Use of an aluminum alloy 4000 for the manufacture of cryogenic liquid storage tanks and its manufacturing process

Abstract

Use of a rolled product of aluminum alloy 4000 for the manufacture of cryogenic liquid storage tanks with a thickness of 0.8 mm to 12.5 mm, such that the composition of the rolled product comprises, in wt%: Si: 11.5–12.5; Fe: ≤ 0.6; Cu ≤ 1.0; Mn ≤ 0.3; Mg: 0.3–1.0; Ti 0–0.15; Sr 0.01–0.05; other elements and impurities ≤ 0.05 each, total ≤ 0.15, remainder aluminum; and such that the rolled product exhibits a yield strength in the transverse rolling direction Rp0.2(TL) of at least 280 MPa, and a Kapp(TL) value of at least 35 MPa√m. Abstract figure: none

Description

Title of the invention: Use of an aluminum alloy 4000 for the manufacture of cryogenic liquid storage tanks and its manufacturing process. Technical field

[0001] The invention relates to the use of an aluminium 4000 alloy comprising a Si content greater than 11.5% for the manufacture of cryogenic liquid storage tanks for civil aviation, as well as its method of manufacture. Previous art

[0002] Cryogenic liquid storage tanks consist of three basic elements:

[0003] An internal pressure vessel: The internal pressure vessel contains the cryogenic liquid and must be made of a material that can withstand extremely low temperatures without cracking or degrading. High-strength aluminum alloys are lightweight and resistant to these conditions, making them an ideal material for such vessels, particularly in weight-critical applications.

[0004] Insulation: The space between the inner and outer tanks contains up to several centimeters of insulating material maintained under vacuum. The vacuum and the insulating material of the cryogenic tanks help to reduce heat transfer and maintain the cryogenic liquids at extremely low temperatures.

[0005] An external tank: tanks used for the long-term storage of cryogenic liquids, for example in a commercial aircraft, are equipped with an external tank which is not generally exposed to cryogenic temperatures.

[0006] The present invention relates preferably to the internal pressure tank, but can also be applied to the external tank.

[0007] Cryogenic liquids are gases that liquefy at low temperatures. For example, hydrogen is liquid at -253°C.

[0008] The use of aluminium alloys for the manufacture of cryogenic liquid storage tanks is known in the space industry.

[0009] The AA2219 alloy was registered in the 1950s by the Aluminium Association and is widely used in space applications. It is distinguished by the addition of vanadium [0.05 - 0.15], titanium [0.02 - 0.10] and zirconium [0.10 - 0.25], elements which promote the formation of a small grain in fusion welds, which is beneficial with regard to the risk of hot cracking.

[0010] More recently, Al-Cu-Li alloys have been used for space applications. These alloys offer a 5% reduction in density compared to the AA2219 alloy and improved properties, allowing for structures with a mass reduction of 4% to 33%. Among the Al-Cu-Li alloys currently used for hydrogen storage tanks, the AA2195 alloy for the American space shuttle can be cited.

[0011] US5455003 discloses a process for the production of aluminium-copper alloys -lithium alloys exhibit improved strength and toughness at cryogenic temperatures. These enhanced cryogenic properties are achieved by controlling the alloy composition, as well as processing parameters such as the amount of work hardening and artificial aging. The ability to achieve strength and fracture toughness substantially equal to or greater at cryogenic temperatures than at ambient temperature allows the use of these alloys in cryogenic tanks for space launch vehicles and similar applications.

[0012] Al-Mg-Si alloys, of the 6XXX series, are also considered for the storage of liquid hydrogen. Oda et al. ("Loading frequency effect on fatigue crack growth rate in low-pressure hydrogen gas environment in the case of 6061-T6 aluminum alloy," A Hen / Transactions of the Japan Society of Mechanical Engineers, Part A, 2009, vol. 75, no. 760, pp. 1746-1753) disclose the advantages of using AA6061 alloy as a reservoir. The 6XXX alloys offer a low density (2.69 - 2.71) compared to AA2219 alloy or similar to that of AA2195 alloy, but with lower mechanical properties.

[0013] The 4XXX alloys have been considered for aerospace applications. WO 95 / 34691 relates to an aluminum alloy sheet intended for mechanical, aeronautical, or space construction, characterized by the following composition (% by weight): Si 6.5–11%, Mg 0.5–1.0%, Cu < 0.8%, Fe < 0.3%, Mn < 0.5%, and / or Cr < 0.5%, Sr 0.008–0.025%, Ti < 0.02%, total other elements < 0.2%, remainder aluminum. The sheets according to this patent application exhibit a high modulus of elasticity and a low density and can be used in particular for wing undersides and aircraft fuselage skinning, as well as for cryogenic rocket tanks.

[0014] Today, hydrogen is being considered for civil aviation applications. Hydrogen is presented as the most suitable "clean" fuel for the aviation of tomorrow. However, its storage in an aircraft appears to be an unresolved issue. It is likely that it will be necessary to completely redesign aircraft whose fuel is currently stored in the wings. Storing hydrogen in liquid form requires a temperature of -253°C. The European CRYOPLANE project (Report 24 / 09 / 2003 - contract no. G4RD-CT-2000-00192) proposes by example of using several cryogenic tanks arranged for example around the fuselage.

[0015] While synergies exist between spaceflight and civil aviation, there are also significant differences in terms of specifications. For space applications, tanks are non-reusable or reusable only a small number of times. For civil applications, density is a critical issue because fuel consumption is highly dependent on the weight of the structure. In commercial aviation, the focus is on improving hydrogen storage systems in terms of weight, cost, and safety. Safety requirements for civil aviation differ from those for space launch vehicles, as hydrogen storage tanks for commercial aircraft must withstand tens of thousands of takeoffs and landings and maintain hydrogen in a liquid state for much longer periods.

[0016] Cryogenic tanks for the storage of cryogenic liquids in civil aviation therefore require that the constituent material have good toughness, as well as sufficient strength, low density, low coefficient of thermal expansion, and high rigidity.

[0017] The present invention was developed to lighten cryogenic liquid storage tanks, particularly for storing liquid hydrogen, in civil aviation, by proposing a material with damage tolerance combined with sufficient mechanical strength, a low coefficient of thermal expansion, and a high modulus of elasticity. This solution ensures good functional performance while simultaneously offering optimized mass, operational endurance, and reduced dimensional changes during temperature cycling. Description of the invention

[0018] A first object of the invention is the use of a rolled product made of aluminum alloy 4000 for the manufacture of cryogenic liquid storage tanks having a thickness of 0.8 mm to 12.5 mm such that the composition of the rolled product comprises, in % by weight: Si 11.5 - 12.5, Fe < 0.6, Cu < 1.0, Mn < 0.3, Mg 0.3-1.0, Ti 0-0.15, Sr 0.01-0.05 other elements and impurities < 0.05 each, total <0.15, remainder aluminum and such that the rolled product exhibits a yield strength in the rolling transverse direction Rpo.2(TL) of at least 280 MPa, and a Kapp value (TL) of at least 35 MPa^m, where the yield strength is measured according to ASTM E8 and the Kapp value is measured according to ASTM E561-2022 with a CCT specimen of width W=406 mm and thickness B=3 mm.

[0019] Preferably, the Cu content is 0.10 to 0.50% by weight.

[0020] Preferably, the rolled product has a yield strength in the transverse direction rolling strength of 280 MPa to 320 MPa and a Kapp (TL) value of 35 to 50 MPa'Vm.

[0021] Preferably, the rolled product has a distributed elongation Ag % in the rolling cross direction according to ASTM E8 greater than 5.5%, preferably 6.5%.

[0022] Preferably, the rolled product in aluminum alloy 4000 is used for the manufacture of an aircraft hydrogen storage tank.

[0023] Another object of the invention relates to a method for manufacturing a rolled product made of aluminum alloy 4000 for the manufacture of cryogenic liquid storage tanks comprising the following steps: a) Casting of an aluminum alloy plate comprising, as a percentage by weight: Si 11.5 - 12.5 Fe < 0.6 Cu < 1.0 Mn < 0.3 Mg 0.3-1.0 Ti 0-0.15 Sr 0.01-0.05 other elements and impurities < 0.05 each, total < 0.15, remainder aluminum, b) Homogenization and / or reheating of the plate to a temperature between 400 and 560°C, c) Hot rolling of the homogenized and / or reheated plate, optionally followed by cold rolling to obtain a rolled product with a thickness of 0.8 to 12.5 mm, d) Dissolving the rolled product at a temperature between 520°C and 555°C, followed by cooling at a rate of at least 1°C / s within the temperature range of 450°C to 250°C, e) Tempering of the rolled product put into solution and quenched at a temperature of 160°C to 180°C for a period of 3 h to 24 h.

