TMCP-state low-cost high-strength ship plate steel for high-heat input welding and manufacturing method of TMCP-state low-cost high-strength ship plate steel

Abstract

The invention discloses TMCP-state low-cost high-strength ship plate steel for high-heat input welding. The TMCP-state low-cost high-strength ship plate steel comprises the chemical components in percentage by weight: 0.04-0.12% of C, 0.15-0.35% of Si, 1.10-1.70% 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, 0.005-0.060% of Alt, 0.32-0.41% of Ceq, 0.005-0.030% of Ti, 0.0005-0.0040% of Ca, 0.05-0.40% of Ni and the balance of Fe and unavoidable impurities. The steel plate disclosed by the invention has the yield strength of larger than or equal to 400MPa and the tensile strength of larger than or equal to 510MPa, is suitable for high-strength ship plate steel with welding heat input being within the range of 150-250kJ / cm, the average impact power of HAZ of the steel plate under 40 DEG C is higher than 150J under the high-heat input welding conditions of 150kJ / cm and 250kJ / cm, heat treatment is not needed, and the production cost is low.

Description

Technical field [0001] The invention belongs to the technical field of metallurgy, and relates to a high-strength ship plate steel for welding with large heat input and a manufacturing method thereof, specifically, a high-strength ship plate steel for welding with a 60mm thick E40 grade TMCP state low-cost and large heat input and its manufacturing method. Background technique [0002] High heat input welding steel is widely used. For example, in the shipbuilding industry, the shipbuilding efficiency of ordinary ship plates is only one-fourth of that of high heat input welding ship plates. When domestic production is not possible, 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 the cost. The "Guide to the Development of Science and Technology of China's Iron and Steel Industry from 2006 to 2020" proposes that high heat input welding steel is ...

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Problems solved by technology

[0003] When the welding heat input is greater than 50kJ / cm, it is called large input energy welding. When the welding heat input of traditional steel plates is greater than 50kJ / cm, due to the excessive coarsening of the structure of the welding heat-affected zone, the mechanical properties of the welded joint will be seriously reduced, and even 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

[0004] Existing patent documents on steel plates for large heat input welding, such as CN1946862A, CN1338528A, CN101050502A, and CN101050504A, all contain alloying element Nb.

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