Low-temperature flexibility 1.5Ni steel and method of manufacturing the same

Abstract

The invention discloses low-temperature ductility 1.5Ni steel and a manufacturing method thereof, wherein the low-temperature ductility 1.5Ni steel comprises the chemical components according to percentages by weight of 0.02-0.10 percent of C, 0.22-0.30 percent of Si, 1.00-1.50 percent of Mn, less than or equal to 0.08 percent of V, 1.20-1.60 percent of Ni, less than or equal to 0.005 percent of S, less than or equal to 0.010 percent of P, less than or equal to 0.03 percent of Nb, less than or equal to 0.04 percent of Ti, less than or equal to 0.04 percent of Al, 0.002-0.005 percent of N and the rest of Fe and unavoidable impurities. The manufacturing method comprises the following steps of smelting and casting into a casting blank, heating the casting blank, controlled rolling and heat treatment. In the invention, after the micro alloy steel finishes the controlled rolling, a high-strength low-temperature pressure vessel steel plate which has yield strength of more than 400MPa, tensile strength of more than 500MPa and satisfies the low-temperature impact ductility requirement of 100 DEG C below is produced through adopting a thermal refining method. The invention is suitable for manufacturing vessels, such as a low-temperature pressure vessel, a liquefied natural gas storage tank, a liquefied petroleum gas storage tank, a petrochemical storage tank, and the like.

Description

technical field [0001] The invention relates to a Ni steel, in particular to a low-temperature toughness 1.5Ni steel and a manufacturing method thereof. Background technique [0002] Low-temperature steel is mainly used to manufacture pressure vessels and storage tanks for storing and transporting various liquefied gases. Ni is an important element in the development of low-temperature steel. According to the different Ni content, different grades of low-temperature steel such as 1.5Ni, 3.5Ni, 5Ni, and 9Ni have been developed to suit different low-temperature environments and media. Among them, 1.5Ni steel is widely used Used in chemical and petrochemical fields—45℃~—80℃ low-temperature pressure vessel steel, such as ethylene equipment in chemical enterprises, low-temperature methanol washing equipment in urban coal pressurized gasification, etc., can also meet the requirements of LPG (liquefied petroleum gas) ) storage and transportation needs. As a low-temperature steel,...

AI Technical Summary

Problems solved by technology

As a low-temperature steel, a very important technical indicator is low-temperature impact toughness. The alloy element Ni is added to the steel and dissolved in ferrite to significantly improve the low-temperature toughness of the matrix. However, Ni is a relatively expensive element, about 280,000 Yuan / ton, while increasing the cost, the cast slab of Ni-containing steel tends to form dense oxide scales that are difficult to remove when heated, which brings difficulties to the heating and rolling process

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