Nanoscale rodlike copper precipitated phase strengthening and toughening marine steel plate and preparation method thereof

The invention discloses a nanoscale rodlike copper precipitated phase strengthening and toughening marine steel plate and belongs to the technical field of metallurgy materials.The steel plate is prepared from C, Cu, Mn, Al, Si, Mo, Ti and the balance Fe and unavoidable impurities.The preparation method comprises the first step of ingot casting, the second step of hot rolling, the third step of warm rolling and the fourth step of heat treatment.In the second step of hot rolling, heat treatment is carried out on a cast ingot, 4-10 passes of hot rolling is carried out, the temperature is rapidly decreased and kept for a period of time, then water cooling is carried out to reach the normal temperature, and a hot-rolled steel plate is obtained; in the third step of warm rolling, 6-10 passes of warm rolling is carried out on the hot-rolled steel plate, and annealing treatment is carried out before each time of warm rolling; in the fourth step of heat treatment, the temperature of the warm-rolled steel plate is rapidly increased to 800-850 DEG C and kept, then, the temperature is rapidly decreased to 380-420 DEG C and kept, and therefore the product is obtained.According to the steel plate, the tensile strength is 1700-1850 MPa, the yield strength is 650-730 MPa, and the stretch rate is 32-38%.The steel material with nanoscale rodlike Cu educt, a submicron austenite betten structure and small ferrite grains is prepared and has the quite high strength and plasticity, and the corrosion resistance of steel is improved.