EP3094915A2

EP3094915A2 - Sealed and thermally insulating tank comprising metal strips

Info

Publication number: EP3094915A2
Application number: EP14831013.9A
Authority: EP
Inventors: Nicolas LAURAIN; Roland PANIER; Pierre-Louis Reydet
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2014-01-17
Filing date: 2014-12-23
Publication date: 2016-11-23
Anticipated expiration: 2034-12-23
Also published as: PH12016501401A1; MY179399A; ES2692284T3; FR3016619B1; RU2016128520A3; KR20160133423A; EP3094915B1; KR102259211B1; WO2015107280A3; CN106133429A; WO2015107280A2; RU2016128520A; SG11201605803YA; JP6576353B2; CN106133429B; PH12016501401B1; AU2014377926A1; RU2666382C2; AU2014377926B2; JP2017507085A

Abstract

A continuous metal strip with turned-up lateral edges suited to creating a sealed membrane is obtained from a blank which along its length has a first, reinforced, end zone (114) having a first thickness and a second, central, zone (113) having a second thickness smaller than the first thickness. The metal strip across its width has a flat central zone and two lateral edges (13) which are bent substantially at right angles to the flat central zone, the two lateral edges being of small width in comparison with the flat central zone. Application to the creation of a sealed and thermally insulated tank built into a bearing structure comprising a plurality of bearing walls.

Description

WATERPROOF TUB AND INSULATING THERAPY WITH METAL BANDS

The invention relates to the field of the manufacture of sealed and thermally insulating tanks and their constituent parts. In particular, the present invention relates to tanks for the storage or transport of cold or hot liquids, for example tanks for the storage and / or transport of liquefied gas by sea.

Waterproof and thermally insulating vessels can be used in different industries to store hot or cold products. For example, in the field of energy, liquefied natural gas (LNG) is a liquid that can be stored at atmospheric pressure at about -1 63 ° C in land-based storage tanks or in tanks embedded in floating structures .

It is known, for example from FR-A-2968284, a storage tank integrated into the hull of a ship, whose sealed barrier, including a primary sealed barrier in contact with the product contained in the tank, consists of metal strakes which are connected together, in a sealed manner, by raised edges defining deformable bellows on either side of a welding wing. These strakes are connected at their ends to a connecting ring through the furring sheets both welded to the connecting ring and strakes. According to one embodiment, the invention provides a sealed and thermally insulating tank integrated in a supporting structure, the supporting structure comprising a plurality of load-bearing walls, the vessel comprising a plurality of tank walls each fixed to a respective bearing wall. , a vessel wall comprising:

a thermal insulation barrier retained on the load-bearing wall, the thermal insulation barrier having a flat support surface parallel to the respective bearing wall,

a sealing barrier supported by the insulation barrier and having a repeating structure alternately having an elongated metal strake and an elongate weld wing bonded to and protruding from the support surface, the weld wing extending parallel to the metal strake over at least a portion of the length of the metal strake, the metal strake having in the width direction a flat central portion on the support surface and raised side edges with respect to the surface of support which are arranged against the adjacent welding wings and welded sealingly to the welding wings,

wherein the metal strake extends between two opposite edges of the vessel wall and has two end portions which are each sealingly joined to a respective stop structure at said opposite sides of the vessel wall,

characterized in that the metal strake consists of at least one continuous metal strip having a plurality of longitudinal portions having different thicknesses, the longitudinal portions having an intermediate portion and at least one end portion having a thickness greater than the thickness of the intermediate portion of the strip, the thicker end portion forming an assembly zone of the strip with the stop structure or with another continuous metal strip joined end to end with the first continuous metal strip to constitute the metal strake.

According to embodiments, such a tank may comprise one or more of the following characteristics.

According to one embodiment, the metal strake consists of a single metal strip extending in one piece between the two opposite edges of the tank wall, and in which the two end portions of the strip are more thick as the intermediate portion and are each assembled to the respective stop structure at opposite edges of the vessel wall. According to one embodiment, the metal strake comprises a second continuous metal strip joined end to end with the first continuous metal strip in the extension of the first continuous metal strip, in which each of the two continuous metal strips has, at the level of the zone assembly of the two metal strips, an end portion thicker than the intermediate portion of the strip.

According to one embodiment, at least one of the two continuous metal strips has, at the end opposite the assembly zone of the two metal strips, a second end portion that is thicker than the intermediate portion of the strip, the second end portion being joined to the stop structure at an edge of the vessel wall.

According to one embodiment, at least one of the two continuous metal strips has, at the end opposite the assembly zone of the two metal strips, a second end portion of the same thickness as the intermediate portion of the strip, the second end portion being joined to the stop structure at an edge of the vessel wall.

According to embodiments, each end portion of the strake is sealingly welded to the respective stop structure.

According to embodiments, the strake is welded to the stop structure by a CMT (Cold Metal Transfer) or TIG (Tungsten Inert Gas) process or by welding. Cold.

According to embodiments, the stop structure comprises a plate positioned above the insulation barrier and the end portion comprises a first segment resting on the plate of the stop structure and a second segment in pressing on the thermal insulation barrier, the first segment and the second segment being connected by a folded segment forming a recess in the direction of thickness of the metal strake. According to embodiments, the welding wings are interrupted before the end of the metal strake, the raised edges of two adjacent metal strips being welded to each other by an edge weld disposed on a portion of their length to the end of the metal strake.

According to embodiments, the edge edge welds are made using a cold metal or TIG with wire transfer method.

According to embodiments, the end portion has a thickness greater than or equal to 0.9 mm.

According to embodiments, the intermediate portion has a thickness of less than 0.9 mm and preferably a thickness of 0.7 mm.

According to embodiments, the stop structure is welded to a supporting wall.

According to embodiments, the metal strake and the stop structure are made of nickel alloy steel with a low coefficient of expansion, in particular known as Invar®.

According to one embodiment, the metal strake is made of iron-based alloy and comprises by weight:

34.5% <Ni <53.5%

0.1 5% <Mn <1.5%

0 <If <0.35%, preferably 0.1% <Si <0.35%

0 <C <0.07%

optionally:

0 <Co <20%

0 <Ti <0.5%

0.01% <Cr <0.5%

the rest being iron and impurities necessarily resulting from the elaboration.

According to embodiments, the vessel wall further comprises:

a secondary thermal insulation barrier similar to the primary insulation barrier,

a secondary sealing barrier supported by the secondary insulation barrier and carrying the primary insulation barrier,

The secondary sealing barrier being made similar to the primary sealing barrier.

According to embodiments, the thickness varies gradually over a distance of 500mm. According to embodiments, the end portion extends over 400mm. Such a tank can be part of a land storage facility, for example to store LNG or be installed in a floating structure, coastal or deep water, including a LNG tank, a floating storage and regasification unit (FSRU) , a floating production and remote storage unit (FPSO) and others.

According to one embodiment, a vessel for the transport of a cold liquid product comprises a double hull and a aforementioned tank disposed in the double hull.

According to one embodiment, the invention also provides a method of loading or unloading such a vessel, in which a cold liquid product is conveyed through isolated pipes from or to a floating or land storage facility to or from the vessel vessel.

