Patent classifications
C21C5/5211
Method for producing metal powders by means of gas atomization and production plant of metal powders according to such method
A method for producing metal powders by gas atomization is provided, including providing a metal charge; melting the metal charge inside an electric-arc furnace, controlling its composition until a molten metal bath having a desired composition is obtained; tapping the bath from the furnace, collecting it inside a ladle; refining the bath under controlled atmosphere, vacuum, or overpressure condition; atomizing the refined bath by feeding it into a gas atomizer, inside which a molten metal bath flow is produced, and impinging the molten metal bath flow with an atomization inert gas stream for the atomization of the molten metal bath into metal powders; and extracting the obtained metal powders from the gas atomizer.
HIGH PERFORMANCE ALLOY FOR CORROSION RESISTANCE
A corrosion resistant alloy, a method for making the corrosion resistant alloy, and a method for using the corrosion resistant alloy are provided. The corrosion resistant alloy includes 13-15 wt. % chromium, 5-7 wt. % nickel, and 2.5-4.5 wt. % molybdenum.
Methods of protecting furnace electrodes with cooling liquid that contains an additive
A method for forming a protective antioxidative barrier on the furnace electrodes using a chemically altered cooling liquid containing an antioxidant additive. This method can be applied to electrodes used in electric arc furnaces and ladle metallurgy furnaces. The method can involve spraying the cooling liquid onto the electrode, thereby forming the protective antioxidative barrier and reducing the oxidation of the electrode.
Method and apparatus for the production of cast iron, cast iron produced according to said method
A method for the production of cast iron starting from pre-reduced iron ore (DRI) with an electric arc furnace includes the steps of preparing a charge of pre-reduced iron ore DRI having a metallization higher than 90% and containing over 2.8% by weight of carbon, wherein at least 80% of the carbon is combined with the iron to form iron carbide Fe.sub.3C; charging the charge of pre-reduced iron ore into the electric arc furnace; and melting the DRI charge to form liquid cast iron having at least 80% by weight of actual carbon content deriving from the carbon in the charge of pre-reduced iron ore, the melting step being in a reducing atmosphere and in a melting chamber of the electric arc furnace subjected to a positive internal pressure generated by the gases produced by reduction reactions that develop during melting.
SPRAY COOLING FURNACE ELECTRODES WITH A COOLING LIQUID THAT CONTAINS SURFACTANTS
A method for cooling furnace electrodes using a cooling liquid containing surfactants. This method can be applied to electrodes used in electric arc furnaces and ladle metallurgy furnaces. The method can involve spraying the cooling liquid onto the electrode, thereby lowering the temperature of the electrode and reducing electrode consumption.
Estimation or control of lengths and positions of one or more transversely localized electric current segments flowing between two conductive bodies
Magnetic field components are measured at multiple longitudinal positions and used to calculate estimated longitudinal position and length of a transversely localized electric current segment flowing across a gap between conductive bodies. The apparatus can be used with a remelting furnace. The electrode and ingot act as the conductive bodies, and arcs, discharges, or slag currents are the current segments spanning the gap. Actuators for movable sensors can be coupled to the sensors in a servomechanism arrangement to move the sensors along with the moving gap. An actuator for moving one of the conductive bodies can be coupled to sensors in a servomechanism arrangement to maintain the gap distance within a selected range as the gap moves.
Arc furnace bottom construction
An arc furnace bottom construction for maintaining the outer surface temperature of the bottom construction essentially at least on the lower part of the arc furnace essentially close to the temperature surrounding the arc furnace. The bottom construction contains at least two constructions to be cooled and being positioned to each other in different heights seen from the side view.
Estimation of arc location in three dimensions
Multiple magnetic field sensors are arranged around a current-containing volume at multiple longitudinal and circumferential positions. Each sensor measures multiple magnetic field components and is characterized by one or more calibration parameters. A longitudinal primary current flows through two end-to-end electrical conductors that are separated by an arc gap, and flows as at least one longitudinal primary electric arc that spans the arc gap and that moves transversely within the arc gap. Estimated transverse position of the primary electric arc is calculated, based on the longitudinal position of the arc gap, and two or more of the measured magnetic field components along with one or more corresponding sensor positions or calibration parameters. In addition, estimated occurrence, position, and magnitude of a transverse secondary current (i.e., a side arc) can be calculated based on those quantities.
METHOD FOR PRODUCING METAL POWDERS BY MEANS OF GAS ATOMIZATION AND PRODUCTION PLANT OF METAL POWDERS ACCORDING TO SUCH METHOD
A method for producing metal powders by gas atomization is provided, including providing a metal charge; melting the metal charge inside an electric-arc furnace, controlling its composition until a molten metal bath having a desired composition is obtained; tapping the bath from the furnace, collecting it inside a ladle; refining the bath under controlled atmosphere, vacuum, or overpressure condition; atomizing the refined bath by feeding it into a gas atomizer, inside which a molten metal bath flow is produced, and impinging the molten metal bath flow with an atomization inert gas stream for the atomization of the molten metal bath into metal powders; and extracting the obtained metal powders from the gas atomizer.
METHOD FOR PRODUCING METAL POWDERS BY MEANS OF GAS ATOMIZATION AND PRODUCTION PLANT OF METAL POWDERS ACCORDING TO SUCH METHOD
A method for producing metal powders by gas atomization is provided, including providing a metal charge; melting the metal charge inside an electric-arc furnace, controlling its composition until a molten metal bath having a desired composition is obtained; tapping the bath from the furnace, collecting it inside a ladle; refining the bath under controlled atmosphere, vacuum, or overpressure condition; atomizing the refined bath by feeding it into a gas atomizer, inside which a molten metal bath flow is produced, and impinging the molten metal bath flow with an atomization inert gas stream for the atomization of the molten metal bath into metal powders; and extracting the obtained metal powders from the gas atomizer.