| CPC C22C 38/48 (2013.01) [C21D 1/185 (2013.01); C21D 6/004 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 9/46 (2013.01); C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C21D 2211/001 (2013.01); C21D 2211/004 (2013.01); C21D 2211/008 (2013.01)] | 22 Claims |

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1. A cryogenic pressure vessel formed from a cryogenic steel alloy, the alloy comprising in wt. %:
C: 0.01-0.06; Mn: up to 2.0; P: up to 0.02; S: up to 0.15; Si: up to 1.0; Ni: 7-11; Cr: up to 1.0; Mo: up to 0.75; V: up to 0.2; Nb: up to 0.1; Al: up to 0.1; and N: up to 0.01;
the alloy having an ultimate tensile strength of at least 900 MPa, a total elongation of at least 20%; a microstructure of between 5 and 20 area % reverted austenite and a remainder of tempered martensite; a transverse Charpy impact energy of at least 27 J at −196° C.; and a lateral expansion of at least 0.381 mm at −196° C.
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