According to one embodiment, the invention also provides a transfer system for a cold liquid product, the system comprising the abovementioned vessel, insulated pipes arranged to connect the vessel installed in the hull of the vessel to a floating storage facility. or terrestrial and a pump for driving a flow of cold liquid product through the insulated pipelines from or to the floating or land storage facility to or from the vessel vessel.

According to one embodiment, the invention also provides a continuous metal strip with raised side edges suitable for the production of a said tank, the metal strip being obtained from a blank having, along its length, a first reinforced end zone having a first thickness and a second central zone having a second thickness less than the first thickness and a third end zone having the first thickness or the second thickness, the metal band having, according to its width, a flat central zone and two lateral flanges folded substantially perpendicular to the flat central zone, the two lateral flanges having a small width relative to the flat central zone.

Preferably, the metal strip consists of an iron-based alloy and comprising by weight:

34.5% <Ni≤ 53.5%

0.15% <Mn <1.5%

0 <If <0.35%, preferably 0, 1% <Si <0.35%

0 <C <0.07%

optionally:

0 <Co <20%

0 <Ti <0.5%

0.01% <Cr <0.5%

the rest being iron and impurities necessarily resulting from the elaboration.

According to one embodiment, the first reinforced zone has a first average grain size and the second zone has a second average grain size, the difference in absolute value between the first grain size and the second grain size being less than or equal to at 0.5 index according to ASTM El 12-10.

According to one embodiment, the iron-based alloy comprises by weight:

34.5 <Ni <42.5%

0.1 5% <Mn <0.5%

0.1% <If <0.35%

0.010% <C <0.050%

optionally: 0 <Co <20%

0 <Τί <0.5%

0.01% ≤Cr <0.5%

the rest being iron and impurities necessarily resulting from the elaboration.

The invention starts from the observation that the quantity of material necessary for the manufacture of a bearing structure comprising a sealed and thermally insulated tank depends on the fatigue resistance of the tank. In particular, the fatigue resistance of the tank depends on the fatigue resistance of the welds present on the impervious barriers forming the tank.

Thus, an idea underlying the invention is to provide a sealed and thermally insulated tank which comprises a sealed barrier having good fatigue resistance while limiting the amount of material necessary for producing such a sealed barrier. According to one aspect of the invention, the impervious barrier is made using strakes extending in one piece between two stop structures, and the strakes have a variable thickness so as to be directly connected to the structures. stop at their ends while having a smaller thickness between these ends. According to another aspect of the invention, the waterproof barrier is made using strakes composed of several bands welded end to end to each other at the reinforced portions of these strips, so that the resistance of this welded assembly is high.

Certain aspects of the invention start from the idea of connecting the strakes to the stop structures with the aid of a weld having good resistance to fatigue.

The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent in the following description of several particular embodiments. of the invention, given solely for illustrative and non-limiting purposes, with reference to the accompanying drawings.

On these drawings:

FIG. 1 is a fragmentary cutaway perspective view of a sealed and thermally insulating vessel wall in which embodiments of the invention may be employed.

• Figure 2 is a partial perspective view of the zone II of Figure 1 showing the primary waterproof membrane.

• Figure 3 is a sectional view of a detail of a sealed membrane of the vessel wall of Figure 1 along the line III-III.

• Figure 4 is a schematic cutaway representation of a tank of LNG tanker and a loading / unloading terminal of the tank.

• Figure 5 is a schematic longitudinal sectional view of an initial strip.

• Figure 6 is a schematic longitudinal sectional view of an intermediate band.

FIG. 7 is a schematic view in longitudinal section of a band of variable thickness.

• Figure 8 is a schematic representation of a blank obtained from the band of varying thickness.

• Figure 9 is a schematic representation in longitudinal section of a first assembly of a blank with a second part.

• Figure 10 is a schematic representation in longitudinal section of two sides assembled end to end.

• Figure 1 1 is a schematic top view showing several embodiments of a strake with side edges raised suitable for producing a waterproof membrane. Figure 1 shows sealed and insulating walls of a vessel integrated in a carrying structure of a ship.

The bearing structure of the tank is here constituted by the inner hull of a double-hulled vessel, the bottom wall of which has been represented by the number 1, and by transverse partitions 2, which define compartments in the inner hull of the ship. The walls of the supporting structure are adjacent two by two at edges.

On each wall of the supporting structure, a corresponding wall of the tank is made by superposing, successively, a secondary insulation layer 3, a secondary sealed barrier 4, a primary insulation layer 5 and a primary sealed barrier 6. At the angle between the two walls 1 and 2, the secondary watertight barriers 4 of the two walls 1 and 2 and the primary watertight barriers 6 of the two walls are connected by a connecting ring 10 in the form of a square tube. . The connecting ring 10 forms a structure which makes it possible to take up the tension forces resulting from the thermal contraction, in particular the metallic elements forming the impermeable barriers, the deformation of the hull at sea and the movements of the cargo. A possible structure of the connecting ring 10 is described in more detail in FR-A-2549575.

The primary insulating layer and the secondary insulating layer consist of heat-insulating element and more particularly parallelepiped heat insulating boxes 20 and 21 juxtaposed in a regular pattern. Each insulating casing 20 and 21 has a bottom panel and a cover panel 23. Side panels 24 and internal webs 25 extend between the bottom panel and the cover panel 23. The panels delimit a space in which is setting up a heat insulating lining which may for example consist of expanded perlite. Each box 20 and 21 is held on the supporting structure by means of anchoring members 26. The boxes 20 and 21 of the primary insulating layer 5 and the secondary insulating layer 3 bear respectively the primary watertight barrier 6 and the secondary watertight barrier 4.

The secondary 4 and primary 6 watertight barriers each consist of a series of parallel Invar® 8 strakes with raised edges, which are alternately arranged with elongate welding supports 9, also in Invar®. The strakes 8 extend from a first square tube at a first transverse partition 2 to a second square tube of a second not shown transverse partition located at an opposite side of the vessel. The raised edges 13 of the strakes are welded to the welding supports 9 in a sealed manner. The soldering supports 9 are retained each time at the underlying insulating layer 3 or 5, for example by being housed in the inverted T-shaped grooves 7 formed in the cover panels 23 of the boxes 20 and 21.

This alternating structure is formed over the entire surface of the walls, which may involve very long lengths of strakes 8. On these long lengths, the sealed welds between the raised edges 13 of the strakes 8 and the welding supports 9 interposed between them can be made in the form of weld seams 1 7 rectilinear and parallel to the wall.

Strakes with raised edges 8 are connected directly to the connecting ring 10. For this purpose, the straightened edge strakes 8 have an end edge 1 1 continuously welded to the fins Invar® 27, 28 of the ring. connection 10 to take up the tension forces. The primary watertight barrier 5 and the secondary watertight barrier 3 are thus welded respectively to a primary fin 27 and a secondary fin 28. Primary heat insulating caissons 20 are positioned between the primary fin 27 and the secondary fin 28. The primary fin 27 is attached to the primary heat insulated casings 20 by screws 30. The secondary vane 28 is fixed in the same way on the secondary heat insulating elements.

