Abstract: 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.

Abstract: A method of producing molten steel supplies gaseous oxygen from a top blowing lance into a converter to perform decarburization refining of molten iron while adding a CaO-containing powdery dephosphorizing agent to simultaneously decarburize and dephosphorize the molten iron and includes supplying the dephosphorizing agent to a bath surface of the molten iron together with at least one gas jet from the top blowing lance and a dynamic pressure determined when a gas jet blown from respective lance nozzles of the top blowing lance impinges onto the bath surface of the molten iron is controlled to not more than 0.50 kgf/cm2.

Abstract: A low alloy steel, which has a chemical composition by mass %, of C: 0.1 to 0.55%, Si: 0.05 to 0.5%, Mn: 0.1 to 1%, S: 0.0001 to 0.005%, Al: 0.005 to 0.08%, Ti: 0.005 to 0.05%, Cr: 0.1 to 1.5%, Mo: 0.1 to 1%, O: 0.0004 to 0.005%, Ca: 0.0005 to 0.0045%, Nb: 0 to 0.1%, V: 0 to 0.5%, B: 0 to 0.005%, Zr: 0 to 0.10%, P?0.03%, and N?0.006%, with the balance being Fe and impurities, is manufactured by adjusting the value of ([Ti]/47.9)([N]/14)/([Ca])/40.1) satisfies not less than 0.0008 and not more than 0.0066, at the time of melting the said low alloy steel, wherein [Ti], [N] and [Ca] are the contents in the molten steel by mass % of Ti, N and Ca respectively. The thus-manufactured low steel alloy has a high SSC resistance with a yield stress of not less than 758 MPa.

Abstract: A particulate carrier material for use with particulate passivated magnesium for injection into molten iron to desulfurize the iron, improve characteristics of the slag and increase iron yield. Material flow of a transport gas and the carrier material is established in a lance prior to inserting the lance into a ladle-contained molten iron, then following insertion the passivated magnesium is added to the material flow. A second embodiment of the invention for iron desulfurization, blends the carrier material and passivated magnesium into a single desulfurization agent. In both embodiments the particulate magnesium is 14-20 mesh with the remaining particulate material being about 200 mesh. The composition of the carrier material is 54-74% calcium oxide, 19-32% aluminum oxide, no more than 4% magnesium oxide, no more than 10% calcium fluoride, no more than 2.5% silicon dioxide, no more than 1.0% iron oxide, no more than 0.025% phosphorus pentoxide, no more than 0.025% titanium dioxide, no more than 0.

Abstract: The invention relates to a process for the desulphurization treatment of a pig iron melt in a container. The characterizing feature of the invention is that the treatment is performed in three phases:In the initial phase such solids are injected that deoxidize the initial slag and increase its basicity and also produce a circulatory movement of the melt and form a basic deoxidized cover slag. In the middle phase the desulphurizing agent is injected for the main desulphurization and in the final phase such solids are injected that purify the melt and produce a final desulphurization and also so influence the desulphurization slag formed that its content of iron granules is low.

Abstract: A lime-based injection powder for use in steel-refining, having excellent waterproofing and desulphurization effects, consists of (a) more than 65% by weight of calcium oxide, (b) less than 30% by weight of fluorite, and 5-10% by weight of Al powder, 5%-7% by weight of the calcium oxide being converted into CaCO3 by reacting the calcium oxide with carbon dioxide in a multi-stage fluidized bed reactor.

Abstract: The present invention provides an agent for the introduction of nitrogen into cast iron, wherein it contains or consists of at least 50% by weight of at least one nitrogen-containing compound with an N--C--N structure and/or a mixture of calcium cyanamide with nitrides of silicon, ferrosilicon, manganese and chromium.The present invention also provides a process for the introduction of nitrogen into cast iron using this agent.