Low-cost high-strength steel plate for shipbuilding and manufacturing method thereof

Abstract

The invention provides a low-cost high-strength steel plate for shipbuilding and a manufacturing method thereof. The steel plate comprises the following chemical ingredients of: by weight, 0.05-0.16% of C, 0.10-0.50% of Si, 0.90-1.50% of Mn, P being less than or equal to 0.020%, S being less than or equal to 0.015%, and the balance Fe and unavoidable impurities. The manufacturing method comprises steps of smelting, continuous casting and hot rolling, and is characterized in that heating temperature of a casting blank is 1100-1150 DEG C; high pressure water is used to remove phosphate before the casting blank enters a rolling mill; initial rolling temperature is 1120-1050 DEG C; continuous rolling is carried out for 3-5 passes; pass reduction is greater than 20%; finishing temperature during the first stage is 970-1000 DEG C; temperature waiting thickness is 2-3 times the thickness of a finished product; initial temperature during the second stage is 920-950 DEG C; rolling is carried out for 5-10 passes; accumulative deformation is greater than 50%; finishing temperature is 800-900 DEG C; cooling is rapidly carried out for 5-10 s at the cooling rate of 30-40 DEG C / s after rolling; and re-reddening temperature is 580-650 DEG C. Without the addition of Nb, V and Ti, performance of the steel plate reaches requirements of 315N / mm<2> strength-grade steel for shipbuilding by the adoption of controlled rolling and ultra-rapid cooling technologies.

Description

technical field [0001] The invention belongs to the production technology of steel plates for shipbuilding with a thickness specification of 10-40mm, in particular to a steel plate for shipbuilding with low cost and yield strength greater than 315N / mm2 and a manufacturing method thereof. Background technique [0002] According to the forecast of future market demand by the world shipbuilding industry, with the development of the shipbuilding industry, the varieties and specifications of marine steel products will be greatly improved, and the demand for high-strength and thick steel plates for shipbuilding will continue to rise. [0003] High-strength shipbuilding steel must not only have high strength, but also have good toughness and plasticity, especially low-temperature impact toughness. Grain refinement is an effective means to improve strength and toughness. The application practice of iron and steel industry has proved that the controlled rolling and controlled coolin...

AI Technical Summary

Problems solved by technology

With the rapid increase in the demand for high-strength shipbuilding steel in the shipbuilding industry, the use of current high-strength shipbuilding steel production technology will consume a large amount of resources such as Nb, V, and Ti, which will cause the price of these raw materials to rise, thereby increasing the demand for high-strength shipbuilding steel. Production costs bring huge cost pressures to steel mills

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