The square tube is connected to the walls 1 and 2 by means of plates 31 which extend in the continuity of the sealed membranes 4 and 6 and fins 27, 28. These plates 31 are welded to flat welded perpendicularly to the walls 1 and 2 of the supporting structure. FIG. 2 shows in more detail the connection zone of two strakes 8 of the primary watertight barrier 6 on the welding fin 27. It should be noted that the zone for connecting the strakes 8 of the secondary watertight barrier 4 to the welding wing 28 is made in the same way.

The raised edges 13 of the raised edge strake 8 have a profile comprising an inclined portion 1 which rises progressively from the edge 1 1 in the direction of the strakes 8, then a horizontal portion 15. The strakes 8 are welded edges with continuously and sealed at their upper edge along a first portion 29 using a CMT automatic process.

The welding support 9 interposed between two strakes 8 ends slightly before the fin 27. Throughout the central portion of the tank wall, and to the vicinity of the end edge area 1 1, the connection between the raised edges 13 of the strakes 8 and the welding supports 9 is formed by the straight weld beads 17, which extend approximately halfway up the raised edges 13 on either side of the support 9 and parallel to the support surface. The weld beads 1 7 are made by a welding machine with wheels.

The rectilinear weld 1 7 extends to near the first portion 29, the weld bead then has an upward curvature to join the edge weld edge to edge on the first portion 29.

Figure 3 illustrates in more detail the arrangement of the vessel wall at the weld between the fin 27 of the connecting ring 10 and the raised edge strake 8 shown in Figure 2.

The fin 27 is fixed on the heat-insulating elements 20 by means of screws 30 passing through the fin 27 and screwed into the upper panels 23 of the heat-insulating elements 20. The fastening by means of a screw enables the fin 27 to be stabilized. The strake 8 extends in one piece between its two end edges January 1. Between these two end edges the strake 8 is, on a first part of its length, resting on the fins 27 and on a second part of its length, resting on the primary insulating layer 5.

The strake 8 has a folded segment 34, to ensure the support of the strake 8 on both the fin 27 and the primary insulating layer 5, for most of its lower surface. The folded section extends near the edge of the fin 27 parallel to the fin 27 and compensates for the thickness thereof.

The strake 8 further has a variable thickness along its length. Thus, the strake 8 has at its end edges 1 1 a thick portion 33 fixed to the fins 27. A thin portion 35 extends between the thick portions 33 and has a constant thickness. The thin portion 35 is connected to the thick portions 33 by transition portions 36 in which the thickness gradually decreases from each thick portion 33 to the thin portion 35.

More particularly, according to one embodiment, the thick portion 33 has a thickness of 0.9mm and extends over a length of 400mm and comprises the folded segment 34. The transition portion 36 then extends over a distance of 500mm and has a thickness decreasing from 0.9mm to 0.7mm. Thus, most of the tank wall is covered by the thin portion 35 of the strake 8 which has a thickness of 0.7mm.

The thick portion 33 is connected to the fin 27 by a weld bead 37 made between the edge 1 1 of the strake 8 and the upper surface of the fin 27, the fin 27 having a thickness of 1.5 mm. Thus, the weld bead making the junction between the strake 8 and the fin 27, namely the welding of a 0.9mm thick strip on a 1.5mm thick strip, has good fatigue resistance.

The use of such a strake 8 of variable thickness makes it possible to avoid or limit the use, in the length of the strake 8, of a set of metal sheets having different thicknesses, interconnected by weld seams that have insufficient fatigue strength. Indeed, a weld made between a sheet of 0.9mm and a sheet of 0.7mm has a lower fatigue resistance than a weld between a sheet of 0.9mm and a sheet of 1, 5mm. However, the lower the fatigue resistance of the sealed barrier, the more necessary hull criteria for the vessel in which the tank is integrated are binding, which requires stiffening of the hull important. This stiffening of the hull is reflected in particular by a large amount of steel necessary for the realization of the hull.

The use of a strake 8 whose thickness varies along its length allows for a waterproof membrane 6 having good fatigue resistance, while avoiding the use of thick strakes along their entire length.

Fatigue resistance being more important, the hull criteria are less restrictive and allow in particular a saving of steel for the realization of the hull. A tank as described above can be incorporated into a ship adapted to a dynamic hull criterion of 95 MPa and a static hull criterion of 145 MPa.

The use of a strake 8 made in one piece over the entire length of the wall also makes it possible to reduce the welding time required for the production of the primary watertight barrier 6 and to reduce the control times of the welds in tank.

The secondary watertight barrier 4 has a configuration similar to the configuration of the primary watertight barrier 6.

Strake 8 of variable thickness can be obtained by a method which will be described below. An example of a method of manufacturing a band of varying thickness according to its alloy length mainly based on iron and nickel will first be described.

In a first step of this process, an initial strip 101 obtained by hot rolling is provided.

The initial band 101 is a cryogenic Invar type alloy strip. This alloy comprises by weight: 34.5% <Ni <53.5%

0.15% <Mn <1.5%

0 <If <0.35%, preferably 0, 1% <Si <0.35%

0 <C <0.07%

opfionnellemenf:

0 <Co <20%

0 <Ti <0.5%

0.01% <Cr <0.5%

the rest being iron and impurities necessarily resulting from the elaboration.

The function of the silicon is notably to allow the deoxidation and to improve the corrosion resistance of the alloy.

A cryogenic Invar-type alloy is an alloy that has three main properties:

It is stable with respect to the martensitic transformation to below the TL temperature of liquefying a cryogenic fluid. This cryogenic fluid is for example butane, propane, methane, nitrogen or liquid oxygen. The contents of gammagene elements, nickel (Ni), manganese (Mn) and carbon (C), of the alloy are adjusted so that the start temperature of the martensitic transformation is strictly lower than the liquefaction temperature TL of the alloy. cryogenic fluid.

- It has a low coefficient of thermal expansion between the ambient temperature and the liquefaction temperature of the cryogenic fluid.

- It does not have a "ductile-fragile" resilience transition.

The alloy used preferably has:

an average coefficient of thermal expansion between 20 ° C. and 100 ° C. of less than or equal to 10.5 × 10 ⁶ Κ -1, in particular less than or equal to 2.5 × 10 ⁶ Κ -1;

- an average thermal expansion coefficient between -180 ° C and 0 ° C or less ^ΙΟ χ 10 ⁶ K ^"1, particularly less than or equal to ^{2x10" é} ^K-1; and a resilience greater than or equal to 100 joule / cm ² , in particular greater than or equal to 150 joule / cm ² , at a temperature greater than or equal to -196 ° C.

Preferably, the alloy used has the following composition, in% by weight:

34.5 <Ni <42.5%

0.15% <Mn <0.5%

0 <If <0.35%, preferably 0, 1% <Si <0.35%

0.010% <C <0.050%

optionally:

0 <Co <20%

0 <Ti <0.5%

0.01% <Cr <0.5%

the rest being iron and impurities necessarily resulting from the elaboration.

