A high-strength, high-toughness non-quenched and tempered low-temperature pressure vessel steel and its manufacturing method

Abstract

The invention provides high-intensity and high-toughness non-quenched-and-tempered type steel for a low-temperature pressure vessel and a manufacturing method of the steel. The steel comprises the following components, by weight percentage, 0.11-0.20% of C, 0.15-0.35% of Si, 1.30-1.60% of Mn, less than or equal to 0.010% of P, less than or equal to 0.003% of S, 0.50-1.0% of Cr, 0.015-0.040% of Nb, 0.005-0.010% of Ti, 0.035-0.050% of Al, 1.10-1.60% of Ni, and the balance Fe and unavoidable impurities. The manufacturing method comprises the steps that a continuous casting billet is subjected to two stages of rolling, and ultra-rapid cooling is carried out after the rolling; and then normalizing heat treatment is carried out. Through chemical component optimization and manufacturing technique parameter design, the steel has excellent comprehensive mechanical properties, and after the type of steel is subjected to the normalizing treatment, -50 DEG C shock absorption energy in different states is likewise kept at a high level.

Description

technical field [0001] The invention belongs to the field of metal materials, in particular to high-strength, high-toughness non-tempered low-temperature pressure vessel steel and a manufacturing method thereof. Background technique [0002] With the rapid development of my country's petrochemical industry, gas liquefaction, separation and production, storage and application of liquefied gas have become quite common. In particular, liquefied petroleum gas, as a clean, convenient, and highly efficient energy source, has been widely used in industrial and domestic fuel fields. As the largest developing country in the world, my country's liquefied petroleum gas market is developing rapidly. In 2010, the domestic output of liquefied petroleum gas was 20.3 million tons, the import volume was 3.5 million tons, the export volume was 850,000 tons, and the apparent consumption reached 22.95 million tons. tons, an increase of about 6.2% over last year. [0003] It is precisely becaus...

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Problems solved by technology

[0005] In view of the above two development trends, the existing technology either adopts off-line quenching and tempering treatment to improve the strength of the steel plate, but the steel plate manufacturing period is longer; or uses a higher alloy content to improve the strength of the steel plate, resulting in high steel plate manufacturing costs

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