High-strength fire-resistant anti-seismic steel bars and production method

Abstract

The invention discloses high-strength fire-resistant anti-seismic steel bars and a production method. The high-strength fire-resistant anti-seismic steel bars comprise the components of, in percentageby weight, 0.15%-0.20% of C, 0.7%-0.9% of Si, 0.5%-1.0% of Mn, 0.8%-2.0% of two and more of Ni+C+Mo, 0.1%-0.25% of one and more of Nb + V, 0.05%-0.15% of Ti, 0.0015%-0.0025% of B, less than or equalto 0.003% of N, less than or equal to 0.003% of O, and the balance Fe and inevitable impurities; after LF white slag is subjected to refining for 5 min, and niobium iron and vanadium iron and titaniumiron core wires are added for alloying, the free oxygen range in the molten steel is 30-50 ppm when LF is refined for tapping, the temperature of a continuous casting tundish is 1525 DEG C-1555 DEG C, and the pull speed is 2.8-3.0 m / min, the secondary cooling special water flow is 2.1-2.4 L / Kg, and the initial rolling temperature is 1000 DEG C-1080 DEG C, and the temperature on a cooling bedis 900 DEG C-990 DEG C; the room temperature yield strength of the prepared hot rolled steel bar finished product is more than or equal to 650 MPa, the yield ratio is less than or equal to 0.8%, the special elongation is more than or equal to 17%, the uniform elongation is more than or equal to 10%, and the yield strength at the high temperature of 600 DEG C is more than or equal to 435 MPa.

Description

technical field [0001] The invention belongs to the field of high-strength steel bar production, and in particular relates to a high-strength fire-resistant and earthquake-resistant steel bar and a production method. Background technique [0002] At present, my country's buildings are still dominated by reinforced concrete, and ribbed steel bars consume the most in construction steel. With the emergence of high-rise, long-span, earthquake-resistant, low-temperature-resistant and fire-resistant multifunctional building structures, the performance and quality of building steel, especially building steel bars, has become a measure of whether the building is safe and reliable, and whether the building design can be guaranteed. An important parameter of life; and the occurrence of fires in high-rise buildings has caused major threats and losses to human life and property, and people have gradually realized the importance of the fire resistance of building steel bars for building ...

AI Technical Summary

Problems solved by technology

Controlled rolling and controlled cooling at a lower temperature has higher requirements on the rolling mill and requires the use of high-load rolling equipment. At present, most steel bar production lines do not have the technological conditions to produce this type of product

In addition, although the steel bars produced by the low-temperature rolling method have improved steel strength, low-temperature rolling is prone to uneven deformation, resulting in uneven performance and reduced plasticity.

[0005] Patents CN 109097682 A and CN 104032234 A both relate to refractory steel bars and their production methods. Refractory steel bars are produced through alloy composition design and rolling process control, but the room temperature yield strength of the refractory steel bars is 456-645MPa, far from 650MPa , can not meet the current and future demand for high-strength building steel bars for fire resistance

[0006] Patent CN 105543704 A relates to a high-strength refractory steel plate that adopts Cr, Mo, Nb, Ti, Ni, V composite alloying design and combined with controlled rolling to produce, but the steel plate needs to be heat-treated to achieve the required performance, production control The process is complicated and the production cost is high

[0007] To sum up, currently, for refractory steel bars, the normal temperature yield strength is ≥650MPa, the high temperature yield strength is ≥435MPa at 600°C, and the steel bars and production methods that meet the comprehensive seismic requirements have not been reported yet.

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