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.

Raw material feed into an electric arc furnace (EAF) is melted into heated liquid metal at a controlled temperature with impurities and inclusions removed as a separate liquid slag layer. The heated liquid metal is removed from the EAF into a passively heatable ladle wherein it is moved into a refining station where they are placed into a inductively heated refining holding vessel and wherein vacuum oxygen decarburization is applied to remove carbon, hydrogen, oxygen, nitrogen and other undesirable impurities from the liquid metal. The ladle and liquid metal is then transferred to a refining station/gas atomizer having a controlled vacuum and inert atmosphere wherein the liquid metal is poured from an inductively heated atomizing holder vessel into a heated tundish at a controlled rate wherein high pressure inert gas is applied through a nozzle to create a spray of metal droplets forming spherical shapes as the droplets that cool and fall into a bottom formed in the chamber. Spherical powder comprising the droplets are removed from the chamber through screen and blenders and then classified by size.

An apparatus is disclosed for a metallurgical furnace having a roof with an integrated off-gas hood. The roof has a hollow metal roof section. The hollow metal roof section has a top and a bottom surface. The hollow metal roof section has a center opening configured for one or more electrodes to pass therethrough. An enclosed space is disposed between the top and the bottom surface. A spray-cooled system is disposed in the enclosed space and configured to spray-coolant on the bottom surface of the roof. The integrated off-gas hood has an inlet open to the center opening. The spray-cooled system is also configured to cool the integrated off-gas hood.

A method for venting a spray-cooled roof of a ladle metallurgical furnace is provided herein. The method begins by processing molten metal materials in a ladle metallurgical furnace having a spray-cooled roof with an opening configured for one or more electrodes to pass there through and an integrated hood. Process gases and fumes are extracted through a channel having walls disposed within an enclosed space of the spray-cooled roof. The walls of the channel are cooled with a spray-cool system extends between the walls of the channel and a top of the spray-cooled roof.

Provided is a molten steel treatment device and a molten steel treatment method using same. The molten steel treatment method may include: preparing slag on molten steel; contacting a first electrode to at least a portion of the slag and a second electrode to at least a portion of the molten steel; and polarizing the slag by applying a voltage to the first electrode and the second electrode, to easily remove inclusions and impurity elements in the molten steel by controlling basicity and oxidation degree of the slag without using separate additives.

A steel for induction hardening according to the present invention includes a chemical composition consisting of, in mass percent: C: 0.53 to less than 0.58%, Si: 0.70 to 1.40%, Mn: 0.20 to 1.40%, P: less than 0.020%, S: 0.025% or less, Al: more than 0.06% to 0.15%, N: 0.0020 to 0.0080%, O: 0.0015% or less, B: 0.0003 to 0.0040%, Ti: 0.010 to 0.050%, and Ca: 0.0005 to 0.005%, with the balance being Fe and impurities, and satisfies Formulae (1) to (3). The steel microstructure is made up of ferrite and pearlite. A ratio of a number of composite inclusions is 20% or more.

C+Si/7+Mn/5+Cr/9+Mo/2.50.98(1)

C+Si/10+Mn/20+Cr/250.70(2)

Cr/Si0.20(3)

A steel for induction hardening according to the present invention includes a chemical composition consisting of, in mass percent: C: 0.58 to 0.68%, Si: 0.70 to 1.40%, Mn: 0.20 to 1.40%, Al: 0.005 to 0.060%, N: 0.0020 to 0.0080%, and Ca: 0.0005 to 0.005%, with the balance being Fe and impurities, and satisfies Formulae (1) to (3). The steel microstructure is made up of ferrite and by area fraction, 85% or more of pearlite. In the steel, a ratio of a number of composite inclusions to a total number of Al.sub.2O.sub.3 inclusions and the composite inclusions that contain 2.0% or more of SiO.sub.2 and 2.0% or more of CaO is 20% or more.

C+Si/7+Mn/5+Cr/9+Mo/2.51.05(1)

C+Si/10+Mn/20+Cr/250.70(2)

Cr/Si0.20(3)

A steel for induction hardening according to the present invention includes a chemical composition consisting of, in mass percent: C: 0.58 to 0.68%, Si: 0.70 to 1.40%, Mn: 0.20 to 1.40%, P: less than 0.020%, S: 0.025% or less, Al: more than 0.06% to 0.15%, N: 0.0020 to 0.0080%, O: 0.0015% or less, and Ca: 0.0005 to 0.005%, with the balance being Fe and impurities, and satisfies Formulae (1) to (3). The steel microstructure is made up of ferrite and pearlite. In the steel, a ratio of a number of composite inclusions to a total number of Al.sub.2O.sub.3 inclusions and the composite inclusions is 20% or more.

C+Si/7+Mn/5+Cr/9+Mo/2.51.05(1)

C+Si/10+Mn/20+Cr/250.70(2)

Cr/Si0.20(3)

A steel for induction hardening according to the present invention includes a chemical composition consisting of, in mass percent: C: 0.53 to less than 0.58%, Si: 0.70 to 1.40%, Mn: 0.20 to 1.40%, P: less than 0.020%, S: less than 0.020%, Al: 0.005 to 0.060%, N: 0.0020 to 0.0080%, O: 0.0015% or less, B: 0.0003 to 0.0040%, Ti: 0.010 to 0.050%, and Ca: 0.0005 to 0.005%, with the balance being Fe and impurities, and satisfies Formulae (1) to (3). The steel microstructure is made up of ferrite and pearlite. A ratio of a number of composite inclusions is 20% or more.

C+Si/7+Mn/5+Cr/9+Mo/2.50.98(1)

C+Si/10+Mn/20+Cr/250.70(2)

Cr/Si0.20(3)

A spring steel includes a predetermined chemical composition and a composite inclusion having a maximum diameter of 2 m or more that TiN is adhered to an inclusion containing REM, O and Al, in which the number of the composite inclusion is 0.004 pieces/mm.sup.2 to 10 pieces/mm.sup.2, the maximum diameter of the composite inclusion is 40 m or less, the sum of the number density of an alumina cluster having the maximum diameter of 10 m or more, MnS having the maximum diameter of 10 m or more and TiN having the maximum diameter of 1 m to 10 pieces/mm.sup.2.