Patents by Inventor Osamu Umezawa

Osamu Umezawa 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).

  • Fine ferrite-based structure steel production method
    Patent number: 6572716
    Abstract: A fine ferrite-based steel is disclosed, wherein at least 60% of the ferrite grain boundary is a large angle grain boundary of at least 15°, and the mean ferrite grain size is not more than 2.5 &mgr;m. The fine ferrite-based steel of the invention has a high strength and a long fatigue life.
    Type: Grant
    Filed: September 21, 1998
    Date of Patent: June 3, 2003
    Assignee: National Research Institute for Metals
    Inventors: Tohru Hayashi, Shiro Torizuka, Kaneaki Tsuzaki, Kotobu Nagai, Osamu Umezawa
  • Production method of ultra fine grain steel
    Patent number: 6464807
    Abstract: A method of producing a ultra fine grain steel made of ferrite having a mean grain size of not larger that 3 &mgr;m as the base phase, after ingoting raw materials, by austenitizing the ingot by heating it to a temperature of at least an Ac 3 point, then, applying compression working of a reduction ratio of at least 50% at a temperature of from an Ae 3 point or lower to an Ar 3 point −150° C., or at a temperature of at least 550° C., and thereafter, cooling, wherein the strain rate as compression working is in the range of from 0.001 to 10/second.
    Type: Grant
    Filed: February 24, 2000
    Date of Patent: October 15, 2002
    Assignee: Japan as represented by Director General of National Research Institute for Metals
    Inventors: Shiro Torizuka, Osamu Umezawa, Kaneaki Tsuzaki, Kotobu Nagai
  • FINE FERRITE-BASED STRUCTURE STEEL AND PRODUCTION METHOD THEREOF
    Publication number: 20020014285
    Abstract: A fine ferrite-based steel is disclosed, wherein at least 60% of the ferrite grain boundary is a large angle grain boundary of at least 15°, and the mean ferrite grain size is not more than 2.5 &mgr;m. The fine ferrite-based steel of the invention has a high strength and a long fatigue life.
    Type: Application
    Filed: September 21, 1998
    Publication date: February 7, 2002
    Inventors: TOHRU HAYASHI, SHIRO TORIZUKA, KANEAKI TSUZAKI, KOTOBU NAGAI, OSAMU UMEZAWA
  • Ultra-fine grain steel and method for producing it
    Patent number: 6221178
    Abstract: The invention provides an ultra-fine grain steel comprising fine ferrite grains as oriented at random and surrounded by large angle grain boundaries. The steel comprises fine ferrite grains having a mean grain size of not larger and 3.0 &mgr;m and surrounded by large angle grain boundaries having an misorientation not smaller than 15°.
    Type: Grant
    Filed: September 21, 1998
    Date of Patent: April 24, 2001
    Assignee: National Research Institute for Metals
    Inventors: Shiro Torizuka, Kaneaki Tsuzaki, Kotobu Nagai, Osamu Umezawa