[0024] Preferably, the income generated in step e) comprises a sequence whose temperature, expressed in °C, is described by a time-dependent function TC(t). t such that the maximum temperature reached Tmax is between 160°C and 180°C and the duration of maintenance at a temperature between 160°C and 180°C is such that the equivalent duration calculated at a temperature of 175°C is between 3h and 8h, where is calculated according to the formula: #175°C _ . .136000 / 1 1— \ 1 leq - 8.314 fq^+273 175+273 / |

[0025] Preferably, the income comprises a single tier.

[0026] Another object of the invention relates to a method of manufacturing a reservoir cryogenic liquid storage, comprising successive steps, a first step of manufacturing a laminated product with a thickness of 0.8 to 12.5 mm according to the second object of the invention, and a second step of shaping said laminated product to form a side wall of the cryogenic liquid storage tank. Preferably, the shaping is done by rolling. Detailed description of the invention

[0027] The invention relates to the use of an aluminum 4000 alloy for the manufacture of cryogenic liquid storage tanks for civil aviation. In accordance with the guidelines of the Aluminum Association (Washington DC 2006, USA), aluminum alloys are designated using a four-digit numerical system. The first digit indicates the principal alloying element: for 4000 alloys, the "4" means that the principal element is silicon.

[0028] All aluminium alloys mentioned below are designated according to the rules and designations defined by The Aluminium Association in Registration Record Series which it publishes regularly, unless otherwise stated.

[0029] The metallurgical states referred to are designated according to the European standard EN-515 (1993) unless otherwise stated.

[0030] All alloy compositions are provided as % by weight (% by weight).

[0031] Unless otherwise specified, the static mechanical properties, in other words the tensile strength Rm, the tensile yield strength Rpo,2, and the elongation at break A%, are determined by a tensile test according to ASTM E8 (version 2024). For the intended use, the uniformly distributed elongation, denoted Ag% (uniform deformation in Anglo-Saxon terminology), is relevant as it reflects the formability of the rolled product. The sampling and direction of the test are defined by EN 485-1.

[0032] Young's modulus is measured according to ASTM 1876.

[0033] The values ​​of the stress intensity factor and the crack extension are effective values ​​as defined in ASTM E561-2022. The critical stress intensity factor Kc, in other words the intensity factor The stress intensity factor, which makes the crack unstable, is calculated from the R-curve. The stress intensity factor, KCo, is also calculated by assigning the initial crack length at the start of the monotonic load to the critical load. Both of these values ​​are calculated for a specimen of the required shape. Kapp represents the KCo factor corresponding to the specimen that was used to perform the R-curve test.

[0034] Unless otherwise stated, the definitions in standard EN 12258 apply.

[0035] Unexpectedly, the inventors found it interesting to use a Aluminum alloy laminate from the 4XXX series with a thickness of 0.8 mm to 12.5 mm for the manufacture of cryogenic liquid storage tanks for civil aviation, with the following composition by weight percentage: Si 11.5 - 12.5, Fe < 0.6, Cu < 1.0, Mn < 0.3, Mg 0.3-1.0, Ti 0-0.15, Sr 0.01-0.05 other elements and impurities < 0.05 each, total <0.15, remainder aluminum.

[0036] The rolled product has a yield strength in the TL direction Rp0.2 (TL) measured according to ASTM E8 of at least 280 MPa, and a Kapp (TL) value measured according to ASTM E561-2022 with a test specimen of width W=406 mm and thickness B = 3 mm of at least 35 MPa'Vm.

[0037] The silicon content is at least 11.5%, so that the density of the alloy is minimized. The density of the rolled product depends on the composition, particularly the Si and Mg content. Typically, the density of the rolled product is between 2.63 and 2.66. A Si content exceeding 12.5% ​​is detrimental to damage tolerance and formability properties.

[0038] The magnesium content is between 0.3 and 1.0% by weight. A content below 0.3% does not allow sufficient mechanical properties to be achieved. The magnesium content is preferably at most 0.8% by weight and preferably at most 0.7% by weight in order to improve formability while obtaining sufficient mechanical strength.

[0039] The copper content is less than 1.0%. Preferably, the copper content is between 0.10 and 0.50% by weight. The copper content is preferably at least 0.10%, preferably 0.20%, or even 0.30% in order to obtain high mechanical strength after tempering. The copper content is preferably at most 0.50% for corrosion resistance.

[0040] The manganese content is preferably at most 0.3% by weight. A manganese content exceeding 0.3% by weight can have a detrimental effect on formability. In one embodiment, it is advantageous for the manganese content to be less than 0.15% by weight, or even 0.10% by weight, or even 0.05% by weight.

