A direct reduction process for the production of ferrochrome from chromite ore or concentrate is disclosed. According to the present invention, calcium chloride (CaCl.sub.2) is added as a catalyst to accelerate the solid reduction and enhance the particle growth of the metallic phase (i.e. ferrochrome) during reduction. The reduction of chromite ore or concentrate takes place at much lower temperatures (e.g. 1200 to 1400 C.) compared to the conventional smelting technologies, and the ferrochrome particles formed are segregated from the unwanted residual gangue and spinel particles, facilitating their subsequent physical separation.

The present invention provides a method for preparing ferrovanadium alloys based on aluminothermic self-propagating gradient reduction and slag washing refining. The method includes the steps of (1) performing aluminothermic self-propagating gradient reduction; (2) performing heat preserving and smelting to obtain an upper layer alumina-based slag and a lower layer alloy melt; (3) jetting refining slags into the lower layer alloy melt, and performing stirring and slag washing refining; and (4) cooling the refined high-temperature melt to room temperature, and removing an upper layer smelting slag to obtain the ferrovanadium alloys.

The present invention provides a method for preparing ferrovanadium alloys based on aluminothermic self-propagating gradient reduction and slag washing refining. The method includes the steps of (1) performing aluminothermic self-propagating gradient reduction; (2) performing heat preserving and smelting to obtain an upper layer alumina-based slag and a lower layer alloy melt; (3) jetting refining slags into the lower layer alloy melt, and performing stirring and slag washing refining; and (4) cooling the refined high-temperature melt to room temperature, and removing an upper layer smelting slag to obtain the ferrovanadium alloys.

A master alloy used to produce the steel part and a process for producing a sinter hardened steel part from the master alloy are described. The powdered master alloy having a composition of iron, about 1 to less than 5 weight % C, about 3 to less than 15 weight % Mn, and about 3 to less than 15 weight % Cr, wherein the master alloy comprises a microstructure composed of a solid solution of the alloying elements and carbon, the microstructure comprising at least 10 volume % austenite and the remainder as iron compounds. The process comprises: preparing the master alloy, mixing the master alloy with a steel powder to produce a mixture wherein the weight % of the master alloy is from 5 to 35 weight % of the mixture, compacting the mixture into a shape of a part and sintering the mixture to produce the steel part, and controlling the cooling rate after sintering to produce sinter hardening. The master alloy powder can also be used as a sinter hardening enhancer when mixed with low-alloy steel powders.

Refined niobium-based ferroalloys are provided by removing lead and other impurities therefrom by a process comprising charging niobium ore concentrate and/or niobium oxide or a mixture of niobium oxides to a metallothermic reaction chamber, admixing the ore concentrate and/or niobium oxide with a reducing agent, initiating a metallothermic reaction, under reduced pressure; and allowing the reaction product to solidify and cool; crushing the reaction product or crushing the niobium-based ferroalloy previously reduced in open air, and charging the crushed product to a melting crucible within a vacuum induction melting furnace, lowering the pressure within the furnace to below 1 mbar, and melting the crushed product while vaporizing the impurities contained therein.

Disclosed is a method for manufacturing a lightweight brake disc with maximized heat dissipation ability. The method includes a first step of mixing gray cast iron and FeCr ferroalloy with each other to produce a mixture, melting and solidifying the mixture to cast an alloy; a second step of heat-treating the alloy cast in the first step to pearlitize a microstructure of the alloy; and a third step of performing nitriding heat treatment of the alloy heat-treated in the second step.

An inoculant for the manufacture of cast iron with spheroidal graphite is disclosed, the inoculant has a particulate ferrosilicon alloy having between 40 and 80% by weight of Si; 0.02-8% by weight of Ca; 0-5% by weight of Sr; 0-12% by weight of Ba; 0-15% by weight of rare earth metal; 0-5% by weight of Mg; 0.05-5% by weight of Al; 0-10% by weight of Mn; 0-10% by weight of Ti; 0-10 by weight of Zr; the balance being Fe and incidental impurities in the ordinary amount, wherein the inoculant additionally contains, by weight, based on the total weight of inoculant: 0.1 to 15% of particulate Bi.sub.2S.sub.3, and optionally between 0.1 and 15% of particulate Bi.sub.2O.sub.3, and/or between 0.1 and 15% of particulate Sb.sub.2O.sub.3, and/or between 0.1 and 15% of particulate Sb.sub.2S.sub.3, and/or between 0.1 and 5% of particulate Fe.sub.3O.sub.4, Fe.sub.2O.sub.3, FeO, or a mixture thereof, and/or between 0.1 and 5% of one or more of particulate FeS, FeS.sub.2, Fe.sub.3S.sub.4, or a mixture thereof, a method for producing such inoculant and use of such inoculant.

An aspect of the present invention provides an FeNi alloy metal foil having excellent heat resilience, where the FeNi alloy metal foil is prepared by an electroforming (EF) method and has a thickness of 100 m or less (except O m), wherein the FeNi alloy metal foil comprises, by wt %, Ni: 34-46 %, a remainder of Fe and inevitable impurities, and wherein the FeNi metal foil has a degree of heat resilience in an amount of 30 ppm or less.

An aspect of the present invention provides an FeNi alloy metal foil having excellent heat resilience, where the FeNi alloy metal foil is prepared by an electroforming (EF) method and has a thickness of 100 m or less (except O m), wherein the FeNi alloy metal foil comprises, by wt %, Ni: 34-46 %, a remainder of Fe and inevitable impurities, and wherein the FeNi metal foil has a degree of heat resilience in an amount of 30 ppm or less.

Method of producing FeSiAI alloys wherein a carbonaceous rock with an ash content >50% to <65%, is being mixed with quartzite, iron-bearing material, and wood chips, if required, high volatile coal, in a preset ratio of the charge components and the homogenized charge material is being loaded into a melting furnace for melting of FeSiAI alloy, the charged carbonaceous rock can contain i.a. the following chemical composition in the mineral part (ash): Fe.sub.2O.sub.3 1.5-4.5% SiO.sub.2 55-65% Al.sub.2O.sub.3 25-35%, especially 32-34% CaO 0.3-3% MgO 0.3-2% TiO.sub.2 up to 1.5 S>0-0.4%, especially 0.01-0.06% P 0.01-0.05%