A steel sheet with excellent surface quality, and a manufacturing method therefor are provided. The present invention provides a pickled steel sheet with excellent surface quality, comprising, by wt %, carbon (C) in an amount greater than or equal to 0.05% and less than 0.4%, 0.5% or less of silicon (Si) (excluding 0%), 0.05% or less of phosphorus (P), 0.03% or less of sulfur (S), 0.01% or less of boron (B), 0.1-2.5% of manganese (Mn) and/or chromium (Cr), and the balance of iron (Fe) and inevitable impurities, wherein the average thickness of an internal oxide layer and/or a tantalum layer, which are formed on the surface layer of the steel sheet, is 1-10 μm, and the standard deviation of the thickness of the internal oxide layer and/or the tantalum layer in the length direction of the steel sheet is 2 μm or less.

Provided are a high-carbon steel sheet having good surface quality and a manufacturing method therefor. The present invention provides a high-carbon pickled steel sheet having good surface quality, the steel sheet containing, in weight %, 0.4% or more and less than 1.2% of carbon (C), 0.5% or less (excluding 0%) of silicon (Si), 0.05% or less of phosphorus (P), 0.03% or less of sulfur (S), 0.1 to 2.5% of at least one of manganese (Mn) and chromium (Cr), and the balance of iron (Fe) and inevitable impurities, wherein the average thickness of an internal oxide layer and/or a decarburized layer formed in a surface layer portion of the steel sheet is 1 to 10 μm and the standard deviation of the thickness of the internal oxide layer and/or the decarburized layer in the length direction of the steel sheet is 2 μm or less.

A tempering-free wear-resistant hot rolled strip, includes components in percentage by weight: 0.08-0.22% of C, 0.1-0.55% of Si, 0.8-1.5% of Mn, less than or equal to 0.012% of P, less than or equal to 0.005% of S, 0.01-0.055% of Als, 0.005-0.019% of Ti, and less than or equal to 0.007% of N. A method for producing the same includes: desulfurizing molten iron, smelting desulfurized molten iron, and casting into a blank; heating the casting blank; performing rough rolling; performing finish rolling; performing rapid cooling; performing coiling; and performing conventional temper rolling. According to the present disclosure, on the premise that the tensile strength of a steel plate is greater than or equal to 1100 MPa and the elongation is greater than or equal to 12%, the steel plate has a surface Brinell hardness of 330-390 and a core hardness that is 95% or above of the surface hardness.

A tempering-free wear-resistant hot rolled strip, includes components in percentage by weight: 0.08-0.22% of C, 0.1-0.55% of Si, 0.8-1.5% of Mn, less than or equal to 0.012% of P, less than or equal to 0.005% of S, 0.01-0.055% of Als, 0.005-0.019% of Ti, and less than or equal to 0.007% of N. A method for producing the same includes: desulfurizing molten iron, smelting desulfurized molten iron, and casting into a blank; heating the casting blank; performing rough rolling; performing finish rolling; performing rapid cooling; performing coiling; and performing conventional temper rolling. According to the present disclosure, on the premise that the tensile strength of a steel plate is greater than or equal to 1100 MPa and the elongation is greater than or equal to 12%, the steel plate has a surface Brinell hardness of 330-390 and a core hardness that is 95% or above of the surface hardness.

A method of forming a canister by means of a mechanical bonding of respective layers of a first metal material (tantalum) and a second metal material (niobium) to form a sheet stock, thereby forming the sheet stock into a canister form, wherein the first metal material comprises tantalum and the second metal material comprises at least one of niobium, molybdenum, or steel. The completed canister comprises a first metal material comprising tantalum, and a second metal material mechanically bonded to the first metal material by subjecting the first and second metal materials to at least 1,000,000 psi, to thereby form a canister having an inner diameter of 13-19 millimeters (mm), the second metal material comprising at least one of niobium, molybdenum, or steel.

A method of forming a canister by means of a mechanical bonding of respective layers of a first metal material (tantalum) and a second metal material (niobium) to form a sheet stock, thereby forming the sheet stock into a canister form, wherein the first metal material comprises tantalum and the second metal material comprises at least one of niobium, molybdenum, or steel. The completed canister comprises a first metal material comprising tantalum, and a second metal material mechanically bonded to the first metal material by subjecting the first and second metal materials to at least 1,000,000 psi, to thereby form a canister having an inner diameter of 13-19 millimeters (mm), the second metal material comprising at least one of niobium, molybdenum, or steel.

The invention relates to the rare metal smelting field, and particularly, the present invention relates to a tantalum powder for preparing capacitors and a process for preparing the tantalum powder, and to a sintered anode prepared from the tantalum powder. As to the tantalum powder as provided by the invention, its primary tantalum powder has a BET of from 3.0 to 4.5 m.sup.2/g. After the secondary agglomeration, the tantalum powder has a large particle size. The tantalum powder has an average Fisher sub-sieve size (FSSS) of 1.2 to 3.0 μm wherein as measured with a standard sieve mesh, more than 75% of tantalum powder has a +325-mesh, and a particle size distribution D50 of more than 60 μm, that is, the secondary particle size is high. A resultant capacitor anode prepared by sintering the tantalum powder of the invention at 1200° C. for 20 minutes and then being energized at the voltage of 20 V has the specific capacitance of from 140,000 to 180,000 μFV/g and the residual current of less than 1.0 nA/μFV. Meantime, the invention provides an economical process for making the tantalum powder.

The invention relates to the rare metal smelting field, and particularly, the present invention relates to a tantalum powder for preparing capacitors and a process for preparing the tantalum powder, and to a sintered anode prepared from the tantalum powder. As to the tantalum powder as provided by the invention, its primary tantalum powder has a BET of from 3.0 to 4.5 m.sup.2/g. After the secondary agglomeration, the tantalum powder has a large particle size. The tantalum powder has an average Fisher sub-sieve size (FSSS) of 1.2 to 3.0 μm wherein as measured with a standard sieve mesh, more than 75% of tantalum powder has a +325-mesh, and a particle size distribution D50 of more than 60 μm, that is, the secondary particle size is high. A resultant capacitor anode prepared by sintering the tantalum powder of the invention at 1200° C. for 20 minutes and then being energized at the voltage of 20 V has the specific capacitance of from 140,000 to 180,000 μFV/g and the residual current of less than 1.0 nA/μFV. Meantime, the invention provides an economical process for making the tantalum powder.

A finish heat treatment apparatus for an iron powder. Raw iron powder is placed on a continuous moving hearth and continuously charged into the apparatus. In a pretreatment zone, the raw iron powder is subjected to a pretreatment of heating the raw iron powder in an atmosphere of hydrogen gas and/or inert gas at 450 to 1100° C. In decarburization, deoxidation, and denitrification zones, the pretreated iron powder is subsequently subjected to at least two treatments of decarburization, deoxidation, and denitrification. In the pretreatment zone, a hydrogen gas and/or an inert gas serving as a pretreatment ambient gas is introduced separately from an ambient gas used in the at least two treatments is introduced from the upstream side of the pretreatment zone and released from the downstream side so as to flow in the same direction as a moving direction of the moving hearth.

A finish heat treatment apparatus for an iron powder. Raw iron powder is placed on a continuous moving hearth and continuously charged into the apparatus. In a pretreatment zone, the raw iron powder is subjected to a pretreatment of heating the raw iron powder in an atmosphere of hydrogen gas and/or inert gas at 450 to 1100° C. In decarburization, deoxidation, and denitrification zones, the pretreated iron powder is subsequently subjected to at least two treatments of decarburization, deoxidation, and denitrification. In the pretreatment zone, a hydrogen gas and/or an inert gas serving as a pretreatment ambient gas is introduced separately from an ambient gas used in the at least two treatments is introduced from the upstream side of the pretreatment zone and released from the downstream side so as to flow in the same direction as a moving direction of the moving hearth.