In this case, the alloy used preferably has:

an average coefficient of thermal expansion between 20 ° C. and 100 ° C. of less than or equal to 5.5 × 10 ^-6 K ^-1 ;

an average coefficient of thermal expansion between -180 ° C. and 0 ° C. of less than or equal to 5 × 10 ⁶ K ^-1 ;

a resilience greater than or equal to 100 joule / cm ² , in particular greater than or equal to 150 joule / cm ² , at a temperature greater than or equal to -196 ° C.

Even more particularly,

35% <Ni <36.5%

0.2% <Mn <0.4%

0.02 <C <0.04%

0.1 5 <If <0.25%

optionally

0 <Co <20%

0 <Ti <0.5%

0.01% <Cr <0.5% the rest being iron and impurities necessarily resulting from the elaboration.

In this case, the alloy preferably has:

an average coefficient of thermal expansion between 20 ° C. and 100 ° C. of less than or equal to 1.5 × 10 ^-6 K ¹ ;

an average coefficient of thermal expansion between -180 ° C. and 0 ° C. of less than or equal to 2 × 10 ^-6 K ^-1 ;

a resilience greater than or equal to 200 joule / cm ² at a temperature greater than or equal to -196 ° C.

Such an alloy is a cryogenic Invar® type alloy. The trade name of this alloy is lnvar®-M93.

Conventionally, the alloys used are produced in electric arc furnace or vacuum induction furnace.

After pocket refining operations to adjust residual alloying material contents, the alloys are cast into semi-finished products, which are heat-treated, in particular by hot rolling, to obtain strips.

These semi-products are for example ingots. Alternatively, it is slabs continuously cast by means of a continuous slab casting plant.

The strip thus obtained is etched and polished in a continuous process in order to limit its defects: calamine, oxidized penetration, straw and inhomogeneity in thickness in the direction of the length and the width of the strip.

The polishing is in particular carried out by means of grinding wheels or abrasive paper. A function of the polishing is to eliminate the residues of the stripping.

At the end of this polishing step, the initial band 1 provided in the first step of the process is obtained.

Optionally, before the homogeneous cold rolling step, the strip is subjected to a homogenization annealing of the microstructure. This homogenization annealing of the microstructure is particularly carried out at run in a heat treatment furnace, called a homogenization annealing furnace of the microstructure in the following description, with a residence time in the homogenization annealing furnace of the microstructure of between 2 minutes and 25 minutes and a temperature of the strip during homogenization annealing of the microstructure between 850 ° C and 1200 ° C.

The initial band 101 has a constant thickness Eo of between 1.9 mm and 18 mm (see FIG. 5).

The initial web 101 is then rolled during a homogeneous cold rolling step. The homogeneous rolling is carried out along the length of the initial band 101.

By homogeneous rolling is meant a rolling transforming a band of constant thickness into a thinner band of constant thickness.

More particularly, the homogeneous rolling step comprises one or more passes in a rolling mill where the band passes through a rolling gap delimited between working rolls. The thickness of this rolling slot remains constant during each pass of the homogeneous rolling step.

This homogeneous rolling step results in an intermediate strip 103 of constant thickness E _c in the rolling direction, that is to say along the length of the intermediate strip 103 (see FIG. 6).

Optionally, the homogeneous rolling step comprises at least one intermediate recrystallization annealing.

When present, the intermediate recrystallization annealing is carried out between two successive homogeneous rolling passes. Alternatively or optionally, it is performed before the flexible rolling step at the end of the homogeneous rolling step, ie after all the rolling passes made during the homogeneous rolling step.

For example, the intermediate recrystallization annealing is carried out by passing through an intermediate annealing furnace with a temperature of the strip during the intermediate annealing of between 850 ° C. and 1200 ° C. and residence time in the intermediate annealing furnace between 30 seconds and 5 minutes.

The intermediate recrystallization annealing, or if several of them are carried out, the last recrystallization intermediate annealing of the homogeneous rolling step, is carried out when the strip has a thickness comprise between the thickness Eo of the initial strip 101 and the thickness E _c of the intermediate band 103.

When the intermediate recrystallization annealing is carried out at the end of the homogeneous rolling step, the thickness E of the strip during the intermediate recrystallization annealing is equal to the thickness E _c of the intermediate strip 103 at the beginning of the flexible rolling step.

Advantageously, in the embodiment in which at least one intermediate recrystallization annealing is carried out, a single recrystallization intermediate annealing is carried out. In particular, this intermediate recrystallization annealing is carried out between two successive homogeneous rolling passes when the strip has a thickness h strictly greater than the thickness E _c of the intermediate strip 103.

Preferably, the homogeneous rolling step does not include intermediate annealing.

The intermediate strip 103 of thickness E _c obtained at the end of the homogeneous rolling step is then subjected to a cold flexible rolling step.

The flexible rolling is carried out in a rolling direction extending along the length of the intermediate strip 103.

Flexible rolling makes it possible to obtain a strip of variable thickness depending on its length.

For this purpose, the thickness of the rolling slot of the rolling mill used is continuously varied. This variation is a function of the desired thickness of the zone of the strip during rolling so as to obtain a strip of variable thickness along its length.

More particularly, and as illustrated in FIG. 7, a strip 104 of variable thickness is obtained at the end of the flexible rolling step. comprising first zones 107 having a first thickness e + s and second zones 1 10 having a second thickness e, smaller than the first thickness e + s. The first thickness e + s and the second thickness e each correspond to a given rolling slot thickness.

The first zones 107 and the second zones 110 each have a substantially constant thickness, respectively e + s and e.

They are interconnected by connecting zones 1 1 1 of non-constant thickness along the length of the band 1 04 of variable thickness. The thickness of the connection areas 1 1 1 varies between e and e + s. In one example, it varies linearly between e and e + s.

The homogeneous rolling step and the flexible rolling step generate in the first zones 107, that is to say in the thickest zones of the strip 104, a plastic strain rate τ ", after a possible annealing. intermediate recrystallization, greater than or equal to 30%, more particularly between 30% and 98%, more particularly between 30% and 80%. In the abovementioned ranges, the rate τ of plastic deformation is advantageously greater than or equal to 35%, more particularly greater than or equal to 40%, and even more particularly greater than or equal to 50%.

The rate r of plastic deformation generated in the first zones 107 is defined as follows:

If no intermediate recrystallization annealing is performed during the homogeneous rolling step, the plastic strain rate τ is the total reduction ratio generated in the first zones 107 of the strip 104 by the homogeneous rolling step. and the flexible rolling step, i.e. resulting from the thickness reduction from the initial thickness Eo to the thickness e + s.

In this case, the rate x _x of plastic deformation, in percentage,

β - ( _e + _s \

is given by the following formula: τ = - - χ ΙΟΟ (1). Thus, in the case where no intermediate recrystallization annealing is performed, the rate r, of plastic deformation is equal to the total reduction rate generated in the first zones 107 by the homogeneous rolling step and the flexible rolling step .

