Niobium-titanium microalloying HRB400-scale screw-thread steel and manufacturing method thereof

Abstract

The invention discloses a kind of niobium-titanium microalloying HRB400-scale screw-thread steel and a manufacturing method thereof. The screw-thread steel comprises C, Si, Mn, P, S, Nb, Ti, N and the balance Fe and impurities. The manufacturing method of the niobium-titanium microalloying HRB400-scale screw-thread steel comprises the following steps of smelting in a revolving furnace, treatment outside the furnace, continuous casting, casting blank heating and rolling. During smelting in the revolving furnace, alloy such as silicomanganese and ferroniobium is added for niobium microalloying treatment. During treatment outside the furnace, argon is blown in an argon station, and refining is conducted in an LF furnace. In the process of refining in the LF furnace, a ferrotitanium core-spun yarn is fed for titanium microalloying treatment. According to the technical scheme, before tapping, alloy such as silicomanganese and ferroniobium is added for niobium microalloying treatment, the ferrotitanium core-spun yarn is fed in the process of refining in the LF furnace for titanium microalloying treatment, after titanium is fused into molten steel, proper niobium-titanium microalloying treatment is conducted, the yield of the niobium-titanium alloy is increased, and stable, sustainable and low-cost production of the screw-thread steel is achieved.

Description

technical field [0001] The invention relates to the technical field of steel manufacture, in particular to a niobium-titanium micro-alloyed HRB400 grade threaded steel and a manufacturing method thereof. Background technique [0002] Rebar is a common name for hot-rolled ribbed steel bars, and its grades are composed of H (Hotrolled), R (Ribbed with ribs), B (Bars steel bar) and the minimum yield point value. At present, China's steel consumption still has the obvious characteristics of developing countries. The consumption of construction and industrial steel accounts for about 90% of the total consumption, while construction steel accounts for more than 50%. Therefore, rebar will still be the single steel series with the largest production and sales volume in China for a period of time. One of the main 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 ...

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Problems solved by technology

[0006] The purpose of the present invention is to propose a niobium-titanium microalloyed HRB400 grade threaded steel and its manufacturing method to solve the problems of low strength level of existing threaded steel, high production cost, and poor yield of titanium microalloyed titanium and nitrogen , the manufacturing method adopts titanium or niobium-titanium composite microalloying instead of vanadium microalloying to produce HRB400 grade rebar, the diameter of the rebar is 12~28mm, the yield strength ReL of the rebar at room temperature ReL≥450MPa, the tensile strength Rm≥600MPa, yield strength ratio Rm / Rel≥1.3, has the advantages of high strength, small weight deviation, good stability, etc., and meets the performance requirements of the new national standard

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