Patents by Inventor Joo-Hyun RYU

Joo-Hyun RYU 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).

  • Publication number: 20250051870
    Abstract: The present invention relates to a hot-rolled steel sheet that can be suitably applied to an automobile chassis structure member or the like and, more specifically, to an ultrahigh-strength hot-rolled steel sheet having tensile strength of 1180 MPa or more, excellent formability, and uniform material distribution in the steel sheet, and a manufacturing method therefor.
    Type: Application
    Filed: November 22, 2022
    Publication date: February 13, 2025
    Applicant: POSCO CO., LTD
    Inventors: Tae-Jin Song, Joo-Hyun Ryu, Je-Woong Lee
  • Publication number: 20240401166
    Abstract: One aspect of the present invention relates to an ultrahigh-strength steel sheet having an excellent yield ratio, comprising, by wt %, 0.3-0.5% of C, 2.0% (excluding 0%) of Si, 3.0-6.5% of Mn, 0.02% or less of P, 0.01% or less of S, 0.01-3.0% of Al, 0.02% or less (excluding 0%) of N, and the balance of Fe and other inevitable impurities, and a microstructure comprises 5-30% of remaining austenite by area fraction and comprises 5% or less of secondary martensite.
    Type: Application
    Filed: August 9, 2024
    Publication date: December 5, 2024
    Applicants: POSCO CO., LTD, POSTECH ACADEMY-INDUSTRY FOUNDATION
    Inventors: Sea-Woong LEE, Bruno C. DE COOMAN, Kyoo-Young LEE, Eun-Jung SEO, Seon-Jong LEE, Joo-Hyun RYU, Won-Hwi LEE
  • Publication number: 20240392407
    Abstract: The present invention relates to: a high-strength cold-rolled steel sheet having excellent quality and low mechanical property deviation; and a manufacturing method therefor. More particularly, the present invention relates to: a high-strength cold-rolled steel sheet that can be suitably used for automotive parts by ensuring high strength and elongation with little surface defects and low mechanical property deviation; and a manufacturing method therefor.
    Type: Application
    Filed: September 20, 2022
    Publication date: November 28, 2024
    Applicant: POSCO CO., LTD
    Inventors: Sung-Il KIM, Joo-Hyun RYU, Chang-Hyo SEO
  • Publication number: 20240384366
    Abstract: Provided is a high-strength cold-rolled steel sheet having excellent surface quality and low material variation, and a method for manufacturing same. More specifically, the present invention pertains to: a high-strength cold-rolled steel sheet which has few surface defects and little material deviation, as well as high strength and elongation, and is thus suitable for use in automotive parts; and a method for manufacturing same.
    Type: Application
    Filed: September 20, 2022
    Publication date: November 21, 2024
    Inventors: Chang-Hyo SEO, Sung-Il KIM, Joo-Hyun RYU
  • Patent number: 12123066
    Abstract: One aspect of the present invention relates to an ultrahigh-strength steel sheet having an excellent yield ratio, comprising, by wt %, 0.3-0.5% of C, 2.0% (excluding 0%) of Si, 3.0-6.5% of Mn, 0.02% or less of P, 0.01% or less of S, 0.01-3.0% of Al, 0.02% or less (excluding 0%) of N, and the balance of Fe and other inevitable impurities, and a microstructure comprises 5-30% of remaining austenite by area fraction and comprises 5% or less of secondary martensite.
    Type: Grant
    Filed: November 7, 2017
    Date of Patent: October 22, 2024
    Assignees: POSCO CO. LTD, POSTECH ACADEMY-INDUSTRY FOUNDATION
    Inventors: Sea-Woong Lee, Bruno C. De Cooman, Kyoo-Young Lee, Eun-Jung Seo, Seon-Jong Lee, Joo-Hyun Ryu, Won-Hwi Lee
  • Publication number: 20240247349
    Abstract: Provided is a high-strength cold-rolled steel sheet having excellent surface quality and low mechanical property deviation; and a manufacturing method thereof and, more particularly, to: a high-strength cold-rolled steel sheet that can be suitably used for automotive parts by ensuring high strength and elongation with little surface defects and low mechanical property deviation; and a manufacturing method thereof.
    Type: Application
    Filed: September 20, 2022
    Publication date: July 25, 2024
    Inventors: Joo-Hyun RYU, Sung-Il KIM, Chang-Hyo SEO
  • Publication number: 20240052468
    Abstract: Provided is an ultra-high-strength cold-rolled steel sheet having excellent yield strength and bending properties, which can be used as a structural component for automobiles such as a member, a seat rail, and a pillar, and a method for manufacturing same. The steel sheet includes: by weight: C: 0.03 to 0.12%, Si: 0.03 to 0.3 Mn: 2.1 to 2.9%, Al: 0.005 to 0.07%, Nb: 0.01 to 0.08%, Ti: 0.005 to 0.08%, B: 0.0005 to 0.005%, Cr: 0.7 to 1.4%, Mo: 0.005 to 0.10%, N: 0.008% or less (excluding 0%), with balance of Fe and inevitable impurities. A microstructure thereof includes by area, fresh martensite: 4 to 19%, a sum of tempered martensite and bainite: 78 to 95%, and retained austenite: 0.2 to 2.0%. An average grain size of the microstructure is 0.5 to 6 ?m.
    Type: Application
    Filed: November 30, 2021
    Publication date: February 15, 2024
    Inventors: Jong-Pan KONG, Yeon-Sang AHN, Joo-Hyun RYU
  • Publication number: 20240026483
    Abstract: Provided is a high-strength hot-dip galvanized steel sheet having excellent ductility and formability. The hot-dip galvanized steel sheet contains, by wt %, 0.06 to 0.16% of carbon (C), 0.8% or less (excluding 0%) of silicon (Si), 2.1 to 2.7% of manganese (Mn), 0.4% or less (excluding 0%) of molybdenum (Mo), 1% or less (excluding 0%) of chromium (Cr), 0.1% or less (excluding 0%) of phosphorus (P), 0.02% or less of sulfur (S), 1% or less (excluding 0%) of aluminum (sol.Al), 0.001 to 0.04% of titanium (Ti), 0.001 to 0.04% of niobium (Nb), 0.01% or less (excluding 0%) of nitrogen (N), 0.01% or less of boron (B), 0.05% or less of antimony (Sb), and a balance of Fe and unavoidable impurities.
    Type: Application
    Filed: November 15, 2021
    Publication date: January 25, 2024
    Inventors: Kang-Hyun CHOI, Yeon-Sang AHN, Joo-Hyun RYU
  • Publication number: 20240002968
    Abstract: Provided are an ultra-high strength cold rolled steel sheet having excellent bendability, and a method of manufacturing the same. The steel sheet includes 0.06 to 0.17% of C, 0.1 to 0.8% of Si, 1.9 to 2.9% of Mn, 0.005 to 0.07% of Nb, 0.004 to 0.05% of Ti, 0.0004 to 0.005% of B, 0.20% or less (excluding 0%) of Cr, and 0.04 to 0.45% of Mo, with a balance of Fe and other unavoidable impurities. a microstructure of the steel sheet includes, by area: 80 to 98% of tempered martensite and a balance of fresh martensite, bainite, ferrite, and residual austenite. An average length of lath short axis of the tempered martensite is 500 nm or less.
    Type: Application
    Filed: November 29, 2021
    Publication date: January 4, 2024
    Inventors: Jong-Pan KONG, Yeon-Sang AHN, Joo-Hyun RYU
  • Publication number: 20230357881
    Abstract: Provided is an ultra-high strength steel sheet having excellent ductility including, 0.1 to 0.2% of carbon (C), 0.1 to 1.0% of silicon (Si), 2.0 to 3.0% of manganese (Mn), 1.0% or less of aluminum (Al), 1.0% or less of chromium (Cr), 0.5% or less of molybdenum (Mo), 0.1% or less of titanium (Ti), 0.1% or less of niobium (Nb), 0.1% or less of antimony (Sb), 0.05% or less of phosphorus (P), 0.02% or less of sulfur (S), 0.02% or less of nitrogen (N), and a balance of Fe and unavoidable impurities. The steel sheet satisfies the following: 1110[C]+41.5[Si]+575[Mn]?1092[Al]?3590[Nb]?5181[Ti]+258[Cr]+664 [Mo]?1380; 2853 [C]+95 [Si]+309 [Mn]?153 [Al]+4661 [Nb]?780[Ti]+210[Cr]+457[Mo]?1300; and ?29[C]+0.6[Si]?7.3[Mn]+7.8[Al]?145.2[Nb]+62.6[Ti]?3.3[Cr]?2.2[Mo]??24.
    Type: Application
    Filed: October 14, 2021
    Publication date: November 9, 2023
    Inventors: Joo-Hyun RYU, Yeon-Sang AHN, Kang-Hyun CHOI, Eul-Yong CHOI
  • Publication number: 20230295759
    Abstract: Provided is a steel sheet suitably used for an automobile structural member and the like, and more particularly, to a steel sheet having high strength and excellent formability that may prevent processing defects such as cracks or wrinkles occurring during the press-forming, and a method for producing the same.
    Type: Application
    Filed: June 29, 2021
    Publication date: September 21, 2023
    Inventors: Yeon-Sang AHN, Joo-Hyun RYU, Kang-Hyun CHOI, Eul-Yong CHOI
  • Patent number: 11655517
    Abstract: The present invention relates to an automotive steel sheet and, more specifically, provides: an ultrahigh-strength and high-ductility steel sheet ensuring ultrahigh strength and high ductility and, simultaneously, having excellent cold formability due to a high yield strength ratio, and improved collision characteristics.
    Type: Grant
    Filed: September 17, 2018
    Date of Patent: May 23, 2023
    Assignee: POSCO CO., LTD
    Inventors: Joo-Hyun Ryu, Kyoo-Young Lee, Sea-Woong Lee
  • Patent number: 11453922
    Abstract: Provided is an ultra-high-strength steel sheet having an excellent hole expandability and yield ratio, including, in terms of wt %: 0.05-0.2% of carbon (C); 2.0% or less of silicon (Si); 4.1-9.0% of manganese (Mn); 0.05% or less (excluding 0%) of phosphorus (P); 0.02% or less (excluding 0%) of sulfur (S); 0.5% or less (excluding 0%) of aluminum (Al); 0.02% or less (excluding 0%) of nitrogen (N); and a balance of iron (Fe) and other inevitable impurities, wherein the following Equation 1 is satisfied, and wherein microstructures includes, in volume percentage, 10-30% or retained austenite, 50% or more of annealed martensite, and 20% or less of other phases including alpha martensite and epsilon martensite, Equation 1: C/12+Ti/48+Nb/93+V/51+Mo/96?0.015.
    Type: Grant
    Filed: October 24, 2017
    Date of Patent: September 27, 2022
    Assignee: POSCO
    Inventors: Joo-Hyun Ryu, Kyoo-Young Lee, Sea-Woong Lee, Won-Hwi Lee
  • Publication number: 20220298596
    Abstract: Provided is a steel sheet which is suitably used for an automobile structural member, etc., and more specifically, to: a steel sheet having excellent uniform elongation and strain hardening rate, while having high strength; and a method for producing same.
    Type: Application
    Filed: June 17, 2020
    Publication date: September 22, 2022
    Inventors: Yeon-Sang AHN, Joo-Hyun RYU, Kang-Hyun CHOI
  • Patent number: 11299793
    Abstract: Provided is a steel sheet having excellent resistance to liquid metal embrittlement cracks and a method for manufacturing the same. The steel sheet includes, by weight %, 0.04% to 0.35% of C, 0.99% or less of Al+Si, 3.5% to 10% of Mn, 0.05% or less of P (excluding 0%), 0.02% or less of S (excluding 0%), and 0.02% or less of N (excluding 0%) with a remainder of Fe and other inevitable impurities, wherein the steel sheet comprises a microstructure comprising at least 10% of residual austenite, at least 60% of annealed martensite and 20% or less of alpha martensite and epsilon martensite, by volume fraction, and an average thickness of a Mn-depleted layer is at least 0.5 ?m from a product surface.
    Type: Grant
    Filed: June 22, 2018
    Date of Patent: April 12, 2022
    Assignee: POSCO
    Inventors: Sea-Woong Lee, Kyoo-Young Lee, Joo-Hyun Ryu, Ki-Cheol Kang
  • Patent number: 11203795
    Abstract: Provided is an ultra-high strength steel plate for automobiles and, more specifically, to an ultra-high strength steel plate having high formability and hole expandability, and a method for manufacturing the ultra-high strength steel plate. The ultra-high strength steel plate includes: by wt %, carbon (C): 0.04% to 0.17%, silicon (Si): 2% or less, manganese (Mn): 4% to 10%, phosphorous (P): 0.05% or less (excluding 0%), sulfur (S): 0.02% or less (excluding 0%), aluminum (Al): 0.5% or less (excluding 0%), nitrogen (N): 0.02% or less (excluding 0%), and a balance of iron (Fe) and inevitable impurities. Carbon (C) and manganese (Mn) satisfy Formula C+(Mn/25)?0.46. The ultra high strength steel plate has a microstructure comprising retained austenite in a volume fraction of 20% or greater and annealed martensite in a volume fraction of 50% or greater.
    Type: Grant
    Filed: October 5, 2016
    Date of Patent: December 21, 2021
    Assignee: POSCO
    Inventors: Kyoo-Young Lee, Joo-Hyun Ryu, Sea-Woong Lee, Won-Hwi Lee, Byun-Mok Hwang
  • Patent number: 11186892
    Abstract: Provided is a hot rolled steel sheet having excellent strength and elongation. The hot rolled steel sheet contains, by wt %: carbon (C): 0.05% or more and less than 0.4%, manganese (Mn): 10% to 15%, aluminum (Al): 2% or less, silicon (Si): 0.1 to 2%, molybdenum (Mo): 0.5% or less (excluding 0), vanadium (V): 0.5% or less (excluding 0), phosphorus (P): 0.01% or less, sulfur (S): 0.01% or less, and a remainder of iron (Fe) and inevitable impurities. The hot rolled steel sheet has a microstructure of the hot rolled steel sheet containing, by area %, tempered martensite: 50% to 70%, secondary martensite: 20% or less (excluding 0), epsilon martensite: 2% or less (excluding 0), and retained austenite: 8% to 30%. The hot rolled steel sheet has a tensile strength of at least 1500 MPa, a yield strength of at least 900 MPa and elongation of at least 20%.
    Type: Grant
    Filed: April 12, 2018
    Date of Patent: November 30, 2021
    Assignees: POSCO, POSTECH ACADEMY-INDUSTRY FOUNDATION
    Inventors: Sung-Hak Lee, Kyoo-young Lee, Joo-Hyun Ryu, Sea-Woong Lee, Seok-Su Sohn, Hyung-Soo Lee, Min-Chul Jo
  • Publication number: 20210317554
    Abstract: An ultra high strength and high ductility steel sheet having an excellent yield ratio contains, in weight %, 0.1-0.3% of carbon (C), 2% or less of silicon (Si), 6-10% of manganese (Mn), 0.05% or less of phosphorus (P), 0.02% or less of sulfur (S), 0.02% or less of nitrogen (N), 0.5% or less (excluding 0%) of aluminum (Al), and the balance Fe and inevitable impurities, and further contains at least one selected from the group consisting of 0.1% or less of titanium (Ti), 0.1% or less of niobium (Nb), 0.2% or less of vanadium (V), and 0.5% or less of molybdenum (Mo), wherein the ultrahigh-strength and high-ductility steel sheet comprises 20 area % or more of residual austenite as a microstructure, the average aspect ratio of the residual austenite being 2.0 or higher.
    Type: Application
    Filed: September 3, 2019
    Publication date: October 14, 2021
    Inventors: Joo-Hyun RYU, Kyoo-Young LEE, Sea-Woong LEE
  • Publication number: 20210180150
    Abstract: The present invention relates to an automotive steel sheet and, more specifically, provides: an ultrahigh-strength and high-ductility steel sheet ensuring ultrahigh strength and high ductility and, simultaneously, having excellent cold formability due to a high yield strength ratio, and improved collision characteristics.
    Type: Application
    Filed: September 17, 2018
    Publication date: June 17, 2021
    Inventors: Joo-Hyun Ryu, Kyoo-Young Lee, Sea-Woong Lee
  • Patent number: 10941467
    Abstract: Provided is a cold-rolled steel sheet, a galvanized steel sheet and a galvannealed steel sheet, comprising, by wt %, 0.06-0.15% of C, 1.2% or less (excluding 0%) of Si, 1.7-2.7% of Mn, 0.15% or less (excluding 0%) of Mo, 1.0% or less (excluding 0%) of Cr, 0.1% or less (excluding 0%) of P, 0.01% or less (excluding 0%) of S, 0.001-0.04% of Ti, 0.001-0.04% of Nb, 0.01% or less (excluding 0%) of N, 0.01% or less (excluding 0%) of B, and a remainder of Fe and unavoidable impurities, wherein the Si, C, Mn, Mo and Cr contents satisfy Relationship 1, and wherein a microstructure comprising, in area %, 10-70% of ferrite, 10-50% of the sum of bainite and retained austenite, and a remainder of fresh martensite, wherein a ratio (Mb/Mt) is 60% or more, and methods of manufacturing these steel sheets. ([Si]+[C]×3)/([Mn]+[Mo]+[Cr])?0.18.
    Type: Grant
    Filed: July 24, 2019
    Date of Patent: March 9, 2021
    Assignee: POSCO
    Inventors: Chang Hyo Seo, Yeon Sang Ahn, Joo Hyun Ryu, Kyoo Young Lee, Won Pyo Hong