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US 2022/0064767 A1Published application
Cryogenic pressure vessels formed from low-carbon, high-strength 9% nickel steels
AssigneeArcelorMittal
InventorsGeorge Jay FRALEY, Frederick FLETCHER
Life of this patent
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Abstract
A cryogenic pressure vessel of formed of an ASTM A553 Type 1 cryogenic steel alloy including in wt. %: C: 0.01-0.04; 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 steel alloy may have an ultimate tensile strength of at least 900 MPa, a total elongation of at least 20%; a microstructure including between 5 and 20 area % reverted austenite and the remainder 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.
Claims20
1-19. (canceled)
20:
- 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.
26 more elements
21:
- The cryogenic pressure vessel as recited in claim 20 wherein the alloy comprises C between 0.04-0.06 wt. %.
22:
- The cryogenic pressure vessel as recited in claim 21 wherein the alloy comprises Mn between 0.5-0.7 wt. %.
23:
- The cryogenic pressure vessel as recited in claim 22 wherein the alloy comprises Si between 0.2-0.4 wt. %
24:
- The cryogenic pressure vessel as recited in claim 23 wherein the alloy comprises Ni between 7.5-9.5 wt. %
25:
- The cryogenic pressure vessel as recited in claim 24 wherein the alloy comprises Cr between 0.25-0.5 wt. %
26:
- The cryogenic pressure vessel as recited in claim 25 wherein the alloy comprises Mo between 0.5-0.7 wt. %
27:
- The cryogenic pressure vessel as recited in claim 26 wherein the alloy comprises P:
- up to 0.006 wt. %;
- S:
- up to 0.002 wt. %;
- V:
- up to 0.1 wt. %;
- Nb:
- up to 0.05 wt. %;
- Al:
- up to 0.06 wt. %;
- and N:
- up to 0.008 wt. %.
9 more elements
28:
- The cryogenic pressure vessel as recited in claim 20 wherein the alloy has undergone a heat treatment comprising:
- austenitizing at a temperature of between 750-1000° C. for 10 minutes to 3 hours;
- quenching to room temperature;
- lamellarizing at a temperature of between 600-725° C. for 10 minutes to 3 hours;
- cooling to room temperature in air;
- tempering at a temperature of between 500-620° C. for 10 minutes to 3 hours;
- and
- cooling to room temperature in air.
5 more elements
29:
- The cryogenic pressure vessel as recited in claim 28 wherein the austenitizing is at a temperature of between 800-950° C. for 30 to 60 minutes;
- the lamellarizing is at a temperature of between 625 and 700° C. for 30 to 60 minutes;
- and the tempering is at a temperature of between 550 and 610° C. for 30 to 60 minutes.
30:
- The cryogenic pressure vessel as recited in claim 29 wherein said austenitizing is at a temperature of between 820-900° C. for 30 to 60 minutes;
- said lamellarizing is at a temperature of between 650 and 675° C. for 30 to 60 minutes;
- and said tempering is at a temperature of 575 and 600° C. for 30 to 60 minutes.
31:
- The cryogenic pressure vessel as recited in claim 20 wherein the alloy has a microstructure of between 8 and 15 area % reverted austenite and the remainder tempered martensite.
32:
- The cryogenic pressure vessel as recited in claim 20 wherein the alloy has a microstructure of between 13 and 15 area % reverted austenite and the remainder tempered martensite.
33:
- The cryogenic pressure vessel as recited in claim 20 wherein the alloy has a lateral expansion of at least 1.0 mm at −196° C.
34:
- The cryogenic pressure vessel as recited in claim 33 wherein the alloy has a lateral expansion of at least 1.5 mm at −196° C.
35:
- The cryogenic pressure vessel as recited in claim 34 wherein the alloy has a lateral expansion of at least 2.0 mm at −196° C.
36:
- The cryogenic pressure vessel as recited in claim 20 wherein the alloy has a transverse Charpy impact energy of at least 50 J at −196° C.
37:
- The cryogenic pressure vessel as recited in claim 36 wherein the alloy has a transverse Charpy impact energy of at least 100 J at −196° C.
38:
- The cryogenic pressure vessel as recited in claim 37 wherein the alloy has a transverse Charpy impact energy of at least 150 J at −196° C.