Abstract: Disclosed are a corrosion-resistant marine composite steel plate and a manufacturing method therefor. The corrosion-resistant composite steel plate has a two-layer structure, wherein one layer is duplex stainless steel, and the other layer is marine carbon steel; said duplex stainless steel comprises the following components by weight: C?0.03%, Mn?2.00%, Si?1.00%, Cr: 21.0-23.0%, Ni: 4.5-6.5%, Mo: 2.5-3.5%, N: 0.08-0.20%, P?0.02%, S?0.025%, and the balance being Fe and inevitable impurities; and said marine carbon steel comprises the following components by weight: 0.03%?C?0.13%, Si?0.50%, Mn: 0.90-1.60%, P?0.020%, S?0.025%, Cu?0.035%, Cr?0.20%, Ni?0.40%, Nb: 0.02-0.05%, Ti?0.02%, Mo?0.08%, Al?0.015%, and the balance being Fe and inevitable impurities.

Abstract: A gradient steel material with a high plastic surface layer and a high strength inner layer, and a manufacturing method are provided. Weight percentages of the components of the gradient steel material are: C?0.15%, Si?1%, Mn?1.5%, and the balance of Fe and inevitable impurities, the surface layer of the steel material being ferrite, and the inner layer being ferrite+bainite. The manufacturing method therefor comprises: smelting, casting, rolling, and a heat treatment, wherein in the heat treatment step, a steel material is heated to an austenite temperature Ac3 or more and kept at said temperature for more than 3 min; thereafter, the material is cooled to a temperature range between Ar3 and Ar1 in a two-phase zone at a cooling rate of less than 0.5° C./s, and is then cooled to room temperature at a cooling rate of greater than 5° C./s. The present steel material does not need to be obtained by means of the compound preparation of different materials as only a single material is processed.

Abstract: Provided are a gradient steel material having a surface layer with ferrite and an inner layer with ferrite+pearlite, and a manufacturing method, the weight percentages of the components are: C?0.15%, Si?1%, Mn?1.5%, the balance of Fe and inevitable impurities, and the surface layer of the steel material is ferrite, the inner layer is ferrite+pearlite. The manufacturing method thereof includes: smelting, casting, rolling, heat treatment; wherein, in the heat treatment step, the steel material is heated above the austenitizing temperature Ac3, and hold at the temperature more than 3 min to ensure that the material is completely austenitized; subsequently, it is cooled to a temperature below Ar1 at a cooling rate lower than 0.5° C./s. The present steel material does not need to be obtained by means of the compound preparation of different materials, and is only processed and prepared by a single material, the process is short, the procedure is simple, and the cost is low.

Abstract: A method of pre-controlling the shapes of a continuous-casting slab head and tail for reducing the cut amount of the head and tail of the hot rolling intermediate slab. The continuous-casting slab head and tail, is cut into a shape such that an end surface of the head concaves inwards and the tail projects outwards. The head and tail of a slab is cut in a curve that is symmetric to the center line in width thereof. Arc height, i.e. a maximum value of the concave amount at the head or that of the projection amount at the tail, is controlled within 0 mm-50 mm.

Abstract: A method of pre-controlling the shapes of a continuous-casting slab head and tail for reducing the cut amount of the head and tail of the hot rolling intermediate slab. The continuous-casting slab head and tail, is cut into a shape such that an end surface of the head concaves inwards and the tail projects outwards. The head and tail of a slab is cut in a curve that is symmetric to the center line in width thereof. Arc height, i.e. a maximum value of the concave amount at the head or that of the projection amount at the tail is controlled within 0 mm-50 mm.