Niobium microalloyed steel for low-temperature reinforcing steel bar and rolling process of steel

Abstract

The invention discloses niobium microalloyed steel for a low-temperature reinforcing steel bar and a rolling process of the steel. The steel for the low-temperature reinforcing steel bar comprises the following chemical components in percentage by weight: 0.05 to 0.15 percent of C, 0.15 to 0.40 percent of Si, 1.40 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, 0.50 to 2.00 percent of Ni, 0.10 to 0.80 percent of Cu, 0.015 to 0.050 percent of Nb and the balance of Fe and impurity elements. The rolling process of the steel for the low-temperature reinforcing steel bar comprises the following steps of: smelting steel in a converter, an electric-arc furnace or other smelting furnaces; performing external refining; performing continuous casting; rolling and forming on a continuous bar mill, wherein the parameters of the rolling process are as follows: steel billets are heated to 1,180 to 1,250 DEG C, the initial rolling temperature is 950 to 1,050 DEG C, and the finishing rolling temperature is 950 to 1,100 DEG C; and performing water passing and cooling after rolling, wherein the cooling bed feeding temperature is 500 to 650 DEG C. According to the steel for the low-temperature reinforcing steel bar and the low-temperature reinforcing steel bar products produced by the rolling process of the steel, low-temperature building engineering reinforced concrete structures such as LNG and the like can resist the low temperature of -165 DEG C, and the steel for the low-temperature reinforcing steel bar has good low-temperature resistance and is safe and reliable.

Description

technical field [0001] The invention relates to a steel for low-temperature reinforcement and a rolling process thereof, in particular to a niobium microalloyed steel for low-temperature reinforcement and a rolling process thereof. Background technique [0002] The hot-rolled ribbed steel bar is the skeleton material of the concrete structure. It bears various stresses in the structure and is sometimes used in a certain low temperature environment. Therefore, not only the steel bar is required to have high strength and process performance, but also high The functionality - the ability to resist low temperature. [0003] A typical example that requires the use of low-temperature steel bars is the low-temperature-resistant steel bars used in the construction of liquefied natural gas storage tanks (LNG for short) in the petrochemical industry. The basic requirements are: [0004] (1) High strength, yield strength ≥ 400MPa or ≥ 500MPa; [0005] (2) The production process is no...

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Problems solved by technology

[0013] None of the above 4 types of low-temperature steel can be used in low-temperature steel bars for LNG and other low-temperature construction projects.

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