E420-W300 ultrahigh-strength ship plate steel and manufacturing method therefor

Abstract

The invention discloses E420-W300 ultrahigh-strength ship plate steel, comprising the following chemical components in percentage by mass: 0.04-0.12% of C, 0.15-0.35% of Si, 1.20-1.40% of Mn, less than or equal to 0.020% of P, less than or equal to 0.0030% of S, 0.030-0.060% of V, 0.010-0.030% of Nb, 0.030-0.080% of Ant, 0.005-0.030% of Ti, 0.0005-0.0040% of Ca, less than or equal to 0.0060% of N.(Alt N) / Ti is controlled within 0.010-0.030; the yield strength is larger than or equal to 420 MPa; the tensile strength is larger than or equal to 530 MPa; the steel plate is suitable for high-strength ship plate steel with the welding linear energy within the range of 300 kJ / cm; and the average impact energy of HAZ of the steel plate at the temperature of -40 DEG C is 42 J or above.

Description

technical field [0001] The invention relates to the technical field of iron and steel production, in particular to an E420-W300 ultra-high-strength ship plate steel and a manufacturing method thereof. Background technique [0002] Steels for high heat input welding are widely used. For example, in the shipbuilding industry, the shipbuilding efficiency of ordinary ship plates is only a quarter of that of high heat input welding ship plates. When the country cannot produce it, it can only be imported from abroad, but the price is expensive. The high heat input welding method is the most practical way to improve the efficiency of welding construction and reduce costs. Steel for high heat input welding is one of the key development goals of my country's iron and steel industry and has broad market prospects. [0003] When the welding heat input is greater than 50kJ / cm, it is high-energy welding. When the welding heat input of traditional steel plates is greater than 50kJ / cm, th...

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Problems solved by technology

[0003] When the welding heat input is greater than 50kJ / cm, it is high-energy welding. When the welding heat input of traditional steel plates is greater than 50kJ / cm, the mechanical properties of the welded joint will be seriously reduced due to the excessive coarsening of the heat-affected zone. It is lower than the standard requirements of the base metal steel plate, and research and development of steel for high-energy-input welding is an effective way to solve the deterioration of low-temperature toughness in the heat-affected zone of high-energy-input welding

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