Fire-resistant and earthquake-resistant steel for construction and production method thereof

Abstract

The invention relates to a fire-resistant and earthquake-resistant steel for construction. The steel comprises the following components by weight percent: 0.1-0.18 % of C, 0.1-0.50 % of Si, 1-1.80 % of Mn, less than or equal to 0.025 % of P, less than or equal to 0.015 % of S, less than or equal to 0.50 % of Cr, less than or equal to 0.30 % of Mo, less than or equal to 0.04 % of Al, less than or equal to 0.007 % of N, less than or equal to 0.006 % of Ca, one or two or more of less than or equal to 0.050 % of Nb, less than or equal to 0.055 % of V and less than or equal to 0.035 % of Ti, with Nb+V+Ti being <= 0.055 %, and the balance being Fe and unavoidable impurities. A production method comprises heating under a temperature of 1180 DEG C, insulating for 3 hours, rolling with a starting temperature of not less than 1180 DEG C, an accumulated reduction rate of last three controlled rolling being not less than 35 %, and a terminating temperature of 860 to 900 DEG C, and then directly air-cooling to a room temperature or cooling with a rate of 5 to 15 DEG C per second to the room temperature. The obtained steel is excellent in fire resistance, low in yield ratio (Rp0.2 / Rm <= 0.75), and good in earthquake-resistance performance, with Rp0.2 (yield strength at 600 DEG C) / Rp0.2 (yield strength at the room temperature) >= 2 / 3.

Description

technical field [0001] The invention relates to building steel, in particular to an economical fire-resistant and earthquake-resistant building steel and its manufacturing method. Background technique [0002] At present, steel structures are widely used in high-rise buildings and long-span buildings due to their light weight, low foundation cost, short construction period, ability to solve complex problems in large spaces, good integrity and earthquake resistance, and renewable utilization of resources. The application of steel structure has obvious advantages, and it is also the development direction of future buildings. However, the Achilles heel of conventional steel structures is low fire resistance—it is easy to soften and lose basic bearing capacity after a fire occurs in a high-temperature environment, which seriously restricts the development of steel structure buildings. [0003] In the prior art, related patents on fire-resistant and earthquake-resistant building...

AI Technical Summary

Problems solved by technology

The content of precious metal alloy elements such as Mo and Cr in these steels can be low, but the production process is too complicated, and it needs to be produced by quenching + tempering heat treatment process after rolling forming

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