[0041] The strontium content is between 0.01 and 0.05% by weight. Strontium allows control of the size of silicon-containing eutectic compounds during solidification and / or modification of their structure, which has a favorable effect on mechanical properties, particularly formability.

[0042] The titanium content is from 0 to 0.15% by weight. Advantageously, an amount of titanium of 0.01 to 0.15% by weight is added.

[0043] It is preferable to limit the content of unavoidable impurities in the alloy in order to achieve the most favorable damage tolerance properties. The iron content is a maximum of 0.6% by weight, preferably less than or equal to 0.5%, or even 0.3%. An iron content exceeding 0.6% by weight can have a detrimental effect on formability and toughness.

[0044] The other impurities have a content less than or equal to 0.05% by weight each and 0.15% by weight in total. The remainder is aluminum.

[0045] Such a 4XXX alloy has the advantage of having a lower density than the alloys traditionally used for cryogenic tanks such as alloy AA2219 or alloy AA2195. In addition to its lower density of 2.63 to 2.66, it has the advantage of a higher Young's modulus, which is beneficial for the rigidity of the structures and a lower coefficient of thermal expansion (also called Thermal expansion coefficient according to Anglo-Saxon terminology), which is beneficial for the compatibility of the structure in the case of temperature cycling, in particular between cryogenic temperature and ambient temperature.

[0046] Typical values ​​of density, Young's modulus and coefficient of expansion for the alloy according to the invention with conventional alloys are compared in Table 1 below.

[0047] [Tables 1] Reference Density Coefficient of thermal expansion (K1) Young's modulus (GPa) Alloy according to the invention 2.63 - 2.66 19 80 AA2219 T8 2.83 - 2.85 22 72 AA2195 T8 2.72 22.5 75 Example according to Sainfort et al. WO 95 / 34691 6.77 Si - 0.59 Mg - 0.24 Cu - 0.06 Fe -0.31 Mn - 0.016 Sr-0.01 Ti 2.68 21 74

[0048] The manufacturing process for the laminated product according to the invention preferably comprises the following successive steps.

[0049] First, the manufacture of a foundry plate whose composition in % by weight is: If 11.5 - 12.5 Fe < 0.6 Cu < 1.0 Mn < 0.3 Mg 0.3-1.0 Ti 0-0.15 Sr 0.01-0.05 other elements and impurities < 0.05 each, total < 0.15, remainder aluminum

[0050] Preferably this alloy contains aluminum alloy scraps or waste.

[0051] Aluminum alloy scrap or waste refers to products made of aluminum and / or aluminum alloys, resulting from the collection and / or recovery of metals produced at different stages of manufacture; called production scrap, or of products after use, called recovery scrap.

[0052] Among production scraps, we can mention foundry dross, drips, shredded scrap and turnings defined according to EN12258-3.

[0053] Among the recovered scrap, we can mention offcuts or waste from out-of-service vehicles.

[0054] Preferably, the 4XXX series alloy contains at least 50% by weight of aluminum alloy scrap or waste; more preferably at least 80% by weight.

[0055] Preferably, the 4XXX series alloy contains at least 50% by weight of recovered scrap, more preferably at least 80% by weight of recovered scrap.

[0056] Preferably the recovered scrap are scraps or waste from out-of-service vehicles, preferably at least 50%, more preferably at least 80%.

[0057] The chosen composition of the laminated product according to the invention is particularly interesting because end-of-life vehicles, for example, but not limited to, passenger cars or light vehicles, vans, and trucks, usually contain Many aluminum parts are found in end-of-life vehicles. Some of these end-of-life vehicles are defined by Directive 2000 / 53 / EC. These aluminum parts are very diverse. They can include components such as heat exchangers like air conditioning condensers and evaporators, engine cooling or cabin heating radiators, charge air coolers, oil coolers and heat exchangers, and fuel coolers. They can also include engine parts such as cylinder heads, cylinder blocks, or engine blocks. Other castings, for example, chassis components, are also included. These parts contain silicon-filled alloys.

[0058] The rolled product according to the invention can be used to create a recycling stream for end-of-life vehicles. The 4xxx alloy of the rolled product according to the invention preferably contains aluminum alloy scraps or waste, preferably scraps or waste from vehicles in use, preferably at least 50%, more preferably at least 80%.

[0059] Preferably, the casting of the foundry plate is carried out by vertical semi-continuous casting. Preferably, the foundry plate is then scalped to remove the cortical layer.

[0060] The foundry plate is then homogenized preferably at a temperature of 400 to 560 °C, preferably for at least 1 hour, preferably at a temperature of at least 480 °C for at least 3 hours.

[0061] The cast plate is then rolled to a thickness of 0.8 mm to 12.5 mm, preferably from 2 mm to 8 mm. It is first hot-rolled to a preferred thickness of 4 mm to 12.5 mm. In a preferred embodiment for achieving thinner plates, cold rolling may be carried out with a preferred reduction ratio of at least 50% to obtain a thickness of 0.8 mm to 5 mm; preferably, the final thickness after cold rolling is 0.8 mm to 4 mm. In one embodiment, the cold rolling is carried out in two stages separated by annealing to prevent the formation of edge cracks that could lead to breakage of the thin plate.

[0062] The rolled product is then dissolved in solution and quenched. Dissolution is carried out at a temperature of 520°C to 555°C, preferably at least 540°C, for at least 30 seconds, preferably at least 1 minute. Quenching takes place in air or water at a rate of at least 1°C / s, preferably 5°C / s, within the temperature range of 450°C to 250°C.

[0063] In one embodiment, the rolled product can be wound at a temperature of 50 to 100°C, preferably 60 to 80°C, then the coil cools naturally to ambient temperature, typically between 10°C and 35°C.

[0064] In a preferred embodiment, the rolled product undergoes a planing step after quenching.

[0065] The quenched rolled product, optionally planed and / or coiled, then undergoes tempering at a temperature of 160°C to 180°C for a period of 3 h to 24 h. The tempering conditions, temperature, and duration are chosen so as to obtain a yield strength in the TL direction, Rp0.2 (TL), measured according to ASTM E8, of at least 280 MPa, and a Kapp (TL) value of at least 35 MPa^m, measured according to ASTM E561-2022 with a specimen of width W=406 mm and thickness B = 3 mm.

[0066] A tempering temperature above 180°C does not allow obtaining sufficient formability, as well as the expected level of toughness of at least 35 MPa^m.

[0067] Preferably, the income comprises a sequence whose temperature, expressed in °C, is described by a function Tc(t) depending on the time t, such that the maximum temperature reached Tmax is between 160°C and 180°C and the duration of maintenance at a temperature between 160°C and 180°C is such that the equivalent time calculated at a temperature of 175°C is between 3 h and 8 h, where teq5" is calculated according to the formula: ,17yc_ 136000 / ___1__1\-| leq -}ai£Xp\ - §314 ~ 175+273 / |

[0068] Preferably, the hardened rolled product, optionally planed and / or coiled, undergoes a tempering process comprising a single step from 160°C to 180°C for a period of 3 h to 24 h.

[0069] After tempering, the rolled product has a yield strength in the TL direction, Rpo,2 (TL), measured according to ASTM E8 of at least 280 MPa, preferably from 280 MPa to 320 MPa.

[0070] After tempering, the rolled product has a Kapp value (TL) of at least 35 MPa'Vm, preferably between 35 and 50 MPa'Vm, measured according to ASTM E561-2022 with a test piece of width W=406 mm and a thickness B of 3 mm.

[0071] Preferably, the rolled product has a distributed elongation Ag% in the TL direction, measured according to ASTM E8, greater than 5.5%, preferably 6.5%, to facilitate forming. Preferably, the distributed elongation Ag% in the TL direction is less than or equal to 7.5% to maintain a Kapp (TL) value of 35 to 50 MPa'Vm.

[0072] After tempering, the rolled product is shaped for the manufacture of cryogenic liquid storage tanks. Cryogenic tanks are airtight, vacuum-insulated tanks that allow for the safe and efficient storage of cryogenic liquids, such as hydrogen. They are preferably cylindrical in shape.

[0073] The cryogenic liquid storage tank is generally made from rolled products that are shaped, preferably by rolling, to form the cylindrical shape that is assembled with domes. The shaping, preferably by rolling, makes it possible to obtain a cylindrical shape that constitutes the side walls of the tank. These walls can be welded together. An advantage of the alloy of the invention is that it can be welded by a fusion process such as TIG welding, which facilitates the industrialization of such manufacturing. Depending on the size of the tank, several rolled products can be used to create the cylindrical shape. The cylindrical shape is then assembled with the domes to obtain a hermetically sealed tank. The rolled product according to the invention can also be used to form the domes. The dome can be made in one piece by spinning (also called metal spin forming in Anglo-Saxon terminology).It can also be made up of several segments.

