-269 DEG C ultralow-temperature high-manganese austenitic stainless steel submerged arc welding wire and welding flux for liquid hydrogen storage and transportation and preparation method and welding method of submerged arc welding wire and welding flux

Abstract

The invention discloses a-269 DEG C ultralow-temperature high-manganese austenitic stainless steel submerged arc welding wire for liquid hydrogen storage and transportation, a welding flux and a preparation method and a welding method of the submerged arc welding wire. The invention belongs to the technical field of welding. The austenitic stainless steel submerged-arc welding material solves the technical problem that the austenitic stainless steel submerged-arc welding material is low in tensile strength and toughness in the liquid hydrogen storage and transportation ultralow-temperature environment of-269 DEG C. The-269 DEG C ultralow-temperature high-manganese austenitic stainless steel submerged-arc welding wire for liquid hydrogen storage and transportation and the welding flux matched with the submerged-arc welding wire are prepared, the welding method is further provided, rare earth elements Y and Co are added into the welding wire, and the toughness, strength and corrosion resistance of a welding seam can be improved; the welding wire is prepared through the six-roller roller die drawing technology, the working procedures can be simplified, energy consumption is reduced, the tensile strength and the elastic limit are improved, and the cold machining difficulty is reduced. The cladding metal still has high strength and high toughness at the ultralow temperature of-269 DEG C, and can be applied to liquid hydrogen storage and transportation.

Description

Technical Field

[0001] The invention belongs to the technical field of welding, and in particular relates to a -269°C ultra-low temperature high manganese austenitic stainless steel submerged arc welding wire and flux for liquid hydrogen storage, and a preparation method and a welding method thereof. Background Art

[0002] Hydrogen energy is a widely available, green, low-carbon, and widely used secondary energy. It is an important component of the modern energy system. However, due to the special physical and chemical properties of hydrogen, the storage and transportation of hydrogen energy has become the key to the efficient use of hydrogen energy. The cost of the storage and transportation link not only accounts for a large proportion of the total cost, but is also a key link restricting the development of hydrogen energy. Low-temperature liquid hydrogen storage has the advantages of high hydrogen storage density, high volume energy density, simple transportation, and high safety performance. It can be transported in various ways and is one of the main directions of the development of hydrogen energy storage and transportation. The liquefaction temperature of hydrogen is -253°C. The relevant storage and transportation equipment needs to ensure that it still has good mechanical properties at -269°C to ensure the safety of the equipment. Therefore, the low-temperature toughness and hydrogen embrittlement resistance of the welded joints, which are weak points, are the main technical indicators of liquid hydrogen storage and transportation equipment.

[0003] Austenitic stainless steel is a commonly used structural material in cryogenic systems. It does not have the ductile-brittle transition phenomenon, so its service environment can even reach the temperature of liquid helium. However, austenitic stainless steel has a greater tendency to thermal cracking during welding, and the deposited metal should avoid problems caused by thermal expansion differences and strength differences as much as possible. In the existing technical research, retaining a part of ferrite in the deposited metal to ensure the crack resistance of the weld is still an extremely effective method. There are technologies that have been disclosed that have good performance at -196°C, but this is still difficult to meet the ultra-low temperature toughness and hydrogen embrittlement resistance of -269°C required for the safe storage and transportation of liquid hydrogen.

[0004] There are few patents related to the use of austenitic stainless steel submerged arc welding materials at ultra-low temperatures of -269°C. In particular, it is extremely difficult to improve toughness under ultra-low temperature conditions to ensure low ferrite or even no ferrite content. Therefore, in order to meet the needs of safe operation of liquid hydrogen storage and transportation containers, the development of a fully austenitic stainless steel submerged arc welding material with high tensile strength and high toughness at ultra-low temperatures of -269°C is the key to solving the problem that existing submerged arc welding materials cannot meet the requirements of liquid hydrogen storage and transportation. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problem of low tensile strength and low toughness of austenitic stainless steel submerged arc welding materials in the ultra-low temperature environment of -269°C for liquid hydrogen storage and transportation. The present invention provides a -269°C ultra-low temperature high manganese austenitic stainless steel submerged arc welding wire, flux and its preparation method and welding method for liquid hydrogen storage.

[0006] The technical solution of the present invention is as follows:

[0007] One of the purposes of the present invention is to provide a -269°C ultra-low temperature high manganese austenitic stainless steel submerged arc welding wire for liquid hydrogen storage, wherein the chemical composition of the welding wire comprises, by weight percentage: C≤0.03%, Si≤1%, Mn: 9.5-13%, S≤0.02%, P≤0.03%, Cr: 17-20%, Ni: 12-14.5%, Mo: 3-4.5%, Cu≤0.5%, N: 0.15-0.3%, Y: 0.001-0.005%, Co: 0.07-0.5%, and the balance is Fe.

[0008] It is further defined that the chemical composition of the welding wire includes by weight percentage: C≤0.03%, Si≤0.7%, Mn: 11-13%, S≤0.01%, P≤0.02%, Cr: 17-20%, Ni: 13-14%, Mo: 3-4.5%, Cu≤0.5%, N: 0.15-0.3%, Y: 0.001-0.005%, Co: 0.1-0.2%, and the balance is Fe.

[0009] The second object of the present invention is to provide a method for preparing a -269°C ultra-low temperature high manganese austenitic stainless steel submerged arc welding wire for liquid hydrogen storage, the method comprising:

[0010] S1: putting the welding wire raw materials into the refining furnace in sequence for smelting, pouring steel ingots, forging and rolling to obtain wire rods;

[0011] S2: After mechanical shelling, straightening and belt grinding, the wire rod is directly drawn into a six-roller die, and a total of 10 continuous drawing steps are performed to obtain the finished product;

[0012] S3: The finished product is cleaned online, the surface is coated with an anti-rust coating, and the densely packed layers are wound on a coil to obtain the welding wire.

[0013] It is further defined that the wire rod diameter in S1 is Φ3.5 mm.

[0014] It is further defined that the diameter of the finished product in S2 is Φ3.2 mm.

[0015] It is further defined that the first 8 of the 10 continuous drawing passes in S2 are roller dies, and the last 2 are eye dies.

[0016] The third object of the present invention is to provide a flux for submerged arc welding of ultra-low temperature high manganese austenitic stainless steel for liquid hydrogen storage at -269°C. The flux is used in conjunction with the above-mentioned submerged arc welding wire for ultra-low temperature high manganese austenitic stainless steel for liquid hydrogen storage at -269°C. The chemical composition of the flux includes, by weight percentage: Nb2O3: 25-40%, Cr2O3: 30-45%, SiO2: 5-15%, Al2O3: 5-10%, and CaO: 5-10%.

[0017] The fourth object of the present invention is to provide a method for preparing a flux for -269°C ultra-low temperature high manganese austenitic stainless steel submerged arc welding for liquid hydrogen storage, the method comprising: screening each component mineral and alloy powder through 100 mesh, weighing, dry mixing evenly, adding 15-25% potassium sodium water glass and stirring, sintering at 800-850°C, and screening.

[0018] The fifth object of the present invention is to provide a welding method for submerged arc welding of ultra-low temperature high manganese austenitic stainless steel at -269°C for liquid hydrogen storage, the welding method uses the above-mentioned welding wire and flux, and the welding method parameters are: welding current 430-450A, arc voltage 28-32V, welding speed 450-550mm / min, and interpass temperature ≤100°C.

[0019] The sixth object of the present invention is to provide a welding method for submerged arc welding of ultra-low temperature high manganese austenitic stainless steel at -269°C for liquid hydrogen storage and transportation.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) A small amount of rare earth elements Y and Co are added to the welding wire of the present invention. Y can form stable compounds with elements such as sulfur and oxygen in steel. These compounds can serve as the core of heterogeneous nucleation, which helps to refine the grains of the weld metal and improve the toughness and strength of the weld. Y can also inhibit oxidation and nitridation, reduce the impact of impurities such as oxygen and nitrogen on the weld joint, and improve corrosion resistance, especially in some special environments, such as welding of steel for marine engineering, and the addition of Y can improve the fluidity and formability of the weld metal, making the welding process smoother and more stable. When the Co content is too high, the corrosion resistance of the alloy will be reduced, but when a small amount of Y is present in the alloy, the corrosion resistance of the material will not decrease. In addition, Co improves the hardness and strength of the alloy by forming a continuous solid solution with iron. In addition, Co can also improve the oxidation resistance of the alloy steel and further improve the toughness of the material.

[0022] (2) The present invention also adopts manganese-nickel substitution technology. Manganese and nitrogen are both austenite-forming elements, which are used to replace nickel in stainless steel. Nitrogen's ability to form austenite is about 30 times that of nickel, while manganese is relatively weak, but its ability to stabilize austenite is very strong. Manganese can also significantly increase the solubility of nitrogen in steel. Therefore, the combined addition of manganese and nitrogen is an effective way to replace nickel.

[0023] (3) The welding wire prepared by the present invention has a high manganese content, which leads to a high cold working hardening index of the material and great difficulty in cold forming. Therefore, the present invention uses a six-roller die drawing technology. Compared with the traditional fixed die drawing, the roller die drawing technology converts the larger sliding friction during metal deformation into smaller rolling friction. This technology can reduce the drawing force, reduce energy consumption, increase the surface reduction rate, improve the processing limit, reduce the number of intermediate annealing times, simplify the process, reduce the requirements for lubrication, increase the drawing speed, and improve the tensile strength and elastic limit. The six-pass roller die further distributes the total processing volume, greatly reducing the difficulty of cold processing. In addition, this product uses a wire rod with a diameter of Ф3.5mm, which is directly drawn to a wire rod with a diameter of Ф3.2mm. The smaller deformation reduces the processing difficulty and eliminates the annealing process, saving time and cost. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained through commercial channels by those skilled in the art.

[0026] The welding wires in the following embodiments and comparative examples are all made by smelting in a refining furnace. The process flow of the welding wire is as follows: 3.5 mm diameter wire rod, mechanical shelling, straightening, belt grinding, and then directly entering the six-roller die for drawing, cleaning, coating with an anti-rust layer, winding in close-packed layers, and packaging.

[0027] Embodiment 1:

[0028] The chemical composition weight percentage of the submerged arc welding wire is C: 0.012%, Si: 0.46%, Mn: 12.78%, S: 0.005%, P: 0.008%, Cr: 19.08%, Ni: 13.48%, Mo: 3.55%, Cu: 0.027%, N: 0.23%, Y: 0.003%, Co: 0.15%, and the balance is Fe.

[0029] Preparation of submerged arc welding wire: The welding wire raw materials are put into the refining furnace in turn for smelting, pouring steel ingots, and forging to obtain wire rods with a diameter of Ф3.5mm; the wire rods are directly drawn into a six-roller die after mechanical shelling, straightening and belt grinding, and undergo a total of 10 continuous drawing passes, the first 8 passes are roller dies, and the last 2 passes are eye dies. The diameter of the finished product is Ф3.2mm; the finished product is cleaned online, the surface is coated with an anti-rust coating, and it is wound in dense layers to obtain the welding wire.

[0030] The chemical composition weight percentage of the submerged arc welding flux is: Nb2O3: 37%, Cr2O3: 39%, SiO2: 11%, Al2O3: 5%, CaO: 8%.

[0031] Preparation of submerged arc welding flux: The mineral and alloy powders of each component are sieved through 100 mesh, weighed, dry-mixed evenly, added with 20% potassium sodium water glass and stirred, sintered at 830°C, and sieved.

[0032] Embodiment 2:

[0033] The chemical composition weight percentage of the submerged arc welding wire is C: 0.019%, Si: 0.76%, Mn: 12.54%, S: 0.006%, P: 0.007%, Cr: 19.21%, Ni: 13.53%, Mo: 3.71%, Cu: 0.031%, N: 0.21%, Y: 0.004%, Co: 0.13%, and the balance is Fe.

[0034] Preparation of submerged arc welding wire: The welding wire raw materials are put into the refining furnace in turn for smelting, pouring steel ingots, and forging to obtain wire rods with a diameter of Ф3.5mm; the wire rods are directly drawn into a six-roller die after mechanical shelling, straightening and belt grinding, and undergo a total of 10 continuous drawing passes, the first 8 passes are roller dies, and the last 2 passes are eye dies. The diameter of the finished product is Ф3.2mm; the finished product is cleaned online, the surface is coated with an anti-rust coating, and it is wound in dense layers to obtain the welding wire.

[0035] The chemical composition weight percentage of the submerged arc welding flux is: Nb2O3: 37%, Cr2O3: 39%, SiO2: 11%, Al2O3: 5%, CaO: 8%.

[0036] Preparation of submerged arc welding flux: The mineral and alloy powders of each component are sieved through 100 mesh, weighed, dry-mixed evenly, added with 20% potassium sodium water glass and stirred, sintered at 830°C, and sieved.

[0037] Embodiment 3:

[0038] The chemical composition weight percentage of the submerged arc welding wire is C: 0.015%, Si: 0.52%, Mn: 12.29%, S: 0.005%, P: 0.009%, Cr: 19.17%, Ni: 13.29%, Mo: 3.56%, Cu: 0.026%, N: 0.22%, Y: 0.003%, Co: 0.31%, and the balance is Fe.

[0039] Preparation of submerged arc welding wire: The welding wire raw materials are put into the refining furnace in turn for smelting, pouring steel ingots, and forging to obtain wire rods with a diameter of Ф3.5mm; the wire rods are directly drawn into a six-roller die after mechanical shelling, straightening and belt grinding, and undergo a total of 10 continuous drawing passes, the first 8 passes are roller dies, and the last 2 passes are eye dies. The diameter of the finished product is Ф3.2mm; the finished product is cleaned online, the surface is coated with an anti-rust coating, and it is wound in dense layers to obtain the welding wire.

[0040] The chemical composition weight percentage of the submerged arc welding flux is: Nb2O3: 37%, Cr2O3: 39%, SiO2: 11%, Al2O3: 5%, CaO: 8%.

[0041] Preparation of submerged arc welding flux: The mineral and alloy powders of each component are sieved through 100 mesh, weighed, dry-mixed evenly, added with 20% potassium sodium water glass and stirred, sintered at 830°C, and sieved.

[0042] Embodiment 4:

[0043] The chemical composition weight percentage of the submerged arc welding wire is C: 0.013%, Si: 0.58%, Mn: 12.37%, S: 0.006%, P: 0.008%, Cr: 18.95%, Ni: 12.48%, Mo: 3.48%, Cu: 0.026%, N: 0.23%, Y: 0.002%, Co: 0.13%, and the balance is Fe.

[0044] Preparation of submerged arc welding wire: The welding wire raw materials are put into the refining furnace in turn for smelting, pouring steel ingots, and forging to obtain wire rods with a diameter of Ф3.5mm; the wire rods are directly drawn into a six-roller die after mechanical shelling, straightening and belt grinding, and undergo a total of 10 continuous drawing passes, the first 8 passes are roller dies, and the last 2 passes are eye dies. The diameter of the finished product is Ф3.2mm; the finished product is cleaned online, the surface is coated with an anti-rust coating, and it is wound in dense layers to obtain the welding wire.

[0045] The chemical composition weight percentage of the submerged arc welding flux is: Nb2O3: 37%, Cr2O3: 39%, SiO2: 11%, Al2O3: 5%, CaO: 8%.

