A method of making steel by deeply dephosphorization in a hot metal tank and decarburization using semi-steel with nearly zero phosphorus load in a converter includes the following steps: putting an efficient dephosphorization agent into the hot metal tank in advance, and conducting dephosphorization during blast furnace tapping and transportation of blast furnace hot metal by the hot metal tank to obtain semi-steel with [P] less than 0.04 wt. % and [C] greater than or equal to 3.5 wt. %; and removing dephosphorization slag, and pouring the semi-steel into the converter for decarburization to obtain molten steel. The efficient dephosphorization agent includes iron oxide scale, lime, and composite calcium ferrite. According to the method, a phosphorus content of the blast furnace hot metal is reduced to be less than or equal to 0.04 wt. % through the efficient dephosphorization agent.

A method of making steel by deeply dephosphorization in a hot metal tank and decarburization using semi-steel with nearly zero phosphorus load in a converter includes the following steps: putting an efficient dephosphorization agent into the hot metal tank in advance, and conducting dephosphorization during blast furnace tapping and transportation of blast furnace hot metal by the hot metal tank to obtain semi-steel with [P] less than 0.04 wt. % and [C] greater than or equal to 3.5 wt. %; and removing dephosphorization slag, and pouring the semi-steel into the converter for decarburization to obtain molten steel. The efficient dephosphorization agent includes iron oxide scale, lime, and composite calcium ferrite. According to the method, a phosphorus content of the blast furnace hot metal is reduced to be less than or equal to 0.04 wt. % through the efficient dephosphorization agent.

A process for smelting steel for ultrafine carborundum sawing wires, comprising: 1) in a vacuum induction furnace, using pure iron and low-phosphorus pig iron as raw materials to be melted into molten steel under the protection of argon; vacuumizing and smelting, and degassing; using silicon iron as a deoxidizer to adjust components of the molten steel; and casting a circular ingot in vacuum; 2) cleaning the surface of the circular ingot to produce an electrode bar; 3) remelting and smelting the electrode bar as raw material to a cylindrical electroslag ingot in an electroslag furnace, wherein the electroslag protecting slag comprises: CaF.sub.2: 45-55%, Al.sub.2O.sub.3: 15-25%, SiO.sub.2: 20-25%, Na.sub.2O: 2-4%, and K.sub.2O: 1-2%; 4) forging the electroslag ingot to a square billet; and 5) rolling the forged billet to a steel wire rod, and the steel wire rod comprising [C]: 0.92-1.1%, [Si]: 0.3-0.4%, [Mn]: 0.5-0.8%, [Al]<0.0008%, [N]<0.005%, [S]<0.01%, and [P]<0.015%.

A process for smelting steel for ultrafine carborundum sawing wires, comprising: 1) in a vacuum induction furnace, using pure iron and low-phosphorus pig iron as raw materials to be melted into molten steel under the protection of argon; vacuumizing and smelting, and degassing; using silicon iron as a deoxidizer to adjust components of the molten steel; and casting a circular ingot in vacuum; 2) cleaning the surface of the circular ingot to produce an electrode bar; 3) remelting and smelting the electrode bar as raw material to a cylindrical electroslag ingot in an electroslag furnace, wherein the electroslag protecting slag comprises: CaF.sub.2: 45-55%, Al.sub.2O.sub.3: 15-25%, SiO.sub.2: 20-25%, Na.sub.2O: 2-4%, and K.sub.2O: 1-2%; 4) forging the electroslag ingot to a square billet; and 5) rolling the forged billet to a steel wire rod, and the steel wire rod comprising [C]: 0.92-1.1%, [Si]: 0.3-0.4%, [Mn]: 0.5-0.8%, [Al]<0.0008%, [N]<0.005%, [S]<0.01%, and [P]<0.015%.

A method for desulfurizing molten steel comprising taking a sample out from molten steel after tapping from a converter or during secondary refining and analyzing the sample rapidly with high accuracy by a method comprising a high frequency induction heating step wherein the sample is combusted and oxidized under the high frequency induction heating in an oxygen atmosphere having an oxygen purity of 99.5 vol % or more to convert S in the sample into SO.sub.2 and an analyzing step wherein SO.sub.2-containing gas produced in the high frequency induction heating step is analyzed through an ultraviolet fluorescence method to quantify S concentration of the sample.

A method for desulfurizing molten steel comprising taking a sample out from molten steel after tapping from a converter or during secondary refining and analyzing the sample rapidly with high accuracy by a method comprising a high frequency induction heating step wherein the sample is combusted and oxidized under the high frequency induction heating in an oxygen atmosphere having an oxygen purity of 99.5 vol % or more to convert S in the sample into SO.sub.2 and an analyzing step wherein SO.sub.2-containing gas produced in the high frequency induction heating step is analyzed through an ultraviolet fluorescence method to quantify S concentration of the sample.

A bearing steel includes, as a metallographic structure, inclusions which contain complex oxysulfides including Rare Earth Metal, Ca, O, S, and Al, TiN, MnS, Al.sub.2O.sub.3, and complex oxides including Al and Ca, wherein, a number fraction of the complex oxysulfides in a total number of the inclusions is 50% to less than 100% and a number of complex oxysulfides having a major axis of 5 μm or more is 0.001 pieces to 2 pieces in an observed section of 1 mm.sup.2, and a number of TiN existing independently from the complex oxysulfides and having a major axis of 5 μm or more is 0.001 pieces to less than 1.0 piece in an observed section of 1 mm.sup.2.

The method employs a desulfurization agent that is introduced into a smelt of one of molten pig iron and molten steel. The desulfurization agent contains calcium oxide, bitumen and at least one flux agent, with the agent containing 1 to 10% by weight bitumen.

Provided is a straight barrel type vacuum refining device comprising a vacuum chamber and a snorkel; during the vacuum refining the snorkel is inserted into the molten steel of the steel ladle, it is characterized in that, disposing a circulating tube being on the circumference of said snorkel, and blowing argon gas into the snorkel through the nozzles on an inner wall of a circulating tube; said circulating tubes are disposed in layers, the nozzles on the circulating tubes in the same layer are individually controlled as 2-6 in one group; disposing an eccentric gas permeable brick at the bottom of said steel ladle, and blowing argon gas into the steel ladle through the eccentric gas permeable brick, driving a circulating flow molten steel between the steel ladle and the vacuum chamber by using different blowing flow rate combinations of a steel ladle bottom blowing and each individually controlled unit of the circulating tube blowing system.

Provided is a straight barrel type vacuum refining device comprising a vacuum chamber and a snorkel; during the vacuum refining the snorkel is inserted into the molten steel of the steel ladle, it is characterized in that, disposing a circulating tube being on the circumference of said snorkel, and blowing argon gas into the snorkel through the nozzles on an inner wall of a circulating tube; said circulating tubes are disposed in layers, the nozzles on the circulating tubes in the same layer are individually controlled as 2-6 in one group; disposing an eccentric gas permeable brick at the bottom of said steel ladle, and blowing argon gas into the steel ladle through the eccentric gas permeable brick, driving a circulating flow molten steel between the steel ladle and the vacuum chamber by using different blowing flow rate combinations of a steel ladle bottom blowing and each individually controlled unit of the circulating tube blowing system.