Titanium micro-alloyed 400MPa grade high-strength steel bar and production method thereof

Abstract

The invention discloses a hot-rolled 400MPa grade high-strength steel bar for reinforced concrete and a production method for the steel bar, and belongs to the technical field of micro-alloying of ferrous metallurgy. The steel in the steel bar comprises the following chemical components in percentage by weight: 0.16 to 0.25 percent of C, 0.20 to 0.80 percent of Si, 1.20 to 1.50 percent of Mn, 0.02 to 0.06 percent of Ti, less than or equal to 0.01 percent of N, less than or equal to 0.045 percent of S, less than or equal to 0.045 percent of P, and the balance of Fe and inevitable impurities. The preparation method for the steel bar comprises the following steps of: a, smelting crude molten steel, tapping, deoxidizing and alloying; b, refining, finely regulating the components, and pouring; and c, hot rolling, wherein titanium is alloyed in the tapping process and after deoxidizing or in the refining process. By using the principle that the titanium plays a role in precipitation and reinforcement in the steel, the mechanical properties of the steel such as yield strength and tensile strength are improved, and the property requirement of the 400MPa grade high-strength steel bar is met..

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy microalloying, and in particular relates to a hot-rolled 400MPa high-strength steel bar for reinforced concrete and a production method thereof. Background technique [0002] At present, my country is in a period of rapid industrialization and urbanization, and the construction industry is developing rapidly to large-scale. The construction industry is developing toward large scale. In order to improve the safety of large buildings, the construction industry at home and abroad generally uses high-strength, high-weldability hot-rolled ribbed steel bars instead of ordinary steel bars. In addition, with the introduction of policies to promote the use of high-strength steel bars in my country, low-strength steel bars below 335 MPa such as HRB335 will be gradually eliminated, and hot-rolled ribbed steel bars of HRB400 and above levels will be vigorously developed. The newly revised na...

AI Technical Summary

Problems solved by technology

However, the production cost of vanadium and its alloys, niobium and its alloys is relatively high, which not only squeezes the profit margin of enterprises, but also causes the shortage of vanadium and niobium resources, which is not conducive to the production and application of 400MPa high-strength steel bars and earthquake-resistant steel bars.

[0004] The Panxi area is rich in vanadium and titanium resources. The use of vanadium to strengthen steel bars by micro-alloy carbonitride precipitation has been widely used, and the use of micro-titanium treatment to refine the austenite grains of steel bars has also been applied, but the use of titanium to strengthen steel bars has been widely used. Precipitation strengthening of microalloyed carbonitrides has not been reported

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