With Working Step Patents (Class 148/504)
  • Patent number: 11332812
    Abstract: A method for manufacturing an electric resistance welded steel tube for high-strength thin hollow stabilizers is provided. A steel with a certain chemical composition is heated to a temperature of 1000 to 1300° C., hot rolled under conditions where the rolling finish temperature is 750 to 950° C., cooled, coiled into a coil at 500 to 650° C., and skin pass rolled with a rolling reduction ratio of not less than 0.3%. The resultant hot rolled sheet is electric resistance welded into an electric resistance welded steel tube, which is then reheated to a temperature of 800 to 1100° C. and hot stretch-reducing rolled under conditions where the rolling finish temperature is not more than 850° C. and the cumulative diameter reduction is not more than 75%. Consequently, a thin electric resistance welded steel tube is produced.
    Type: Grant
    Filed: October 19, 2017
    Date of Patent: May 17, 2022
    Assignee: JFE Steel Corporation
    Inventors: Masatoshi Aratani, Shinsaku Kokubo, Hiromichi Hori, Yoshikazu Kawabata, Ryoji Matsui
  • Patent number: 11268164
    Abstract: A steel sheet having a specified chemical composition and a method for producing the steel sheet. The steel sheet has a microstructure including martensite and bainite. The total area fraction of the martensite and the bainite to the entirety of the microstructure is 95% or more and 100% or less. The balance of the microstructure is at least one of ferrite and retained austenite. The microstructure includes specific inclusion clusters, the content of the inclusion clusters in the microstructure being 5 clusters/mm2 or less. The microstructure includes prior-austenite grains having an average size of more than 5 ?m. The steel sheet has a tensile strength of 1320 MPa or more.
    Type: Grant
    Filed: September 28, 2017
    Date of Patent: March 8, 2022
    Assignee: JFE STEEL CORPORATION
    Inventors: Shimpei Yoshioka, Yoshihiko Ono, Kenta Hidaka, Ryosuke Yamaguchi
  • Patent number: 11268163
    Abstract: A 980 MPa-grade hot-rolled dual-phase steel and a manufacturing method therefor. The chemical components of the steel comprise, in percentage by weight, 0.10%-0.20% of C, 0.8%-2.0% of Si, 1.0%-2.0% of Mn, 0-0.02% of P, 0-0.005% of S, 0-0.003% of O, 0.02%-0.06% of Al, 0-0.006% of N, 0.01%-0.06% of Nb, 0.01%-0.05% of Ti, and the balance of Fe and inevitable impurities. In addition, the components need to meet the following relation: 0.05%?Nb+Ti?0.10. The microstructure of the steel is made of ferrite and martensite. The average grain size of the ferrite is 5-10 ?m, and the equivalent grain size of the martensite is 15-20 ?m.
    Type: Grant
    Filed: June 19, 2017
    Date of Patent: March 8, 2022
    Assignee: BAOSHAN IRON & STEEL CO., LTD.
    Inventors: Huanrong Wang, Ana Yang, Jiansu Zhang, Wei Wang
  • Patent number: 11261516
    Abstract: The present disclosure provides systems and methods for depositing a metal layer adjacent to or on a substrate. Substrates may comprise, for example, one or more of iron, chromium, nickel, silicon, vanadium, titanium, boron, tungsten, aluminum, molybdenum, cobalt, manganese, zirconium, and niobium, oxides thereof, nitrides thereof, sulfides thereof, or any combination thereof. A substrate may be a steel substrate. A metal layer may be deposited via, for example, roll coating, vapor deposition, slurry deposition, or electrochemical deposition.
    Type: Grant
    Filed: November 16, 2018
    Date of Patent: March 1, 2022
    Assignee: PUBLIC JOINT STOCK COMPANY “SEVERSTAL”
    Inventors: Zachary M. Detweiler, Joseph E. McDermott, Adam G. Thomas, Daniel E. Bullard, Martin Janousek
  • Patent number: 11180823
    Abstract: Provided are a high-strength galvanized steel sheet having excellent delayed fracture resistance by reducing the diffusible hydrogen content in the steel and a method for producing the same. The high-strength galvanized steel sheet includes a steel sheet having a prescribed composition and a microstructure including martensite and tempered martensite, the total area fraction of the martensite and the tempered martensite being 30% or more, and a galvanizing layer formed on the surface of the steel sheet. The diffusible hydrogen content in the high-strength galvanized steel sheet is 0.50 wt. ppm or less. The half-width of the hydrogen release peak of the high-strength galvanized steel sheet is 70° C. or less. The diffusible hydrogen content and the half-width of the hydrogen release peak are determined by a prescribed analysis method.
    Type: Grant
    Filed: April 19, 2017
    Date of Patent: November 23, 2021
    Assignee: JFE STEEL CORPORATION
    Inventors: Takuya Hirashima, Tatsuya Nakagaito, Masaki Koba, Tatsuya Ehashi, Makoto Imamura
  • Patent number: 11035020
    Abstract: A method for producing a coated steel sheet having a tensile strength of at least 1450 MPa and a total elongation of at least 17% is provided. The method includes providing a cold rolled steel sheet having a chemical composition in weight %: 0.34%?C?0.45%, 1.50%?Mn?2.30%, 1.50%?Si?2.40%, 0%<Cr?0.7%, 0%?Mo?0.3%, 0.10%?Al?0.7%, optionally 0%?Nb?0.05%, and a remainder of Fe and unavoidable impurities. The sheet is annealed at an annealing temperature higher than the Ac3 transformation point of the steel, quenched to a quenching temperature lower than the Ms transformation point of the steel and between 150° C. and 250° C., reheated to a partitioning temperature between 350° C. and 450° C., maintained at the partitioning temperature for at least 80 s, then coated by galvannealing, with an alloying temperature between 470° C. and 520° C. A steel sheet is also provided.
    Type: Grant
    Filed: December 29, 2015
    Date of Patent: June 15, 2021
    Assignee: ARCELORMITTAL
    Inventors: Olga A. Girina, Damon Panahi
  • Patent number: 10913988
    Abstract: A hot-rolled steel sheet includes a predetermined chemical composition, and a structure which include, by area ratio, ferrite and bainite in a range of 80% to 98% in total, and martensite in a range of 2% to 10%, in which in the structure, in a case where a boundary having an orientation difference of equal to or greater than 15° is defined as a grain boundary, and an area which is surrounded by the grain boundary, and has an equivalent circle diameter of equal to or greater than 0.3 ?m is defined as a grain, the ratio of the grains having an intragranular orientation difference in a range of 5° to 14° is, by area ratio, in a range of 10% to 60%.
