690MPa-yield-strength low-yield-tensile-ratio antiseismic steel and manufacturing method thereof

Abstract

The invention relates to a 690MPa-yield-strength low-yield-tensile-ratio antiseismic steel and a manufacturing method thereof, belonging to the technical field of architectural structural steel. The antiseismic steel comprises the following chemical components: 0.05-0.13wt.% of C, 0.00-0.50wt.% of Si, 1.50-2.50wt.% of Mn, less than 0.012wt.% of P, less than 0.006wt.% of S, 0.15-0.50wt.% of Mo, 0.02-0.12wt.% of Nb, 0.00-0.15wt% of V, 0.01-0.025wt.% of Ti, 0.0010-0.0030wt.% of B, 0.01-0.06wt.% of Al and the balance of Fe and inevitable impurities. On such basis, one or more of the following alloy elements are added: 0.00-0.80wt% of Cu, 0.00-0.50wt% of Cr and 0.00-1.00wt% of Ni. The total addition amount of the alloy elements in the steel is not greater than 5%. A heavy and medium plate mill is utilized to perform controlled rolling and controlled cooling to obtain the fine-grain bainite-martensite structure; and two-phase region secondary isothermal heat treatment is combined to obtain a certain amount of metastable austenite/microalloy precipitate enhanced substrate; the antiseismic steel satisfies the requirements for mechanical properties of 690MPa-yield-strength architectural antiseismic design code, can be used in an antiseismic structure, and can also be used in the field of engineering machinery.

Description

technical field [0001] The invention belongs to the technical field of structural steel for construction, and in particular relates to an anti-seismic steel with a yield strength of 690 MPa and a low yield strength ratio and a manufacturing method thereof. Background technique [0002] Because of good earthquake resistance, high space utilization, flexible and beautiful design, recyclable use, short construction period, reliable quality and easy control, steel structure buildings have appeared in large numbers. Steel plates with a yield strength below 460MPa in China and a tensile strength below 590MPa in foreign countries have been widely used and popularized for earthquake-resistant building structures. High-rise, long-span, high safety, energy conservation and environmental protection are the development trends of modern large-scale buildings. In order to adapt to this development trend, the structural steel used in earthquake-resistant buildings is developing towards a ...

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Problems solved by technology

Especially the steel for earthquake-resistant building structures with a yield strength of 690MPa, according to the requirements of GB50011-2010, the low yield ratio requires its tensile strength to reach about 900MPa, and its strong plastic product to reach about 18GPa%. For example, TRIP steel and Q&P steel can achieve it, but medium and thick plates that achieve this performance have not been reported.

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