A kind of heat treatment method of low-alloy steel plate and steel plate

Abstract

The invention discloses a low-alloy steel plate and a heat treatment method for the steel plate. The strong-strength low-alloy steel plate comprises the following chemical components in percentage by weight: 0.12 to 0.20 percent of C, 0.20 to 0.60 percent of Si, 1.20 to 1.80 percent of Mn, less than or equal to 0.030 percent of P, less than or equal to 0.030 percent of S, 0.020 to 0.080 percent of Nb, less than or equal to 0.050 percent of V, 0.010 to 0.060 percent of Ti, 0.015 to 0.045 percent of Al and the balance of Fe and trace impurities. According to the low-alloy steel plate and the heat treatment method for the steel plate, the strength loss of the steel plate after heat treatment can be effectively reduced, the yield strength and the tensile strength of the steel plate are strengthened by more than 30MPa compared with those of a conventional normalized steel plate, the alloy element content of the normalized steel plate can be effectively reduced, and the production cost is lowered.

Description

technical field [0001] The invention belongs to the field of production of medium and thick steel plates, and mainly relates to a low-alloy steel plate and a heat treatment method for the steel plate. Background technique [0002] Normalizing steel plates are widely used in pressure vessels, high-rise buildings, bridges, construction machinery and other fields, and play an irreplaceable role. Especially in some wind power and container projects, the use of normalizing steel plates is mandatory in project design. [0003] The traditional normalizing process is air-cooled after heating, and the cooling speed is slow. The grains of the steel plate grow up at high temperature, and the mechanical properties, especially the strength properties, decrease greatly. The method of increasing the content of carbon elements and alloy elements to ensure the strength performance of the steel plate will lead to deterioration of the welding performance and increase the smelting cost. [000...

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Problems solved by technology

[0008] The technical solutions disclosed in the above-mentioned patent documents have the following deficiencies: one is that microalloying elements such as Ni, V or Ni, Mo, Nb, V, Ti, Cu need to be added, the alloy content is large, and the cost is high; Coarse grains, poor uniformity in the thickness direction, poor toughness of the steel plate, and high energy consumption; third, the cooling rate is low, the controllable final cooling temperature of the steel plate is high, and the application flexibility of the water cooling process after normalizing is poor

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