Title:
MARTENSITIC STAINLESS-STEEL SEAMLESS PIPE FOR OIL WELL PIPE AND PROCESS FOR PRODUCING THE SAME
Document Type and Number:
WIPO Patent Application WO/2009/004741
Kind Code:
A1
Abstract:
A seamless steel pipe for oil well pipes which combines a high yield strength of
a 110-ksi class with excellent low-temperature toughness; and a process for
producing the seamless steel pipe. A stainless-steel seamless pipe having
a composition containing, in terms of mass%, less than 0.010% carbon, up to 1.0%
silicon, 0.1-2.0% manganese, up to 0.020% phosphorus, up to 0.010% sulfur, up
to 0.10% aluminum, 10-14% chromium, 0.1-4.0% nickel, and up to 0.05% nitrogen,
the remainder being iron and incidental impurities, is subjected to a quenching
treatment in which the pipe is heated to a hardening temperature not lower than
transformation point Ac3 and then cooled to a temperature of 100°C
of lower at a cooling rate higher than in air cooling. Subsequently to the quenching
treatment, the pipe is subjected to a tempering treatment in which it is heated
to a tempering temperature of 450-550°C, excluding 450°C, and then
cooled. Thus, a martensitic stainless-steel seamless pipe for oil well pipes
is obtained which combines a high yield strength of a 110-ksi class with excellent
low-temperature toughness, i.e., a vTrs of -60°C or lower. The composition
may further contain one or more members selected among copper, molybdenum, vanadium,
niobium, and titanium.
Inventors:
MIYATA, Yukio (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 1000011, JP)
宮田由紀夫 (〒11 東京都千代田区内幸町二丁目２番３号ＪＦＥスチール株式会社 知的財産部内 Tokyo, 1000011, JP)
KIMURA, Mitsuo (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 1000011, JP)
木村光男 (〒11 東京都千代田区内幸町二丁目２番３号ＪＦＥスチール株式会社 知的財産部内 Tokyo, 1000011, JP)
宮田由紀夫 (〒11 東京都千代田区内幸町二丁目２番３号ＪＦＥスチール株式会社 知的財産部内 Tokyo, 1000011, JP)
KIMURA, Mitsuo (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 1000011, JP)
木村光男 (〒11 東京都千代田区内幸町二丁目２番３号ＪＦＥスチール株式会社 知的財産部内 Tokyo, 1000011, JP)
Application Number:
JP2007/070209
Publication Date:
January 08, 2009
Filing Date:
October 10, 2007
Export Citation:
Assignee:
JFE STEEL CORPORATION (2-3 Uchisaiwai-cho 2-chome, Chiyoda-ku Tokyo, 11, 1000011, JP)
ＪＦＥスチール株式会社 (〒11 東京都千代田区内幸町二丁目２番３号 Tokyo, 1000011, JP)
MIYATA, Yukio (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 1000011, JP)
宮田由紀夫 (〒11 東京都千代田区内幸町二丁目２番３号ＪＦＥスチール株式会社 知的財産部内 Tokyo, 1000011, JP)
KIMURA, Mitsuo (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 1000011, JP)
ＪＦＥスチール株式会社 (〒11 東京都千代田区内幸町二丁目２番３号 Tokyo, 1000011, JP)
MIYATA, Yukio (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 1000011, JP)
宮田由紀夫 (〒11 東京都千代田区内幸町二丁目２番３号ＪＦＥスチール株式会社 知的財産部内 Tokyo, 1000011, JP)
KIMURA, Mitsuo (JFE STEEL CORPORATION 2-3, Uchisaiwai-cho 2-chome, Chiyoda-k, Tokyo 11, 1000011, JP)
International Classes:
C22C38/00; B21D3/00; C21D9/08; C22C38/58
Attorney, Agent or Firm:
OCHIAI, Kenichiro (JFE Techno-Research Corporation7th Floor, Yanagiya Building, 1-10,Nihonbashi 2-chome, Chuo-ku, Tokyo 27, 1030027, JP)