A method for manufacturing a low carbon equivalent high strength steel for a ship plate by TMCP

Abstract

The application discloses a TMCP preparation method of a low-carbon equivalent high-strength steel of a ship plate, and belongs to the technical field of metal material processing. The steel material comprises C, Si, Mn, Ni, Cr, Mo, Al, Nb, P, S, Fe and impurities. The preparation method comprises the following steps: smelting and continuous casting, slab heating, controlled rolling, quenching treatment and reverse phase transformation annealing. The application adopts low-carbon medium-nickel collaborative design, replaces interstitial atom carbon with substitution atom nickel as an austenite stabilizing element, introduces high-density crystal defects through controlled rolling, obtains full martensite structure in combination with offline quenching, and then is subjected to two-phase zone reverse phase transformation annealing to obtain the final structure of a tempered martensite matrix with 10% to 20% thin film-shaped reverse transformation austenite distributed thereon. The obtained steel material has high yield strength and high impact energy at-80 DEG C, and welding does not need preheating, and has high strength, excellent low-temperature toughness and excellent welding performance, and is suitable for high-value-added application scenarios such as polar ships.

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