Patents by Inventor Sea-Woong LEE

Sea-Woong LEE 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: 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: 20240401173
    Abstract: The present disclosure relates to a plated steel sheet for hot press forming, having excellent paint adhesion and corrosion resistance after hot press forming; a preparation method for the plated steel sheet; and a hot press formed member. The plated steel sheet according to an aspect of the present disclosure comprises a base steel sheet and a plating layer consisting of Al—Fe alloy formed on the base steel sheet, wherein the sum of contents of Al and Fe in the plating layer is 80% or more by weight, the average content of Fe in the plating layer is 20% or more by weight, and the product of Ra and RPC of the surface of the plating layer may be 60-150 ?m/cm. Here, Ra represents arithmetic mean roughness and the unit thereof is ?m, and RPc represents the number of peaks per unit length and the unit thereof is /cm.
    Type: Application
    Filed: December 20, 2022
    Publication date: December 5, 2024
    Applicant: POSCO CO., LTD
    Inventors: Jin-Keun Oh, Seong-Woo Kim, Sea-Woong Lee, Sang-Heon Kim, Jae-Seong Park, Ru-Ri Lee
  • 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: 20240309499
    Abstract: The present disclosure relates to: a plated steel sheet which is for hot forming, has excellent hydrogen embrittlement resistance, and includes an Al-based plating layer formed on the surface of a base steel sheet, wherein the average Ni content in the Al-based plating layer is 0.05 to 0.35 wt %; and a method for manufacturing same.
    Type: Application
    Filed: May 13, 2022
    Publication date: September 19, 2024
    Applicant: POSCO Co., Ltd
    Inventors: Sang-Heon Kim, Jin-Keun Oh, Seong-Woo Kim, Sea-Woong Lee, Hyo-Sik Chun, Seul-Gi So
  • Publication number: 20240182996
    Abstract: The present invention relates to: a steel material for hot forming, used for a vehicle and the like; a hot-formed member; and a method for manufacturing same. In the method, when the formed steel material is skin pass rolled, rolling pressure and roughness of skin pass rolling rolls are controlled so that bendability can be improved.
    Type: Application
    Filed: August 12, 2022
    Publication date: June 6, 2024
    Applicant: POSCO CO., LTD
    Inventors: Sea-Woong Lee, Jin-Keun Oh, Seong-Woo Kim, Sang-Heon Kim, Hyo-Sik Chun, Sang-Bin Han
  • 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
  • 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
  • Publication number: 20220056564
    Abstract: Provided is a zinc plated steel sheet having excellent spot weldability and a manufacturing method thereof. The zinc plated steel sheet includes a steel sheet and a zinc plated layer formed on the surface of the steel sheet, wherein the ratio (a/b) between a widthwise average value (a) of thickness of an internal oxidized layer and a widthwise standard deviation (b) of thickness of the internal oxidized layer in the steel sheet may be 1.5 or more.
    Type: Application
    Filed: December 18, 2019
    Publication date: February 24, 2022
    Inventors: Ki-Cheol KANG, Sea-Woong LEE, Kyoo-Young LEE, Jong-Ho KIM, Young-Roc IM
  • 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: 10907230
    Abstract: Provided is an ultrahigh-strength steel sheet for a vehicle and, more specifically, to an ultrahigh-strength and high-ductility steel sheet having excellent yield ratio and a manufacturing method therefor. Provided is an ultrahigh-strength and high-ductility steel sheet for cold press forming and a manufacturing method therefor, the steel sheet ensuring ultrahigh strength and high ductility since an alloy component of steel and manufacturing conditions are controlled and, simultaneously, having excellent impact characteristics due to a high yield strength ratio (yield ratio). Provided is the steel sheet capable of satisfying formability and impact stability, which are required for a vehicle steel sheet for cold forming, and replacing a conventional steel sheet for hot press forming, thereby reducing manufacturing costs.
    Type: Grant
    Filed: April 20, 2017
    Date of Patent: February 2, 2021
    Assignees: POSCO, POSTECH ACADEMY-INDUSTRY FOUNDATION
    Inventors: Joo-Hyun Ryu, Nack-Joon Kim, Sung-Hak Lee, Won-Hwi Lee, Kyoo-Young Lee, Sea-Woong Lee
  • Patent number: 10752968
    Abstract: Provided is an ultrahigh-strength high-ductility steel sheet having excellent yield strength, comprising, by wt %, 0.04-0.18% of C, 2% or less of Si, 4-10% of Mn, 0.05% or less of P (except 0%), 0.02% or less of S (except 0%), 0.5% or less of Al (except 0%), 0.02% or less of N (except 0%) and the balance of Fe and the other inevitable impurities, wherein Si+Mn satisfies 6-10% and the microstructure comprises, by volume fraction, 12% or more of retained austenite and 60% or more of annealed martensite.
    Type: Grant
    Filed: May 18, 2017
    Date of Patent: August 25, 2020
    Assignee: POSCO
    Inventors: Kyoo-Young Lee, Joo-Hyun Ryu, Sea-Woong Lee
  • Publication number: 20200248281
    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: Application
    Filed: October 5, 2016
    Publication date: August 6, 2020
    Inventors: Kyoo-Young LEE, Joo-Hyun RYU, Sea-Woong LEE, Won-Hwi LEE, Byun-Mok HWANG
  • Publication number: 20200157649
    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: Application
    Filed: April 12, 2018
    Publication date: May 21, 2020
    Inventors: Sung-Hak LEE, Kyoo-young LEE, Joo-Hyun RYU, Sea-Woong LEE, Seok-Su SOHN, Hyung-Soo LEE, Min-Chul JO
  • Publication number: 20200140971
    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: Application
    Filed: June 22, 2018
    Publication date: May 7, 2020
    Inventors: Sea-Woong LEE, Kyoo-Young LEE, Joo-Hyun RYU, Ki-Cheol KANG
  • Publication number: 20190292615
    Abstract: Provided is an ultrahigh-strength high-ductility steel sheet having excellent yield strength, comprising, by wt %, 0.04-0.18% of C, 2% or less of Si, 4-10% of Mn, 0.05% or less of P (except 0%), 0.02% or less of S (except 0%), 0.5% or less of Al (except 0%), 0.02% or less of N (except 0%) and the balance of Fe and the other inevitable impurities, wherein Si+Mn satisfies 6-10% and the microstructure comprises, by volume fraction, 12% or more of retained austenite and 60% or more of annealed martensite.
    Type: Application
    Filed: May 18, 2017
    Publication date: September 26, 2019
    Inventors: Kyoo-Young LEE, Joo-Hyun RYU, Sea-Woong LEE
  • Publication number: 20190256940
    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: November 7, 2017
    Publication date: August 22, 2019
    Inventors: Sea-Woong LEE, Bruno C. DE COOMAN, Kyoo-Young LEE, Eun-Jung SEO, Seon-Jong LEE, Joo-Hyun RYU, Won-Hwi LEE