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 |
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.
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