    Type: Grant
    Filed: February 22, 2016
    Date of Patent: February 9, 2021
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Hiroshi Shuto, Natsuko Sugiura, Mitsuru Yoshida, Tatsuo Yokoi, Masayuki Wakita
  • Patent number: 10876181
    Abstract: In a cold-rolled steel sheet having a predetermined chemical composition, a metallographic structure contains 40.0% or more and less than 60.0% of a polygonal ferrite, 30.0% or more of a bainitic ferrite, 10.0% to 25.0% of a residual austenite, and 15.0% or less of a martensite, by an area ratio, in the residual austenite, a proportion of the residual austenite in which an aspect ratio is 2.0 or less, a length of a long axis is 1.0 ?m or less, and a length of a short axis is 1.0 ?m or less, is 80.0% or more, in the bainitic ferrite, a proportion of the bainitic ferrite in which an aspect ratio is 1.7 or less and an average value of a crystal orientation difference in a region surrounded by a boundary in which a crystal orientation difference is 15° or more is 0.5° or more and less than 3.0°, is 80.0% or more, and a connection index D value of the martensite, the bainitic ferrite, and the residual austenite is 0.70 or less.
    Type: Grant
    Filed: February 24, 2016
    Date of Patent: December 29, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Kengo Takeda, Kunio Hayashi, Akihiro Uenishi, Masafumi Azuma, Takayuki Nozaki, Yuri Toda
  • Patent number: 10689737
    Abstract: A hot-rolled steel sheet includes a chemical composition represented by, in mass %, C: 0.010% to 0.100%, Si: 0.30% or less, Cr: 0.05% to 1.00%, Nb: 0.003% to 0.050%, Ti: 0.003% to 0.200% and others, wherein a proportion of grains having an intragranular misorientation of 5° to 14° in all grains is 20% or more by area ratio, the grain being defined as an area which is surrounded by a boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 ?m or more.
    Type: Grant
    Filed: February 25, 2015
    Date of Patent: June 23, 2020
    Assignee: NIPPON STEEL CORPORATION
    Inventors: Masayuki Wakita, Mitsuru Yoshida, Natsuko Sugiura, Hiroshi Shuto, Tatsuo Yokoi
  • Patent number: 10533235
    Abstract: A hot-working tool material has an annealed structure and is to be quenched and tempered before using, wherein: the hot-working tool material has a composition from which a martensite structure can be prepared by the quenching; and, in ferrite crystal grains in the annealed structure in a cross section of the hot-working tool material, the ratio by number of ferrite crystal grains having a largest diameter (L) of 100 ?m or more is not more than 10.0% relative to the total ferrite crystal grains, and the ratio by number of ferrite crystal grains having an aspect ratio (L/T) [wherein (L) stands for a largest diameter, and (T) stands for the largest transverse width orthogonally crossing the same] of 3.0 or more is not more than 10.0% relative to the total ferrite crystal grains.
    Type: Grant
    Filed: May 8, 2015
    Date of Patent: January 14, 2020
    Assignee: HITACHI METALS, LTD.
    Inventor: Taishiroh Fukumaru
  • Patent number: 10266906
    Abstract: A high-strength galvanized steel sheet has a chemical composition containing, by mass %, C: 0.16% or more and 0.24% or less, Si: 0.8% or more and 1.8% or less, Mn: 1.0% or more and 3.0% or less, P: 0.020% or less, S: 0.0040% or less, Al: 0.01% or more and 0.1% or less, N: 0.01% or less, Ca: 0.0001% or more and 0.0020% or less, and the balance including Fe and incidental impurities, and a microstructure, in which the total area ratio of a ferrite phase and a bainite phase with respect to the whole microstructure is 30% or more and 70% or less, in which the area ratio of a tempered martensite phase with respect to the whole microstructure is 20% or more and 40% or less, in which the area ratio of a retained austenite phase with respect to the whole microstructure is 10% or more and 20% or less, and in which the area ratio of a martensite phase with respect to the whole microstructure is 2% or more and 20% or less.
    Type: Grant
    Filed: March 26, 2014
    Date of Patent: April 23, 2019
    Assignee: JFE STEEL CORPORATION
    Inventors: Hidetaka Kawabe, Takeshi Yokota
  • Patent number: 10106873
    Abstract: A hot-rolled steel sheet including, in terms of % by mass, 0.030% to 0.120% of C, 1.20% or less of Si, 1.00% to 3.00% of Mn, 0.01% to 0.70% of Al, 0.05% to 0.20% of Ti, 0.01% to 0.10% of Nb, 0.020% or less of P, 0.010% or less of S, and 0.005% or less of N, and a balance consisting of Fe and impurities, in which 0.106?(C %-Ti %*12/48-Nb %*12/93)?0.012 is satisfied; a pole density of {112}(110) at a position of ¼ plate thickness is 5.7 or less; an aspect ratio (long axis/short axis) of prior austenite grains is 5.3 or less; a density of (Ti, Nb)C precipitates having a size of 20 nm or less is 109 pieces/mm3 or more; a yield ratio YR, which is the ratio of a tensile strength to a yield stress, is 0.80 or more; and a tensile strength is 590 MPa or more.
    Type: Grant
    Filed: January 8, 2013
    Date of Patent: October 23, 2018
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Eisaku Sakurada, Kunio Hayashi, Koichi Sato, Shunji Hiwatashi
  • Patent number: 10100394
    Abstract: A high-strength galvannealed steel sheet has a chemical composition containing, by mass %, C: 0.14% or more and 0.24% or less, Si: 0.8% or more and 1.8% or less, Mn: 1.0% or more and 3.0% or less, P: 0.020% or less, S: 0.0040% or less, Al: 0.01% or more and 0.1% or less, N: 0.01% or less, Ca: 0.0001% or more and 0.
