Abstract: A joining portion of an opposed surface of workpieces is heated by generating an induced current due to a change of a magnetic field as well as by applying a frictional heat to the joining portion, so that productivity and quality of welding can be improved.

Abstract: An electrolysis-type apparatus for treating ballast water using NaOCl and a method thereof is provided. The apparatus includes: a ballast tank; an electrolyzer; a first circulation pump; a second circulation pump; and a controller. The ballast tank is installed in a ship to store seawater. The electrolyzer is connected with the ballast tank and electrolyzes the seawater. The circulation pumps are installed to allow the ballast water to flow into the electrolyzer and to discharge the electrolyzed water containing NaOCl to the ballast tank. The controller supplies power to the electrolyzer so as to control an NaOCl density and controls the circulation pumps. The apparatus and the method safely treat the seawater. Thus, environment pollution and ecosystem destruction can be minimized.

Abstract: A cold spray apparatus having a powder preheating device, capable of obtaining high deposition rate and excellent coating layer under the same spray processing conditions by preheating coating powder before a coating process. Also, a manufacturing method of nano-structured super-high hardness WC—Co coating having high abrasive wear resistance and fracture toughness obtained by spraying WC—Co powder using the cold spray apparatus. In the cold spray apparatus, a gas controller controls gas supply amount of main gas and residual gas (gas that is not supplied toward the main gas), and a gas heater heats the main gas supplied under the control of the gas controller. A powder feeder receives the residual gas under the control of the gas controller and supplies a coating powder together with the residual gas. A powder preheating device preheats the coating powder supplied from the powder feeder, and a mixing chamber mixes the heated main gas with the preheated coating powder.

Abstract: A nozzle distributor base for distributing a gas which is laden with fine solids particles, preferably for use in a fluidized-bed unit, in particular for the reduction of metal oxide-containing solids particles. At least one movable cleaning device on the distributor base reduces the formation of deposits on the distributor base or the nozzles thereof or at least partially removes deposits which have already formed. Elements in the distributor base, like chains, ropes or movable rods, clean the distributor base by direct mechanical striking action on the distributor base and/or the nozzles of the nozzle distributor base. A method for reducing the formation of deposits and/or for at least partially removing deposits on a distributor base uses the striking action.

Abstract: An apparatus for preventing bulging of both edges of a strip while preventing contamination of a roll surface in a twin roll strip caster including a meniscus shield (5) and a plurality of weirs (12).

Abstract: Provided is a strengthening device to increase the strength of a grout layer. In the strengthening device, clamp members are interconnected and clamped to surround a grout layer on a concrete base, on which an upper structure is installed, so as to increase the strength of the grout layer. Connection members are provided to edges of the clamp members to connect the clamp members. Fastening means is fastened between the connection members in order to enable the clamp members to clamp the grout layer. This strengthening device acts as a mold to facilitate easy construction when grout is placed, and surrounds the grout layer to increase the strength of the grout layer after grout is cured, thereby effectively preventing and minimizing failure of the grout layer caused by loads transferred from an upper structure such as a column member or a bridge bearing.

Abstract: A molten metal holding apparatus for the continuous hot dip coating of a metal strip includes a vessel that is substantially rectangular in cross section having long sides and short sides and has formed a slot-shaped opening in a bottom surface, the vessel containing molten metal; subsidiary vessels formed following an outer circumference of an upper end of the vessal and for temporarily storing molten metal that overflows from the upper end of the vessel; chambers formed outwardly following long sides of a lower end of the vessel and that communicate with the vessel via slit-shaped branch openings formed at a predetermined slant toward the vessel; a plurality of subsidiary tubes communicating with the subsidiary vessels; and alternating current electromagnets including a core mounted adjacent to outside side surfaces of the vessel and between the subsidiary vessels and the chambers and a coil wound around the core and to which an alternating current is supplied.

Abstract: The steel plate is manufactured from a composition comprising C, N and S in an amount of 0.0150% by weight or less in total; Mn in an amount of 0.2 to 0.8% by weight; Al inan amount of 0.6% by weight or less; Si in an amount of 0.4% by weight or less; Cu and/or Sn in an amount of 0.1 to 0.6% by weight in total; and Fe for the remainder, and inevitably present elements, whereby the steel plate can show excellent electromagnetic shield effect and hot-dip galvanization properties.

Abstract: A steel plate and a hot-dip galvanized steel plate, superior in terms of high electromagnetic shield capacity. The steel plate is prepared from a composition comprising C, N and S in an amount of 0.150% by weight or less in total; Mn in an amount of 0.1 to 1.0% by weight; Si in an amount of 0.5% by weight or less; Al in an amount of 1.0% by weight or less; P in an amount of 0.06% by weight or less; and Fe for the remainder, and inevitable elements, and shows a yield strength of 18 kg/mm2 or higher, and an elongation of 40% or higher. The hot-dip galvanized steel plate is prepared from a composition comprising C, N and S in an amount of 0.0150 % by weight or less in total; Mn in an amount of 0.2 to 0.8% by weight; Al in an amount of 0.6% by weight or less; Si in an amount of 0.4% by weight or less; P in an amount of 0.06% by weight or less, with the proviso that the sum of Mn, Al, Si and P amounts to 0.2-1.0% by weight; and Fe for the remainder, and inevitably present elements.

Abstract: The present invention relates to a martensitic stainless steel that can be used in manufacturing articles such as a shaft or an impeller which require high mechanical strength and corrosion resistance and provides a martensitic stainless steel comprising less than 0.06 wt. % C, less than 2.5 wt. % Si, less than 2.5 wt. % Mn, 1.0-6.0 wt. % Ni, 10.0-19.0 wt. % Cr, 0.5-6.0 wt. % W, less than 3.5 wt. % Mo, less than 0.5 wt. % Nb, less than 0.5 wt. % V, less than 3.0 wt. % Cu, 0.05-0.25 wt. % N, and the remainder being Fe and minor impurities.

Abstract: Disclosed are far-infrared emission powders and resin-coated steel plates with antibacterial activity and far-infrared emission properties. In addition to being 0.9 or higher in emissivity, the far-infrared emission powders are inhibitory against the growth of bacteria, with a pH value of 7.5-10.5 in its saturate aqueous solution. A coating material comprising 5-100 parts by weight of the powder per 100 parts by weight of a resin is coated to a dry thickness of 5-60 &mgr;m on an electromagnetic shield steel plate without interruption of the intrinsic electromagnetic shield properties of the steel plate.

Abstract: A fluidized bed reduction reactor (100) for supplying a reduced iron to a melter-gasifier (1) of a smelting reduction system includes an exhaust gas supply unit (3) for supplying an exhaust gas to a reduction gas supply tube (4) interconnecting the melter-gasifier (1) and fluidized bed reduction furnaces (20, 30, 40) when the pressure of the reduction gas in each fluidized bed reduction furnace radically decreases with the occurrence of pressure peak in the melter-gasifier (1). The fluidized bed reduction reactors further include iron ore flow blockage prevention units for directly bypassing some of the reduction gas from each iron ore discharge tube (33, 43) disposed between the neighboring furnaces to the scrubber (50) when the inner pressure of the melter-gasifier (1) radically increases with the occurrence of pressure peak, and a backup gas supply unit supplying a backup nitrogen gas to the bottom of each fluidized bed reduction furnace when a nozzle of a distribution plate (24, 34, 44) is clogged.

Abstract: In a process for producing a metal melt by reducing metal-oxide-containing material in a fluidized-bed reactor by the fluidized-bed method and by subsequently melting down the reduced material in a melt-down gasifier, in the melt-down gasifier there is generated from carbon-containing material a reducing gas which is used for reducing the metal-oxide containing material by the fluidized-bed method. Both the reducing and the melting-down are effected under atmospheric excess pressure. For the purposes of transferring the reduced material from the fluidized-bed reactor into the melt-down gasifier in a simple manner, a lower pressure is set in an intermediate vessel situated above the melt-down gasifier than in fluidized-bed reactor, and the reduced material is allowed to flow, under relaxation, upwards from the fluidized-bed reactor into the intermediate vessel and conducted from the intermediate vessel via a sluice system into the melt-down gasifier while being pressurized.

Abstract: A smelting reduction apparatus which separates exhaust gas, which is exhausted from a melter-gasifier or a fluidized bed reactor, into dusts and reducing gas to supply them to each fluidized bed reactor respectively is disclosed, in which the smelting reduction apparatus includes a three-stage type fluidized bed reactor, a melter-gasifier for manufacturing molten pig iron by finally reducing the fine iron ores of which reaction is finished in a final fluidized bed reactor, and a dust separating device, which performs separation of exhausted gas from the melter-gasifier into dusts and reducing gas, so as to supply the separated reducing gas to a lower part of the final fluidized bed reactor, dusts having a larger particle sizes in the separated dusts to the melter-gasifier again, and fine dusts having a smaller particle sizes in the separated dusts to an upper part of a gas distributor of the final fluidized bed reactor.

Abstract: An apparatus and method for measuring the level of a free surface of molten metal in an electromagnetic continuous casting process using an AC electromagnetic field. A detection coil is provided to detect the sum of a magnetic field applied from an induction coil and an induced magnetic field based on eddy current in the molten metal. An arithmetic unit is provided to detect the surface level of the molten metal by removing a variation of the applied magnetic field with a variation in current to the induction coil from an output signal from the detection coil. The surface level of the molten metal can be accurately measured by determining whether a variation in the output of the detection coil results from a variation in the applied magnetic field or a variation in the surface level of the molten metal.

Abstract: Plant for charging metal carriers which contain a portion of fines and are at least partially reduced to a melter gasifier in which a melt-down gasifying zone formed by a bed is maintained, the metal carriers and carbon carriers are fed into the melter gasifier above the level of the melt-down gasifying zone. The metal carriers descend to the melt-down gasifying zone and travel through the same forming a metal melt and producing a reducing gas by coal gasification.

Abstract: A two-stage fluidized bed reducing apparatus and a reducing method for fine iron ore of a wide particle size distribution with an increased degree of utilization of the reducing gas. Fine iron particles dropping through the holes of a gas distributor can be recycled into the fluidized bed furnace, thereby preventing an impediment of the reducing gas flow due to abnormal defluidizing or channeling. A first fluidized bed furnace dries, pre-heats and pre-reduces the fine iron ore, and a second fluidized bed furnace finally reduces the pre-reduced iron ore. Downstream of the respective fluidized beds are installed intermediate hoppers and gas/solid sealing valves. Thus, the fine iron ore particles which drop through the holes of gas distributors during the abnormal operation are recycled to the furnaces. Accordingly, the gas flow is not impeded.

Abstract: A combustion chamber in a melter gasifier extends into a fluidized bed to isolate fine particulate ore introduced into the chamber from the remaining internal portion of the melter gasifier. The fine particulate ore is melted in the chamber and falls on the bed to be reduced as it trickles down to the molten metal in the melter gasifler bottom. Reducing gases withdrawn from the melter gasifier are filtered through the bed, thereby preventing the fine particulate ore from being withdrawn with the gases. The chamber can be liquid cooled and use a burner to provide combustion temperatures.

Abstract: The present invention provides an apparatus for measuring flatness of a hot rolled strip based on a contact load of the hot rolled strip to split rolls of a looper in the hot rolling process. The split rolls are assembled in a bracket such that each split roll can be separated from the bracket. A normal-movement control unit for moving the split rolls in the normal direction, and a tangent-movement control unit for moving the split rolls in the tangent direction are porvided at a side of the bracket bearing the split rolls. An impact absorption unit is mounted at a support that is movably connected to the tangent-movement control unit. A pre-pressure application unit is provided at the support to prevent a sensor cap and a load sensor from being released. A heat-shielding ring surrounds the load sensor to prevent the load sensor from being overheated.

Abstract: In the process for the production of liquid pig iron 943) or liquid steel pre-products from charging substances comprising iron ore (5) and fluxes and at least partially containing a portion of fines, the iron ore is directly reduced to sponge iron in at least two reduction stages (1, 2) by the fluidized bed method, the sponge iron is melted in a melt-down gasifying zone (39) under the supply of carbon carriers and an oxygen-containing gas, and a CO- and H2-containing reducing gas is produced which is injected into reduction zones of the reduction stages (1, 2), is reacted there, is withdrawn as a top gas and optionally is supplied to a consumer.