- If at least one intermediate recrystallization annealing is performed during homogeneous rolling step, the _{τ rate of plastic deformation is the rate of reduction caused in the first zone 1 07 of a result of the thickness reduction of the strip the thickness B that it exhibits during the last intermediate recrystallization annealing carried out during the homogeneous rolling step up to the thickness e + s.

In this case, the rate τ _ι of plastic deformation, in percentage,

E _ _e + _s

is given by the following formula: r, = - χ 100 (2).

^Ε ι

Thus, in the case where one or more intermediate annealings are carried out during the homogeneous rolling step, the rate r, of plastic deformation is strictly less than the total reduction rate generated in the first zones 107 by the homogeneous rolling step and the cold flexible rolling step.

The rate r ₂ of plastic deformation, after a possible intermediate recrystallization annealing, generated in the second zones 1 10, is strictly greater than the rate τ of plastic deformation in the first zones 107. It is calculated analogously, replacing e + s in formulas (1) and (2) above.

The difference Δτ of plastic strain rate between the second zones 1 10 and the first zones 107 is given by the relationship Δ Γ = r ₂ - Γ _] .

This difference Δτ is advantageously less than or equal to 13% if the thickness Eo is strictly greater than 2 mm. It is advantageously less than or equal to 10% if the thickness Eo is less than or equal to 2 mm. More particularly, the difference Δτ is less than or equal to 1 0% if Eo is strictly greater than 2mm, and the difference Δτ is less than or equal to 8% if Eo is less than or equal to 2mm.

Advantageously, the thickness E _c of the intermediate strip 1 03 before the flexible rolling step is in particular equal to the thickness e of the second zones 1 1 0 multiplied by a reduction coefficient k of between 1.05 and 1, 5. Advantageously, k is approximately equal to 1, 3.

Advantageously, the thicknesses e + s and e of the first and second zones 1 07, 1 1 0 respect the equation:

e + s = (n + \). e

where n is a constant coefficient between 0.05 and 0.5.

In other words, the first thickness e + s is equal to the second thickness e multiplied by a multiplication coefficient of between 1.05 and 1.5.

This equation is rewritten as follows: s = ne, that is to say that the excess thickness s of the first zones 1 07 with respect to the second zones 1 1 0 is equal to the coefficient n multiplied by the thickness e of the second zones 1 1 0.

The thickness e of the second zones 110 is between 0.05 mm and 10 mm, more particularly between 0.15 mm and 10 mm, more particularly between 0.25 mm and 8.5 mm. When making strips, the thickness e is less than or equal to 2 mm, advantageously between 0.25 mm and 2 mm. When making sheets, the thickness e is strictly greater than 2 mm, in particular between 2.1 mm and 1 mm, more particularly between 2.1 mm and 8.5 mm.

The band 104 of variable thickness resulting from the flexible rolling step is then subjected to a final recrystallization anneal.

The final recrystallization annealing is carried out in a final annealing furnace. The temperature of the final annealing furnace is constant during the final recrystallization annealing. The temperature of the web 104 during the final recrystallization anneal is between 850 ° C and 1200 ° C. The residence time in the final annealing furnace is between 20 seconds and 5 minutes, more particularly between 30 seconds and 3 minutes.

The running speed of the web 104 in the final annealing furnace is constant. It is for example between 2m / min and 20m / min for a final annealing furnace with a heating length equal to 10m.

Advantageously, the temperature of the band 104 during the final annealing is 1025 ° C. In this case, the residence time in the final annealing furnace is for example between 30 seconds and 60 seconds for a band 104 of variable thickness having second zones 1 10 of thickness e less than or equal to 2 mm. The residence time in the final annealing furnace is for example between 3 minutes and 5 minutes for a band 104 of variable thickness having second zones 1 10 of thickness e strictly greater than 2 mm.

The residence time in the final annealing furnace, as well as the final annealing temperature, are chosen so as to obtain, after the final recrystallization annealing, a strip 104 having mechanical properties and grain sizes that are almost homogeneous between the first zones 107 and the second zones 1 10. The remainder of the description specifies the meaning of "almost homogeneous".

Preferably, the final annealing is carried out under a reducing atmosphere, that is to say for example under pure hydrogen or under H2-N2 atmosphere. The frost temperature is preferably below -40 ° C. In the case of an H2-N2 atmosphere, the N2 content may be between 0% and 95%. The H2-N2 atmosphere comprises for example approximately 70% of H ₂ and 30% of N ₂ .

According to one embodiment, the band 104 of variable thickness passes continuously from the flexible rolling mill to the final annealing furnace, that is to say without intermediate winding of the variable thickness band 104.

Alternatively, at the end of the flexible rolling step, the variable-thickness strip 104 is rolled up for transport to the final annealing furnace, then rolled out and subjected to the final recrystallization anneal. According to this variant, the wound strip 104 has for example a length of between 100 m and 2500 m, especially if the thickness e of the second zones 1 10 of the strip 104 is approximately 0.7 mm.

At the end of the final recrystallization annealing, a strip 104 of variable thickness along its length having the following characteristics is obtained.

It comprises first zones 107 of thickness e + s and second zones of thickness e, possibly connected to each other by connecting zones 11 1 of thickness varying between e and e + s.

Preferably, the difference in absolute value between the average grain size of the first zones 107 and the average grain size of the second zones 1 10 is less than or equal to 0.5 index according to the ASTM El 12-10 standard. The average grain size in ASTM index is determined using the standard image comparison method described in ASTM El 12-10. According to this method, in order to determine the average grain size of a sample, an image of the screen grain structure obtained by means of an optical microscope at a given magnification of the sample having undergone a dye attack is compared ( Contrast etch in English) with typical images illustrating twinned grains of different sizes having undergone a coloring attack (corresponding to plate III of the standard). The average grain size index of the sample is determined as the index corresponding to the magnification used on the standard image most closely resembling the image seen on the microscope screen.

If the image seen on the screen of the microscope is intermediate between two successive standard images of grain sizes, the index of the average grain size of the image seen under the microscope is determined as being the arithmetic mean between the corresponding indices. magnification used worn on each of the two typical images.

More particularly, the GI ASTM index of the average grain size of the first zones 107 is at most 0.5 less than the G2ASTM index of the average grain size of the second zones 1 10. The band 104 of variable thickness may have almost homogeneous mechanical properties.

In particular :

the difference in absolute value between the elasticity limit at 0.2% of the first zones, denoted Rpl, and the 0.2% elasticity limit of the second zones denoted by Rp2, is less than or equal to 6 MPa, and

the difference in absolute value between the breaking load of the first zones 107 noted Rm l and the breaking load of the second zones 1 10 denoted Rm2 is less than or equal to 6 MPa.

By elastic limit at 0.2% is meant, in a conventional manner, the value of the stress at 0.2% of plastic deformation.

Conventionally, the load at break corresponds to the maximum stress before necking of the test sample.

In the example illustrated, the band 104 of variable thickness has a pattern repeated periodically over the entire length of the strip 104. This pattern comprises successively a half of the first zone 107 of length a connecting zone January 1 of length L3, a second area

1 10 of length L2, a connecting zone 1 1 1 of length L3 and a half of first zone 107 of length. Advantageously, the length L2 of the second zone 1 10 is very clearly greater than the length L1 of the first zone 107. By way of example, the length L2 is between 20 and 100 times the length L1.

