-196℃ ultra-low temperature seismic structural steel

Abstract

The invention discloses a -196°C ultra-low temperature anti-seismic structural steel. The chemical composition of steel is by weight percentage: C: 0.02~0.10, Si: 0.10~0.25, Mn: 0.3~0.8, Ni: 6.5~12.5, Cr+Mo+Cu: ≤0.5, Nb+V+Ti: ≤0.05 , Als: 0.02~0.04, S: ≤0.005, P: ≤0.015, the total amount of O and N ≤0.008, and the balance is Fe and unavoidable impurities. After high-temperature quenching + low-temperature quenching + tempering heat treatment on the steel plate, a multi-phase structure composed of massive ferrite, tempered martensite and austenite is formed, and the percentage content of each component ( %) are 6~14, 65~80, 15~20, respectively, and the content of Ni in each component is 2~7, 4~12, 15~20 in order by weight percentage. The steel has low Excellent seismic comprehensive mechanical properties such as yield ratio (0.67-0.80), high uniform elongation (17-24%), high strength (yield strength 830-925MPa) and high toughness (impact energy 160-198J). The invention has simple process and is easy to realize industrialized production.

Description

technical field [0001] The invention belongs to the field of anti-seismic structural steel, and in particular relates to a structural steel with excellent anti-seismic comprehensive mechanical properties such as low yield ratio, high uniform elongation, high strength and high toughness in an ultra-low temperature service environment of -196°C. Background technique [0002] Seismic zones are widely distributed in my country, and many low-temperature steel structures such as liquefied natural gas (LNG) storage tanks and LNG transmission network pipes under construction and planned, as well as low-temperature equipment such as liquefaction and gasification, are inevitably built and operated in seismic zones. The main hazards of earthquakes to steel structures are: when the earthquake horizontal force exceeds the yield strength of steel, large plastic deformation occurs in the components, causing structural instability or even failure, resulting in catastrophic damage. Therefore...

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Problems solved by technology

However, there are almost no reports on the literature and patented technologies of structural steel that can meet the requirements of low yield ratio, high uniform elongation, high strength and high toughness under the ultra-low temperature service environment of -196°C.

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