196 DEG C below zero ultralow-temperature quake-proof structural steel

Abstract

The invention discloses a 196 DEG C below zero ultralow-temperature quake-proof structural steel. The steel contains the following chemical components in percentage by weight: 0.02-0.10 percent of C, 0.10-0.25 percent of Si, 0.3-0.8 percent of Mn, 6.5-12.5 percent of Ni, at most 0.5 percent of Cr, Mo and Cu, at most 0.015 percent of Nb, V and Ti, 0.02-0.04 percent of Als, at most 0.005 percent of S, at most 0.015 percent of P, at most 0.008 percent of O and N and the balance of Fe and unavoidable impurities. A steel plate containing the chemical components is subjected to tempered heat treatment of high temperature quenching, low temperature quenching and tempering, then a multiphase tissue comprising 6-14 percent of block ferrite, 65-80 percent of tempered martensite, 15-20 percent of austenite, and the like are formed in the steel, wherein the contents of Ni in the block ferrite, the tempered martensite and the austenite are respectively 2-7, 4-12 and 15-20 in sequence so that the steel has excellent quake-proof comprehensive mechanical properties, such as a low yield ratio of 0.67-0.80, a high homogeneous elongation of 17-24 percent, high strength (a yield strength of 830-925MPa), high tenacity (a ballistic work of 160-198J), and the like at 196 DEG C below zero. The invention has simple process, easy realization of 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...

AI Technical Summary

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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