Low-temperature steel reinforcement for liquefied petroleum gas storage tank and production process thereof

Abstract

The invention relates to a low-temperature steel reinforcement for a liquefied petroleum gas storage tank and a production process thereof and belongs to the technical field of steel for a petroleum storage tank. The steel reinforcement comprises the following chemical components in percentage by weight: less than or equal to 0.25 percent of C, 0.15 to 0.40 percent of Si, 1.20 to 1.60 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.010 percent of S, 0.3 to 1.0 percent of Ni, 0.01 to 0.05 percent of Nb, 0 to 0.10 percent of V and the balance of Fe and impurity elements. In the process, the technical parameters are controlled as follows: the heating temperature is 1,100 DEG C to 1,200 DEG C, the start rolling temperature is 900 to 950 DEG C, the rolling temperature is controlled to be 800 to 900 DEG C, the finish rolling temperature is 700 to 800 DEG C and the temperature on a cooling table is 450 to 700 DEG C; and the steel reinforcements are bundled and stacked after being naturally cooled on the cooling table. The low-temperature steel reinforcement has the advantage of excellent performance at the low temperature of minus 105 DEG C.

Description

Technical field [0001] The invention belongs to the technical field of steel for petroleum storage tanks, and particularly relates to a low-temperature steel bar for liquefied petroleum gas storage tanks and a production process thereof. The steel bar produced according to the process has excellent performance at low temperature -105°C. Background technique [0002] Liquefied petroleum gas (LPG) is widely used as an important energy source, and its storage safety is very important. For large fixed storage tanks, it is more economical to use a single-layer tank + an outer cement tank as the cold protection tank. The hot-rolled ribbed steel bars used to build the inner layer of the cement tank are not only required to meet the performance indicators of conventional hot-rolled steel bars, but also have good low-temperature properties. [0003] According to the composition and structure, low temperature steel can be divided into low alloy steel, 6% Ni steel, 9% Ni steel, Cr-Mn or Cr-M...

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Problems solved by technology

[0004] Published patent: "A high-toughness -110°C low-temperature steel and its manufacturing method" (Patent No.: 200810046958.9), in which the Ni content range (weight percent): 3.2-3.8%, Ni content is high, and rolling is used in the process After normalizing + tempering heat treatment process, the yield strength of the steel is lower than 500MPa, and the low temperature performance is measured by the impact toughness index, there is no notch sensitivity (NSR) and total elongation under the maximum force (A gt ) index requirements, not applicable to the production and processing of low-temperature steel bars for liquefied petroleum gas storage tanks

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