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The invention discloses duplex stainless steel containing rare earth elements and a preparation process of the duplex stainless steel. The duplex stainless steel comprises the following components in percentage by weight: less than 0.04% of C, 0.2-0.8% of Si, 0.8-1.5% of Mn, less than or equal to 0.005% of S, less than or equal to 0.02% of P, 22.0-27.0% of Cr, 5.0-7.0% of Ni, 3.0-4.0% of Mo, 0.24-0.32% of N, 0.002-0.005% of B, 0.05-0.10% of mischmetal and the balance of iron and other inevitable impurities. The preparation method comprises the steps of metal smelting; adding alloy for refining; mixed rare earth with the oxygen content smaller than 1000 ppm is added in batches; pouring under the protection of argon; rolling is conducted; and carrying out solution treatment. The method has the characteristics that the purity, the corrosion resistance, the hot working performance and the yield of the duplex stainless steel are improved.

This invention belongs to the field of iron and steel smelting technology, specifically relating to a method for controlling the nitrogen content in S460NL steel. The method includes: primary refining in an electric furnace or converter → refining in an LF furnace → refining in a VD furnace → casting. After vacuuming in the VD furnace, nitrogen gas is blown into the ladle through two permeable bricks at the bottom to achieve the target nitrogen content. After nitrogen blowing, argon gas is switched for soft stirring. This invention, by simultaneously blowing nitrogen gas through two permeable bricks at the bottom of the ladle to increase the nitrogen content of high-strength S460NL steel used in wind power flanges after vacuum refining in the VD furnace, offers advantages such as lower cost, higher steel purity, higher composition hit rate, and simpler operation compared to adding manganese nitride ferroalloys.

The invention discloses Q460D-grade low-temperature-resistant angle steel and a production method thereof. The Q460D-grade low-temperature-resistant angle steel comprises the following chemical components in percentage by weight: 0.17%-0.20% of C, 0.30%-0.40% of Si, 1.40%-1.55% of Mn, 0.070%-0.080% of V, less than or equal to 0.020% of P, less than or equal to 0.020% of S, 0.0050%-0.0200% of Als, 0.42%-0.46% of CEV, 0.0120%-0.0150% of N and the balance of Fe and inevitable impurities. The production method comprises the steps of KR pretreatment, converter smelting, LF refining, continuous casting, heating and profile steel rolling. The impact property of the Q460D-grade angle steel at-20 DEG C is larger than or equal to 34 J, the upper yield strength ReH is larger than or equal to 470 MPa, the tensile strength Rm is larger than or equal to 630 MPa and smaller than or equal to 680 MPa, and the percentage elongation after fracture A is larger than or equal to 22%.

The application relates to the field of steel production, in particular to a preparation method of a steel plate casting blank. The method comprises the following steps: converter smelting of molten iron, and control of the TFe content in a ladle top slag to obtain first molten steel; RH vacuum refining of the first molten steel to obtain target molten steel; wherein the weight ratio of Als and Alt in the target molten steel is controlled; tundish molten steel is obtained through the target molten steel, and the total oxygen content of the tundish molten steel, the Als loss amount of the tundish molten steel and the weight ratio of Als and Alt in the tundish molten steel are controlled to perform continuous casting pouring to obtain a first casting blank; wherein the process parameters of the continuous casting pouring include: intermediate ladle superheat, argon blowing flow and the amount of protective slag; the first casting blank is in-furnace heated, and the surface temperature of the first casting blank when entering the furnace and the in-furnace time are controlled to obtain a steel plate casting blank. The method reduces the surface defects of the casting blank, and can realize cleaning-free casting blank.

The invention relates to a blade steel smelting and casting process adopting EBT electric arc furnace smelting, LF furnace refining, VOD / VD vacuum treatment and electrode blank pouring. The tapping temperature of an electric arc furnace is controlled to be 1620-1660 DEG C; the method comprises the following steps: carrying out LF furnace alloying treatment, considering blowing loss, ensuring that components after VD meet a set target, controlling the carbon content to be 0.5-0.55% and the temperature to be greater than or equal to 1580 DEG C, carrying out VOD / VD vacuum treatment, ending VD, adding 2-5Kg / t of ferrosilicon alloy, 1.5-3Kg / t of aluminum blocks and 2-3Kg / t of fluorite, adjusting slag system reduction, maintaining the temperature by using chemical heat of carbon-oxygen reaction in a VOD stage, and stirring for 35 minutes to meet the requirement of a crane ladle at 1545-1560 DEG C; the method comprises the following steps: directly transferring to a pouring station, standing for more than or equal to 15 minutes, carrying out pouring molding by adopting a bottom pouring method, carrying out argon protection pouring in the pouring process, carrying out annealing, cap cutting and inspection on an electrode blank, transferring to an electroslag process, and carrying out electroslag remelting, so that the material cost can be reduced, and the purity of molten steel can be improved.