    Type: Grant
    Filed: March 26, 2014
    Date of Patent: October 16, 2018
    Assignee: JFE Steel Corporation
    Inventors: Hidetaka Kawabe, Takeshi Yokota
  • Patent number: 10072316
    Abstract: A cold-rolled steel sheet having a steel composition comprising, by mass %, 0.12% to 0.22% C, 0.8% to 1.8% Si, 1.8% to 2.8% Mn, 0.020% or less P, 0.0040% or less S, 0.005% to 0.08% Al, 0.008% or less N, 0.001% to 0.040% Ti, 0.0001% to 0.0020% B, 0.0001% to 0.0020% Ca, and Fe and incidental impurities. The steel sheet includes a microstructure in which ferrite and bainite phases are 50% to 70% of the total area, the average grain size of the ferrite and bainite phase is 1 to 3 ?m, a tempered martensite phase is 25% to 45% of the total area, the average grain size of the tempered martensite phase is 1 to 3 ?m, and a retained austenite phase is 2% to 10% of the total area.
    Type: Grant
    Filed: October 16, 2013
    Date of Patent: September 11, 2018
    Assignee: JFE STEEL CORPORATION
    Inventors: Hidetaka Kawabe, Takeshi Yokota, Reiko Sugihara, Daigo Itoh, Kazunori Tahara
  • Patent number: 10000831
    Abstract: Disclosed are a steel composition and a spring steel comprising the same. The steel composition comprises: an amount of about 0.51 to 0.57% by weight of carbon (C), an amount of about 1.35 to 1.45% by weight of silicon (Si), an amount of about 0.95 to 1.05% by weight of manganese (Mn), an amount of about 0.60 to 0.80% by weight of chromium (Cr), an amount of about 0.25 to 0.35% by weight of copper (Cu), an amount of about 0.05 to 0.15% by weight of vanadium (V), an amount of about 0.25 to 0.35% by weight of nickel (Ni), an amount of about 0.003 to 0.015% by weight of phosphorus (P), an amount of about 0.003 to 0.010% by weight of sulfur (S), and iron (Fe) constituting the remaining balance of the steel composition, all the % by weights are based on the total weight of the steel composition.
    Type: Grant
    Filed: May 11, 2016
    Date of Patent: June 19, 2018
    Assignees: Hyundai Motor Company, Hyundai Steel Company
    Inventors: Jeen Woo Park, Sung Chul Cha, Jong Hwi Park, Kyu Ho Lee
  • Patent number: 9708679
    Abstract: There is provided a high-strength hot-dip galvanized steel sheet and the like excellent in mechanical cutting property, which are capable of obtaining high ductility while ensuring high strength with maximum tensile strength of 900 MPa or more. The high-strength hot-dip galvanized steel sheet has a sheet thickness of 0.6 to 5.0 mm and has a plating layer on a surface of a steel sheet with component compositions being set in appropriate ranges, in which the steel sheet structure contains a 40 to 90% ferrite phase and a 3% or more retained austenite phase by volume fraction. In the retained austenite phase, a solid solution carbon amount is 0.70 to 1.00%, an average grain diameter is 2.0 ?m or less, an average distance between grains is 0.1 to 5.0 ?m, a thickness of a decarburized layer in a steel sheet surface layer portion is 0.01 to 10.0 ?m, an average grain diameter of oxides contained in the steel, sheet surface layer portion is 30 to 120 nm and an average density thereof is 1.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: July 18, 2017
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Hiroyuki Kawata, Naoki Maruyama, Akinobu Murasato, Akinobu Minami, Takeshi Yasui, Takuya Kuwayama, Hiroyuki Ban, Kaoru Hiramatsu
  • Patent number: 9551047
    Abstract: A high strength electric resistance welded steel pipe has a yield strength of 450 MPa or more and excellent resistance to softening for a long period in an intermediate temperature range and a method of manufacturing the steel pipe are provided. The steel pipe has a chemical composition containing, by mass%, C: 0.026% or more and 0.084% or less, Si: 0.10% or more and 0.30% or less, Mn: 0.70% or more and 1.90% or less, Al: 0.01% or more and 0.10% or less, Nb: 0.001% or more and 0.070% or less, V: 0.001% or more and 0.065% or less, Ti: 0.001% or more and 0.033% or less, Ca: 0.0001% or more and 0.0035% or less, in which the condition that Pcm is 0.20 or less is satisfied.
    Type: Grant
    Filed: June 17, 2013
    Date of Patent: January 24, 2017
    Assignee: JFE Steel Corporation
    Inventors: Shunsuke Toyoda, Sota Goto, Takatoshi Okabe, Tomohiro Inoue
  • Patent number: 9458520
    Abstract: This high-strength cold-rolled steel sheet having excellent uniform elongation and hole expandability contains, C: 0.01 to 0.4%; Si: 0.001 to 2.5%; Mn: 0.001 to 4.0%; P: 0.001 to 0.15%; S: 0.0005 to 0.03%; Al: 0.001 to 2.0%; N: 0.0005 to 0.01%; and O: 0.0005 to 0.01%; in which Si+Al is limited to less than 1.0%, and a balance being composed of iron and inevitable impurities, in which at a sheet thickness center portion, an average value of pole densities of the {100}<011> to {223}<110> orientation group is 5.0 or less, and a pole density of the {332}<113> crystal orientation is 4.0 or less, a metal structure contains 5 to 80% of ferrite, 5 to 80% of bainite, and 1% or less of martensite in terms of an area ratio and the total of martensite, pearlite, and retained austenite is 5% or less, and an r value (rC) in a direction perpendicular to a rolling direction is 0.70 or more and an r value (r30) in a direction 30° from the rolling direction is 1.10 or less.
    Type: Grant
    Filed: April 19, 2012
    Date of Patent: October 4, 2016
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yuri Toda, Riki Okamoto, Nobuhiro Fujita, Kohichi Sano, Hiroshi Yoshida, Toshio Ogawa
  • Patent number: 9409221
    Abstract: A hardenable steel sheet is treated with press-forming by means of a die. The method is comprised of: heating the steel sheet to a temperature of an Ac3 point or higher; carrying out a primary press on the heated steel sheet so as to give a local strain to a limited part of the steel sheet; keeping the steel sheet in a state apart from the die shortly after the primary press; and carrying out a press on the steel sheet kept in the state and retain the steel sheet in close contact with the die.
    Type: Grant
    Filed: March 28, 2011
    Date of Patent: August 9, 2016
    Assignee: TOPRE CORPORATION
    Inventor: Masanori Kobayashi
  • Patent number: 9347122
    Abstract: This high-strength cold-rolled steel sheet contains, in mass %, C: 0.02% to 0.20%; Si: 0.001% to 2.5%; Mn: 0.01% to 4.0%; P: 0.001% to 0.15%; S: 0.0005% to 0.03%; Al: 0.001% to 2.0%; N: 0.0005% to 0.01%; and O: 0.0005% to 0.01%; in which Si+Al is limited to less than 1.0%, and a balance being composed of iron and inevitable impurities, in which an area ratio of bainite in a metal structure is 95% or more, at a sheet thickness center portion being a range of ? to ? in sheet thickness from the surface of the steel sheet, an average value of pole densities of the {100}<011> to {223}<110> orientation group is 4.0 or less, and a pole density of the {332}<113> crystal orientation is 5.0 or less, and a mean volume diameter of crystal grains in the metal structure is 7 ?m or less.
    Type: Grant
    Filed: April 12, 2012
    Date of Patent: May 24, 2016
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Yoshihiro Suwa, Kazuaki Nakano, Kunio Hayashi, Riki Okamoto, Nobuhiro Fujita, Kohichi Sano
  • Patent number: 9284618
    Abstract: A high strength hot-rolled steel sheet with a tensile strength of not less than 590 MPa which exhibits excellent bake hardenability and stretch-flangeability has a chemical composition including, in terms of mass %, C at 0.040 to 0.10%, Si at not more than 0.3%, Mn at 1.7 to 2.5%, P at not more than 0.030%, S at not more than 0.005%, Al at not more than 0.1% and N at 0.006 to 0.025%, and microstructure wherein a bainite phase represents not less than 60%, the total of a ferrite phase and a pearlite phase represents not more than 10%, and the bainite phase includes grains among which cementite grains have been precipitated at not less than 1.4×104 grains/mm2 and the cementite grains have an average grain diameter of not more than 1.5 ?m.
    Type: Grant
    Filed: May 23, 2011
    Date of Patent: March 15, 2016
    Assignee: JFE Steel Corporation
    Inventors: Noriaki Kohsaka, Kazuhiro Seto, Hidetaka Kawabe, Yasushi Tanaka
  • Patent number: 9200342
    Abstract: A hot-rolled steel sheet according to the present invention is a steel sheet containing a predetermined components, and satisfying O<S/Ca<0.8, N?14/48×Ti?“0” (zero) %. It is a high-strength hot-rolled steel sheet for a spiral pipe excellent in low-temperature toughness in which a pro-eutectoid ferrite fraction is 3% or more and 20% or less, and the other is a low-temperature transformation phase in a microstructure at a depth of a half thickness of a sheet thickness from a steel sheet surface, a number average crystal grain size of a whole of the microstructure is 2.5 ?m or less, an area average grain size is 9 ?m or less, a standard deviation of the area average grain size is 2.3 ?m or less, and a reflected X-ray intensity ratio {211}/{111} in a direction and in a {111} direction relative to a plane in parallel to the steel sheet surface at the depth of the half thickness of the sheet thickness from the steel sheet surface is 1.1 or more.
    Type: Grant
    Filed: June 30, 2011
    Date of Patent: December 1, 2015
    Assignee: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Tatsuo Yokoi, Hiroshi Abe, Osamu Yoshida, Yasuhiro Miyatani, Shinichi Araki, Osamu Kawano
  • Patent number: 9200344
    Abstract: A steel sheet including C at 0.05 to 0.15%, Si at 0.2 to 1.2%, Mn at 1.0 to 2.0%, P at not more than 0.04%, S at not more than 0.0030%, Al at 0.005 to 0.10%, N at not more than 0.005% and Ti at 0.03 to 0.13%, the balance being Fe and inevitable impurities, includes surface regions having an area fraction of bainite of less than 80% and an area fraction of a ferrite phase with a grain diameter of 2 to 15 ?m of not less than 10%, the surface regions extending from both surfaces of the steel sheet each to a depth of 1.5 to 3.0% relative to a total sheet thickness, as well as an inner region other than the surface regions having an area fraction of a bainite phase of more than 95%, and has a tensile strength of not less than 780 MPa.
    Type: Grant
    Filed: September 15, 2011
    Date of Patent: December 1, 2015
    Assignee: JFE Steel Corporation
    Inventors: Hayato Saito, Katsumi Nakajima, Yoshimasa Funakawa, Noriaki Moriyasu, Takayuki Murata
  • Patent number: 9144839
    Abstract: A method produces microalloyed tubular steel from a steel melt having a chemical composition of 0.04-0.05% C, 1.3-1.5% Mn, 0.035-0.05% Nb, 0.035-0.06% V, 0.2-0.4% Cr, 0.2-0.3% Si, >0.015% Al and <0.008% N in percent by weight, the remainder consisting of Fe and unavoidable impurities. The method includes roughening an uncut thin slab strand formed from the steel melt to form a rough strip, reheating the rough strip to produce a reheated rough strip, and finish-rolling the descaled rough strip in a first group of rolling stands and in a second group of the rolling stands.
    Type: Grant
    Filed: September 10, 2013
    Date of Patent: September 29, 2015
    Assignee: PRIMETALS TECHNOLOGIES AUSTRIA GMBH
    Inventors: Bernd Linzer, Axel Rimnac
  • Patent number: 9133532
    Abstract: Provided is a method of manufacturing a high-carbon hot-rolled steel sheet, including the steps of i) preparing high-carbon steel materials comprising C: 0.7 to 0.9%, Si: 0.5% or less, Mn: 0.1 to 1.5%, Cr: 0.5% or less, P: 0.05% or less, and S: 0.03% or less in wt % and remaining Fe and other inevitable impurities; ii) heating the high-carbon steel materials again and manufacturing a steel sheet by performing hot rolling in an austenite region in which a finishing temperature for the hot rolling is an Ar3 transformation temperature or higher; iii) rapidly cooling the steel sheet at 520 to 620° C. before phase transformation is started in a Run-Out Table (ROT); iv) uniformly maintaining a cooling retention temperature so that the cooled steel sheet is subject to phase transformation in any one temperature between 520 to 620° C.; and v) winding the steel sheet in the cooling retention temperature. Also provided is the high-carbon steel sheet made by the above-described method.
    Type: Grant
    Filed: September 15, 2011
    Date of Patent: September 15, 2015
    Assignee: POSCO
    Inventors: Kyong-Su Park, Han-Chul Shin
  • Publication number: 20150144228
    Abstract: A quenched steel pipe member is formed of a GI galvanized steel pipe, in a middle section in a longitudinal direction of the GI galvanized steel pipe, a cross-section perpendicular to the longitudinal direction has a substantially V shape including a contact section at which opposite parts of an inner circumferential surface of the GI galvanized steel pipe come into contact with each other, the contact section is bonded using a Fe—Zn alloy phase, and a micro Vickers hardness at a location 50 ?m deep from a base material surface layer is 95% or more of a micro Vickers hardness at a location 200 ?m deep from the base material surface layer.
    Type: Application
    Filed: September 12, 2013
    Publication date: May 28, 2015
    Applicant: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Takaaki Fukushi, Koichi Sato, Satoshi Kato, Hideki Hamatani, Yoshiaki Hirota
  • Patent number: 9028626
    Abstract: A method of manufacturing a high-strength galvanized steel sheet includes hot-rolling a slab to form a steel sheet; during continuous annealing, heating the steel sheet to a temperature of 750° C. to 900° C. at an average heating rate of at least 10° C./s at a temperature of 500° C. to an A1 transformation point; holding that temperature for at least 10 seconds; cooling the steel sheet from 750° C. to a temperature of (Ms point—100° C.) to (Ms point—200° C.) at an average cooling rate of at least 10° C./s; reheating the steel sheet to a temperature of 350° C. to 600° C.; holding that temperature for 10 to 600 seconds; and galvanizing the steel sheet.
    Type: Grant
    Filed: March 25, 2013
    Date of Patent: May 12, 2015
    Assignee: JFE Steel Corporation
    Inventors: Tatsuya Nakagaito, Saiji Matsuoka, Shinjiro Kaneko, Yoshiyasu Kawasaki, Yoshitsugu Suzuki
  • Publication number: 20150107725
    Abstract: The present invention relates to a high carbon hot rolled steel sheet having excellent material uniformity and a method for manufacturing the same, in which components and structure of the steel are precisely controlled and manufacturing conditions are adjusted to achieve excellence in material uniformity among hot rolled structures, thereby improving the dimensional precision of parts after formation, preventing defects during processing, and obtaining uniform structures and hardness distribution even after a final heat treatment process.
    Type: Application
    Filed: December 27, 2012
    Publication date: April 23, 2015
    Inventors: Young-Roc Im, Jea-Chun Jeon, Byoung-Ho Lee
  • Patent number: 8993120
    Abstract: A hot-dip galvanizing layer or an alloyed hot dip galvanizing layer is formed on the surface of a base steel sheet in which in volume fraction, 40 to 90% of a ferrite phase and 5% or less of a retained austenite phase are contained, and a ratio of non-recrystallized ferrite to the entire ferrite phase is 50% or less in volume fraction, and further a grain diameter ratio being a value of, of crystal grains in the ferrite phase, an average grain diameter in the rolling direction divided by an average grain diameter in the sheet width direction is 0.75 to 1.33, a length ratio being a value of, of hard structures dispersed in island shapes, an average length in the rolling direction divided by an average length in the sheet width direction is 0.75 to 1.33, and an average aspect ratio of inclusions is 5.0 or less.
    Type: Grant
    Filed: September 28, 2012
    Date of Patent: March 31, 2015
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Hiroyuki Kawata, Naoki Maruyama, Akinobu Murasato, Akinobu Minami, Takeshi Yasui, Takuya Kuwayama, Hiroyuki Ban, Kaoru Hiramatsu
  • Publication number: 20150050519
    Abstract: In a hot stamped steel, when [C] represents an amount of C (mass %), [Si] represents an amount of Si (mass %), and [Mn] represents an amount of Mn (mass %), an expression of 5×[Si]+[Mn])/[C]>10 is satisfied, a metallographic structure includes 80% or more of a martensite in an area fraction, and optionally, further includes one or more of 10% or less of a pearlite in an area fraction, 5% or less of a retained austenite in a volume ratio, 20% or less of a ferrite in an area fraction, and less than 20% of a bainite in an area fraction, TS×?, which is a product of TS that is a tensile strength and ? that is a hole expansion ratio is 50000 MPa·% or more, and a hardness of the martensite measured with a nanoindenter satisfies H2/H1<1.10 and ?HM<20.
    Type: Application
    Filed: January 11, 2013
    Publication date: February 19, 2015
    Inventors: Toshiki Nonaka, Satoshi Kato, Kaoru Kawasaki, Toshimasa Tomokiyo
  • Publication number: 20150047751
    Abstract: A high strength steel sheet is formed of steel having the composition containing by mass % over 0.015% and less than 0.100% C, less than 0.50% Si, over 1.0% and less than 2.0% Mn, 0.05% or less P, 0.03% or less S, 0.01% or more and 0.3% or less sol. Al, 0.005% or less N, less than 0.35% Cr, 0.0010% or more and 0.0050% or less B, less than 0.15% Mo, less than 0.030% Ti, and iron and unavoidable impurities as a balance, wherein the steel satisfies 2.1?[Mneq]?3.1, the microstructure of the steel includes a ferrite and a second phase, a volume fraction of the second phase is set to 2.0 to 12.0%, a total ratio of a volume fraction of martensite and a volume fraction of retained ? to the volume fraction of second phase is 60% or more, and the number of carbides which are present within ferrite particles, have an aspect ratio of 3.0 or less and have a diameter of 0.25 to 0.90 ?m is set to 10000 pieces/mm2 or less.
    Type: Application
    Filed: September 28, 2011
    Publication date: February 19, 2015
    Applicant: JFE Steel Corporation
    Inventors: Yoshihiko Ono, Kenji Takahashi, Kaneharu Okuda, Yusuke Fushiwaki, Michitaka Sakurai
  • Patent number: 8951366
    Abstract: A high-strength cold-rolled steel sheet includes, by mass %, C: 0.10% to 0.40%, Mn: 0.5% to 4.0%, Si: 0.005% to 2.5%, Al: 0.005% to 2.5%, Cr: 0% to 1.0%, and a balance of iron and inevitable impurities, in which an amount of P is limited to 0.05% or less, an amount of S is limited to 0.02% or less, an amount of N is limited to 0.006% or less, the microstructure includes 2% to 30% of retained austenite by area percentage, martensite is limited to 20% or less by area percentage in the microstructure, an average particle size of cementite is 0.01 ?m to 1 ?m, and 30% to 100% of the cementite has an aspect ratio of 1 to 3.
