A method for manufacturing molten iron by melting a cold iron source in an electric arc furnace having a carbonaceous material-injecting device. The method includes, in the carbonaceous material-injecting device, while a carbonaceous material is injected with a carrier gas through a central portion of the carbonaceous material-injecting device, injecting a fuel and a combustion-supporting gas through respective outer peripheral portions of the carbonaceous material-injecting device. The carbonaceous material injected through the central portion passes through a cylindrical combustion flame generated by a combustion reaction between the fuel and the combustion-supporting gas and is injected into molten slag and molten iron.

A method for manufacturing molten iron by melting a cold iron source in an electric arc furnace having a carbonaceous material-injecting device. The method includes, in the carbonaceous material-injecting device, while a carbonaceous material is injected with a carrier gas through a central portion of the carbonaceous material-injecting device, injecting a fuel and a combustion-supporting gas through respective outer peripheral portions of the carbonaceous material-injecting device. The carbonaceous material injected through the central portion passes through a cylindrical combustion flame generated by a combustion reaction between the fuel and the combustion-supporting gas and is injected into molten slag and molten iron.

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.

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.

An oxygen blowing lance comprising: a lance body including an oxygen conduit and cooling water inlet and outlet conduits surrounding said oxygen conduit; a lance head connected to said lance body and comprising a nozzle body, said nozzle body including a central strut having bore hole, a plurality of nozzles arranged about said central strut, and a plurality of cooling chambers arranged about said central strut, wherein said plurality of nozzles are in fluid communication with said oxygen conduit for discharging oxygen from said oxygen conduit onto a metal bath in a converter vessel, and wherein said plurality of cooling chambers are in fluid communication with said cooling water inlet and outlet conduits; a temperature probe or camera assembly received in said bore hole for monitoring the temperature of said lance head or molten heat in which the lance is inserted; signal lines connected to said temperature probe for conveying signals from said temperature probe whereby operation of said blowing lance is regulated in response to said signals; and a protective pipe pressurized with a gas disposed in the bore and surrounding said temperature probe assembly and the signal lines.

An oxygen blowing lance comprising: a lance body including an oxygen conduit and cooling water inlet and outlet conduits surrounding said oxygen conduit; a lance head connected to said lance body and comprising a nozzle body, said nozzle body including a central strut having bore hole, a plurality of nozzles arranged about said central strut, and a plurality of cooling chambers arranged about said central strut, wherein said plurality of nozzles are in fluid communication with said oxygen conduit for discharging oxygen from said oxygen conduit onto a metal bath in a converter vessel, and wherein said plurality of cooling chambers are in fluid communication with said cooling water inlet and outlet conduits; a temperature probe or camera assembly received in said bore hole for monitoring the temperature of said lance head or molten heat in which the lance is inserted; signal lines connected to said temperature probe for conveying signals from said temperature probe whereby operation of said blowing lance is regulated in response to said signals; and a protective pipe pressurized with a gas disposed in the bore and surrounding said temperature probe assembly and the signal lines.

A long-life service method for powder-bottom-injecting converter based on collaborative hot replacement of furnace bottom and bottom purging brick belongs to the field of steelmaking technologies using powder-bottom-injecting converters. According to equipment characteristics, process characteristics, and erosion characteristics of the powder-bottom-injecting converter, the design, arrangement, installation, use, maintenance, and replacement of the bottom purging/powder injection bricks are systematically optimized and improved, a technology of automatically detecting the erosion height of bottom purging bricks is adopted, and hot replacement of bottom purging/powder injection bricks and hot replacement of the converter furnace bottom are used collaboratively, which not only can prolong the service life of a single bottom purging/powder injection brick, but also can greatly prolong the overall life of the powder-bottom-injecting converter from 1000-3000 heats in the prior art to 6000-10000 heats. Hence, the life of the powder-bottom-injecting converter is as long as that of a conventional converter.

A long-life service method for powder-bottom-injecting converter based on collaborative hot replacement of furnace bottom and bottom purging brick belongs to the field of steelmaking technologies using powder-bottom-injecting converters. According to equipment characteristics, process characteristics, and erosion characteristics of the powder-bottom-injecting converter, the design, arrangement, installation, use, maintenance, and replacement of the bottom purging/powder injection bricks are systematically optimized and improved, a technology of automatically detecting the erosion height of bottom purging bricks is adopted, and hot replacement of bottom purging/powder injection bricks and hot replacement of the converter furnace bottom are used collaboratively, which not only can prolong the service life of a single bottom purging/powder injection brick, but also can greatly prolong the overall life of the powder-bottom-injecting converter from 1000-3000 heats in the prior art to 6000-10000 heats. Hence, the life of the powder-bottom-injecting converter is as long as that of a conventional converter.

A long-life service method for powder-bottom-injecting converter based on collaborative hot replacement of furnace bottom and bottom purging brick belongs to the field of steelmaking technologies using powder-bottom-injecting converters. According to equipment characteristics, process characteristics, and erosion characteristics of the powder-bottom-injecting converter, the design, arrangement, installation, use, maintenance, and replacement of the bottom purging/powder injection bricks are systematically optimized and improved, a technology of automatically detecting the erosion height of bottom purging bricks is adopted, and hot replacement of bottom purging/powder injection bricks and hot replacement of the converter furnace bottom are used collaboratively, which not only can prolong the service life of a single bottom purging/powder injection brick, but also can greatly prolong the overall life of the powder-bottom-injecting converter from 1000-3000 heats in the prior art to 6000-10000 heats. Hence, the life of the powder-bottom-injecting converter is as long as that of a conventional converter.

A long-life service method for powder-bottom-injecting converter based on collaborative hot replacement of furnace bottom and bottom purging brick belongs to the field of steelmaking technologies using powder-bottom-injecting converters. According to equipment characteristics, process characteristics, and erosion characteristics of the powder-bottom-injecting converter, the design, arrangement, installation, use, maintenance, and replacement of the bottom purging/powder injection bricks are systematically optimized and improved, a technology of automatically detecting the erosion height of bottom purging bricks is adopted, and hot replacement of bottom purging/powder injection bricks and hot replacement of the converter furnace bottom are used collaboratively, which not only can prolong the service life of a single bottom purging/powder injection brick, but also can greatly prolong the overall life of the powder-bottom-injecting converter from 1000-3000 heats in the prior art to 6000-10000 heats. Hence, the life of the powder-bottom-injecting converter is as long as that of a conventional converter.