Patents by Inventor Taketo Maejima
Taketo Maejima has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20240091847Abstract: A crankshaft with improved fatigue strength and machinability is provided. The crankshaft includes a pin and journal, having a chemical composition of, in mass %: 0.40 to 0.60% C; 0.01 to 1.50% Si; 0.4 to 2.0% Mn; 0.01 to 0.50% Cr; 0.20 to 0.50% Al; 0.001 to 0.02% N; up to 0.03% P; 0.005 to 0.20% S; 0.005 to 0.060% Nb; 0 to 0.060% Ti; and balance Fe and impurities, wherein, for each of the pin and journal, the hardness measured at a position at a depth of ¼ of the diameter from the surface is higher than HV 245, the microstructure at that position is mainly composed of ferrite/pearlite, and the fraction of ferrite is not lower than 16%.Type: ApplicationFiled: November 2, 2020Publication date: March 21, 2024Inventors: Manabu KUBOTA, Taketo MAEJIMA
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Patent number: 11890894Abstract: The railway wheel according to the present embodiment has a chemical composition consisting of: in mass %, C: 0.80 to 1.15%, Si: 0.45% or less, Mn: 0.10 to 0.85%, P: 0.050% or less, S: 0.030% or less, Al: 0.200 to 1.500%, N: 0.0200% or less, Nb: 0.005 to 0.050%, Cr: 0 to 0.25%, and V: 0 to 0.12%, with the balance being Fe and impurities, wherein at least in the microstructure of the rim part and the web part, the amount of pro-eutectoid cementite defined by Formula (1) is 2.00 pieces/100 ?m or less: Amount of pro-eutectoid cementite(pieces/100 ?m)=a total sum of the number of pieces of pro-eutectoid cementite which intersect with two diagonal lines in a square visual field of 200 ?m×200 ?m/(5.66×100 ?m)×100??(1).Type: GrantFiled: September 27, 2019Date of Patent: February 6, 2024Assignee: NIPPON STEEL CORPORATIONInventors: Taketo Maejima, Manabu Kubota
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Patent number: 11761053Abstract: A railway wheel having, in mass %, C: 0.80 to 1.15%, Si: 1.00% or less, Mn: 0.10 to 1.25%, P: 0.050% or less, S: 0.030% or less, Al: 0.025 to 0.650%, N: 0.0030 to 0.0200%, Cr: 0 to 0.60%, and V: 0 to 0.12%, with the balance being Fe and impurities. The railway wheel has a hub part, a rim part including a tread and a flange, and a web part disposed between the hub part and the rim part. The area fraction of pearlite in the hub, web, and rim parts is 95% or more, and the amount of pro-eutectoid cementite is not more than 1.0 pieces/100 ?m. The amount of pro-eutectoid cementite is calculated as (pieces/100 ?m)=a total sum of the number of pieces of pro-eutectoid cementite which intersect with two diagonal lines in a square visual field of 200 ?m×200 ?m/(5.66×100 ?m).Type: GrantFiled: March 30, 2018Date of Patent: September 19, 2023Assignee: NIPPON STEEL CORPORATIONInventors: Taketo Maejima, Manabu Kubota
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Publication number: 20230119875Abstract: A railway wheel in which formation of a quenched layer can be suppressed in the production process is provided. The railway wheel according to the present embodiment has a chemical composition consisting of, in mass %, C: 0.80 to 1.15%, Si: 1.00% or less, Mn: 0.10 to 1.20%, P: 0.050% or less, S: 0.030% or less, Al: 0.005 to 0.190%, N: 0.0200% or less, Nb: 0.005 to 0.050%, Cr: 0 to 0.25%, and V: 0 to 0.12%, with the balance being Fe and impurities. In the microstructure of a rim part of the railway wheel, an area fraction of pro-eutectoid cementite is 0.1 to 1.5% and an area fraction of pearlite is 95.0% or more.Type: ApplicationFiled: March 25, 2021Publication date: April 20, 2023Inventors: Taketo MAEJIMA, Manabu KUBOTA