    Type: Grant
    Filed: January 26, 2011
    Date of Patent: February 10, 2015
    Assignee: Nippon Steel & Sumitomo Metal Corporation
    Inventors: Kohichi Sano, Chisato Wakabayashi, Hiroyuki Kawata, Riki Okamoto, Naoki Yoshinaga, Kaoru Kawasaki, Natsuko Sugiura, Nobuhiro Fujita
  • Publication number: 20150037610
    Abstract: A high-strength cold-rolled steel sheet includes a composition having controlled amounts of carbon, silicon, manganese, phosphorous, sulfur, titanium, niobium, sol. Aluminum, chromium, molybdenum, vanadium, boron, calcium, REM, and iron. A microstructure thereof has a main phase of ferrite of at least 40 area %, and a second phase of a low-temperature transformation phase consisting either or both of martensite and bainite, which comprises at least 10 area % in total and retained austenite (?) at least comprising 3 area %. An average grain diameter of ferrite has a tilt angle of at least 15° is at most 5.0 mm, an average grain diameter of the low-temperature transformation-produced phase is at most 2.0 mm, an average grain diameter of lump-like retained ? having an aspect ratio of less than 5 is at most 1.5 mm, and an area fraction of the lump-like retained ? relative to the retained ? is at least 50%.
    Type: Application
    Filed: February 13, 2013
    Publication date: February 5, 2015
    Inventors: Kengo Hata, Toshiro Tomida, Norio Imai, Jun Haga, Takuya Nishio
  • Publication number: 20150027593
    Abstract: A high-strength cold-rolled steel sheet having excellent ductility and stretch flangeability includes: a chemical composition consisting, in mass %, C: 0.06 to 0.3, Si: 0.6 to 2.5%, Mn: 0.6 to 3.5%, P: at most 0.1%, S: at most 0.05%, Ti: 0 to 0.08%, Nb: 0 to 0.04%, total of Ti and Nb: 0 to 0.10%, sol.Al: 0 to 2.0%, Cr: 0 to 1%, Mo: 0 to 0.3%, V: 0 to 0.3%, B: 0 to 0.005%, Ca: 0 to 0.003%, REM: 0 to 0.003% and the remainder of Fe and impurities; a microstructure having a main phase including at least 40 area % in total of martensite and/or bainite; and a texture in which proportion of an average X-ray intensity in an {100}<011> to {211}<011> orientations relative to an average X-ray intensity of a random structure not having a texture is less than 6.
    Type: Application
    Filed: February 13, 2013
    Publication date: January 29, 2015
    Inventors: Kengo Hata, Toshiro Tomida, Norio Ima, Jun Haga, Takuya Nishio
  • Patent number: 8936687
    Abstract: In a method for manufacturing grain oriented electrical steel sheets from a slab, controlling the steel sheet temperature so as to satisfy T (t)<FDT?(FDT?700)×t/6 (wherein T (t): steel sheet temperature (° C.), FDT: finishing temperature (° C.) and t: time (sec) after the completion of finish rolling) throughout the entire length of a coil during cooling after the completion of finish rolling in hot rolling, and controlling the steel sheet temperature of a tip portion of the coil representing 10% of the length of the coil to be not less than 650° C. at a lapse of 3 seconds from the completion of hot rolling, thus manufacturing a grain oriented electrical steel sheet exhibiting excellent magnetic properties throughout the entire coil length.
    Type: Grant
    Filed: March 9, 2011
    Date of Patent: January 20, 2015
    Assignee: JFE Steel Corporation
    Inventor: Kenichi Sadahiro
  • Publication number: 20150017471
    Abstract: There are provided a high-strength hot-rolled steel sheet securing low-temperature toughness and having excellent stretch flangeability by controlling a structural fraction and a hardness difference among structures, and a manufacturing method thereof. A hot-rolled steel sheet contains: C: 0.01 to 0.2%; Si: 0.001 to 2.5% or less; Mn: 0.10 to 4.0% or less; P: 0.10% or less; S: less than 0.03%; Al: 0.001 to 2.0%; N: less than 0.01%; Ti: (0.005+48/14[N]+48/32[S]) % or more and 0.3% or less; Nb: 0 to 0.06%; Cu: 0 to 1.2%; Ni: 0 to 0.6%; Mo: 0 to 1%; V: 0 to 0.2%; Cr: 0 to 2%; Mg: 0 to 0.01%; Ca: 0 to 0.01%; REM: 0 to 0.1%; and B: 0 to 0.002%, and has: an texture in which, at a central portion of a sheet thickness located between ? to ? thickness positions of the sheet thickness from a surface of the steel sheet, an average value of X-ray random intensity ratios of a group of {100}<011> to {223}<110> orientations of a sheet plane is 6.
    Type: Application
    Filed: December 27, 2012
    Publication date: January 15, 2015
    Inventors: Hiroshi Shuto, Tatsuo Yokoi, Yuuki Kanzawa, Nobuhiro Fujita, Ryohta Niiya, Shinya Saitoh
  • Publication number: 20150010775
    Abstract: A hot stamped steel according to the present invention satisfies an expression of (5×[Si]+[Mn])/[C]>11 when [C] represents an amount of C by mass %, [Si] represents an amount of Si by mass %, and [Mn] represents an amount of Mn by mass %, a metallographic structure after hot stamping includes 40% to 90% of a ferrite and 10% to 60% of a martensite in an area fraction, a total of an area fraction of the ferrite and an area fraction of the martensite is 60% or more, a hardness of the martensite measured with a nanoindenter satisfies an H2/H1<1.10 and ?HM<20, and TS×?, which is a product of a tensile strength TS and a hole expansion ratio ? is 50000 MPa·% or more.
    Type: Application
    Filed: January 11, 2013
    Publication date: January 8, 2015
    Inventors: Toshiki Nonaka, Satoshi Kato, Kaoru Kawasaki, Toshimasa Tomokiyo
  • Publication number: 20150004433
    Abstract: A steel sheet includes, by mass %: C: 0.020% to 0.080%; Si: 0.01% to 0.10%; Mn: 0.80% to 1.80%; and Al: more than 0.10% and less than 0.40%; and further includes: Nb: 0.005% to 0.095%; and Ti: 0.005% to 0.095%, in which a total amount of Nb and Ti is 0.030% to 0.100%, and the steel sheet includes, as a metallographic structure, ferrite, bainite, and other phases, an area fraction of the ferrite is 80% to 95%, an area fraction of the bainite is 5% to 20%, a total fraction of the other phases is less than 3%, a tensile strength is 590 MPa or more, and a fatigue strength ratio as a fatigue strength to the tensile strength is 0.45 or more.