[0046] Preparation of submerged arc welding flux: The mineral and alloy powders of each component are sieved through 100 mesh, weighed, dry-mixed evenly, added with 20% potassium sodium water glass and stirred, sintered at 830°C, and sieved.

[0047] Comparative Example 1:

[0048] The chemical composition weight percentage of the submerged arc welding wire is C: 0.012%, Si: 0.46%, Mn: 8.10%, S: 0.005%, P: 0.008%, Cr: 19.43%, Ni: 13.24%, Mo: 3.55%, Cu: 0.027%, N: 0.22%, Y: 0.003%, Co: 0.12%, and the balance is Fe.

[0049] Preparation of submerged arc welding wire: The welding wire raw materials are put into the refining furnace in turn for smelting, pouring steel ingots, and forging to obtain wire rods with a diameter of Ф3.5mm; the wire rods are directly drawn into a six-roller die after mechanical shelling, straightening and belt grinding, and undergo a total of 10 continuous drawing passes, the first 8 passes are roller dies, and the last 2 passes are eye dies. The diameter of the finished product is Ф3.2mm; the finished product is cleaned online, the surface is coated with an anti-rust coating, and it is wound in dense layers to obtain the welding wire.

[0050] The chemical composition weight percentage of the submerged arc welding flux is: Nb2O3: 37%, Cr2O3: 39%, SiO2: 11%, Al2O3: 5%, CaO: 8%.

[0051] Preparation of submerged arc welding flux: The mineral and alloy powders of each component are sieved through 100 mesh, weighed, dry-mixed evenly, added with 20% potassium sodium water glass and stirred, sintered at 830°C, and sieved.

[0052] Comparative Example 2:

[0053] The chemical composition weight percentage of the submerged arc welding wire is C: 0.017%, Si: 0.49%, Mn: 11.53%, S: 0.006%, P: 0.007%, Cr: 19.57%, Ni: 13.26%, Mo: 3.64%, Cu: 0.019%, N: 0.11%, Y: 0.002%, Co: 0.16%, and the balance is Fe.

[0054] Preparation of submerged arc welding wire: The welding wire raw materials are put into the refining furnace in turn for smelting, pouring steel ingots, and forging to obtain wire rods with a diameter of Ф3.5mm; the wire rods are directly drawn into a six-roller die after mechanical shelling, straightening and belt grinding, and undergo a total of 10 continuous drawing passes, the first 8 passes are roller dies, and the last 2 passes are eye dies. The diameter of the finished product is Ф3.2mm; the finished product is cleaned online, the surface is coated with an anti-rust coating, and it is wound in dense layers to obtain the welding wire.

[0055] The chemical composition weight percentage of the submerged arc welding flux is: Nb2O3: 37%, Cr2O3: 39%, SiO2: 11%, Al2O3: 5%, CaO: 8%.

[0056] Preparation of submerged arc welding flux: The mineral and alloy powders of each component are sieved through 100 mesh, weighed, dry-mixed evenly, added with 20% potassium sodium water glass and stirred, sintered at 830°C, and sieved.

[0057] Comparative Example 3:

[0058] The chemical composition weight percentage of the submerged arc welding wire is C: 0.014%, S: 0.51%, Mn: 12.01%, S: 0.005%, P: 0.008%, Cr: 19.14%, Ni: 13.61%, Mo: 3.71%, Cu: 0.014%, N: 0.21%, Y: 0%, Co: 0.14%, and the balance is Fe.

[0059] Preparation of submerged arc welding wire: The welding wire raw materials are put into the refining furnace in turn for smelting, pouring steel ingots, and forging to obtain wire rods with a diameter of Ф3.5mm; the wire rods are directly drawn into a six-roller die after mechanical shelling, straightening and belt grinding, and undergo a total of 10 continuous drawing passes, the first 8 passes are roller dies, and the last 2 passes are eye dies. The diameter of the finished product is Ф3.2mm; the finished product is cleaned online, the surface is coated with an anti-rust coating, and it is wound in dense layers to obtain the welding wire.

