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.

Disclosed are a non-oriented electrical steel sheet with excellent magnetic properties and a manufacturing method thereof, wherein the mass percentage of the chemical components thereof are: C: 0-0.005%; Si: 2.1-3.2%, Mn: 0.2-1.0%, P: 0-0.2%, Al: 0.2-1.6%, N: 0-0.005%, Ti: 0-0.005%, Cu: 0-0.2%, and the balance of Fe and inevitable impurities; and at the same time, (the S content for forming MnS+the S content for forming CuxS)/the S content in the steel is required to be less than or equal to 0.2. The process for manufacturing the non-oriented electrical steel sheet of the present invention is simple and convenient, the chemical components of the steel are easy to control, the manufacturing process is stable, and the technical requirements are easy to realize.

Process to decarburize steel are described. A process can include contacting carbon dioxide with molten steel in an electric arc furnace, a ladle furnace, or a vacuum degassing unit, or a combination thereof.

The invention discloses a method for preparing a stainless steel seamless tube with ultra-high cleanliness for an integrated circuit and an IC industry preparation device, and a stainless steel seamless tube with ultra-high cleanliness. The stainless steel seamless tube which comprises, by mass, C≤0.010%, P≤0.020%, S≤0.010%, Mn≤0.10%, Si≤0.30%, Se≤0.010%, Al≤0.010%, Cu≤0.20%, Cr16.50-17.00%, Ni14.50-15.00%, Mo2.20-2.50%, N≤0.010%, Ni≤0.010%, Ti≤0.010% and the balance Fe and impurities is prepared through a: a stainless steel refining process; b: a vacuum induction melting and vacuum consumable remelting process; c: a stainless steel forging process; d: a hot piercing process; e: a cold working process; f: an inner bore electrolytic polishing, pickling and passivation process; and g: a cleaning process. The stainless steel seamless tube with ultra-high cleanliness prepared through these processes meet the requirements for ultra-high cleanliness and high performance of 316L stainless steel tubes for a semiconductor preparation device.

A method for producing chromium-containing molten steel from a raw material including a chromium-containing raw material includes a first step in which a slag basicity before rough decarburization by oxygen blowing is adjusted to be not less than 1.5 and not more than 3.0, a slag basicity after rough decarburization by oxygen blowing is adjusted to be not less than 2.0 and not more than 3.5, and then tapping is performed while slag containing a chromium oxide generated by the oxygen blowing is made to remain in the furnace, and a second step in which the slag containing a chromium oxide made to remain is reduced by using a carbon source or a metal source newly added into the same furnace so that chromium is recovered into molten steel. The slag basicity is determined by dividing a CaO concentration by an SiO.sub.2 concentration on a mass basis in the slag.

A method for producing chromium-containing molten steel from a raw material including a chromium-containing raw material includes a first step in which a slag basicity before rough decarburization by oxygen blowing is adjusted to be not less than 1.5 and not more than 3.0, a slag basicity after rough decarburization by oxygen blowing is adjusted to be not less than 2.0 and not more than 3.5, and then tapping is performed while slag containing a chromium oxide generated by the oxygen blowing is made to remain in the furnace, and a second step in which the slag containing a chromium oxide made to remain is reduced by using a carbon source or a metal source newly added into the same furnace so that chromium is recovered into molten steel. The slag basicity is determined by dividing a CaO concentration by an SiO.sub.2 concentration on a mass basis in the slag.

The present disclosure provides a method of making non-grain oriented (NGO) electrical steel. The method includes tapping the liquid steel out of a primary steelmaking furnace. Deoxidizing the liquid steel before or after transferring the deoxidized liquid steel to a ladle metallurgy furnace. Removing sulfur at the ladle metallurgy furnace (LMF). Adding fluxes and deoxidizer to the ladle slag and/or skimming off ladle slag to prevent sulfur reversion. Transferring the liquid steel from the ladle metallurgy furnace to an RH degasser for carbon removal by blowing oxygen. Adding fluxes at the RH before oxygen blowing to fortify the bottom layer of the ladle slag to prevent sulfur reversion. The removal of oxygen and sulfur prior to transferring the liquid steel to the RH degasser facilitates nitrogen removal and prevents carbon pick up during the step of adding fluxes and arcing for sulfur removal if sulfur removal is carried out at the LMF after carbon removal at the RH degasser in the conventional process. Oxygen blowing at the RH also lowered the titanium pickup from the earlier desulfurization process. The ultra low levels of carbon, nitrogen, sulfur, and titanium in the NGO steel made using this method enabled the excellent magnetic properties achieved in the finishing NGO products.

The present disclosure provides a method of making non-grain oriented (NGO) electrical steel. The method includes tapping the liquid steel out of a primary steelmaking furnace. Deoxidizing the liquid steel before or after transferring the deoxidized liquid steel to a ladle metallurgy furnace. Removing sulfur at the ladle metallurgy furnace (LMF). Adding fluxes and deoxidizer to the ladle slag and/or skimming off ladle slag to prevent sulfur reversion. Transferring the liquid steel from the ladle metallurgy furnace to an RH degasser for carbon removal by blowing oxygen. Adding fluxes at the RH before oxygen blowing to fortify the bottom layer of the ladle slag to prevent sulfur reversion. The removal of oxygen and sulfur prior to transferring the liquid steel to the RH degasser facilitates nitrogen removal and prevents carbon pick up during the step of adding fluxes and arcing for sulfur removal if sulfur removal is carried out at the LMF after carbon removal at the RH degasser in the conventional process. Oxygen blowing at the RH also lowered the titanium pickup from the earlier desulfurization process. The ultra low levels of carbon, nitrogen, sulfur, and titanium in the NGO steel made using this method enabled the excellent magnetic properties achieved in the finishing NGO products.

Fe—Ni—Cr alloy contains, in mass, from 0.001% to 0.050% of C, from 0.18% to 1.00% of Si, from 0.20% to 0.80% of Mn, 0.030% or less of P, 0.0001% to 0.0020% of S, from 12% to 21% of Ni, from 18% to 24% of Cr, from 0.20% to 1.50% of Mo, 0.30% or less of Cu, from 0.10% to 0.70% of Al, from 0.10% to 0.70% of Ti, from 0.002% to 0.015% of N, from 0.0001% to 0.0010% of B, from 0.0002% to 0.0030% of O, 0.002% or less of Ca, and from 0.0010% to 0.0150% of REM in total, said REM being composed of one or more elements selected from among La, Ce and Y, with the balance being made up of Fe and unavoidable impurities, and which satisfies formulae 1 and 2. Formula 1: 0.575xNi+1.25xCr+3.43xMo-39xP-5.3xAl-641xREM-1018xO≥20.0 Formula 2: 1.5xMn+41.3xSi+1469xS-1.67xAl-1.34xTi-150xO-620xREM≥5.0.