Patents by Inventor Bong-Year Ma

Bong-Year Ma 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).

  • Patent number: 8043446
    Abstract: A high manganese duplex stainless steel with excellent hot workability, comprising (in weight %): less than 0.1% of C; 0.05-2.2% of Si; 2.1-7.8% of Mn; 20-29% of Cr; 3.0-9.5% of Ni; 0.08-0.5% of N; less than 5.0% of Mo and 1.2-8% of W, alone or composite; the balance Fe and inevitable impurities; and a method for manufacturing the duplex stainless steel, comprising the steps of: solution heating the duplex stainless steel composition at a temperature of 1,050 to 1,250° C., hot working at a starting temperature of 1,130 to 1,280° C. and then ending at a temperature greater than 1,000° C., and then cooling within the temperature range from 1,000 to 700° C. at a cooling rate of more than 3° C./min. The duplex stainless steel exhibits a reduction in area of more than 50% at 1,050° C., and possesses a yield strength of more than 400 MPa, and a corrosion rate of less than 0.36 mm/year, after solution heating.
    Type: Grant
    Filed: April 26, 2002
    Date of Patent: October 25, 2011
    Assignee: Research Institute of Industrial Science and Technology
    Inventors: Jae-Young Jung, Bong-Year Ma
  • Publication number: 20040050463
    Abstract: A high manganese duplex stainless steel with excellent hot workability, comprising (in weight %): less than 0.1% of C; 0.05-2.2% of Si; 2.1-7.8% of Mn; 20-29% of Cr; 3.0-9.5% of Ni; 0.08-0.5% of N; less than 5.0% of Mo and 1.2-8% of W, alone or composite; the balance Fe and inevitable impurities; and a method for manufacturing the duplex stainless steel, comprising the steps of: solution heating the duplex stainless steel composition at a temperature of 1,050 to 1,250° C., hot working at a starting temperature of 1,130 to 1,280° C. and then ending at a temperature greater than 1,000° C., and then cooling within the temperature range from 1,000 to 700° C. at a cooling rate of more than 3° C./min. The duplex stainless steel exhibits a reduction in area of more than 50% at 1,050° C., and possesses a yield strength of more than 400 MPa, and a corrosion rate of less than 0.36 mm/year, after solution heating.
    Type: Application
    Filed: March 31, 2003
    Publication date: March 18, 2004
    Inventors: Jae-Young Jung, Bong-Year Ma