[0060] The chemical composition weight percentage of the submerged arc welding flux is: Nb2O3: 37%, Cr2O3: 39%, SiO2: 11%, Al2O3: 5%, CaO: 8%.

[0061] Preparation of submerged arc welding flux: The mineral and alloy powders of each component are sieved through 100 mesh, weighed, dry-mixed evenly, added with 20% potassium sodium water glass and stirred, sintered at 830°C, and sieved.

[0062] Comparative Example 4:

[0063] The chemical composition weight percentage of the submerged arc welding wire is C: 0.011%, Si: 0.52%, Mn: 11.83%, S: 0.004%, P: 0.006%, Cr: 19.27%, Ni: 13.42%, Mo: 3.46%, Cu: 0.025%, N: 0.24%, Y: 0.002%, and the balance is Fe.

[0064] Preparation of submerged arc welding wire: The welding wire raw materials are put into the refining furnace in turn for smelting, pouring steel ingots, and forging to obtain wire rods with a diameter of Ф3.5mm; the wire rods are directly drawn into a six-roller die after mechanical shelling, straightening and belt grinding, and undergo a total of 10 continuous drawing passes, the first 8 passes are roller dies, and the last 2 passes are eye dies. The diameter of the finished product is Ф3.2mm; the finished product is cleaned online, the surface is coated with an anti-rust coating, and it is wound in dense layers to obtain the welding wire.

[0065] The chemical composition weight percentage of the submerged arc welding flux is: Nb2O3: 37%, Cr2O3: 39%, SiO2: 11%, Al2O3: 5%, CaO: 8%.

[0066] Preparation of submerged arc welding flux: The mineral and alloy powders of each component are sieved through 100 mesh, weighed, dry-mixed evenly, added with 20% potassium sodium water glass and stirred, sintered at 830°C, and sieved.

[0067] Mechanical properties of deposited metals were tested on Examples 1-4 and Comparative Examples 1-4:

[0068] The welding process parameters are welding current 450A, arc voltage 30V, welding speed 500mm / min, and interpass temperature ≤100℃. The welding method of the deposited metal is carried out in accordance with GB / T17854, and the tensile property test of the weld metal is carried out in accordance with GB / T2652. The test results are shown in Table 1.

[0069] Table 1 shows the mechanical properties of deposited metals of Examples 1-4 and Comparative Examples 1-4 at -269°C

[0070] -269℃ tensile strength -269℃ fracture toughness Example 1 620MPa <![CDATA[153MPa·m 1 / 2 ]]> Example 2 630MPa <![CDATA[117MPa·m 1 / 2 ]]> Example 3 645MPa <![CDATA[126MPa·m 1 / 2 <!-- 5 -->]]> Example 4 615MPa <![CDATA[139MPa·m 1 / 2 ]]> Comparative Example 1 585MPa <![CDATA[63MPa·m 1 / 2 ]]> Comparative Example 2 600MPa <![CDATA[103MPa·m 1 / 2 ]]> Comparative Example 3 610MPa <![CDATA[81MPa·m 1 / 2 ]]> Comparative Example 4 580MPa <![CDATA[110MPa·m 1 / 2 ]]>

[0071] From the data analysis in Table 1, it can be seen that the deposited metals obtained in Examples 1-4 still show high strength and fracture toughness in an ultra-low temperature environment of -269°C. In Comparative Example 1, even if other elements are within the scope of the invention requirements, the strength of the deposited metal obtained at -269°C is greatly reduced due to the low Mn content, and stable austenite cannot be formed, which greatly reduces the fracture toughness. In Comparative Examples 2 and 4, due to the reduction in the content of N and Co elements, the strength of the deposited metal in an environment of -269°C is reduced, and the ultra-low temperature fracture toughness is also slightly reduced. In Comparative Example 3, due to the lack of addition of rare earth element Y, the ultra-low temperature fracture toughness of the deposited metal is greatly reduced, and the strength is also slightly reduced.

[0072] In summary, the -269°C ultra-low temperature high manganese austenitic stainless steel welding material for liquid hydrogen storage prepared by the present invention still has high strength and high toughness in an ultra-low temperature environment of -269°C, and the deposited metal is a fully austenitic structure without a ferrite phase, has high stability, and has good resistance to hydrogen embrittlement and cracking resistance. The welding material prepared by the present invention can ensure stable operation in an ultra-low temperature environment of -269°C.

[0073] The above are only preferred specific embodiments of the present invention, which are all different implementations based on the overall concept of the present invention, and the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A liquid hydrogen storage -269℃ ultra-low temperature high manganese austenitic stainless steel submerged arc welding wire, characterized in that: The chemical composition by weight percentage includes: C≤0.03%, Si≤1%, Mn: 9.5~13%, S≤0.02%, P≤0.03%, Cr: 17~20%, Ni: 12~14.5%, Mo: 3~4.5%, Cu≤0.5%, N: 0.15~0.3%, Y: 0.001~0.005%, Co: 0.07~0.5%, and the balance is Fe.

2. The -269°C ultra-low temperature high manganese austenitic stainless steel submerged arc welding wire for liquid hydrogen storage according to claim 1 is characterized in that: The chemical composition by weight percentage includes: C≤0.03%, Si≤0.7%, Mn: 11-13%, S≤0.01%, P≤0.02%, Cr: 17-20%, Ni: 13-14%, Mo: 3-4.5%, Cu≤0.5%, N: 0.15-0.3%, Y: 0.001-0.005%, Co: 0.1-0.2%, and the balance is Fe.

3. The method for preparing -269°C ultra-low temperature high manganese austenitic stainless steel submerged arc welding wire for liquid hydrogen storage according to claim 1, characterized in that: The method: S1: putting the welding wire raw materials into the refining furnace in sequence for smelting, pouring steel ingots, forging and rolling to obtain wire rods; S2: After mechanical shelling, straightening and belt grinding, the wire rod is directly drawn into a six-roller die, and a total of 10 continuous drawing steps are performed to obtain the finished product; S3: The finished product is cleaned online, the surface is coated with an anti-rust coating, and the densely packed layers are wound on a coil to obtain the welding wire.

4. The preparation method according to claim 3, characterized in that: The diameter of the wire rod in S1 is Ф3.5mm.

5. The preparation method according to claim 3, characterized in that: The diameter of the finished product in S2 is Ф3.2mm.

6. The preparation method according to claim 3, characterized in that: The first 8 of the 10 continuous drawing passes in S2 are roller dies, and the last 2 are eye dies.

7. A flux for submerged arc welding of ultra-low temperature high manganese austenitic stainless steel at -269°C for liquid hydrogen storage, characterized in that: The flux is used in conjunction with the -269°C ultra-low temperature high manganese austenitic stainless steel submerged arc welding wire for liquid hydrogen storage as claimed in claim 1. The chemical composition of the flux includes, by weight percentage: Nb2O3: 25-40%, Cr2O3: 30-45%, SiO2: 5-15%, Al2O3: 5-10%, and CaO: 5-10%.

8. The method for preparing the flux for submerged arc welding of -269°C ultra-low temperature high manganese austenitic stainless steel for liquid hydrogen storage as claimed in claim 7, characterized in that: The method comprises the following steps: screening the mineral and alloy powders of each component through 100 meshes, weighing, dry-mixing evenly, adding 15-25% potassium sodium water glass, stirring, sintering at a high temperature of 800-850°C, and screening.

9. A welding method for -269°C ultra-low temperature high manganese austenitic stainless steel submerged arc welding for liquid hydrogen storage, characterized in that: The welding method uses the welding wire described in claim 1 and the flux described in claim 7, and the welding process parameters are: welding current 430-450A, arc voltage 28-32V, welding speed 450-550mm / min, and interpass temperature ≤100°C.

10. Application of the welding method according to claim 9 in storage and transportation of liquid hydrogen.