AS-ROLLED TYPE K55 ELECTRIC-RESISTANCE-WELDED OIL WELL PIPE, AND HOT-ROLLED STEEL PLATE

Title:

AS-ROLLED TYPE K55 ELECTRIC-RESISTANCE-WELDED OIL WELL PIPE, AND HOT-ROLLED STEEL PLATE

Document Type and Number:

WIPO Patent Application WO/2017/110254

Kind Code:

A1

Abstract:

An As-rolled type K55 electric-resistance-welded oil well pipe which comprises, in terms of mass%, 0.30-0.50% C, 0.05-0.40% Si, 0.50-1.20% Mn, 0-0.030% P, 0-0.020% S, 0.002-0.080% Al, 0-0.0080% N, 0-0.30% Cu, 0-0.30% Ni, 0-0.30% Cr, 0-0.10% Mo, 0-0.10% V, 0-0.050% Nb, 0-0.030% Ti, 0-0.0100% Ca, and Fe and impurities as the remainder. In an L cross-section of the base material located at a position of 90º, the metallographic structure at a depth of 1/4 the wall thickness is a ferrite/pearlite structure including flattened prior γ grains, includes grain-boundary ferrite and intragranular ferrite, and has a total areal proportion of the grain-boundary ferrite and intragranular ferrite of 10-30%.

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Inventors:

ISHITSUKA TETSUO (JP)
TSUSUE TAKASHI (JP)
IWAMOTO SHUJI (JP)
KOBAYASHI SHUNICHI (JP)
OGATA TOSHIYUKI (JP)
YOSHIDA OSAMU (JP)
KAWANO HIDETO (JP)

Application Number:

PCT/JP2016/082340

Publication Date:

June 29, 2017

Filing Date:

October 31, 2016

Export Citation:

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Assignee:

NIPPON STEEL & SUMITOMO METAL CORP (JP)

International Classes:

C22C38/00; B21C37/08; C21D8/02; C21D8/10; C22C38/06; C22C38/50

Domestic Patent References:

WO2013153676A1

2013-10-17

Foreign References:

JPS6148518B2	1986-10-24
JPS61221331A	1986-10-01
JP2012132060A	2012-07-12
JPS63247311A	1988-10-14
JPS6289813A	1987-04-24
JPS57145928A	1982-09-09
JP2011089152A	2011-05-06

Other References: