Longitudinal variable-thickness ultrahigh-strength ship plate and production method

Abstract

The invention discloses a longitudinal variable-thickness ultrahigh-strength ship plate and a production method. The steel plate comprises the following chemical components: 0.060% to 0.120% of C, 0.15% to 0.50% of Si, 1.10% to 1.70% of Mn, 0.040% to 0.070% of V, 0.20% to 0.50% of Cu, 0.10% to 0.50% of Ni, 0.005% to 0.020% of Ti, 0.0120% to 0.0180% of N, smaller than or equal to 0.010% of P, smaller than or equal to 0.005% of S and 0.015% to 0.030% of Als. The method comprises the following steps of performing nitrogen blowing treatment on molten steel in a converter or RH, heating a casting blank to 1130 to 1250 DEG C and keeping for 40 to 240 minutes; enabling the initial rolling temperature to be 1040 to 1120 DEG C, and rolling the thickness of the casting blank to 2.0 to 3.0 times of the maximum thickness of the final LP steel plate; rolling an intermediate billet at 850 to 910 DEG C, and rolling the thickness to be 1.5 to 2.0 times of the maximum thickness of the final LP steel plate; adopting variable-thickness rolling, and controlling the finish rolling temperature of the steel plate to be 800 to 850 DEG C; and performing air-cooling on the steel plate to the room temperature in order to obtain the final longitudinal variable-thickness steel plate. The steel plate is good in mechanical property uniformity in the length direction, the strength difference between the thickposition and the thin position is within 15 MPa, the toughness and plasticity are consistent, and the steel plate is suitable for the longitudinal variable-thickness high-strength ship plates in anyshape.

Description

technical field [0001] The invention belongs to the technical field of metal material production, and in particular relates to a longitudinally variable-thickness ultra-high-strength ship plate and a production method thereof. Background technique [0002] Longitudinal variable thickness (LP) steel plate is a steel plate whose thickness changes along the length direction. It is a steel plate whose longitudinal thickness is changed by continuously changing the opening of the roll during the rolling process. According to the different ways of thickness change, it can be divided into 10 different types. shape. Since LP steel plate can change its thickness according to the load bearing conditions, it has unique advantages in optimizing the design of structural sections such as the hull. The equal thickness of the steel plate improves its operability, such as omitting the backing plate and taper processing. In recent years, with the increase in the demand for lightweight ships, ...

AI Technical Summary

Problems solved by technology

[0005] 1) High alloying elements and high production costs

[0006] 2) The uniformity of the mechanical properties of the steel plate along the length direction is poor

[0007] 3) The production process is complex

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