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Patent number: 11458762Abstract: A railway wheel is capable of suppressing formation of pro-eutectoid cementite even if the C content is high. The railway wheel has a chemical composition consisting of: in mass %, C: 0.80 to 1.15%; Si: 0.45% or less; Mn: 0.10 to 0.85%; P: 0.050% or less; S: 0.030% or less; Al: 0.120 to 0.650%; N: 0.0030 to 0.0200%; Cr: 0 to 0.25%; and V: 0 to 0.12%, with the balance being Fe and impurities, wherein an amount of pro-eutectoid cementite, which is defined by Formula (1), in a microstructure of the railway wheel is not more than 1.50 pieces/100 ?m: Amount of pro-eutectoid cementite (pieces/100=a total sum of the number of pieces of pro-eutectoid cementite which intersect with two diagonal lines in a square visual field of 200 ?m×200 ?m/(5.66×100 ?m) (1).Type: GrantFiled: March 30, 2018Date of Patent: October 4, 2022Assignee: NIPPON STEEL CORPORATIONInventors: Taketo Maejima, Manabu Kubota
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Publication number: 20220032681Abstract: The chemical composition of the railway wheel of the present embodiment consists of: in mass %, C: 0.80 to 1.60%, Si: 1.00% or less, Mn: 0.10 to 1.25%, P: 0.050% or less, S: 0.030% or less, Al: 0.010 to 0.650%, and N: 0.0030 to 0.0200%, with the balance being Fe and impurities, and wherein, in a microstructure of the web part of the railway wheel, an area fraction of pearlite is 85.0% or more, an area fraction of pro-eutectoid cementite is 0.90 to 15.00%, and an average value of a width W of the pro-eutectoid cementite defined by Formula (1) is less than 0.70 ?m: W=½×(P/2?((P/2)2?4A)1/2)??(1) where, in Formula (1), A is an area (?m2) of the pro-eutectoid cementite, and P is a circumference length (?m) of the pro-eutectoid cementite.Type: ApplicationFiled: September 27, 2019Publication date: February 3, 2022Inventors: Taketo MAEJIMA, Manabu KUBOTA
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Publication number: 20220024247Abstract: The railway wheel according to the present embodiment has a chemical composition consisting of: in mass %, C: 0.80 to 1.15%, Si: 0.45% or less, Mn: 0.10 to 0.85%, P: 0.050% or less, S: 0.030% or less, Al: 0.200 to 1.500%, N: 0.0200% or less, Nb: 0.005 to 0.050%, Cr: 0 to 0.25%, and V: 0 to 0.12%, with the balance being Fe and impurities, wherein at least in the microstructure of the rim part and the web part, the amount of pro-eutectoid cementite defined by Formula (1) is 2.00 pieces/100 ?m or less: Amount of pro-eutectoid cementite (pieces/100 ?m)=a total sum of the number of pieces of pro-eutectoid cementite which intersect with two diagonal lines in a square visual field of 200 ?m×200 ?m/(5.Type: ApplicationFiled: September 27, 2019Publication date: January 27, 2022Inventors: Taketo MAEJIMA, Manabu KUBOTA
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Publication number: 20210115966Abstract: An induction-hardened crankshaft is provided that offers an excellent balance of fatigue strength, machinability and quench-cracking resistance. An induction-hardened crankshaft has a chemical composition of, in mass %: 0.30 to 0.60% C; 0.01 to 1.50% Si; 0.4 to 2.0% Mn; 0.01 to 0.50% Cr; 0.001 to 0.06% Al; 0.001 to 0.02% N; up to 0.03% P; 0.005 to 0.20% S; 0.005 to 0.060% Nb; and balance Fe and impurities, the non-induction-hardened portion having a microstructure mainly composed of ferrite-pearlite and having a fraction of ferrite F? satisfying the expression (1) provided below, the induction-hardened portion having a microstructure mainly composed of martensite or tempered martensite, and having a prior austenite grain diameter not larger than 30 ?m, F??150×[C %]+84 ??(1), where the C content in mass % in the induction-hardened crankshaft is substituted for [C %].Type: ApplicationFiled: June 13, 2019Publication date: April 22, 2021Applicant: Nippon Steel CorporationInventors: Manabu KUBOTA, Taketo MAEJIMA
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Publication number: 20200102623Abstract: A railway wheel in which formation of pro-eutectoid cementite is suppressed is stably produced. After heating an intermediate product containing, in mass %, C: 0.80 to 1.15% to a temperature not less than Acm transformation point, the intermediate product is cooled such that the cooling rate (° C./sec) in a range from 800 to 500° C. satisfies the following conditions: Surface other than the tread and the flange surface: not more than Fn1 defined by Formula (1), Cooling rate in a region in which cooling rate is slowest: not less than Fn2 defined by Formula (1), and Tread and flange surface: not less than Fn2: Fn1=?5.0+exp(5.651?1.427×C?1.280×Si?0.7723×Mn?1.815×Cr?1.519×Al?7.798×V)??(1) Fn2=0.515+exp(?24.816+24.121×C+1.210×Si+0.529×Mn+2.458×Cr?15.116×Al?5.Type: ApplicationFiled: March 30, 2018Publication date: April 2, 2020Inventors: Taketo MAEJIMA, Manabu KUBOTA
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Publication number: 20200070569Abstract: Provided is a railway wheel capable of suppressing formation of pro-eutectoid cementite even if the C content is high. A railway wheel according to an embodiment of the present invention has a chemical composition consisting of: in mass %, C: 0.80 to 1.15%; Si: 0.45% or less; Mn: 0.10 to 0.85%; P: 0.050% or less; S: 0.030% or less; Al: 0.120 to 0.650%; N: 0.0030 to 0.0200%; Cr: 0 to 0.25%; and V: 0 to 0.12%, with the balance being Fe and impurities, wherein an amount of pro-eutectoid cementite, which is defined by Formula (1), in a microstructure of the railway wheel is not more than 1.50 pieces/100 ?m: Amount of pro-eutectoid cementite (pieces/ 100 ?m)=a total sum of the number of pieces of pro-eutectoid cementite which intersect with two diagonal lines in a square visual field of 200 ?m×200 ?m/(5.Type: ApplicationFiled: March 30, 2018Publication date: March 5, 2020Inventors: Taketo MAEJIMA, Manabu KUBOTA
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Patent number: 9239075Abstract: To provide a forged crankshaft having an excellent wear resistance. The forged crankshaft according to the present embodiment includes a non-heat treated steel material. The non-heat treated steel material has a chemical composition which contains, by mass %, C: 0.45 to 0.70%, Si: 0.75 to 1.30%, Mn: 1.00 to 2.00%, S: 0.03 to 0.30%, Cr: 0.05 to 0.30%, Al: 0.005 to 0.050%, and N: 0.005 to 0.020%, the balance being Fe and impurities, and satisfies the following Formula (1): 1.1C+Mn+0.2Cr>2.0??(1) where a symbol of each element in Formula (1) is substituted by the content (mass %) of the each element. A matrix of the non-heat treated steel material is a ferrite-pearlite microstructure in which an area ratio of pro-eutectoid ferrite is less than 10% or a pearlite microstructure.Type: GrantFiled: June 13, 2011Date of Patent: January 19, 2016Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kisung Kim, Hiroaki Tahira, Taketo Maejima
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Publication number: 20130087014Abstract: To provide a forged crankshaft having an excellent wear resistance. The forged crankshaft according to the present embodiment includes a non-heat treated steel material. The non-heat treated steel material has a chemical composition which contains, by mass %, C: 0.45 to 0.70%, Si: 0.75 to 1.30%, Mn: 1.00 to 2.00%, S: 0.03 to 0.30%, Cr: 0.05 to 0.30%, Al: 0.005 to 0.050%, and N: 0.005 to 0.020%, the balance being Fe and impurities, and satisfies the following Formula (1): 1.1C+Mn+0.2Cr>2.0 ??(1) where a symbol of each element in Formula (1) is substituted by the content (mass %) of the each element. A matrix of the non-heat treated steel material is a ferrite-pearlite microstructure in which an area ratio of pro-eutectoid ferrite is less than 10% or a pearlite microstructure.Type: ApplicationFiled: June 13, 2011Publication date: April 11, 2013Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATIONInventors: Kisung Kim, Hiroaki Tahira, Taketo Maejima