STEEL MATERIAL SUITABLE FOR USE IN SOUR ENVIRONMENT

Title:

STEEL MATERIAL SUITABLE FOR USE IN SOUR ENVIRONMENT

Document Type and Number:

WIPO Patent Application WO/2019/167945

Kind Code:

A1

Abstract:

The present invention provides a steel pipe having a yield strength of 655-1172 MPa (95-155 ksi grade) and superior SSC resistance. The steel pipe according to the present disclosure has a chemical composition containing, in mass%, 0.10-0.60% of C, 0.05-1.00% of Si, 0.05-1.00% of Mn, 0.025% or less of P, 0.0100% or less of S, 0.005-0.100% of Al, 0.20-1.50% of Cr, 0.25-1.50% of Mo, 0.01-0.60% of V, 0.002-0.050% of Ti, 0.0001-0.0050% of B, 0.0020-0.0100% of N, and 0.0100% or less of O, the balance being Fe and impurities. The dislocation density ρ is 3.5 × 1015 m-2 or less. In fine deposits, the proportion of the number of deposits having a Mo content ratio of 50% or less is 15% or more. The yield strength is 655-1172 MPa.

Inventors:

YOSHIDA SHINJI (JP)
ARAI YUJI (JP)

Application Number:

PCT/JP2019/007319

Publication Date:

September 06, 2019

Filing Date:

February 26, 2019

Export Citation:

Click for automatic bibliography generation Help

Assignee:

NIPPON STEEL CORP (JP)

International Classes:

C22C38/00; C22C38/54; C21D6/00; C21D8/10; C21D9/08

Domestic Patent References:

WO2010150915A1	2010-12-29
WO2016013205A1	2016-01-28
WO2016059763A1	2016-04-21
WO2018074109A1	2018-04-26
WO2010150915A1	2010-12-29

Foreign References:

JP2015038247A	2015-02-26
JP2017166060A	2017-09-21
CN103695786A	2014-04-02
JP2000256783A	2000-09-19
JP2000297344A	2000-10-24
JP2005350754A	2005-12-22
JP2012026030A	2012-02-09

Other References: