The invention relates to a mixture to be introduced into the slag located on a metal melt in iron and steel metallurgy, the use of such a mixture, and a method for conditioning a slag located on a metal melt in a metallurgical vessel, for example in a converter, in an electric arc furnace or in a ladle, in iron and steel metallurgy.

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.

Composite particles are used in combination with ore particles in an ore-refining or purification process, such as in a steel- or iron-making process. The composite particles comprise a core, which may be an aggregate of limestone, dolomite, or another ore particle. The core is surrounded by a coating layer of a metal dust and a binder. The metal dust may be iron oxide dust, which, along with limestone, is prevalent in the iron smelting process anyway. In this way, the composite particles help to recycle otherwise wasted and hazardous iron dust. The binder may be mineral clay such as bentonite, montmorillonite or kaolinite, and may comprise about 2-10% by weight of the particle.

Method to remove copper from a bath of molten metal material, by using a reactive additive to remove copper from a bath of molten metal material and applying a depression.

Provided in the present application are a rare-earth microalloyed steel and a control process. The steel has a special microstructure, and the microstructure comprises a rare earth-rich nanocluster having a diameter of 1-50 nm. The nanocluster has the same crystal structure type as a matrix. The rare earth-rich nanocluster inhibits the segregation of the elements S, P and As on a grain boundary, and obviously improves the fatigue life of the steel. In addition, a rare-earth solid solution also directly affects a phase change dynamics process so that the diffusion-type phase change starting temperature in the steel changes at least to 2° C., and even changes to 40-60° C. in some kinds of steel, thereby greatly improving the mechanical properties thereof, and providing a foundation for the development of more kinds of high-performance steel.

A method for producing a nitrided packaging steel from a hot-rolled steel product with a carbon content of 400 to 1200 ppm, utilizing a cold-rolling of the steel product to a flat steel product, subsequent recrystallization annealing of the cold-rolled flat steel product in an annealing furnace, in particular a continuous annealing furnace. A nitrogen-containing gas is supplied into the annealing furnace and is directed at the flat steel product to introduce unbonded nitrogen into the flat steel product in an amount corresponding to a concentration of more than 100 ppm, or to increase the amount of unbonded nitrogen in the flat steel product to a concentration of more than 100 ppm, and subsequent cooling of the recrystallized annealed flat steel product at a cooling rate of at least 100 K/s directly after the recrystallization annealing. Using this method, cold-rolled flat steel products may be produced for packaging purposes with a tensile strength of more than 650 MPa and in particular between 700 and 850 MPa.

A method for producing a nitrided packaging steel from a hot-rolled steel product with a carbon content of 400 to 1200 ppm, utilizing a cold-rolling of the steel product to a flat steel product, subsequent recrystallization annealing of the cold-rolled flat steel product in an annealing furnace, in particular a continuous annealing furnace. A nitrogen-containing gas is supplied into the annealing furnace and is directed at the flat steel product to introduce unbonded nitrogen into the flat steel product in an amount corresponding to a concentration of more than 100 ppm, or to increase the amount of unbonded nitrogen in the flat steel product to a concentration of more than 100 ppm, and subsequent cooling of the recrystallized annealed flat steel product at a cooling rate of at least 100 K/s directly after the recrystallization annealing. Using this method, cold-rolled flat steel products may be produced for packaging purposes with a tensile strength of more than 650 MPa and in particular between 700 and 850 MPa.

Disclosed is a method for controlling a Ti concentration in a steel when manufacturing a silicon-deoxidized steel comprising 0.1 to 3% by mass of Si and 0.0001 to 0.005% by mass of Al by ladle refining of a molten steel, the method including the step of: adding an oxide including TiO.sub.2 to a slag in a ladle during the ladle refining, wherein the slag produced at end of the ladle refining satisfies formulas (1) to (7) below:

0.5≦CaO/SiO.sub.2≦1.8  (1)

4% by mass≦Al.sub.2O.sub.3≦20% by mass  (2)

MgO≦15% by mass  (3)

1.5% by mass≦TiO.sub.2≦10% by mass  (4)

CaO+SiO.sub.2+Al.sub.2O.sub.3+MgO+TiO.sub.2≧90% by mass  (5)

0.4≦TiO.sub.2/MnO≦5  (6)

1≦TiO.sub.2/T.Fe≦10  (7)

where a compound represented by a chemical formula represents the content of the compound in percent by mass; and T.Fe represents the total concentration, in mass ratio, of Fe contained in Fe oxides in the slag.

An oxygen lance assembly that is at least capable of moving towards or away from the object to be lanced, said assembly including a supply of gaseous oxygen and metallic tubing wherein the oxygen supply is continuously feed through the said tubing when the lance is in use, and the said lance assembly includes a reel, and the said metallic tubing is coiled upon and carried by the said reel, and when in use, the metallic tubing is continuously uncoiled from the said reel as the said metallic tubing is consumed during use.

A carburizer, which effects carburization with respect to molten iron accommodated in an electric furnace or a ladle, includes a mixture of quicklime and a carbon material having an ash content of from 5 mass % to 18 mass %, and satisfies the conditions 0.6≤(mc+Mc)/ms≤2.7 and 0.7≤(mc+Mc)/ma≤6.5. A method of carburization uses this carburizer. Here, mc represents the mass of CaO in the carbon material, ms represents the mass of SiO.sub.2 in the carbon material, ma represents the mass of Al.sub.2O.sub.3 in the carbon material, and Mc represents the mass of the quicklime.