A wire for out-of-furnace treatment of metallurgical melts comprises a metallic sheath which encloses a core comprising at least one element selected from the group consisting of Ca, Ba, Sr, Mg, Si and Al, wherein at least one layer of a composite coating is applied to an inner and/or outer surface of said sheath, which coating consists of a lacquer paint material and contains high-melting ultrafine particles selected from compounds of metal carbides and/or nitrides and/or carbonitrides and/or silicides and/or borides. The composite coating comprises a protector material, for which ferroalloys and/or flux agents are used. The metals contained in the high-melting compounds are titanium and/or tungsten and/or silicon and/or magnesium and/or niobium and/or vanadium. Said coating is applied evenly onto the surface of the sheath.

A method for producing steel includes: (a) a step of adding the first group of alloys to molten steel having an amount of dissolved oxygen of 0.0050 mass % or more; (b) a step of, after the step of (a), adding deoxidizer to the molten steel for deoxidation; (c) a step of, after the step of (b), adding the second group of alloys to the deoxidized molten steel; and (d) a step of, after the step of (c), adding REM to the molten steel, wherein amounts of oxygen O.sub.b introduced from the first group of alloys (mass %) and amounts of oxygen O.sub.a introduced from the second group of alloys (mass %) satisfy [O.sub.a≤0.00100], [O.sub.b+O.sub.a≥0.00150], and [O.sub.b/O.sub.a≥2.0], and satisfy a formula [0.05≤REM/T.O≤0.5] after the step of (d).

Provided is an alloy steel manufacturing method, the method including: preparing a manganese-containing first molten ferroalloy; preparing a chromium-containing second molten alloy; preparing molten steel; mixing the first molten ferroalloy and the second molten ferroalloy to manufacture third molten ferroalloy; and mix pouring the third molten ferroalloy and the molten steel to manufacture an alloy steel, wherein the phosphorous concentration in the molten steel may efficiently be controlled by reducing the converter end point temperature of the molten steel to improve a phosphorous control capacity during converter refining.

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.

Proposed is a method for removing phosphorus from a phosphorus-containing substance which is applicable in an industrial scale so as to effectively reduce phosphorus contained in the phosphorus-containing substance. In this method, the phosphorus-containing substance used as a raw material for metal smelting or metal refining is reacted with a nitrogen-containing gas at a treatment temperature T ( C.) which is lower than a melting temperature (T.sub.m) of the substance, so that phosphorus is removed preferably in the form of phosphorus nitride (PN). In this regard, a nitrogen partial pressure and an oxygen partial pressure in the nitrogen-containing gas are preferably controlled, thereby reducing a load of dephosphorization process, for example.

Disclosed is a slag discharging method in a process of producing ultra-low phosphorus steel, which relates to the technical field of iron and steel smelting, and in which molten steel is mixed with lime first to produce basic slag; then converting is performed with oxygen to increase the oxidizability of the basic slag; and a carbon-containing reducing agent is finally added, so that in the process that the carbon is oxidized to release a large amount of carbon monoxide gas, phosphates are captured, and the basic slag is rapidly foamed and overflows from the opening of the steel ladle, so that conditions are no longer available for rephosphorization. The slag discharging method is simple and convenient to operate, does not have high requirements on the equipment, has relatively good dephosphorization effect, and can be used to prepare an ultra-low phosphorus steel containing less than 0.003% phosphorus. Also disclosed is a method for producing ultra-low phosphorus steel, which comprises the above-described slag discharging method in a process of producing ultra-low phosphorus steel, and refining and ingotting after slag discharge. The production method has good dephosphorization effect, has a low production cost, and can high-efficiently produce an ultra-low phosphorus steel containing less than 0.003% phosphorus.

The present invention concerns the field of refining metal melts or slags and provides in particular a reactive material based on calcium aluminate and carbon, its process of preparation and various methods for refining metal melts using the same.

When performing dephosphorization treatment of hot metal by adding a refining agent as a lime source and an oxygen source (dephosphorizing agent(s) and a gaseous oxygen source into the hot metal accommodated in a hot metal holding container, the refining agent used is a refining agent having an Ig-loss value of from 4.0% by mass to 35.0% by mass and including 60% by mass or more of quicklime.

The present invention relates to a method for obtaining calcium aluminates for metallurgical use from non-saline aluminum slags by means of reactive grinding and thermal treatment.

Process for dephosphorization of molten metal during a refining process using a lime composition in the form of compacted particles having a Shatter Test Index of less than 20%, leading to a refined metal reduced in phosphorus components to the extent that the refined metal reduced in phosphorus is showing a phosphorus content lower than 0.02 w % based on the total weight of the refined metal reduced in phosphorus.