The invention relates to a method for extracting metal from metal-containing raw material in a batch process by using a direct current electric arc furnace (100) having one or more than one top electrode (125) and at least one bottom electrode (115), wherein the method comprises the following steps: adding the metal-containing raw material to the furnace (100), thereby obtaining a loaded bath, moving the top electrode(s) (125) onto the raw material, heating the loaded bath in a heating step by applying direct current through the top electrode(s) to provide an arc to melt the raw material, thereby obtaining molten metal (202), wherein an average voltage during the heating step is from 20 V to 110 V, and forming solid metal from the molten metal (202). The invention further relates to a direct current electric arc furnace, a system comprising a direct current electric arc furnace, and a solid metal obtainable by the method.

Provided is steel for a wind power gear with improved purity and reliability. The chemical components thereof comprise, in percentages by mass: 0.15-0.19% of C, ≤0.4% of Si, 0.5-0.7% of Mn, ≤0.012% of P, ≤0.006% of S, 1.5-1.8% of Cr, 0.28-0.35% of Mo, 1.4-1.7% of Ni, and 0.02-0.04% of Al, with the balance being Fe and inevitable impurities. A smelting method therefor comprises adding raw materials to a converter for primary melting, transferring same to a refining furnace for refining, carrying out continuous casting after vacuum degassing, and transferring same to a gas protection furnace for electroslag remelting. According to the present invention, a pure electroslag master batch is obtained by continuous casting, and the purity of the material is further improved by means of an electroslag remelting procedure; and the prepared steel material is used in a wind power gear, such that the flaw detection pass rate is significantly increased, large-particle inclusions in the steel material are significantly reduced, and the inclusions are fine and dispersed.

Complex concentrated alloys include five or more elements, at least one of which is ruthenium. Example complex concentrated alloys can include nickel and chromium, iron, ruthenium, molybdenum, and/or tungsten. Example complex concentrated alloys have single phase microstructure of face centered cubic (FCC) and can be homogenous. Example complex concentrated alloys can exhibit improved corrosion resistance.

Complex concentrated alloys include five or more elements, at least one of which is ruthenium. Example complex concentrated alloys can include nickel and chromium, iron, ruthenium, molybdenum, and/or tungsten. Example complex concentrated alloys have single phase microstructure of face centered cubic (FCC) and can be homogenous. Example complex concentrated alloys can exhibit improved corrosion resistance.

Disclosed are an iron-aluminum alloy and its preparation method. The iron-aluminum alloy comprises, by weight, 50% to 80% of iron and the balance of aluminum. The method comprises: adding metal aluminum or molten aluminum to a container, wherein the temperature of the molten aluminum is between 700° C. and 800° C.; adding a metal iron raw material to the molten aluminum, closing a furnace cover, measuring the pressure, and introducing argon to ensure that the interior of a magnetic induction furnace is in a positive-pressure state, and stirring the mixture with a graphite stirring head; powering on and heating so that the metal aluminum or the molten aluminum is heated to 1000° C. or above and molten, and holding the temperature between 1000° C. and 1500° C.; and after alloying is completed, cooling to about 1000 t, opening the furnace cover, and taking the iron-aluminum alloy out.

Disclosed are an iron-aluminum alloy and its preparation method. The iron-aluminum alloy comprises, by weight, 50% to 80% of iron and the balance of aluminum. The method comprises: adding metal aluminum or molten aluminum to a container, wherein the temperature of the molten aluminum is between 700° C. and 800° C.; adding a metal iron raw material to the molten aluminum, closing a furnace cover, measuring the pressure, and introducing argon to ensure that the interior of a magnetic induction furnace is in a positive-pressure state, and stirring the mixture with a graphite stirring head; powering on and heating so that the metal aluminum or the molten aluminum is heated to 1000° C. or above and molten, and holding the temperature between 1000° C. and 1500° C.; and after alloying is completed, cooling to about 1000 t, opening the furnace cover, and taking the iron-aluminum alloy out.

A pre-alloyed powder having a composition consisting of, in weight % (wt. %): C, 0.02-0.04; Si, 0.1-0.4; Mn, 0.1-0.5; Cr, 11-13; Ni, 7-10; Cr+Ni, 19-23; Mo, 1-25; Al, 1.4-2.0; N, 0.01-0.75. Optionally, the pre-alloyed powder contains: Cu, 0.05-2.5; B, 0.002-2.0; S, 0.01-0.25; Nb, 0.01 max; Ti, 2 max; Zr, 2, max; Ta, 2 max; Hf, 2 max; Y, 2 max; Ca, 0.0003-0.009; Mg, 0.01 max; O, 0.003-0.80; and REM, 0.2 max. Fe and impurities comprise the balance.

A pre-alloyed powder having a composition consisting of, in weight % (wt. %): C, 0.02-0.04; Si, 0.1-0.4; Mn, 0.1-0.5; Cr, 11-13; Ni, 7-10; Cr+Ni, 19-23; Mo, 1-25; Al, 1.4-2.0; N, 0.01-0.75. Optionally, the pre-alloyed powder contains: Cu, 0.05-2.5; B, 0.002-2.0; S, 0.01-0.25; Nb, 0.01 max; Ti, 2 max; Zr, 2, max; Ta, 2 max; Hf, 2 max; Y, 2 max; Ca, 0.0003-0.009; Mg, 0.01 max; O, 0.003-0.80; and REM, 0.2 max. Fe and impurities comprise the balance.

Disclosed are a high strength thin specification high corrosion resistance steel and a manufacturing method therefor. The chemical ingredients of the steel in percentages by weight are as follows: 0.02-0.06% of C, 0.1-0.5% of Si, 0.4-1.7% of Mn, ≤0.02% of P, 4.0-6.0% of Cr, 1.0-3.0% of Ni, ≤0.007% of S, 0.004-0.010% of N, <0.001% of Als, 0.001-0.006% of B, 0.007-0.020% of total oxygen [O].sub.T, and the balance is Fe and inevitable impurities, and same simultaneously satisfy: comprising one or both elements of 0.01-0.08% of Nb or 0.01-0.08% of V; and Mn/S≥250. In the invention, micro-alloy elements such as Nb/V and a B element are selectively added to steel, the basicity of slag, the type and melting point of the inclusion in steel, the content of free oxygen in molten steel and the content of acid-soluble aluminum Als during the smelting process are controlled, and a strip is then cast by means of twin-roll thin strip continuous casting, and enters an online rolling mill for hot rolling in closed conditions, and after rolling, the strip steel is cooled by air atomization cooling.

The present invention discloses a wire rod for an ultrahigh-strength steel cord and a manufacturing method thereof. The manufacturing method includes: smelting molten steel where inclusions in sizes ≥5 μm are at a number density ≤0.5/mm.sup.2 and sizes of inclusions are ≤30 μm; casting the molten steel into an ingot blank with a center carbon segregation value of 0.92-1.08; cogging the ingot blank into an intermediate blank with a center carbon segregation value of 0.95-1.05; rolling the intermediate blank into a wire rod; and performing temperature control cooling on the wire rod to obtain a wire rod with high purity, high homogeneity and tensile strength ≤1,150 MPa. The wire rod may be used for an ultrahigh-strength steel cord with single tensile strength ≥3,600 MPa.