US 11,807,910 B2
Austenitic alloy pipe and method for producing same
Masaki Ueyama, Tokyo (JP); Yusaku Tomio, Tokyo (JP); and Yuhei Suzuki, Tokyo (JP)
Assigned to Nippon Steel Corporation, Tokyo (JP)
Appl. No. 16/617,765
Filed by Nippon Steel Corporation, Tokyo (JP)
PCT Filed Jun. 8, 2018, PCT No. PCT/JP2018/022122
§ 371(c)(1), (2) Date Nov. 27, 2019,
PCT Pub. No. WO2018/225869, PCT Pub. Date Dec. 13, 2018.
Claims priority of application No. 2017-114286 (JP), filed on Jun. 9, 2017.
Prior Publication US 2021/0292864 A1, Sep. 23, 2021
Int. Cl. C21D 9/08 (2006.01); C21D 6/00 (2006.01); C21D 8/10 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01)
CPC C21D 9/08 (2013.01) [C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 8/105 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01); C21D 2211/001 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An austenitic alloy pipe, having a chemical composition consisting of, in mass %:
C: 0.004 to 0.030%,
Si: 1.00% or less,
Mn: 0.30 to 2.00%,
P: 0.030% or less,
S: 0.0020% or less,
Al: 0.001 to 0.100%,
Cu: 0.50 to 1.50%,
Ni: 25.00 to 55.00%,
Cr: 20.00 to 30.00%,
Mo: 2.00 to 10.00%,
N: 0.005 to 0.100%,
W: 0 to 0.30%,
Nb: 0 to 0.050%,
Ca: 0 to 0.0100%,
Mg: 0 to 0.0100%, and
Nd: 0 to 0.050%,
with the balance being Fe and impurities, wherein
a grain size number of austenite crystal grain is 2.0 to 4.8 and a mixed grain ratio is not more than 5%, wherein
when a yield strength obtained by a compression test is defined as a compressive YS (MPa) and a yield strength obtained by a tensile test as a tensile YS (MPa), the tensile YS is not less than 758 MPa and the compressive YS/tensile YS is 0.85 to 1.10, and wherein
the austenitic alloy pipe has an outer diameter of not less than 170 mm.