    Type: Application
    Filed: February 7, 2013
    Publication date: January 1, 2015
    Inventors: Hiroyuki Tanaka, Kunio Hayashi, Toshio Ogawa, Koichi Goto, Kazuaki Nakano
  • Publication number: 20150003935
    Abstract: A steel is used for providing a bolt that has a high strength and still exhibits excellent hydrogen embrittlement resistance. The steel contains C of 0.30% to 0.50%, Si of 1.0% to 2.5%, Mn of 0.1% to 1.5%, P of greater than 0% to 0.015%, S of greater than 0% to 0.015%, Cr of 0.15% to 2.4%, Al of 0.010% to 0.10%, N of 0.001% to 0.10%, Cu of 0.1% to 0.50%, Ni of 0.1% to 1.0%, Ti of 0.05% to 0.2%, and V of 0% to 0.2%, with the remainder including iron and inevitable impurities, in which a ratio [Ni]/[Cu] is 0.5 or more, and a total content [Ti]+[V] is 0.085% to 0.30%.
    Type: Application
    Filed: November 26, 2012
    Publication date: January 1, 2015
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Yosuke Matsumoto, Atsushi Inada, Masamichi Chiba
  • Publication number: 20150000796
    Abstract: This high-strength steel sheet contains, in mass %, 0.05 to 0.3% of C, 1 to 3% of Si, 0.5 to 3% of Mn, up to 0.1% (inclusive of 0%) of P, up to 0.01% (inclusive of 0%) of S, 0.001 to 0.1% of Al and 0.002 to 0.03% of N with the balance consisting of iron and unavoidable impurities, and has a microstructure which comprises, in area fraction relative to the microstructure, 40 to 85% of bainitic ferrite, 5 to 20% of retained austenite (?R), 10 to 50% (in total) of martensite and ?R, and 5 to 40% of ferrite. The retained austenite (?R) has a C concentration of 0.5 to 1.0 mass %, while the quantity of ?R present in the ferrite grains is 1% or more (in area fraction) relative to the microstructure.
    Type: Application
    Filed: February 6, 2013
    Publication date: January 1, 2015
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)
    Inventors: Elijah Kakiuchi, Toshio Murakami, Katsura Kajihara, Tatsuya Asai, Naoki Mizuta, Hideo Hata
  • Publication number: 20140370329
    Abstract: When the amount of C, the amount of Si and the amount of Mn are respectively represented by [C], [Si] and [Mn] in unit mass %, the cold rolled steel sheet satisfies a relationship of (5×[Si]+[Mn])/[C]>10, the metallographic structure contains, by area ratio, 40% to 90% of a ferrite and 10% to 60% of a martensite, further contains one or more of 10% or less of a pearlite by area ratio, 5% or less of a retained austenite by volume ratio and 20% or less of a bainite by area ratio, the hardness of the martensite measured using a nanoindenter satisfies H20/H10<1.10 and ?HM0<20, and TS×? representing the product of TS that is a tensile strength and ? that is a hole expansion ratio is 50000 MPa·% or more.
    Type: Application
    Filed: January 11, 2013
    Publication date: December 18, 2014
    Inventors: Toshiki Nonaka, Satoshi Kato, Kaoru Kawasaki, Toshimasa Tomokiyo
  • Publication number: 20140360631
    Abstract: This high strength hot-rolled steel sheet includes: in terms of percent by mass, C: 0.05 to 0.12%; Si: 0.8 to 1.2%; Mn: 1.6 to 2.2%; Al: 0.30 to 0.6%; P: 0.05% or less; S: 0.005% or less; and N: 0.01% or less, with the remainder being Fe and unavoidable impurities, wherein a microstructure includes specific ranges (in area %) of ferrite phases as well as martensite phases, and a maximum concentration of Al detected by a glow discharge emission spectroscopic analysis is in a range of 0.75 mass % or less in a region from a surface of the steel sheet to a thickness of 500 nm after being acid-pickled.
    Type: Application
    Filed: August 27, 2014
    Publication date: December 11, 2014
    Inventors: Hiroyuki TANAHASHI, Shinya SAITOH, Masashi FUKUDA, Hiroyuki OKADA, Kunio HAYASHI, Toshimasa TOMOKIYO, Nobuhiro FUJITA
  • Publication number: 20140352850
    Abstract: A cold-rolled steel sheet includes, by mass %: C: 0.020% or more and 0.080% or less, Si: 0.20% or more and 1.00% or less; Mn: 0.80% or more and 2.30% or less: and Al: 0.010% or more and 0.100% or less; and further includes: one or more of Nb and Ti which satisfy a requirement of 0.005%?Nb+Ti<0.030%, in which a structure consists of, ferrite, bainite, and other phases, an area ratio of the ferrite is 80% or more and less than 95%, an area ratio of a non-recrystallization ferrite in the ferrite is 1% or more and less than 10%, an area ratio of the bainite is 5% or more and 20% or less, a total amount of the other phases is less than 8%, an equivalent circle diameter of a carbonitride including one or both of Nb and Ti is 1 nm or more and 10 nm or less, and a tensile strength is 590 MPa or more.
    Type: Application
    Filed: February 6, 2013
    Publication date: December 4, 2014
    Inventors: Yusuke Kondo, Kunio Hayashi, Toshio Ogawa, Naoki Matsutani, Koichi Goto
  • Publication number: 20140342184
    Abstract: The present invention provides a high-strength steel sheet having a tensile strength of 980 MPa or more and also excellent bending property stably over the entire steel sheet, due to a predetermined chemical composition in combination with a specific microstructure wherein an average crystallized grain diameter of ferrite phase is 10 ?m or less, a volume fraction of ferrite phase is within the range from 30% to 70%, a volume fraction of the total of martensite and retained austenite phases is 10% or less, and a ratio of interphases each having an interphase nano-hardness difference within 4 GPa is 90% or more.