Each sequence formed of a first zone 107 flanked by two bonding areas 11 January 1 forms a zone of extra thickness of the band 104 of variable thickness, that is to say a zone of thickness greater than e. Thus, the band 104 of variable thickness comprises second zones 1 10 of length L2 of thickness e, separated from each other by zones of extra thickness.

After the final recrystallization annealing, the strip 104 of variable thickness is cut in the zones of excess thickness, preferably in the middle of the zones of extra thickness. Thus blanks 1 12 illustrated in FIG. 8 are obtained, comprising a second zone of length L2 framed at each of its longitudinal ends by a connecting zone 11 of length L3 and by a first zone half 107 of length. At the end of the cutting step, the blanks 1 12 are planed according to a known planing method.

The blanks 1 12 are then wound in coils to the unit.

According to a variant of the manufacturing method described above, the strip of strip 104 of variable thickness is planed after the final recrystallization annealing and before the blanks 1 12 are cut.

According to this variant, the strip 104 of variable thickness planar is cut in the areas of extra thickness to form the blanks 1 12. Preferably, the strip 104 is cut in the middle of the thickening zones.

The cutting is for example carried out on the leveling machine used for the flattening of the strip 104. As a variant, the flat strip 104 is wound into a coil and then cut on a machine different from the planer.

The blanks 1 12 are then wound in coils to the unit.

By means of the manufacturing method described above, blanks 112 formed of a workpiece comprising a central zone 13 of thickness e framed by reinforced ends 14, ie of thickness greater than the thickness e, are obtained. of the central zone 1 13. The ends 1 14 correspond to zones of excess thickness of the band 104 of variable thickness and the central zone 1 13 corresponds to a second zone 1 10 of the band 104 of variable thickness from which the blank 1 12 has been cut.

These blanks January 12, which have a variable thickness along their length while being formed of a part, do not have the weaknesses of the welded joints of the state of the art. In addition, their reinforced ends 1 14 can be assembled by welding to other parts while minimizing the mechanical weaknesses due to this assembly by welding. According to variants, the blanks 1 12 may for example be obtained by cutting the strip 104 at other places than in two successive thickening zones. For example, they can be obtained by cutting alternately in a zone of extra thickness and in a second zone 1 10. In this case, blanks 1 12 having a single reinforced end 1 14 of thickness greater than e are obtained. Such a flank makes it possible to obtain the strake 108 of FIG.

They can also be obtained by cutting in two successive second zones 1 10.

By way of example, and as illustrated in FIG. 9, it is possible to assemble a blank 1 12 with a second part 1 1 6 by welding one of the reinforced ends 1 14 of the blank 1 12 to an edge of the second piece 1 6. The thickness of the second part 1 16 is preferably greater than the thickness of the central zone January 13 of the blank 1 12. The weld is more particularly a weld clap, also called lap weld.

The part 1 1 6 may be a blank 1 12 as described above.

Thus, in Figure 10, there is illustrated two blanks 1 12 assembled end to end by welding. These two blanks January 12 are welded together by their reinforced ends 1 14. The strakes 108 and 208 of Figure 1 1 can be roped in the same manner, as will be described below.

In the examples illustrated in FIGS. 9 and 10:

- The length of the central zone 1 13 is for example between 40 m and 60 m; and

- The length of each reinforced end 1 14 is for example between 0.5 m and 2 m.

The second thickness e is in particular approximately equal to 0.7 mm.

The first thickness e + s is approximately equal to 0.9 mm.

Alternatively, a non-planar piece is formed from the blank 1 12.

The method of manufacturing a strip of variable thickness along its length described above is particularly advantageous. Indeed, it makes it possible to obtain an alloy strip mainly based on iron and nickel having the chemical composition defined above having zones of different thicknesses but quasi-homogeneous mechanical properties. These properties are obtained through the use of a plastic deformation rate after a possible recrystallization intermediate annealing generated by the homogeneous rolling and flexible rolling steps in the thickest zones greater than or equal to 30%.

The following experimental examples illustrate the importance of the claimed plastic deformation rate range for this type of alloy.

In a first series of experiments, strips of variable thickness have been manufactured, that is to say strips 104 of variable thickness whose thickness e of the second zones 10 is less than or equal to 2 mm.

Table 1 below illustrates the manufacturing trials of strips of variable thickness without intermediate recrystallization annealing.

Table 2 below contains characteristics of the strips obtained by the tests in Table 1.

Table 3 below illustrates the manufacturing trials of strips of variable thickness with an intermediate recrystallization annealing at the thickness 6.

Table 4 below contains characteristics of the strips obtained by the tests in Table 3.

In a second series of experiments, sheets of variable thickness, that is to say strips 104 of variable thickness whose thickness e of the second zones 1 10 is strictly greater than 2 mm, were manufactured.

Table 5 illustrates tests for manufacturing sheets of variable thickness with or without intermediate annealing.

Table 6 below contains characteristics of the sheets obtained by the tests in Table 5.

In all the tables, it was pointed out the tests according to a method of manufacturing a strip of thickness varying according to its length, made of iron-based alloy, the iron-based alloy comprising, by weight:

34.5% <Ni <53.5%

0.1 5% <Mn <1.5% 0 <If <0.35%, preferably 0, 1% <Si <0.35%

0 <C <0.07%

opfionnellemenf:

0 <Co <20%

0 <Ti <0.5%

0.01% <Cr <0.5%

the rest being iron and impurities necessarily resulting from the elaboration,

the process successively comprising the following steps:

providing an initial band (101) of constant thickness (Eo) obtained by hot rolling;

cold homogeneous rolling of the initial strip (101) along its length to obtain an intermediate strip (103) of constant thickness (E _c ) according to the rolling direction;

cold flexible rolling of the intermediate strip (103) along its length to obtain a strip (104) of variable thickness in the rolling direction, the strip (104) of variable thickness having, according to its length, first zones (107) having a first thickness (e + s) and second areas (1 10) having a second thickness (e), less than the first thickness (e + s),

final recrystallization annealing at the passage of the band (104) of variable thickness in a final annealing furnace,

in which the rate of plastic deformation generated, after any intermediate recrystallization annealing, by the homogeneous cold rolling and cold rolling steps in the first zones (107) of the variable thickness band (104) is greater than or equal to 30%.

It is found that when the rate of plastic deformation τι after a possible recrystallization intermediate annealing is greater than or equal to 30% (tests 1 to 7 of Table 1, 1 to 3 of Table 3 and 1 to 9 of Table 5), the strip 104 of variable thickness obtained has a difference in average grain size between the average grain size of the first zones 107 (thickness e + s) and the grain size of the second zones 1 10 (thickness e) less than or equal to 0.5 ASTM index in absolute value. This small average grain size difference between the first zones 107 and the second zones 1 10 results in quasi-homogeneous mechanical properties, namely a 0.2% ARp yield strength difference between the first zones 107 and the second zones 107. second zones 1 10 less than or equal to 6 MPa in absolute value, and a difference between the breaking load ARm of the first zones 107 and the second zones 1 10 less than or equal to 6 MPa in absolute value.

