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