    Type: Application
    Filed: December 26, 2012
    Publication date: November 20, 2014
    Applicant: JFE STEEL CORPORATION
    Inventors: Shusaku Takagi, Shinjiro Kaneko
  • Publication number: 20140332119
    Abstract: A high strength cold rolled steel sheet has a chemical composition including, by mass %, C: 0.06 to 0.13%, Si: 1.2 to 2.3%, Mn: 0.6 to 1.6%, P: not more than 0.10%, S: not more than 0.010%, Al: 0.01 to 0.10% and N: not more than 0.010%, the balance comprising Fe and inevitable impurities. The steel sheet includes a microstructure containing not less than 90% in terms of volume fraction of ferrite with an average grain diameter of less than 20 ?m and 1.0 to 10% in terms of volume fraction of pearlite with an average grain diameter of less than 5 ?m. The ferrite has an average Vickers hardness of not less than 130. The steel sheet has a yield ratio of not less than 65% and a tensile strength of not less than 590 MPa.
    Type: Application
    Filed: December 3, 2012
    Publication date: November 13, 2014
    Applicant: JFE STEEL CORPORATION
    Inventors: Katsutoshi Takashima, Yuki Toji, Kohei Hasegawa
  • Publication number: 20140318672
    Abstract: The present invention has as its object the provision of hot rolled steel sheet (hot coil) for line pipe use in which API5L-X80 standard or better high strength and low temperature toughness and ductile fracture arrest performance are achieved and a method of production of the same. For this purpose, the hot rolled steel sheet of the present invention comprises C, Si, Mn, Al, N, Nb, Ti, Ca, V, Mo, Cr, Cu, and Ni in predetermined ranges and a balance of Fe and unavoidable impurities, in which the microstructure is a continuously cooled transformed structure, in which continuously cooled transformed structure, precipitates containing Nb have an average size of 1 to 3 nm and are included dispersed at an average density of 3 to 30×1022/m3, granular bainitic ferrite and/or quasi-polygonal ferrite are included in 50% or more in terms of fraction, furthermore, precipitates containing Ti nitrides are included, and they have an average circle equivalent diameter of 0.
    Type: Application
    Filed: July 11, 2014
    Publication date: October 30, 2014
    Applicant: Nippon Steel Corporation
    Inventors: Tatsuo Yokoi, Hiroshi Abe, Osamu Yoshida
  • Patent number: 8871035
    Abstract: A process for producing grain oriented magnetic sheets by subjecting a steel slab ?100 mm, containing 2.5-3.5% si, to the following operations: optional first heating, to a temperature T1?1250° C.; first rough hot-rolling at T2 between 900 and 1200° C., the reduction ratio (% Rid) being at least 80% in the absence of a subsequent heating or, in the presence of a subsequent heating to T3?1300° C., at least 60% determined by % Rid=80?(T3?T2)/5; second finishing hot-rolling at T4<1300° C. to a rolled-section thickness of 1.5 3.0 mm; cold-rolling, in one or more stages with optional intermediate annealing and with a cold reduction ratio ?60% applied in the last stage; primary recrystallization annealing, optionally in a decarburizing atmosphere; second recrystallization annealing.
    Type: Grant
    Filed: November 18, 2009
    Date of Patent: October 28, 2014
    Assignee: Centro Sviluppo Materiali S.p.A.
    Inventors: Stefano Fortunati, Giuseppe Abbruzzese, Stefano Cicale′
  • Publication number: 20140311632
    Abstract: A method for producing a steel tube of high strength and toughness for air bag subjects a steel tube to high-frequency induction heating such that the outer surface temperature T1 (° C.) of the tube measured at the end of high-frequency induction heating is within the range defined by TAc3+40° C.?T1?1100° C., TAc3 is the temperature (° C.) of Ac3 transformation point. Using the measured outer surface temperature of the tube, time x (second) elapsed from when the outer surface temperature of steel tube reaches the temperature of Ac3 transformation point by high-frequency induction heating is calculated. Based on the calculated time x, time t (second) required from measurement of the outer surface temperature of steel tube to the start of rapid cooling is controlled so that the time t is within the range defined by 0 (sec)<t?10 (sec)?x.
    Type: Application
    Filed: November 16, 2012
    Publication date: October 23, 2014
    Applicant: NIPPON STEEL & SUMITOMO METAL CORPORATION
    Inventors: Kazuhiro Uchida, Takeshi Miki
  • Publication number: 20140311631
    Abstract: This high-strength steel sheet includes: in terms of percent by mass, 0.03 to 0.10% of C; 0.01 to 1.5% of Si; 1.0 to 2.5% of Mn; 0.1% or less of P; 0.02% or less of S; 0.01 to 1.2% of Al; 0.06 to 0.15% of Ti; and 0.01% or less of N; and contains as the balance, iron and inevitable impurities, wherein a tensile strength is in a range of 590 MPa or more, and a ratio between the tensile strength and a yield strength is in a range of 0.80 or more, a microstructure includes bainite at an area ratio of 40% or more and the balance being either one or both of ferrite and martensite, a density of Ti(C,N) precipitates having sizes of 10 nm or smaller is in a range of 1010 precipitates/mm3 or more, and a ratio (Hvs/Hvc) of a hardness (Hvs) at a depth of 10 ?m from a surface to a hardness (Hvc) at a center of a sheet thickness is in a range of 0.85 or more.
    Type: Application
    Filed: July 2, 2014
    Publication date: October 23, 2014
    Inventors: Kunio Hayashi, Toshimasa Tomokiyo, Nobuhiro Fujita, Naoki Matsutani, Koichi Goto
  • Publication number: 20140299235
    Abstract: Disclosed herein are embodiments of a seamless quenched and tempered steel pipe having a wall thickness (WT) higher than or equal to 35 mm and lower than or equal to 80 mm. Embodiments of the steel pipe can comprise C, Mn, Cr, Ni, Mo, Al, Ca, N, Nb, Ti, Zr, and Ta. Further, for some embodiments of the steel pipe wherein, defining a first parameter P1=50×C+Cr+10×Mo+70×V, the chemical composition can satisfy a first condition P1?8.0.
    Type: Application
    Filed: April 8, 2014
    Publication date: October 9, 2014
    Applicant: Dalmine S.p.A.
    Inventors: Ettore Anelli, Emanuele Paravicini Bagliani, Stefano Fare