Ultrahigh-impact-toughness high-purity-degree steel for low temperature pressure vessel and production method thereof

Abstract

The invention discloses ultrahigh-impact-toughness high-purity-degree steel for a low temperature pressure vessel. The ultrahigh-impact-toughness high-purity-degree steel comprises the chemical components of, by mass, 0.06-0.08% of C, 0.20-0.35% of Si, 1.15-1.35% of Mn, 0.01-0.02% of Ti, 0.12-0.15% of Ni, 0.020-0.045% of Al, 0-0.010% of P, 0-0.003% of S, 0-0.0015% of [O], 0-0.0050% of [N], 0-0.00015% of [H] and the balance Fe. In this way, according to the ultrahigh-impact-toughness high-purity-degree steel for the low temperature pressure vessel and a production method thereof, the content ofthe C is decreased through precise control, strong deoxidization and crystalline grain refining are conducted through the Al, alloying is conducted through the Ni and the Ti, thus, compared with 09MnD steel of Q / TDGG 0040-2004, the ultrahigh-impact-toughness high-purity-degree steel is suitable for the lower medium temperature which is from -50 DEG C to -55 DEG C, and has higher low-temperature impact toughness, and the overall mechanical property of the ultrahigh-impact-toughness high-purity-degree steel is more stable.

Description

Technical field [0001] The invention relates to the technical field of low-alloy steel in the iron and steel industry, in particular to a steel for low-temperature pressure vessels with ultra-high impact toughness and high purity and a production method thereof. Background technique [0002] Cryogenic pressure vessel is a kind of cryogenic vessel. The ferritic steel commonly used in general pressure vessels reaches the brittle transition temperature when the temperature drops to a certain temperature, the toughness of the steel drops sharply, and it is extremely easy to break. When the pressure vessel is used below the transition temperature, if there is a local stress concentration in the vessel caused by defects, residual stress and other factors, the vessel is likely to undergo brittle fracture without obvious plastic deformation, resulting in Catastrophic accident. [0003] For low-temperature pressure vessels, appropriate materials must first be selected according to the pur...

AI Technical Summary

Problems solved by technology

At present, the 09MnD steel commonly used in China is difficult to stably meet the above toughness requirements after normalizing, and can only ensure the safe use at -45°C. In order to ensure the safe use of pressure vessels at -50°C-55°C, it must be re- Design composition and optimize process

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