Abstract: Disclosed are a V-N microalloyed steel and a method for producing a V-N microalloyed and surface-crack-free continuous casting blank. The V-N microalloyed steel is composed of the following chemical components by mass percentage: 0.09%-0.13% of C, 0.1%-0.4% of Si, 1.0%-3.0% of Mn, less than or equal to 0.05% of P, less than or equal to 0.05% of S, 0.1%-0.4% of V, 0.011%-0.2% of N and the balance of Fe and unavoidable impurity elements. A continuous casting blank is subjected to component control according to the chemical components of the V-N microalloyed steel; and the production method therefor comprises converter smelting, LF refining and continuous casting steps in sequence.

Abstract: An ultra-high phosphorus molten iron low-cost smelting method for polar steel includes successively deoxidizing and tapping alloying raw materials including molten iron; performing slag adjusting and refining on the molten steel obtained in the converter smelting step to obtain a refined molten steel; vacuum degassing the refined molten steel; and performing continuous casting on the molten steel obtained after the RH degassing step to obtain a cast billet.

Abstract: A steel board for polar marine engineering and a preparation method therefor. According to weight percentage, the components of the steel board are: C: 0.06-0.09%, Si: 0.20-0.35%, Mn: 1.48-1.63%, Nb: 0.020%-0.035%, Ti: 0.010%-0.020%, V: 0.020%-0.035%, Ni: 0.08%-0.17%, Als: 0.015%-0.040%, P: ?0.013% and S: ?0.005%. The preparation method for the steel board comprises: pre-refining, refining and casting to obtain a cast billet, and the slowly cooling down same. The slowly cooled billet is heated and then rolled out to obtain the steel board; and the steel board is cooled down and ready. The steel has an excellent comprehensive performance in terms of having high strength and low temperature resistance, being easy to weld and corrosion proof, and the steel has good low-temperature aging impact toughness.