A process for producing clean steel products with low nitrogen content, below 35 ppm, in a steelmaking plant comprising a direct reduced iron (DRI) source, which may be a direct reduction plant or a DRI storage facility, an electric arc furnace (EAF), a vacuum degassing system (DS), and a continuous casting system (CC) is disclosed. The process comprises a first stage of melting and refining a metallic iron charge, a second stage of tapping molten steel from the electric arc furnace (EAF) into a ladle, a third stage of exposing molten steel to a pressure below the atmospheric pressure and a fourth stage of casting molten steel to clean steel products. Optionally, the molten steel tapped from the EAF is treated in a ladle furnace (LF) prior to being treated in the degassing system (DS). The metallic iron charge fed to the EAF comprises more than 70% by weight of DRI in the form of pellets or briquettes having a carbon content above 2.5 weight %. Preferably, the metallic iron charge is fed to the EAF at a temperature of 400 C. or higher. The low nitrogen level in the steel products made according to the Application is achieved by forming a first foamy slag in said first process stage and is maintained in a foamy state by controlling the feed of fluxes, oxygen, and carbonaceous materials to the EAF and by forming a second slag, after molten steel is tapped from the EAF, having a predetermined composition capable of continuing the desulfurization and providing a thermal and chemical insulation to prevent nitrogen pickup and promote nitrogen removal of molten steel. The process also comprises carrying out one or more of the following actions: (a) controlling the concentration of nitrogen and sulfur in the raw materials at each process stage, (b) promoting nitrogen removal from steel, (c) decreasing the time spent by the molten steel at each process stage and between each and subsequent process stages, and (d) preventing nitrogen pickup by the molten steel all along said process stages. Steel products made according to the Application comprise the following elements expressed in weight %: C0.05%, Si4.5%, Al2.0%; Mn2.0%; P0.20%; Ni0.200%, Cu0.200%; N0.0030%, Ni0.200%, S0.0035%.

Provided are a joint regulation method of material flow, energy flow, and carbon emission flow in a long-process steel enterprise, which belongs to a field of intelligent regulation and control technology of electric power system in the steel industry. The method includes: coupling a material-energy characteristic model of each production process of a steel enterprise and a carbon emission model of the steel enterprise, constructing a material flow-energy flow-carbon emission flow coupling model of the long-process steel enterprise, establishing an objective function using a minimize sum of an electricity purchase cost from a superior grid, a park carbon emission cost, and a production raw material cost as an object, and solving and obtaining an optimal operation mode of a joint regulation of the material flow-energy flow-carbon emission flow in the steel enterprise.

A method for producing and preparing a steel bar for automotive bushings by means of an ecological and economical arc furnace is provided. The steer bar contains, in percentage by mass: 0.18-0.23% of C, 0.20-0.35% of Si, 0.42-0.60% of Mn, less than or equal to 0.015% of P, less than or equal to 0.010% of S, 0.82-1.00% of Cr, less than or equal to 0.25% of Ni, 0.41-0.53% of Mo, less than or equal to 0.15% of Cu, and the balance of Fe and inevitable impurities. By means of smelting in an ecological and economical arc furnace, LF refining, RH refining, continuous casting, a heating process and a rolling process, the method enables batch production of the steel bar for an automobile shaft sleeve by means of a continuous casting procedure using the ecological and economical arc furnace.

Provided are a joint regulation method of material flow, energy flow, and carbon emission flow in a long-process steel enterprise, which belongs to a field of intelligent regulation and control technology of electric power system in the steel industry. The method includes: coupling a material-energy characteristic model of each production process of a steel enterprise and a carbon emission model of the steel enterprise, constructing a material flow-energy flow-carbon emission flow coupling model of the long-process steel enterprise, establishing an objective function using a minimize sum of an electricity purchase cost from a superior grid, a park carbon emission cost, and a production raw material cost as an object, and solving and obtaining an optimal operation mode of a joint regulation of the material flow-energy flow-carbon emission flow in the steel enterprise.

A method for manufacturing steel according to an embodiment of the present invention comprises the steps of: preparing a first molten metal manufactured using a first raw material including iron ore and a second molten metal manufactured using a second raw material including iron scrap; mixing the first molten metal and the second molten metal to manufacture a third molten metal; adjusting components of the third molten metal to manufacture a fourth molten metal; and manufacturing a product by processing the fourth molten metal.