Title:
DUPLEX STAINLESS SEAMLESS STEEL PIPE AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2020/110597
Kind Code:
A1
Abstract:
The present invention addresses the problem of providing: a duplex stainless seamless steel pipe which has excellent corrosion resistance, high tensile yield strength in the pipe axis direction, and a small difference between the tensile yield strength and the compressive yield strength both in the pipe axis direction; and a method for manufacturing the duplex stainless seamless steel pipe.
A duplex stainless seamless steel pipe having a component composition containing, in % by mass, 0.005 to 0.08% of C, 0.01 to 1.0% of Si, 0.01 to 10.0% of Mn, 20 to 35% of Cr, 1 to 15% of Ni, 0.5 to 6.0% of Mo, 0.150% or more and less than 0.400% of N, further containing at least one component selected from Ti in an amount of 0.0001 to 0.3%, Al in an amount of 0.0001 to 0.3%, V in an amount of 0.005 to 1.5% and Nb in an amount of 0.005% or more and less than 1.5%, with the remainder made up by Fe and unavoidable impurities, wherein N, Ti, Al, V and Nb are contained in such a manner that the requirement represented by formula (1) can be satisfied, the tensile yield strength in the pipe axis direction is 757 MPa or more, and the (compressive yield strength in the pipe axis direction)/(tensile yield strength in the pipe axis direction) ratio is 0.85 to 1.15.
0.150 > N-(1.58Ti+2.70Al+1.58V+1.44Nb) (1)
In the formula, "N", "Ti", "Al", "V" and "Nb" respectively represent the contents (% by mass) of these elements. (When each of the elements are not contained, the value is 0 (zero) %.)
Inventors:
SASAKI SHUNSUKE (JP)
KATSUMURA TATSURO (JP)
OTA HIROKI (JP)
FUJIMURA KAZUKI (JP)
YUGA MASAO (JP)
KATSUMURA TATSURO (JP)
OTA HIROKI (JP)
FUJIMURA KAZUKI (JP)
YUGA MASAO (JP)
Application Number:
PCT/JP2019/042969
Publication Date:
June 04, 2020
Filing Date:
November 01, 2019
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
C21D8/10; C21D9/08; C22C38/00; C22C38/58
Domestic Patent References:
| WO2017086169A1 | 2017-05-26 |
Foreign References:
| JP2009007638A | 2009-01-15 | |||
| JPS55324B1 | 1980-01-07 |
Other References:
"The Japan Institute of Metals and Materials Newsletter", TECHNICAL DATA, vol. 17, no. 8, 1978
See also references of EP 3854890A4
See also references of EP 3854890A4
Attorney, Agent or Firm:
KUMASAKA Akira et al. (JP)
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