[0074] It is particularly advantageous to be able to shape the rolled product in the tempered state without needing to perform additional tempering after shaping. This allows for a simple and economical process. Example 1

[0075] Two plates with a thickness of 560 mm were cast. Their composition according to the invention is indicated in Table 2 below.

[0076] [Table 2] - Composition by weight % Compo Si Fe Cu Mn Mg Cr Ti Sr Density 1 12.0 0.2 0.2 0.17 0.6 0.02 <0.1 0.03 2.64 2 12.0 0.5 0.4 0.27 0.6 0.02 <0.1 0.03 2.64

[0077] The plates were heated to 500°C for over 4 hours, then hot-rolled to a thickness of 7.3 mm and subsequently cold-rolled to a thickness of 3 mm with an intermediate annealing. The resulting thin sheets were solution-treated at 540°C for a holding time of approximately 70 seconds, and then quenched. The sheets were then aged at room temperature for one month to achieve a T4 condition, and each underwent a single-step tempering as shown in Table 2.

[0078] The sheets were then characterized in tension according to the recommendations of ASTM E8 in the direction perpendicular to the rolling direction, denoted TL. The value of the apparent stress intensity factor at break Kapp, expressed in MPa'Vm, defined according to ASTM E561-2022, was measured in the TL direction on CCT specimens with a width of 406 mm and a thickness of 3 mm (see Table 3).

[0079] [Table 3] - Measured Mechanical Properties and Toughness. Ref Compo Income / 175° Module Rp0.2 Rm Ag % A% ^app Young's time (TL) (TL) (TL) (TL) (TL) (TL) (GPa) (MPa) (MPa) % % (MPa^m) IA 1 6h 175°C 6h 80 285 7.1 43 2A 2 6h 175°C 6h 80 307 6.8 39 2R 2 1h 205°C 9.9h 80 296 4.9 28 (*)

[0080] (*) Kapp value not measured but estimated based on static properties measured.

[0081] It is observed that the product tempered at a temperature above 200°C (2R) exhibits a distributed elongation Ag% of less than 5.5% and a lower estimated Kapp value. The inventors believe this is a disqualifying factor for achieving a Kapp toughness (TL) of at least 35 MPa'Vm.

Claims

Demands

1. Method of manufacturing a rolled product of aluminum alloy 4000 for the manufacture of cryogenic liquid storage tanks comprising the following steps: a) Casting an aluminum alloy plate comprising, by weight percentage: Si 11.5 - 12.5, Fe < 0.6, Cu < 1.0, Mn < 0.3, Mg 0.3 - 1.0, Ti 0-0.15, Sr 0.01 - 0.05, other elements and impurities < 0.05 each, total < 0.15, remainder aluminum; b) Homogenizing and / or heating the plate to a temperature of 400 to 560°C; c) Hot rolling the homogenized and / or heated plate, optionally followed by cold rolling to obtain a rolled product of thickness from 0.8 to 12.5 mm; d) Dissolving the product rolled at a temperature between 520°C and 555°C, followed by cooling at a rate of at least 1°C / s within the temperature range of 450°C to 250°C,e) Tempering of the rolled product, which has been put into solution and quenched at a temperature of 160°C to 180°C for a period of 3 to 24 hours.

2. Method of manufacturing a rolled product of aluminum alloy 4000 for the manufacture of cryogenic liquid storage tanks according to claim 1, wherein the tempering comprises a sequence whose temperature, expressed in °C, is described by a time-dependent function TC(t), such that the maximum temperature reached Tmax is from 160°C to 180°C and the holding time at a temperature from 160°C to 180°C is such that the equivalent time calculated at a temperature of 175°C is from 3h to 8h, where is calculated according to the formula: t175>C~ .1.36000 / _____I____ ____1___\ T . leq -jai.CXp\ - - 175+273 J |

3. Method of manufacturing a rolled product of aluminium alloy 4000 for the manufacture of cryogenic liquid storage tanks according to claim 2 wherein the tempering comprises a single bearing.

4. Method of manufacturing a cryogenic liquid storage tank, comprising as successive steps, a first step of manufacturing a laminated product of thickness from 0.8 mm to 12.5 mm obtained according to any one of claims 1 to 3, and a second step of shaping said laminated product to form a side wall of the cryogenic liquid storage tank.

5. Method of manufacturing a cryogenic liquid storage tank according to claim 4 wherein the second shaping step is done by rolling.