Method for producing steel plate of petroleum storage tank by using direct quenching process

Abstract

The invention discloses a method for producing a steel plate of a petroleum storage tank by using a direct quenching process. The invention provides a chemical composition of special petroleum storage tank steel and adopts a direct quenching process. The method comprises the following steps of: heating a steel blank to 1100 to 1280 DEG C, rolling into a steel plate in re-crystallization and non-recrystallization stages; carrying out on-line quenching operation under the conditions that the temperature of the steel plate is between 780 DEG C and 900 DEG C, the average cooling rate ranges from 25 DEG C / s to 60 DEG C / s, the cooling terminal temperature is less than or equal to 350 DEG C, and performing off-line tempering on the steel plate subjected to quenching. Compared with the conventional high-energy-consumption hardening process based on the combination of off-line tempering and tempering, the method provided by the invention has the advantages of short production flow and low energy consumption and the prepared steel plate has good general mechanical properties and high heat input welding property. The yield strength of the steel plate is more than 490 MPa and the tensile strength of the steel plate is more than 610 MPa. In case of high heat input welding (less than or equal to 400 KJ / cm), a welding heat affected zone maintains excellent low-temperature toughness, and the mean value of work done by impact at -20 DEG C is more than 50 J.

Description

technical field [0001] The invention belongs to the field of low-alloy steel plate production technology, and in particular relates to a method for producing steel plates for petroleum storage tanks by adopting a direct quenching process. Background technique [0002] The construction of oil storage tanks in the world is gradually developing towards a large-scale one with a single volume of 100,000 to 300,000 cubic meters, mainly made of high-strength quenched and tempered steel plates. In order to improve the construction efficiency, the automatic gas-electric vertical welding method has been adopted in the construction of the longitudinal seam of the tank wall, and the welding heat input of the tank wall is required to reach 120kJ / cm. Due to the increase of welding heat input, the high-temperature residence time in the welding heat-affected zone becomes longer, the austenite grains are severely coarsened, and due to the slow cooling rate after welding, coarse side lath fer...

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Problems solved by technology

[0007] The purpose of the present invention is to provide a method for producing steel plates for petroleum storage tanks using direct quenching technology, which can solve the problems of high equipment investment, large energy consumption and long production cycle caused by traditional off-line quenching and tempering processes for producing steel plates for petroleum storage tanks while reducing expensive metals. long technical bottleneck

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