It is thus possible to obtain a band 104 of variable thickness having mechanical properties and substantially homogeneous grain sizes at the end of a very simple recrystallization annealing, since carried out at constant temperature and speed of scrolling.

Figure 1 1 is a schematic top view of the primary waterproof membrane of a wall of a sealed and insulating tank similarly constructed to the tank of Figure 1. The ends of the tank wall are symbolized by the welding fins 27 partially shown.

For purposes of illustration, the three metal strakes 8, 108 and 208 shown in Figure 1 1 are manufactured according to three different embodiments. In practice, a waterproof membrane can be constructed with strakes all corresponding to the same embodiment, or by combining strakes of several embodiments in any appropriate order. The welding supports 9 are also sketched in FIG. 11, in an exploded representation that places the welding supports 9 at a distance from the strakes 8, 108 and 208 to facilitate understanding.

The strakes of the three embodiments have the common point of extending longitudinally from one end to the other of the tank wall to be welded to the two solder fins 27 and have two raised side edges 13. For example , the width of the flat central portion of the strake is between 40 and 60 cm and the height of the raised edge 13 is between 2 and 6 cm. The raised edges 13 of the variable thickness strake 8 can be obtained from the flat side 1 12 with the aid of a folder comprising three rollers on each side of the sidewall 12. The rollers exert a pressure on the sidewall in order to deform the flank to generate the raised edges. Hydraulic jacks are used to change the position of the rollers and the pressure exerted by them depending on the variation of the thickness of the sidewall.

Strake 8 corresponds to the embodiment described above with reference to FIGS. 2 e 3: it is a metal strip extending in one piece from one end to the other of the tank wall. and having the reinforced portions 1 14 at both ends of the strip and the central portion of smaller thickness 1 13 therebetween. For the purposes of the representation, the boundaries between the smaller thickness portion 13 and the thicker reinforced portions 14 have been drawn in fine broken lines, but it is understood that this limit may extend over a transition zone relatively extensive.

The strake 8 is placed in one piece in the tank. Cutting the inclined portion 14 at both ends of the two raised edges of the strake 8, before proceeding to the assembly and sealing welds with the connecting rings.

The strake 108 or 208, on the other hand, consists of several successive longitudinal strips with raised edges which can be placed one after the other, which makes these embodiments particularly suitable for a very long tank wall, for example approximately 30 to 50m per longitudinal band, ie a total length greater than 50m. Each successive band is continuous, that is to say that it is obtained from a single flank described above, and not by welding several flanks together.

More specifically, the strake 108 comprises two metal strips with raised edges 13 which are assembled end to end in the extension of one another at an assembly area 40, for example by welding. Each metal band is continuous and has a portion a thicker reinforced end 1 14 adjacent to the joining zone 40 and having a lower uniform thickness over the rest of its length 1 13, to the edge of the tank wall where it is assembled to the fin welding 27.

The strake 208 is constructed similarly to the strake 108, but with strips whose two ends 1 14 are reinforced by a greater thickness. As a result, the thicker reinforced ends 14 of the strips constituting the strake 208 are present both at the connection zone 40 between the strips and at the edges of the vessel wall where the strake 208 is assembled to the As a variant, the strake 208 may be constructed with a higher number of continuous strips laid end to end in the same manner.

When a tank wall is covered with a waterproof membrane manufactured with the strakes 108 or 208, the assembly area 40 of each strake 108 or 208 may be placed in the middle of the tank wall or at other locations. Preferably, these locations are offset longitudinally from one strake to another, thereby to avoid forming a continuous weld line in the transverse direction of the wall.

Although there have been described insulating elements in the form of caissons with expanded perlite, other forms of heat insulating elements are possible. In particular, the boxes can be made with other forms of insulating materials. For example, the boxes may include a layer of insulating foam. The tanks described above can be used in various types of installations such as land installations or in a floating structure such as a LNG tank or other.

Referring to Figure 4, a broken view of a LNG tank 70 shows a sealed and insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the ship. The wall of the tank 71 comprises a primary sealed barrier intended to be in contact with the LNG contained in the tank, a secondary sealed barrier arranged between the primary watertight barrier and the double hull of the ship, and two thermally insulating barriers respectively arranged between the primary watertight barrier and the secondary watertight barrier, and between the secondary watertight barrier and the double hull 72.

In a manner known per se, loading / unloading lines arranged on the upper deck of the ship can be connected, by means of appropriate connectors, to a marine or port terminal to transfer a cargo of LNG from or to the tank 71.

FIG. 4 represents an example of a marine terminal comprising a loading and unloading station 75, an underwater pipe 76 and an onshore installation 77. The loading and unloading station 75 is an off-shore fixed installation comprising an arm mobile 74 and a tower 78 which supports the movable arm 74. The movable arm 74 carries a bundle of insulated flexible pipes 79 that can connect to the loading / unloading pipes 73. The movable arm 74 can be adapted to all gauges of LNG carriers . A link pipe (not shown) extends inside the tower 78. The loading and unloading station 75 enables the loading and unloading of the LNG tank 70 from or to the shore facility 77. liquefied gas storage tanks 80 and connecting lines 81 connected by the underwater line 76 to the loading or unloading station 75. The underwater line 76 allows the transfer of the liquefied gas between the loading or unloading station 75 and the onshore installation 77 over a large distance, for example 5 km, which makes it possible to keep the tanker vessel 70 at great distance from the coast during the loading and unloading operations.

In order to generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the shore installation 77 and / or pumps equipping the loading and unloading station 75 are used. Although the invention has been described in connection with several particular embodiments, it is obvious that it is not limited thereto and that it comprises all the technical equivalents of the means described and their combinations if they are within the scope of the invention.

The use of the verb "to include", "to understand" or "to include" and its conjugated forms does not exclude the presence of other elements or steps other than those set out in a claim. The use of the indefinite article "a" or "an" for an element or a step does not exclude, unless otherwise stated, the presence of a plurality of such elements or steps.

In the claims, any reference sign in parentheses can not be interpreted as a limitation of the claim.

Table 1

Table 2

Table 3

Table 4

Table 5

Claims

1. Sealed and thermally insulating vessel integrated into a supporting structure, the carrier structure comprising a plurality of carrier walls (1, 2), the vessel comprising

a plurality of tank walls each fixed to a respective bearing wall (1, 2), a tank wall comprising:

a thermal insulation barrier retained (3, 5) on the carrier wall, the thermal insulation barrier having a flat support surface parallel to the respective carrier wall,

a sealing barrier (4, 6) supported by the insulation barrier and having a repeating structure alternately having an elongate metal strake (8, 108, 208) and an elongated welding flange (9) bonded to the support surface and protruding therefrom, the welding flange (9) extending parallel to the metal strake (8) over at least a portion of the length of the metal strake, the metal strake having in the direction of the a planar central portion lying on the support surface and lateral edges (13) raised with respect to the support surface which are arranged against the adjacent welding wings and sealingly welded to the welding wings (9),

wherein the metal strake extends between two opposite edges of the vessel wall and has two end portions which are each sealingly joined to a respective stop structure (10, 27, 28) at said opposite edges of the tank wall,

characterized in that the metal strake (8, 108, 208) consists of at least one continuous metal strip having a plurality of longitudinal portions having different thicknesses, the longitudinal portions having an intermediate portion (1 13, 35) and at least one end portion (1 14, 33) whose thickness is greater than the thickness of the intermediate portion of the strip, the thicker end portion (1 1 4, 33) forming an assembly area of the strip with stop structure (10) or with another continuous metal strip assembled end-to-end with the first continuous metal band to form the metal strake.

