Large-size high-strength marine flat-bulb steel and production process thereof

Abstract

The invention discloses a large-size high-strength E36 flat-bulb steel which is 40# steel or above. The large-size high-strength E36 flat-bulb steel comprises the following chemical components in percentage by weight: 0.08-0.13% of C, 0.10-0.40% of Si, 1.15-1.75% of Mn, S and P equal to or less than 0.020%, 0.08-0.12% of V, 0.10-0.50% of Ni, 0.01-0.03% of Ti, 0.001-0.01% of Mg, 0.001-0.01% of Ca, 0.001-0.01% of O, 0.016-0.025% of N and the balance of Fe and unavoidable impurities, wherein Mn / C is greater than or equal to 14.0%, Ni is equal to or greater than 0.15%, and (Mg+Ca) / O is equal to or greater than 1.0%. The production process of the large-size high-strength E36 flat-bulb steel comprises smelting and hot rolling, wherein the heating temperature of the hot-rolled blank is 1100-1200 DEG C, the finish rolling temperature is equal to or lower than 865 DEG C, the large deformation of the finish rolling pass is 20%, and the cooling speed is 2-10 DEG C. Through controlling the heating temperature, finish rolling temperature and finish rolling deformation of the steel blank raw material, the produced large-size high-strength E36 flat-bulb steel which is 40# steel or above accords with the standard required strength and toughness indexes and is capable of achieving the impact toughness value at ultralow temperature of -60 DEG C, and the impact toughness can be above 200 J.

Description

technical field [0001] The invention relates to a flat bulb steel for ships, in particular to a large-size high-strength E36 flat bulb steel for ships of No. 40 or above and a production process thereof, belonging to the technical field of smelting. Background technique [0002] No. 40 and above large-scale high-strength E36 marine flat bulbs are used as stiffeners for large ships, which can significantly increase the hull stiffness and safety factor under low temperature conditions without greatly increasing the hull weight. At present, there is no domestic enterprise that can produce large-scale high-strength E36 spherical flat steel of No. 40 or above, and the demand is all dependent on imports. The main reason is that domestic enterprises have not mastered the reasonable control of the chemical composition of steel billets and the rolling process technology, and the products cannot meet the strength and toughness indicators that meet the requirements of the standards. T...

AI Technical Summary

Problems solved by technology

The main reason is that domestic enterprises have not mastered the reasonable control of the chemical composition of the steel billet and the rolling process technology, and the products cannot meet the strength and toughness indicators that meet the requirements of the standard.

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