LOW ALLOY STEEL FOR OIL WELL PIPE HAVING EXCELLENT SULFIDE STRESS CRACKING RESISTANCE

Title:

LOW ALLOY STEEL FOR OIL WELL PIPE HAVING EXCELLENT SULFIDE STRESS CRACKING RESISTANCE

Document Type and Number:

WIPO Patent Application WO/2006/003775

Kind Code:

A1

Abstract:

Disclosed is a low alloy steel for oil well pipes which has excellent sulfide stress cracking resistance and is suitable for casing and tubing for oil wells or gas wells. Specifically disclosed is a low alloy steel for oil well pipes containing, in mass%, 0.2-0.35% of C, 0.05-0.5% of Si, 0.05-1.0% of Mn, not more than 0.025% of P, not more than 0.01% of S, 0.005-0.10% of Al, 0.1-1.0% of Cr, 0.5-1.0% of Mo, 0.002-0.05% of Ti, 0.05-0.3% of V, 0.0001-0.005% of B, not more than 0.01% of N, not more than 0.01% of O (oxygen), 0-0.1% of Nb, 0-0.01% of Ca, 0-0.01% of Mg and 0-0.1% of Zr, and having a half-value breadth (H) and a hydrogen diffusion coefficient (D)(10^-6cm²/s) satisfying the following formula (1). 30H + D ≤ 19.5 (1)

Inventors:

OMURA TOMOHIKO (JP)
KOBAYASHI KENJI (JP)

Application Number:

PCT/JP2005/010225

Publication Date:

January 12, 2006

Filing Date:

June 03, 2005

Export Citation:

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Assignee:

SUMITOMO METAL IND (JP)
OMURA TOMOHIKO (JP)
KOBAYASHI KENJI (JP)

International Classes:

C22C38/32; C22C38/00; (IPC1-7): C22C38/00; C22C38/32

Foreign References:

JP2002060893A	2002-02-28
JP2004002978A	2004-01-08
JPH0959719A	1997-03-04
JPS62253720A	1987-11-05
JPS59232220A	1984-12-27
JPH06322478A	1994-11-22
JPH08311551A	1996-11-26
JPH11335731A	1999-12-07
JP2000178682A	2000-06-27
JP2000256783A	2000-09-19
JP2000297344A	2000-10-24
JP2001073086A	2001-03-21
JP2001271134A	2001-10-02
JPH11286720A	1999-10-19
EP0828007A1	1998-03-11
JP2000119798A	2000-04-25

Other References: