Austenitic stainless steel and method for producing austenitic stainless steel material
View Patent ↗Austenitic stainless steel having high temperature strength and excellent nitric acid corrosion resistance is provided. The austenitic stainless steel according to the present embodiment including, in mass percent, C: at most 0.050%, Si: 0.01 to 1.00%, Mn: 1.75 to 2.50%, P: at most 0.050%, S: at most 0.0100%, Ni: 20.00 to 24.00%, Cr: 23.00 to 27.00%, Mo: 1.80 to 3.20%, and N: 0.110 to 0.180%, the balance being Fe and impurities, a grain size number of crystal grains based on JIS G0551 (2005) is at least 6.0, and an area fraction of a σ phase is at most 0.1%.
1. Austenitic stainless steel comprising: in mass percent,
C: at most 0.050%;
Si: 0.01 to 1.00%;
Mn: 1.75 to 2.50%;
P: at most 0.050%;
S: at most 0.0100%;
Ni: 20.00 to 24.00%;
Cr: 23.00 to 27.00%;
Mo: 1.80 to 3.20%; and
N: 0.130 to 0.180%,
the balance being Fe and impurities,
wherein a grain size number of crystal grains based on JIS G0551 (2005) is at least 6.0, and
an area fraction of a σ phase is at most 0.1%, and
wherein yield strength at 230° C. is at least 220 MPa, and a corrosion rate in a 65% nitric acid corrosion test in conformity with JIS G0573 (1999) is at most 0.085 g/m 2 /h.
2. The austenitic stainless steel according to claim 1 , further comprising:
in place of some of the Fe,
at least one type selected from a group consisting of
Ca: at most 0.0100%;
Mg: at most 0.0100%; and
rare earth metal (REM): at most 0.200%.