Granted Patent
Utility
US 6,379,821 · App. 09/822,233
Martensitic stainless steel welded pipe
Inventors:
Takahiro Kushida, Tomohiko Omura, Kunio Kondo, Kazuhiro Ogawa, Masahiko Hamada
Patented Case
View Patent ↗
Granted: Apr 30, 2002
Filed: Apr 2, 2001
Inventors
Takahiro Kushida
Tomohiko Omura
Kunio Kondo
Kazuhiro Ogawa
Masahiko Hamada
Assignee (at issue)
SUMITOMO METAL INDUSTRIES, LTD.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.