JFE Steel Patente

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Proposed is a method for producing a reduced iron briquette that can improve both the apparent density and strength thereof when briquetting reduced iron through hot briquetting. The method for producing a reduced iron briquette of the present invention is a method for producing a reduced iron briquette including performing hot briquetting on a reduced iron aggregate including pellet-shaped reduced iron containing an iron component, using briquetting rolls, and thus briquetting the reduced iron aggregate, the method also including performing hot briquetting on the reduced iron aggregate by changing a rotation speed of the briquetting rolls and/or a gap between the briquetting rolls in accordance with a T.Fe content of the pellet-shaped reduced iron. As a preferred embodiment, the rotation speed of the briquetting rolls is changed to be slower and/or the gap between the briquetting rolls is changed to be narrower as the proportion of gangue components is higher.

There are provided a method capable of evaluating delayed fracture in a sheared end surface with higher accuracy and a method for manufacturing a press-formed article using the method. A method for evaluating delayed fracture for evaluating the delayed fracture characteristics of a sheared end surface of a metal sheet including: testing whether the delayed fracture occurs with respect to application of forming strain and load stress to the sheared end surface of the metal sheet; for each of two or more evaluation positions along the sheet thickness direction of the sheared end surface, determining evaluation information on whether the delayed fracture occurs with respect to the forming strain and the load stress at the evaluation position based on the test; and determining, from the determined evaluation information, evaluation criteria for the delayed fracture evaluation with the evaluation position, the forming strain, and the load stress as variables.

To provide a method for melting a metal raw material that can perform a process of melting a large amount of metal raw material by appropriately setting the conditions for performing a process of melting a metal raw material composed partially or entirely of reduced iron, using a submerged arc furnace (SAF), and by passing a stable current. Specifically, provided is a method for melting a metal raw material using an electric furnace comprising accommodating molten iron, molten slag, a metal raw material, and an auxiliary raw material in stacked layers in the electric furnace, and discharging the molten iron and the molten slag, in which the resistivity within the electric furnace is set within a range of 0.01 to 0.02 (Ω·m) when a current is supplied to the molten metal to heat the molten metal through an arc or via the molten slag and the metal raw material.

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Provided is a method for operating an electric furnace that achieves high productivity and involves little wear of a refractory material when producing molten metal by melting a metal raw material in the electric furnace. Specifically, provided is a method for operating an electric furnace operated by accommodating molten metal, molten slag, a metal raw material, and an auxiliary raw material in this order in stacked layers within the electric furnace, and continuously discharging the molten metal and the molten slag, characterized in that the electric furnace includes a bottom portion, a furnace wall, a furnace cover, and stirring means for molten metal, input power per unit surface area of molten metal is set to 300 kW/m<2> or greater, and a stirring power density of the stirring means for the molten metal is set in a range of 5 to 100 W/t.

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Provided is an electric furnace equipment/system that prevents overheating of molten metal by converting heat transfer between the molten metal and slag from thermal conduction to forced convection, thereby improving productivity without requiring oversized equipment. The electric furnace equipment/system is configured to accommodate molten metal, slag, a metal raw material, and an auxiliary raw material in stacked layers, and to discharge the molten metal and slag. The electric furnace equipment/system comprises: an arc furnace having a bottom portion, a furnace wall, and a furnace cover; and an electromagnetic stirrer disposed at a predetermined position at the bottom portion or on the side wall of the arc furnace to enable stirring of the molten metal within the arc furnace.

There is provided a method for producing a Cu-Sn-containing steel which, even in hot working using a heating furnace with a low heating capacity, can prevent surface cracking of a Cu-Sn-containing steel and avoid troubles in the heating furnace, thus enabling stable production of the steel. The method for producing a Cu-Sn-containing steel includes: a hot heating step of attaching a first flux, which includes at least one of B<2>O<3>, P<2>O<5>, K<2>O, PbO, Na<2>O-FeO, Na<2>O-SiO<2>, Na<2>O-TiO<2>, and Li<2>O-SiO<2> as a component, and has a liquid fraction of 10 mass % or more at 1000°C, to a surface of a Cu-Sn-containing slab such that the mass of the first flux per unit area of the surface of the slab falls within the range of not less than 50 g/m<2> and not more than 5000 g/m<2>, and then attaching a second flux, which has a liquid fraction of 0 mass % at 1400°C or lower, to the surface of the Cu-Sn-containing slab such that the mass of the second flux per unit area of the surface of the slab falls within the range of not less than 50 g/m<2> and not more than 5000 g/m<2>, and heating the Cu-Sn-containing slab at a temperature of not less than 1000°C and not more than 1400°C; and a hot working step of hot-working the Cu-Sn-containing slab.

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A method for predicting delayed fracture in a press formed part according to the present invention includes: calculating a stress distribution and a strain distribution in a press formed part (S1); calculating a stress gradient in a direction of crack propagation due to delayed fracture at a delayed fracture portion-of-concern in the press formed part (S3); setting a hydrogen concentration distribution corresponding to the strain distribution in the press formed part (S5); performing hydrogen diffusion analysis on the press formed part based on the stress distribution and the hydrogen concentration distribution to calculate a hydrogen concentration distribution after hydrogen diffusion (S7); and predicting whether delayed fracture will occur at the delayed fracture portion-of-concern based on delayed fracture determination conditions based on stress, strain, and hydrogen concentration at the stress gradient, and stress, strain, and hydrogen concentration at the delayed fracture portion-of-concern (S9).

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An energy operation support device in a steel mill includes: an optimization unit configured to optimize operation of an energy utility in a facility in the steel mill; and an upper-limit relaxation unit configured to set an operational upper limit, which is an upper limit in operation, with respect to a facility upper limit, which is an upper limit in output of facility capacity of the facility, in which the upper-limit relaxation unit is configured to set the operational upper limit at a target time or in a target calculation period by determining a predetermined ratio with respect to the facility upper limit, and a total energy operation cost of the steel mill and an adjustment variable of an energy utility with a difference between the facility upper limit and the operational upper limit as an upper limit are included as an objective function of optimization calculation in the optimization unit.

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A polyester film, a laminated metal sheet, and a laminated metal container are provided which can be produced stably in an energy-saving manner at any stage of their production. For example, a polyester film, etc. is provided which has a sufficient corrosion resistance after it is subjected to a process for forming a two-piece can or the like. The polyester film contains a polyester including polyethylene terephthalate as a component. In the polyester film, net intensities of pole figures, obtained by X-ray diffractometry and indicating a crystal orientation distribution, satisfy predetermined conditions.

A pallet monitoring system capable of identifying a grate bar that is likely to detach before the grate bar actually detaches is provided. A pallet monitoring system for monitoring a pallet of a sintering machine, the pallet having a floor surface formed by multiple grate bars includes: an imaging unit that captures an image of the multiple grate bars and generates image data; a calculation unit that calculates an inclination angle of each of the multiple grate bars based on the image data; and a determination unit that determines whether the inclination angle is greater than or equal to a predetermined threshold.

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