2. A tank according to claim 1, wherein the metal strake (8) consists of a single metal strip extending in one piece between the two opposite edges of the tank wall, and wherein the two portions of end (33) of the strip are thicker than the intermediate portion (35, 36) and are each joined to the respective stop structure (10, 27, 28) at the opposite edges of the vessel wall.

3. A vessel according to claim 1, wherein the metal strake (108, 208) comprises a second continuous metal strip joined end to end with the first continuous metal strip in the extension of the first continuous metal strip, in which each of the two strips continuous metal has, at the assembly area (40) of the two metal strips, an end portion (1 14) thicker than the intermediate portion (1 13) of the strip.

4. Tank according to claim 3, wherein at least one of the two continuous metal strips has, at the end opposite the assembly zone (40) of the two metal strips, a second end portion (1 14 ) thicker than the intermediate portion (1 13) of the strip, the second end portion (1 14) being assembled to the stop structure (10, 27, 28) at an edge of the wall of tank.

5. Tank according to claim 3 or 4, wherein at least one of the two continuous metal strips has, at the end opposite the assembly zone (40) of the two metal strips, a second end portion ( 1 14) of the same thickness as the intermediate portion (1 13) of the strip, the second end portion (1 14) being assembled to the stop structure (10, 27, 28) at an edge of the tank wall.

6. Tank according to one of claims 1 to 5, wherein each end portion of the metal strake (8, 108, 208) is sealed welded to the respective stop structure (1 0).

7. A tank according to claim 6, wherein the strake (8) is welded to the stop structure by a cold metal transfer process.

CMT or by TIG welding with filler metal or by cold welding.

8. A tank according to one of claims 1 to 7, wherein the stop structure (10) comprises a plate (27, 28) positioned above the insulation barrier and the end portion of the strake. metal (8, 108, 208) comprises a first segment bearing on the plate of the stop structure and a second segment bearing on the thermal insulation barrier, the first segment and the second segment being connected by a folded segment (34) forming a recess in the thickness direction of the metal strake.

9. Tank according to one of claims 1 to 8, wherein the welding wings (9) are interrupted before the end of the metal strake (8, 108, 208), the raised edges of two adjacent metal strakes being welded to one another by an edge weld disposed over a portion of their length to the end of the metal strake.

Tank according to claim 9, wherein the edge weld of the raised edges (13) is carried out by means of a cold metal transfer process.

1. A vessel according to one of claims 1 to 10, wherein the thicker end portion (1 14, 33) of the metal strip has a thickness greater than or equal to 0.9mm.

12. Tank according to one of claims 1 to 1 1, wherein the intermediate portion (35) of the metal strip has a thickness of less than 0.9mm and preferably a thickness of 0.7mm.

13. Tank according to one of claims 1 to 1 2, wherein the stop structure (10) is welded to a carrier wall.

14. A tank according to one of claims 1 to 13, wherein said metal strake and the stop structure are made of nickel alloy steel with a low coefficient of expansion.

15. Tank according to one of claims 1 to 14, wherein the metal strip is an iron-based alloy and comprises by weight:

34.5% <Ni <53.5%

0.1 5% <Mn <1.5%

0 <If <0.35%, preferably 0, 1% <Si <0.35%

0 <C <0.07%

optionally:

0 <Co <20%

0 <Ti <0.5%

0.01% Cr <0.5%

the rest being iron and impurities necessarily resulting from the elaboration.

16. Tank according to one of claims 1 to 1 5 wherein the vessel wall further comprises:

a secondary thermal insulation barrier (3), the thermal insulation barrier having a planar support surface parallel to the respective carrier wall, and

a secondary sealing barrier (4) supported by the secondary insulation barrier and carrying the primary insulation barrier (5), the secondary sealing barrier having a repeated structure alternately having an elongate metal strake (8, 108, 208) and an elongate welding flange (9) bonded to and projecting from the support surface, the welding flange (9) extending parallel to the metal strake (8) over at least a portion of the length of the metal strake, the metal strake having in the width direction a flat central portion placed on the support surface and lateral edges (13) raised relative to the support surface which are arranged against the wings of adjacent welded and welded sealingly to the welding wings (9), wherein the metal strake extends between two opposite edges of the vessel wall and has two end portions which are each sealingly joined to a respective stop structure (1 0, 28) at said opposite edges of the tank wall,

characterized in that the metal strake (8, 1 08, 208) consists of at least one continuous metal strip having a plurality of longitudinal portions having different thicknesses, the longitudinal portions having an intermediate portion (1 13, 35) and at least one an end portion (1, 14, 33) whose thickness is greater than the thickness of the intermediate portion of the strip, the thicker end portion (1 1 4, 33) forming an assembly area of the strip with the stop structure (10) or with another continuous metal strip joined end to end with the first continuous metal strip to form the metal strake.

17. Ship (70) for the transport of a cold liquid product, the ship having a double hull (72) and a tank (71) according to one of claims 1 to 1 6 disposed in the double hull.

18. Use of a ship (70) according to claim 1 7 for the loading or unloading of a cold liquid product, in which a cold liquid product is conveyed through isolated pipes (73, 79, 76, 81) from or to a floating or land storage facility (77) to or from the vessel vessel (71).

19. Transfer system for a cold liquid product, the system comprising a ship (70) according to claim 1 7, insulated pipes (73, 79, 76, 81) arranged to connect the tank (71) installed in the vessel hull at a floating or land storage facility (77) and a pump for driving a flow of cold liquid product through the insulated pipelines from or to the floating or land storage facility to or from the vessel vessel.

20. Continuous metal strip with raised side edges suitable for producing a tank according to claim 1, the metal strip being obtained from a blank (1 1 2) having, depending on its length, a first reinforced end zone (1 1 4) having a first thickness (e + s) and a second central region (1 13) having a second thickness (e) smaller than the first thickness (e + s) and a third end zone having the first thickness (e + s) or the second thickness (e), the metal strip having, according to its width, a flat central zone and two lateral edges bent substantially perpendicular to the central plane zone, the two edges side having a small width relative to the flat central area.

21. Metal strip according to claim 20, the metal strip consisting of an alloy based on iron and comprising by weight:

34.5% <Ni <53.5%

0, 1 5% <Mn <1.5%

0 <If <0.35%, preferably 0.1% <Si <0.35%

0 <C <0.07%

optionally:

0 <Co <20%

0 <Ti <0.5%

0.01% <Cr <0.5%

the rest being iron and impurities necessarily resulting from the elaboration.