ELECTRIC-RESISTANCE-WELDED STEEL PIPE FOR LINE PIPE

Title:

ELECTRIC-RESISTANCE-WELDED STEEL PIPE FOR LINE PIPE

Document Type and Number:

WIPO Patent Application WO/2020/170333

Kind Code:

A1

Abstract:

An electric-resistance-welded steel pipe for a line pipe, in which the chemical composition of a matrix part contains, in % by mass, 0.04 to 0.12% of C, 0.01 to 0.50% of Si, 0.5 to 2.0% of Mn, 0.005 to 0.030% of Ti, 0.005 to 0.050% of Nb, 0.001 to 0.008% of N and a remainder made up by Fe and unavoidable impurities and, when the thickness of the matrix part is defined as tB and the thickness of an electric-resistance-welded part is defined as tS, the value determined by subtracting a value of the hardness of a 1/2tB part in the matrix part from a value of the hardness of an outer surface layer part B that is located at a depth of 1 mm from the outer surface of the matrix part is 30 HV10 or less, the value determined by subtracting a value of the hardness of a 1/2tS part in the electric-resistance-welded part from a value of the hardness of an outer surface layer S that is located at a depth of 1 mm from the outer surface of the electric-resistance-welded part is 0 to 30 HV10 inclusive, and each of tB and tS is 15 mm or more.

Inventors:

HARA TAKUYA (JP)
SAKAMOTO SHINYA (JP)
IWAMOTO SHUJI (JP)
KOBAYASHI SHUNICHI (JP)
AMANO TOSHIHIKO (JP)
TASHIMA KENZO (JP)
NAGAI KENSUKE (JP)

Application Number:

PCT/JP2019/006104

Publication Date:

August 27, 2020

Filing Date:

February 19, 2019

Export Citation:

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Assignee:

NIPPON STEEL CORP (JP)

International Classes:

C22C38/00; C22C38/58; C21D9/08

Domestic Patent References:

WO2010087511A1	2010-08-05
WO2013145770A1	2013-10-03
WO2013145771A1	2013-10-03
WO2015079661A1	2015-06-04
WO2018186274A1	2018-10-11

Foreign References:

JP2001207220A	2001-07-31
JP2003293089A	2003-10-15
JP2007138289A	2007-06-07
US20070267110A1	2007-11-22
JP2007138290A	2007-06-07

Other References: