A gas shielded arc welding method for ultra-thin plate dissimilar metal connection

Abstract

The present invention relates to the field of welding technology, and specifically discloses a gas shielded arc welding method for connecting dissimilar metals of ultra-thin plates. The arc welding method comprises the following steps: first, designing and preparing a metal transition section C; second, designing and preparing a welding wire 1; third, setting the distance between the connected end faces of a base material A and the metal transition section C and the position of the welding wire 1, determining the type of arc welding, setting the welding mode and process parameters, and implementing welding; fourth, designing and preparing a welding wire 2; fifth, setting the distance between the connected end faces of a base material B and the metal transition section C and the position of the welding wire 2, determining the type of arc welding, setting the welding mode and process parameters, and implementing welding. The welding method provided by the present invention has the advantages of simple welding process, good flexibility, high efficiency, low cost, precise controllable heat input and temperature, ability to avoid the formation of brittle structure, small stress and deformation, excellent internal quality of the weld, no defects such as pores, cracks, weld penetration, lack of fusion and lack of penetration, and good comprehensive performance of the joint.

Description

Technical Field

[0001] The invention belongs to the technical field of welding, and in particular relates to a gas shielded arc welding method for connecting dissimilar metals of ultra-thin plates. Background Art

[0002] Dissimilar metal connection structures can maximize the performance advantages of each material and make the best use of materials. They have broad application prospects in rail transportation, aerospace, energy and chemical industry, marine equipment, daily utensils, sports equipment and medical equipment. The thickness requirements for dissimilar metal connections range from ultra-thin plates to thick plates. Especially in recent years, with the rapid development of the economy and the widespread use of new materials, the demand for ultra-thin plate dissimilar metal connections has become increasingly widespread. However, due to the significant differences in physical and chemical properties of ultra-thin plate dissimilar metals and the thin thickness of the plate, the welding methods that can be used are limited, and it is extremely difficult to achieve efficient and reliable connections.

[0003] At present, the overall ultra-thin plate dissimilar metal connection technology has problems such as low welding efficiency, high cost and poor performance. The strength and sealing of the welded joints still cannot meet the use requirements. For example, the brazing filler metal is expensive, the assembly requirements are high, the mechanical properties are low, and the requirements for structures with high airtightness requirements cannot be met; the equipment for resistance spot welding is complex, difficult to maintain, and the cost is high; laser welding equipment is expensive, the processing accuracy requirements are high, and it is difficult to connect dissimilar metals with high reflectivity; friction welding is only suitable for round section parts, and its equipment is also relatively complex. For ultra-thin plate dissimilar metal connection, the main disadvantages of various methods are as follows:

[0004] (1) Poor welding flexibility. For example, composite transition joints cannot adapt to the connection of complex dissimilar metal components.

[0005] (2) The welding efficiency is low and the welding cost is high. For example, the diffusion welding connection time is long and the electron beam welding cost is high.

[0006] (3) The form and size of the welded joint are limited. For example, brazing mostly uses lap joints, and the vacuum conditions of electron beam welding limit the size.

[0007] (4) The welding joint performance is low and the sealing performance is poor, such as brazing method;

[0008] (5) The welding process is complicated, the weld formation is poor, and defects such as pores, cracks, weld penetration, and lack of fusion are easily generated;

[0009] (6) It is difficult to completely avoid the formation of brittle structure, which reduces the overall performance of the welded joint;

[0010] (7) The stress and residual deformation of the connection structure are large, and the forming accuracy is difficult to meet the use requirements.

[0011] In summary, how to efficiently and massively achieve the connection of ultra-thin plates with dissimilar metals in order to reduce costs, how to effectively avoid the performance degradation or even cracking caused by the formation of brittle structures in the weld, how to reduce the large welding stress and deformation caused by the difference in the physical properties of dissimilar metals, and how to achieve high-quality connection of ultra-thin plates with dissimilar metals to meet performance requirements and avoid various welding defects are the core issues that need to be solved in the connection of ultra-thin plates with dissimilar metals. In order to solve these connection problems, it is necessary to adopt new combined welding materials, develop new connection processes, accurately control the heat input and temperature of the connection area, eliminate brittle structures, control stress and deformation, and form a new type of ultra-thin plate dissimilar metal connection technology. Summary of the invention

[0012] In view of the problems that the welding method for connecting dissimilar metals of ultra-thin plates has complex welding process, low efficiency, high cost, difficulty in accurately controlling heat input and temperature in the connection area, easy generation of brittle structure, poor weld formation, large welding stress and deformation, easy generation of defects such as pores, cracks, weld penetration, and lack of fusion, difficulty in regulating the structure of the welded joint, and poor sealing and mechanical properties, the present invention proposes a gas shielded arc welding method for connecting dissimilar metals of ultra-thin plates.

[0013] In order to achieve the above-mentioned object of the invention, the present invention is implemented by adopting the following technical solutions:

[0014] A gas shielded arc welding method for ultra-thin plate dissimilar metal connection comprises the following steps:

[0015] (1) designing and preparing a metal transition section C according to the composition, components, physical and chemical properties and shape characteristics of the base material A and base material B in the dissimilar metals to be connected;

[0016] (2) designing the type, composition and content of the welding wire 1 having good chemical compatibility with the base material A and the metal transition section C according to the composition, components, physical and chemical properties of the base material A and the metal transition section C to be connected, and preparing the welding wire 1;

[0017] (3) The connected end face of the base material A and the connected end face of the metal transition section C have a suitable spacing, the type of gas shielded arc welding is determined, the gas shielded arc welding mode and welding process parameters are set, the welding gas supply system and welding equipment are started, the axial extension line of the welding wire 1 is directed to the connected end face, and gas shielded arc welding is performed;

[0018] (4) designing the type, composition and content of the welding wire 2 having good chemical compatibility with the base material B and the metal transition section C according to the composition, components, physical and chemical properties of the base material B and the metal transition section C to be connected, and preparing the welding wire 2;

[0019] (5) The connected end face of the base material B and the connected end face of the metal transition section C have an appropriate spacing, the type of gas shielded arc welding is determined, the gas shielded arc welding mode and welding process parameters are set, the welding gas supply system and welding equipment are started, the intersection of the axial extension line of the welding wire 2 and the surface of the metal transition section C is at an appropriate distance from the point closest to the connected end face of the metal transition section C, and the distance is kept unchanged during the welding process, and gas shielded arc welding is implemented.

[0020] The basic principle of a gas shielded arc welding method for ultra-thin plate dissimilar metal joining is as follows:

[0021] First, a metal transition section C is designed, which requires good chemical compatibility between the metal transition section C and the base material A, and the designed welding wire 1 is required to have good chemical compatibility with both the base material A and the metal transition section C, so as to avoid the formation of brittle structures such as brittle intermetallic compounds at the connection joint between the base material A and the metal transition section C, which leads to poor weld performance or even cracking. Since the chemical compatibility between the base material A and the base material B is poor, brittle intermetallic compounds will be formed if they are directly melted and connected. Therefore, the metal transition section C is used for isolation to achieve the connection between the base material A and the metal transition section C. The designed metal transition section C has good chemical compatibility with the base material A, and the used welding wire 1 has good chemical compatibility with both the metal transition section C and the base material A. The connected end face of the base material A and the connected end face of the metal transition section C have a suitable spacing. Therefore, the connection joint between the metal transition section C and the base material A can eliminate the brittle structure, so that the weld is well formed, and the welding quality between the base material A and the metal transition section C is ensured.

[0022] Secondly, the melting point of the designed metal transition section C is greater than that of the base material B, and the heat input and temperature of the connection zone are precisely controlled by designing the welding wire 2, adjusting the welding position of the welding wire 2, and regulating the distance between the end face of the connected metal transition section C and the end face of the base material B, so as to avoid the formation of brittle structure in the connection joint of the base material B and the metal transition section C. Due to the large difference in physical properties and poor chemical compatibility between the dissimilar metal base materials A and B, it is difficult to simultaneously meet the requirements of good chemical compatibility with both the base materials A and B by using a single metal transition section C. If the types and quantities of metal transition sections need to be increased in order to meet the chemical compatibility, the welding process will be complicated, the number of welds will increase, the cost will increase, the welding efficiency will decrease, and the welding stress and deformation will be large. Therefore, a single metal transition section must be used. However, due to the poor chemical compatibility between the metal transition section C and the base material B, in order to avoid the formation of brittle structures such as intermetallic compounds when the two are connected, strict requirements need to be imposed on the physical and chemical properties of the metal transition section C, the base material B and the welding wire 2, as well as the welding process. Therefore, on the one hand, it is required that the connected end face of the base material B and the connected end face of the metal transition section C have an appropriate spacing to isolate the base material B and the metal transition section C. At the same time, it is required that the chemical compatibility of the welding wire 2 with the metal transition section C and the base material B is good, so that after the welding wire 2 is melted, it fills the gap between the connected end face of the base material B and the connected end face of the metal transition section C to avoid direct contact between the metal transition section C and the base material B and eliminate the brittle structure. On the other hand, it is required that the melting point of the metal transition section C is greater than that of the base material B, and the melting point of the base material B is greater than the melting point of the welding wire 2. The position of the welding wire 2 is set, and the distance between the intersection of the axial extension line of the welding wire 2 and the surface of the metal transition section C and the point closest to the connected end face of the metal transition section C is appropriate. Therefore, first of all, since the melting point of the metal transition section C is the highest, by pointing the welding wire 2 to the side of the metal transition section C, that is, directing the corresponding arc to On one side of the metal transition section C, the metal transition section C is slightly melted, and a micro-melting connection is achieved on the side of the metal transition section C to avoid forming a brazing connection. At the same time, it also avoids excessive melting of the metal transition section C, that is, the dilution rate of the metal transition section is high, resulting in excessive diffusion of the melted elements of the metal transition section C into the molten pool, thereby mixing and contacting with the elements of the parent material B entering the molten pool to form brittle structures such as intermetallic compounds. Secondly, the welding wire 2 is directed to one side of the metal transition section C, that is, the arc center is deviated from the parent material B, thereby reducing the heat input of the parent material B, reducing the heat absorbed by the parent material B, and lowering the temperature of the parent material B, thereby avoiding the parent material temperature being too high and excessive melting, resulting in the parent material B being welded through. At the same time, it also avoids the dilution rate of the parent material B being too large, resulting in excessive diffusion of the melted elements of the parent material B into the molten pool, thereby mixing and contacting with a small amount of elements of the metal transition section C entering the molten pool to form brittle structures such as intermetallic compounds.Therefore, by designing the metal transition section C and the welding wire 2, setting the distance between the connected end faces, and adjusting the position of the welding wire 2, it is possible to avoid the formation of brittle structure and the formation of a brazing joint on one side of the high-melting-point metal transition section, thereby reducing the mechanical properties and sealing properties, avoid welding penetration of the low-melting-point base material B and excessive dilution rate of the base material B, eliminate welding defects and brittle structure, and ensure the welding quality and performance between the base material B and the metal transition section C.

[0023] Thirdly, appropriate gas shielded arc welding types, welding modes and welding processes are used, as well as the position of the welding wire 2 is precisely adjusted and the distance between the connected end faces of the base material B and the connected end faces of the metal transition section C is regulated, so as to precisely control the heat input and temperature of the connection area between the base material B and the metal transition section C, and ensure that a micro-melting connection with a low dilution rate is formed on one side of the metal transition section C, so as to avoid the reduction in sealing and low mechanical properties of the connection joint caused by brazing, and to avoid the formation of brittle structure or even cracking in the weld area caused by a high dilution rate.

[0024] From this, the shapes of the base material A, base material B and metal transition section C include plane type and three-dimensional type. The shape of the metal transition section C is determined according to the shapes of the connected base materials A and B and the requirements of the connected components. If the shapes of the connected base materials A and B are circular plane type, then the shape of the metal transition section C can be circular plane type or cylindrical three-dimensional type. If the shapes of the connected base materials A and B are cylindrical three-dimensional type, then the shape of the metal transition section C is also cylindrical three-dimensional type, thereby ensuring that ultra-thin plate dissimilar metals of any shape can be connected and complex ultra-thin plate dissimilar metal connection components can be prepared.

[0025] Finally, appropriate gas shielded arc welding types, welding modes and welding processes are used, the distance between the connected end faces is optimized, the position of the welding wire is accurately adjusted, and the heat input and temperature of the connection areas between the base material A and the metal transition section C, and the base material B and the metal transition section C are accurately controlled, thereby achieving comprehensive regulation of the organization and performance of each connection area, reducing stress and deformation, avoiding defects such as welding through, lack of fusion, cracks, and incomplete penetration, and achieving excellent weld formation, so that the internal quality of the weld and the overall performance of the joint are excellent.

[0026] Compared with the prior art, the gas shielded arc welding method for ultra-thin plate dissimilar metal connection provided by the present invention has the beneficial effect of being able to solve the problems of ultra-thin plate dissimilar metal connection such as large stress and deformation caused by large difference in physical properties, poor chemical compatibility and too thin plate, easy formation of brittle structure in weld, poor performance of weld joint and easy welding through. The welding method provided by the present invention has simple welding process, good welding flexibility, high welding efficiency, low cost, precise and controllable heat input and temperature in the connection zone, can avoid coarse grains in the heat affected zone, can avoid the formation of brittle structure, can avoid the formation of brazing, has small welding stress and deformation, good weld formation, easy regulation of weld joint structure and performance, excellent internal quality of weld, no defects such as pores, cracks, welding through, incomplete fusion and incomplete welding, and excellent comprehensive performance of the weld joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a welding flow chart of gas shielded arc welding for joining dissimilar metals on ultra-thin plates.

[0028] Figure 2 It is a schematic diagram of the gas shielded arc welding process for connecting dissimilar metals in ultra-thin plates, wherein 1 is base material A, 2 is metal transition section C, 3 is base material B, 4 is welding wire 1, 5 is welding wire 2, 6 is the distance between the connected end face of base material A and the connected end face of metal transition section C, 7 is the distance between the connected end face of base material B and the connected end face of metal transition section C, 8 is the distance between the intersection of the axial extension line of welding wire 2 and the surface of metal transition section C and the point closest to the connected end face of metal transition section C, 9 is the welding direction connecting base material A and metal transition section C, and 10 is the welding direction connecting base material B and metal transition section C. DETAILED DESCRIPTION

[0029] 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.

[0030] The embodiment of the present invention provides a gas shielded arc welding method for ultra-thin plate dissimilar metal connection. The method comprises the following steps:

[0031] (1) designing and preparing a metal transition section C according to the composition, components, physical and chemical properties and shape characteristics of the base material A and base material B in the dissimilar metals to be connected;

[0032] (2) designing the type, composition and content of the welding wire 1 having good chemical compatibility with the base material A and the metal transition section C according to the composition, components, physical and chemical properties of the base material A and the metal transition section C to be connected, and preparing the welding wire 1;

[0033] (3) The connected end face of the base material A and the connected end face of the metal transition section C have a suitable spacing, the type of gas shielded arc welding is determined, the gas shielded arc welding mode and welding process parameters are set, the welding gas supply system and welding equipment are started, the axial extension line of the welding wire 1 is directed to the connected end face, and gas shielded arc welding is performed;

[0034] (4) designing the type, composition and content of the welding wire 2 having good chemical compatibility with the base material B and the metal transition section C according to the composition, components, physical and chemical properties of the base material B and the metal transition section C to be connected, and preparing the welding wire 2;

[0035] (5) The connected end face of the base material B and the connected end face of the metal transition section C have an appropriate spacing, the type of gas shielded arc welding is determined, the gas shielded arc welding mode and welding process parameters are set, the welding gas supply system and welding equipment are started, the intersection of the axial extension line of the welding wire 2 and the surface of the metal transition section C is at an appropriate distance from the point closest to the connected end face of the metal transition section C, and the distance is kept unchanged during the welding process, and gas shielded arc welding is implemented.

[0036] Specifically, in step (1), a metal transition section C is designed according to the composition, components, physical and chemical properties and shape characteristics of the base materials A and B in the dissimilar metals to be connected, so that the base materials A and the metal transition section C are connected, and the metal transition section C and the base material B are connected, that is, the base materials A and the base material B are indirectly connected, so as to avoid the brittle structure formed by the poor compatibility of chemical elements caused by the direct connection of the base materials A and the base material B, which makes the weld performance deteriorate or even crack.

[0037] In step (2), a welding wire 1 having good chemical compatibility with both the base material A and the metal transition section C is designed according to the composition, components, physical and chemical properties of the base material A and the metal transition section C to be connected. The base material A and the metal transition section C are connected by the welding wire 1. Due to the good chemical compatibility of the three, the molten welding wire 1 is mixed with the partially molten base material A and the partially molten metal transition section C to form a molten pool, and the weld formed after solidification can avoid the formation of a brittle structure.

[0038] In step (3), the connected end faces of the base material A and the connected end faces of the metal transition section C have a suitable spacing, the gas shielded arc welding mode and welding process parameters are set, the axial extension line of the welding wire 1 points to the connected end faces, and by optimizing the connected end face spacing, welding mode, process parameters and welding wire position, the heat input and temperature of the connection area are precisely controlled to ensure that the base material A and the metal transition section C can be connected with high quality after the welding wire is melted, the weld is well formed, and the stress and deformation are small.

[0039] In step (4), a welding wire 2 having good chemical compatibility with both the base material B and the metal transition section C is designed according to the composition, components, physical and chemical properties of the base material B and the metal transition section C to be connected, so that the welding wire 2 is filled into the gap between the connected end face of the base material B and the connected end face of the metal transition section C after melting, thereby connecting the base material B and the metal transition section C, avoiding direct contact between the metal transition section C and the base material B, and eliminating the brittle structure.

[0040] In step (5), the connected end face of the base material B and the connected end face of the metal transition section C have a suitable spacing, the gas shielded arc welding mode and welding process parameters are set, the intersection of the axial extension line of the welding wire 2 and the surface of the metal transition section C is at a suitable distance from the point closest to the connected end face of the metal transition section C, and the distance is kept unchanged during the welding process. In this way, by setting the optimal distance between the connected end faces, optimizing the welding mode, process parameters and welding wire position, and accurately controlling the heat input and temperature of the connection area, it is possible to avoid the formation of brittle structure, avoid the formation of brazing joints at the connection of the high melting point metal transition section C, thereby reducing the mechanical properties and sealing, avoid the low melting point base material B being welded through and the base material B being too diluted, thereby eliminating welding defects and brittle structure, ensuring welding quality and performance. On the one hand, the welding wire 2 is directed to the side of the metal transition section C, that is, the corresponding arc is directed to the side of the metal transition section C, so that the high melting point metal transition section C is slightly melted, and the metal transition section C is melted in the metal transition section. A micro-melting connection is achieved on the side of the transition section C to avoid the formation of a brazing connection. At the same time, it also avoids excessive melting of the metal transition section C, which makes the dilution rate of the metal transition section C high, causing the molten elements of the metal transition section C to diffuse too much into the molten pool, thereby mixing and contacting with the elements of the parent material B entering the molten pool to form a brittle structure. In addition, by controlling the distance between the connected end faces, the parent material B and the metal transition section C are isolated, and the contact and reaction of the partially melted elements of the metal transition section C with the partially melted elements of the parent material B to form a brittle structure. On the other hand, the welding wire 2 is directed to one side of the metal transition section C, that is, the arc center deviates from the parent material B, thereby reducing the heat input of the parent material B, reducing the heat absorbed by the parent material B, and reducing the temperature of the parent material B, avoiding excessive melting and causing welding through of the parent material B. At the same time, it also avoids an excessively large dilution rate of the parent material B, causing the molten elements of the parent material B to diffuse too much into the molten pool, thereby mixing and contacting with a small amount of elements of the metal transition section C entering the molten pool to form a brittle structure.

[0041] Preferably, the shapes of the base material A, base material B and metal transition section C include planar and three-dimensional types, so that the shape of the metal transition section C is determined according to the shapes of the connected base materials A and base materials B and the requirements of the connected components, thereby realizing the connection of ultra-thin plate dissimilar metals of any shape and preparing various complex ultra-thin plate dissimilar metal connection components.

[0042] Preferably, the base material A and the metal transition section C have good chemical compatibility, thereby avoiding the formation of brittle structures such as intermetallic compounds at the connection joint between the base material A and the metal transition section C, which may lead to poor weld performance or even cracking.

[0043] Preferably, the melting point of the metal transition section C is greater than the melting point of the base material B, and the melting point of the base material B is greater than the melting point of the welding wire 2, so that the metal transition section C melts slightly to avoid forming a brazing connection, and at the same time avoids excessive melting of the metal transition section C, so that the elements of the metal transition section C diffuse too much into the molten pool, mix and contact with the elements of the base material B entering the molten pool, and form a brittle structure. In addition, the base material B is melted appropriately to avoid welding through, and it is also avoided that the base material B melts too much, resulting in an excessive dilution rate, so that the elements of the base material B diffuse too much into the molten pool, mix and contact with a small amount of elements of the metal transition section C entering the molten pool, and form a brittle structure.

[0044] Preferably, the thickness of the base material A, base material B and metal transition section C in the dissimilar metals is 0.2-1.5 mm, thereby meeting the connection thickness requirement of ultra-thin plate dissimilar metals.

[0045] Preferably, the types of welding wires include solid welding wires and flux-cored welding wires, so that the composition and content design of welding wire 1 for connecting base material A and metal transition section C and welding wire 2 for connecting base material B and metal transition section C are easier and more efficient.

[0046] Preferably, the distance between the connected end face of the base material A and the connected end face of the metal transition section C is 0 to 2 mm. By adjusting and optimizing the distance between the connected end face of the base material A and the connected end face of the metal transition section C, it is convenient to regulate heat input and temperature, control weld formation, eliminate welding defects, and improve welding quality.

[0047] Preferably, the distance between the connected end face of the base material B and the connected end face of the metal transition section C is 0.1 to 2 mm. By adjusting and optimizing the distance between the connected end face of the base material B and the connected end face of the metal transition section C, the base material B and the metal transition section C can be isolated, so that the molten welding wire can be easily filled into the gap, and direct contact between the elements in the base material B and the metal transition section C can be avoided, that is, the brittle structure caused by poor chemical compatibility can be eliminated. At the same time, it is easy to regulate the heat input and temperature to obtain excellent weld formation, eliminate welding defects, avoid the formation of brazing connection, and improve welding quality and performance.

[0048] Preferably, the distance between the intersection of the axial extension line of the welding wire 2 and the surface of the metal transition section C and the point closest to the connected end face of the metal transition section C is 0.1 to 2 mm. On the one hand, due to the high melting point of the metal transition section C, a suitable distance between the intersection of the axial extension line of the welding wire 2 and the surface of the metal transition section C and the point closest to the connected end face of the metal transition section C is set, so that the welding wire 2 points to one side of the metal transition section C, and the arc center heats this part. Due to the high temperature of the arc center, the connected part of the metal transition section C can be prevented from not melting, and the metal transition section C can be melted slightly, thereby avoiding the formation of the metal transition section C not melting. Brazing connection. At the same time, due to the high melting point of the metal transition section C, the dilution rate of the metal transition section C is low, which avoids the molten elements of the metal transition section C from diffusing too much into the molten pool, and mixing and contacting with the elements of the base material B entering the molten pool to form a brittle structure. On the other hand, the arc center deviates from the base material B, which reduces the heat input and temperature of the base material B, making the dilution rate of the base material B lower, avoiding the molten elements of the base material B from diffusing too much into the molten pool, and thus mixing and contacting with a small amount of elements of the metal transition section C entering the molten pool to form a brittle structure, and also avoiding excessive melting of the base material B to cause welding penetration. In addition, the melting flow of the low-melting point welding wire 2 can ensure excellent weld formation.

[0049] Preferably, the gas shielded arc welding types include metal-metal gas shielded arc welding and non-metal-metal gas shielded arc welding, which facilitates the selection of a suitable gas shielded arc welding method according to the plate thickness and physical and chemical properties of the connected base materials A, base materials B and metal transition section C.

[0050] Preferably, the non-melting electrode gas shielded arc welding includes tungsten inert gas arc welding and plasma arc welding, which is convenient for selecting a suitable non-melting electrode gas shielded arc welding method according to the plate thickness and physical and chemical properties of the connected base materials A, base materials B and metal transition section C.

[0051] Preferably, the shielding gas of the gas supply system is at least one of Ar, He, CO2, O2, and N2. Different shielding gases are selected according to the types of base materials A, base materials B, and metal transition section C, connection costs, and efficiency, so that the connection is carried out under gas protection to ensure the internal quality of the weld and excellent weld formation. At the same time, the shielding gas serves as a medium for generating an arc, maintaining stable burning of the arc and ensuring a stable welding process.

[0052] Preferably, the welding mode of the consumable electrode gas shielded arc welding is a CMT mode, a pulse mode, a DC mode or an AC mode, and the welding mode of the non-consumable electrode gas shielded arc welding is a pulse mode, a DC mode or an AC mode, so as to select a suitable welding mode according to the composition, physical and chemical properties of the base material A, the base material B, the metal transition section C and the two welding wires, the thickness of the base material A, the base material B and the metal transition section C, and the diameters of the two welding wires, so as to accurately control the heat input and temperature of each connection area, avoid coarse grains in the heat-affected zone, avoid welding through due to excessive heat input, avoid the formation of brittle structure or even cracking in the weld zone due to a large dilution rate of the base material B and the metal transition section C, and avoid the formation of brazing due to insufficient heat input, so as to eliminate welding defects, improve weld formation, and improve welding quality and performance.

[0053] Preferably, the welding process parameters of the consumable electrode gas shielded arc welding are: an average welding current of 20 to 200A, an average arc voltage of 6 to 20V, a welding speed of 0.3 to 4m / min, a wire extension length of 6 to 20mm, a wire diameter of 0.6 to 1.6mm, and a gas flow rate of 5 to 30L / min. By adjusting the welding process parameters, the welding heat input and temperature are precisely controlled, and the melting amount of the welding wire and the base material is controlled to avoid coarse grains in the heat affected zone, avoid welding penetration caused by excessive heat input, avoid the formation of brittle structure or even cracking in the weld zone due to a large dilution rate of the base material B and the metal transition section C, and avoid problems such as brazing caused by the failure of the metal transition section C to melt due to insufficient heat input. This ensures that the welding process is stable, the weld is beautiful, defects such as pores, cracks, welding penetration, incomplete fusion and incomplete penetration are eliminated, the internal quality of the weld is excellent, and a connection joint with excellent comprehensive performance is formed.

[0054] Preferably, the non-melting electrode gas shielded arc welding welding process parameters are: average welding current of 20-150A, average arc voltage of 6-15V, welding speed of 0.3-2m / min, wire diameter of 0.6-1.6mm, gas flow rate of 5-30L / min. By adjusting the welding process parameters, the welding heat input and temperature are precisely controlled, the melting amount of the welding wire and the base material is controlled, the coarse grains in the heat affected zone are avoided, the welding penetration caused by excessive heat input is avoided, the formation of brittle structure or even cracking in the weld zone due to the large dilution rate of the base material B and the metal transition section C is avoided, and the problem of brazing caused by the failure of the metal transition section C to melt due to insufficient heat input is avoided. The welding process is stable, the weld is beautiful, defects such as pores, cracks, welding penetration, incomplete fusion and incomplete penetration are eliminated, the internal quality of the weld is excellent, and a connection joint with excellent comprehensive performance is formed.

[0055] The gas shielded arc welding method for connecting dissimilar metals of ultra-thin plates has the advantages of simple welding process, good welding flexibility, high welding efficiency, low welding cost, precise and controllable heat input and temperature in the connection zone, and can avoid coarse grains in the heat-affected zone, avoid the formation of brittle structure, avoid the formation of brazing, small welding stress and deformation, excellent weld formation, easy regulation of weld joint structure and performance, excellent internal weld quality, no defects such as pores, cracks, weld penetration, lack of fusion and lack of penetration, and excellent comprehensive performance of the weld joint, which can effectively solve the connection problems of large stress and deformation, easy formation of brittle structure in the weld, poor performance of the weld joint and easy weld penetration in the connection of dissimilar metals of ultra-thin plates.

[0056] In order to better illustrate the gas shielded arc welding method for ultra-thin plate dissimilar metal connection provided by the present invention, further examples are given below.

[0057] Example 1

[0058] A gas shielded arc welding method for connecting ultra-thin TC4 titanium alloy and 316L stainless steel dissimilar metals, wherein the connecting parent materials are TC4 titanium alloy and 316L stainless steel, the thickness of the TC4 titanium alloy is 0.6 mm, the thickness of the 316L stainless steel is 0.6 mm, and the shapes are both cylindrical three-dimensional. The two materials have poor chemical compatibility, and the Ti element in the TC4 titanium alloy and the Fe, Ni, and Cr elements in the 316L stainless steel are easy to generate brittle structures. The linear expansion coefficient, thermal conductivity, specific heat capacity and other physical properties of the TC4 titanium alloy and the 316L stainless steel are also quite different. In order to implement the ultra-thin TC4 titanium alloy and 316L stainless steel dissimilar metal connection, the method specifically includes the following steps:

[0059] (1) According to the composition, components, physical and chemical properties and shape characteristics of the parent materials TC4 titanium alloy and 316L stainless steel in the dissimilar metals to be connected, the metal transition section is designed to be pure vanadium, with a thickness of 0.6 mm and a cylindrical three-dimensional shape. Its composition is shown in Table 1. The parent material TC4 titanium alloy and the pure vanadium of the metal transition section have good chemical compatibility, and the melting point of the pure vanadium of the metal transition section is greater than the melting point of the parent material 316L stainless steel, so as to prepare the pure vanadium of the metal transition section;

[0060] (2) according to the composition, components, physical and chemical properties of the base material TC4 titanium alloy and the pure vanadium in the metal transition section to be connected, a welding wire 1 having good chemical compatibility with the base material TC4 titanium alloy and the pure vanadium in the metal transition section is designed, the type, composition and content of the welding wire 1 are shown in Table 1, and the welding wire 1 is prepared;

[0061] (3) The spacing between the connected end face of the parent material TC4 titanium alloy and the connected end face of the metal transition section pure vanadium is set to 0.2 mm, the gas shielded arc welding type is determined to be metal-metal gas shielded arc welding, the gas shielded arc welding mode is set to CMT mode, and the metal-metal gas shielded arc welding process parameters are set to: average welding current is 70 A, average arc voltage is 9 V, welding speed is 1.6 m / min, wire dry extension length is 8 mm, wire diameter is 0.8 mm, shielding gas is a mixed gas of Ar and He, gas flow rate is 10 L / min, welding gas supply system and welding equipment are started, the axial extension line of welding wire 1 is pointed to the connected end face, and metal-metal gas shielded arc welding is performed;

[0062] (4) according to the composition, components, physical and chemical properties of the base material 316L stainless steel and the pure vanadium in the metal transition section to be connected, a welding wire 2 having good chemical compatibility with the base material 316L stainless steel and the pure vanadium in the metal transition section is designed, the type, composition and content of the welding wire 2 are shown in Table 1, and the welding wire 2 is prepared;

[0063] (5) The spacing between the connected end face of the base material 316L stainless steel and the connected end face of the pure vanadium in the metal transition section is set to 0.7 mm, the gas shielded arc welding type is determined to be non-melting electrode gas shielded arc welding, the gas shielded arc welding mode is set to pulse mode, and the non-melting electrode gas shielded arc welding process parameters are set to: average welding current is 30 A, average arc voltage is 7 V, welding speed is 0.3 m / min, welding wire diameter is 0.8 mm, shielding gas is Ar gas, gas flow rate is 7 L / min, welding gas supply system and welding equipment are started, and the distance between the intersection of the axial extension line of welding wire 2 and the surface of the pure vanadium in the metal transition section and the point closest to the connected end face of the pure vanadium in the metal transition section is set to 0.5 mm, and the distance is kept unchanged during the welding process to implement non-melting electrode gas shielded arc welding.

[0064] Table 1 Type, composition and content of metal transition section and welding wire

[0065]

[0066] Example 2

[0067] A gas shielded arc welding method for connecting ultra-thin TA0 pure titanium and 304 stainless steel dissimilar metals, wherein the connecting parent materials are TA0 pure titanium and 304 stainless steel, the thickness of TA0 pure titanium is 0.2 mm, the thickness of 304 stainless steel is 0.2 mm, and the shapes are both circular ring planes. The two materials have poor chemical compatibility, and the Ti element in TA0 pure titanium and the Fe, Ni, and Cr elements in 304 stainless steel are easy to generate brittle structures. The linear expansion coefficient, thermal conductivity, specific heat capacity and other physical properties of TA0 pure titanium and 304 stainless steel are also quite different. In order to implement the ultra-thin TA0 pure titanium and 304 stainless steel dissimilar metal connection, the method specifically includes the following steps:

[0068] (1) According to the composition, components, physical and chemical properties and shape characteristics of the parent materials TA0 pure titanium and 304 stainless steel in the dissimilar metals to be connected, the metal transition section is designed to be pure niobium, with a thickness of 0.2 mm and a circular plane shape. Its composition is shown in Table 2. The parent material TA0 pure titanium and the metal transition section pure niobium have good chemical compatibility, and the melting point of the metal transition section pure niobium is greater than the melting point of the parent material 304 stainless steel, so the metal transition section pure niobium is prepared;

[0069] (2) According to the composition, components, physical and chemical properties of the base material TA0 pure titanium and the metal transition section pure niobium to be connected, a welding wire 1 having good chemical compatibility with the base material TA0 pure titanium and the metal transition section pure niobium is designed. The type, composition and content of the welding wire 1 are shown in Table 2, and the welding wire 1 is prepared;

[0070] (3) The distance between the connected end face of the parent material TA0 pure titanium and the connected end face of the metal transition section pure niobium is set to 0 mm, the gas shielded arc welding type is determined to be metal-metal gas shielded arc welding, the gas shielded arc welding mode is set to CMT mode, and the metal-metal gas shielded arc welding process parameters are set to: average welding current is 30 A, average arc voltage is 8 V, welding speed is 0.4 m / min, wire dry extension length is 6 mm, wire diameter is 0.6 mm, shielding gas is Ar gas, gas flow rate is 6 L / min, welding gas supply system and welding equipment are started, the axial extension line of welding wire 1 is pointed to the connected end face, and metal-metal gas shielded arc welding is performed;

[0071] (4) According to the composition, components, physical and chemical properties of the base material 304 stainless steel and the pure niobium in the metal transition section to be connected, a welding wire 2 having good chemical compatibility with the base material 304 stainless steel and the pure niobium in the metal transition section is designed. The type, composition and content of the welding wire 2 are shown in Table 2, and the welding wire 2 is prepared;

[0072] (5) The spacing between the connected end face of the base material 304 stainless steel and the connected end face of the pure niobium in the metal transition section is set to 0.3 mm, the gas shielded arc welding type is determined to be metal-metal gas shielded arc welding, the gas shielded arc welding mode is set to CMT mode, and the metal-metal gas shielded arc welding process parameters are set to: average welding current is 45 A, average arc voltage is 8.6 V, welding speed is 1.2 m / min, wire dry extension length is 7 mm, wire diameter is 0.6 mm, shielding gas is a mixed gas of Ar and He, gas flow rate is 15 L / min, welding gas supply system and welding equipment are started, and the distance between the intersection of the axial extension line of welding wire 2 and the surface of the pure niobium in the metal transition section and the point closest to the connected end face of the pure niobium in the metal transition section is set to 0.1 mm, and the distance is kept unchanged during the welding process, and metal-metal gas shielded arc welding is implemented.

[0073] Table 2 Type, composition and content of metal transition section and welding wire

[0074]

[0075] Example 3

[0076] A gas shielded arc welding method for connecting ultra-thin TA1 pure titanium and 316 stainless steel dissimilar metals, wherein the connecting parent materials are TA1 pure titanium and 316 stainless steel, the thickness of TA1 pure titanium is 0.5 mm, the thickness of 316 stainless steel is 0.5 mm, and the shapes are both elliptical ring plane type. The two materials have poor chemical compatibility, and the Ti element in TA1 pure titanium and the Fe, Ni, and Cr elements in 316 stainless steel are easy to generate brittle structures. The physical properties such as linear expansion coefficient, thermal conductivity and specific heat capacity of TA1 pure titanium and 316 stainless steel are also quite different. In order to implement the ultra-thin TA1 pure titanium and 316 stainless steel dissimilar metal connection, the method specifically includes the following steps:

[0077] (1) According to the composition, components, physical and chemical properties and shape characteristics of the parent materials TA1 pure titanium and 316 stainless steel in the dissimilar metals to be connected, the metal transition section is designed to be a niobium-based alloy with a thickness of 0.5 mm and an elliptical ring plane shape. Its composition is shown in Table 3. The parent material TA1 pure titanium and the niobium-based alloy of the metal transition section have good chemical compatibility. The melting point of the niobium-based alloy of the metal transition section is greater than the melting point of the parent material 316 stainless steel. The niobium-based alloy of the metal transition section is prepared;

[0078] (2) According to the composition, components, physical and chemical properties of the base material TA1 pure titanium and the metal transition section niobium-based alloy to be connected, a welding wire 1 having good chemical compatibility with the base material TA1 pure titanium and the metal transition section niobium-based alloy is designed. The type, composition and content of the welding wire 1 are shown in Table 3, and the welding wire 1 is prepared;

[0079] (3) The spacing between the connected end face of the base material TA1 pure titanium and the connected end face of the metal transition section niobium-based alloy is set to 0.3 mm, the gas shielded arc welding type is determined to be metal-shielded gas shielded arc welding, the gas shielded arc welding mode is set to pulse mode, and the metal-shielded gas shielded arc welding process parameters are set to: average welding current is 80 A, average arc voltage is 14 V, welding speed is 2.4 m / min, wire dry extension length is 14 mm, wire diameter is 1.2 mm, shielding gas is He gas, gas flow rate is 25 L / min, welding gas supply system and welding equipment are started, the axial extension line of welding wire 1 is pointed to the connected end face, and metal-shielded gas shielded arc welding is performed;

[0080] (4) According to the composition, components, physical and chemical properties of the base material 316 stainless steel and the niobium-based alloy in the metal transition section to be connected, a welding wire 2 having good chemical compatibility with the base material 316 stainless steel and the niobium-based alloy in the metal transition section is designed. The type, composition and content of the welding wire 2 are shown in Table 3, and the welding wire 2 is prepared;

[0081] (5) The spacing between the connected end face of the base material 316 stainless steel and the connected end face of the niobium-based alloy in the metal transition section is set to 0.5 mm, the gas shielded arc welding type is determined to be metal-metal gas shielded arc welding, the gas shielded arc welding mode is set to CMT mode, and the metal-metal gas shielded arc welding process parameters are set to: average welding current is 55 A, average arc voltage is 8.5 V, welding speed is 0.8 m / min, wire dry extension length is 12 mm, wire diameter is 0.8 mm, shielding gas is a mixed gas of Ar and He, gas flow rate is 20 L / min, welding gas supply system and welding equipment are started, and the distance between the intersection of the axial extension line of welding wire 2 and the surface of the niobium-based alloy in the metal transition section and the point closest to the connected end face of the niobium-based alloy in the metal transition section is set to 0.9 mm, and the distance is kept unchanged during the welding process, and metal-metal gas shielded arc welding is implemented.

[0082] Table 3 Type, composition and content of metal transition section and welding wire

[0083]

[0084] Example 4

[0085] A gas shielded arc welding method for connecting ultra-thin TA15 titanium alloy and CP800 high-strength steel dissimilar metals, wherein the connecting parent materials are TA15 titanium alloy and CP800 high-strength steel, the thickness of the TA15 titanium alloy is 1.2 mm, the thickness of the CP800 high-strength steel is 1.2 mm, and the shapes are both cylindrical three-dimensional. The two materials have poor chemical compatibility, and the Ti element in the TA15 titanium alloy and the Fe element in the CP800 high-strength steel are easy to generate brittle structures. The linear expansion coefficient, thermal conductivity, specific heat capacity and other physical properties of the TA15 titanium alloy and the CP800 high-strength steel are also quite different. In order to implement the ultra-thin TA15 titanium alloy and CP800 high-strength steel dissimilar metal connection, the method specifically includes the following steps:

[0086] (1) According to the composition, components, physical and chemical properties and shape characteristics of the parent materials TA15 titanium alloy and CP800 high-strength steel in the dissimilar metals to be connected, the metal transition section is designed to be a niobium-based alloy with a thickness of 1.2 mm and a cylindrical three-dimensional shape. Its composition is shown in Table 4. The parent material TA15 titanium alloy and the niobium-based alloy of the metal transition section have good chemical compatibility. The melting point of the niobium-based alloy of the metal transition section is greater than the melting point of the parent material CP800 high-strength steel. The niobium-based alloy of the metal transition section is prepared;

[0087] (2) According to the composition, components, physical and chemical properties of the base material TA15 titanium alloy and the metal transition section niobium-based alloy to be connected, a welding wire 1 having good chemical compatibility with the base material TA15 titanium alloy and the metal transition section niobium-based alloy is designed, the type, composition and content of the welding wire 1 are shown in Table 4, and the welding wire 1 is prepared;

[0088] (3) The spacing between the connected end face of the parent material TA15 titanium alloy and the connected end face of the metal transition section niobium-based alloy is set to 1.2 mm, the gas shielded arc welding type is determined to be non-melting electrode gas shielded arc welding, the gas shielded arc welding mode is set to DC mode, and the non-melting electrode gas shielded arc welding process parameters are set to: average welding current is 80 A, average arc voltage is 9 V, welding speed is 0.9 m / min, wire diameter is 1.0 mm, shielding gas is a mixed gas of Ar and He, gas flow rate is 15 L / min, the welding gas supply system and welding equipment are started, the axial extension line of the welding wire 1 is pointed to the connected end face, and non-melting electrode gas shielded arc welding is performed;

[0089] (4) According to the composition, components, physical and chemical properties of the parent material CP800 high-strength steel and the metal transition section niobium-based alloy to be connected, a welding wire 2 having good chemical compatibility with the parent material CP800 high-strength steel and the metal transition section niobium-based alloy is designed. The type, composition and content of the welding wire 2 are shown in Table 4, and the welding wire 2 is prepared;

[0090] (5) The spacing between the connected end face of the base material CP800 high-strength steel and the connected end face of the niobium-based alloy in the metal transition section is set to 1.5 mm, the gas shielded arc welding type is determined to be non-melting electrode gas shielded arc welding, the gas shielded arc welding mode is set to pulse mode, and the non-melting electrode gas shielded arc welding process parameters are set to: average welding current is 60 A, average arc voltage is 10 V, welding speed is 0.8 m / min, welding wire diameter is 0.8 mm, shielding gas is He gas, gas flow rate is 28 L / min, welding gas supply system and welding equipment are started, and the distance between the intersection of the axial extension line of welding wire 2 and the surface of the niobium-based alloy in the metal transition section and the point closest to the connected end face of the niobium-based alloy in the metal transition section is set to 2 mm, and the distance is kept unchanged during the welding process, and non-melting electrode gas shielded arc welding is implemented.

[0091] Table 4 Type, composition and content of metal transition section and welding wire

[0092]

[0093] Example 5

[0094] A kind of ultra-thin TiB P / TC4 composite material and 316L stainless steel dissimilar metal connection gas shielded arc welding method, the connecting base material is TiB P / TC4 composite material and 316L stainless steel, TiB P The thickness of the TC4 composite material is 0.6 mm, and the thickness of the 316L stainless steel is 0.8 mm. Both are rectangular flat. The chemical compatibility of the two materials is poor. P Ti element in TiBP / TC4 composite material and Fe, Ni, Cr elements in 316L stainless steel are easy to form brittle structure. The linear expansion coefficient, thermal conductivity and specific heat capacity of TiBP / TC4 composite material and 316L stainless steel are also quite different. In order to implement the dissimilar metal connection of ultra-thin plate TiBP / TC4 composite material and 316L stainless steel, the following steps are specifically included:

[0095] (1) The base material TiB in the dissimilar metals to be connected as required P The composition, components, physical and chemical properties and shape characteristics of the / TC4 composite material and 316L stainless steel. The metal transition section is designed to be a niobium-based alloy with a thickness of 0.7 mm and a rectangular plane shape. Its composition is shown in Table 5. The parent material TiB P / TC4 composite material has good chemical compatibility with the metal transition section niobium-based alloy, the melting point of the metal transition section niobium-based alloy is greater than the melting point of the parent material 316L stainless steel, and the metal transition section niobium-based alloy is prepared;

[0096] (2) Base material TiB to be connected as requiredP The composition, components, physical and chemical properties of TC4 composite materials and niobium-based alloys in the transition metal section are designed to be similar to the parent material TiB P A welding wire 1 having good chemical compatibility with the TC4 composite material and the niobium-based alloy in the metal transition zone, the type, composition and content of the welding wire 1 are shown in Table 5, and the welding wire 1 is prepared;

[0097] (3) Setting the base material TiB P The spacing between the connected end face of the / TC4 composite material and the connected end face of the niobium-based alloy in the metal transition section is 0.8 mm, the gas shielded arc welding type is determined to be metal-metal gas shielded arc welding, the gas shielded arc welding mode is set to CMT mode, and the metal-metal gas shielded arc welding process parameters are set to: average welding current is 100 A, average arc voltage is 12 V, welding speed is 2.8 m / min, wire dry extension length is 16 mm, wire diameter is 1.2 mm, shielding gas is a mixed gas of Ar and O2, gas flow rate is 28 L / min, welding gas supply system and welding equipment are started, the axial extension line of welding wire 1 points to the connected end face, and metal-metal gas shielded arc welding is performed;

[0098] (4) According to the composition, components, physical and chemical properties of the base material 316L stainless steel and the niobium-based alloy in the metal transition section to be connected, a welding wire 2 having good chemical compatibility with the base material 316L stainless steel and the niobium-based alloy in the metal transition section is designed. The type, composition and content of the welding wire 2 are shown in Table 5, and the welding wire 2 is prepared;

[0099] (5) The spacing between the connected end face of the base material 316L stainless steel and the connected end face of the niobium-based alloy in the metal transition section is set to 0.9 mm, the gas shielded arc welding type is determined to be metal-shielded gas-shielded arc welding, the gas shielded arc welding mode is set to AC mode, and the welding process parameters of metal-shielded gas-shielded arc welding are set to: average welding current is 190 A, average arc voltage is 19 V, welding speed is 3.6 m / min, wire dry extension length is 20 mm, wire diameter is 1.6 mm, shielding gas is a mixed gas of Ar and He, gas flow rate is 19 L / min, welding gas supply system and welding equipment are started, and the distance between the intersection of the axial extension line of welding wire 2 and the surface of the niobium-based alloy in the metal transition section and the point closest to the connected end face of the niobium-based alloy in the metal transition section is set to 1.2 mm, and the distance is kept unchanged during the welding process, and metal-shielded gas-shielded arc welding is implemented.

[0100] Table 5 Type, composition and content of metal transition section and welding wire

[0101]

[0102] Example 6

[0103] A gas shielded arc welding method for connecting ultra-thin plate TC4 titanium alloy and Inconel718 nickel-based alloy dissimilar metals, wherein the connecting parent materials are TC4 titanium alloy and Inconel718 nickel-based alloy, the thickness of TC4 titanium alloy is 1.5 mm, the thickness of Inconel718 nickel-based alloy is 1.5 mm, the shape of TC4 titanium alloy is an elliptical ring plane type, and the shape of Inconel718 nickel-based alloy is an elliptical plane type, the two materials have poor chemical compatibility, the Ti element in TC4 titanium alloy and the Fe, Ni, and Cr elements in Inconel718 nickel-based alloy are easy to generate brittle structure, and the physical properties such as linear expansion coefficient, thermal conductivity and specific heat capacity of TC4 titanium alloy and Inconel718 nickel-based alloy are also quite different. In order to implement the dissimilar metal connection of ultra-thin plate TC4 titanium alloy and Inconel718 nickel-based alloy, the method specifically comprises the following steps:

[0104] (1) According to the composition, components, physical and chemical properties and shape characteristics of the parent materials TC4 titanium alloy and Inconel718 nickel-based alloy in the dissimilar metals to be connected, the metal transition section is designed to be a niobium-based alloy with a thickness of 1.5 mm and an elliptical ring plane shape. Its composition is shown in Table 6. The parent material TC4 titanium alloy and the metal transition section niobium-based alloy have good chemical compatibility, and the melting point of the metal transition section niobium-based alloy is greater than the melting point of the parent material Inconel718 nickel-based alloy. The metal transition section niobium-based alloy is prepared;

[0105] (2) According to the composition, components, physical and chemical properties of the base material TC4 titanium alloy and the metal transition section niobium-based alloy to be connected, a welding wire 1 having good chemical compatibility with the base material TC4 titanium alloy and the metal transition section niobium-based alloy is designed. The type, composition and content of the welding wire 1 are shown in Table 6, and the welding wire 1 is prepared;

[0106] (3) The spacing between the connected end face of the parent material TC4 titanium alloy and the connected end face of the metal transition section niobium-based alloy is set to 1.6 mm, the gas shielded arc welding type is determined to be non-melting electrode gas shielded arc welding, the gas shielded arc welding mode is set to AC mode, and the non-melting electrode gas shielded arc welding process parameters are set to: average welding current is 100 A, average arc voltage is 12 V, welding speed is 1.4 m / min, wire diameter is 1.0 mm, shielding gas is a mixed gas of Ar and He, gas flow rate is 20 L / min, the welding gas supply system and welding equipment are started, the axial extension line of the welding wire 1 is pointed to the connected end face, and non-melting electrode gas shielded arc welding is performed;

[0107] (4) According to the composition, components, physical and chemical properties of the parent material Inconel718 nickel-based alloy and the metal transition section niobium-based alloy to be connected, a welding wire 2 having good chemical compatibility with the parent material Inconel718 nickel-based alloy and the metal transition section niobium-based alloy is designed. The type, composition and content of the welding wire 2 are shown in Table 6, and the welding wire 2 is prepared;

[0108] (5) The spacing between the connected end face of the parent material Inconel718 nickel-based alloy and the connected end face of the metal transition section niobium-based alloy is set to 1.6 mm, the gas shielded arc welding type is determined to be metal-shielded gas-shielded arc welding, the gas shielded arc welding mode is set to be direct current mode, and the welding process parameters of the metal-shielded gas-shielded arc welding are set to be: average welding current is 140 A, average arc voltage is 15 V, welding speed is 1.8 m / min, wire dry extension length is 12 mm, wire diameter is 0.8 mm, shielding gas is Ar gas, gas flow rate is 15 L / min, the welding gas supply system and welding equipment are started, and the distance between the intersection of the axial extension line of the welding wire 2 and the surface of the metal transition section niobium-based alloy and the point closest to the connected end face of the metal transition section niobium-based alloy is set to 1.6 mm, and the distance is kept unchanged during the welding process, and metal-shielded gas-shielded arc welding is implemented.

[0109] Table 6 Type, composition and content of metal transition section and welding wire

[0110]

[0111] Example 7

[0112] A gas shielded arc welding method for connecting ultra-thin TaW2.5 tantalum alloy and Inconel625 nickel-based alloy dissimilar metals, wherein the connecting parent materials are TaW2.5 tantalum alloy and Inconel625 nickel-based alloy, the thickness of TaW2.5 tantalum alloy is 0.3 mm, the thickness of Inconel625 nickel-based alloy is 0.4 mm, and the shapes are both cylindrical three-dimensional. The two materials have poor chemical compatibility, and the Ta and W elements in TaW2.5 tantalum alloy and the Fe, Ni, and Cr elements in Inconel625 nickel-based alloy are easy to generate brittle structures. The linear expansion coefficient, thermal conductivity, specific heat capacity and other physical properties of TaW2.5 tantalum alloy and Inconel625 nickel-based alloy are also quite different. In order to implement the dissimilar metal connection of ultra-thin TaW2.5 tantalum alloy and Inconel625 nickel-based alloy, the method specifically includes the following steps:

[0113] (1) According to the composition, components, physical and chemical properties and shape characteristics of the parent materials TaW2.5 tantalum alloy and Inconel625 nickel-based alloy in the dissimilar metals to be connected, the metal transition section is designed to be a vanadium-based alloy with a thickness of 0.3 mm and a cylindrical three-dimensional shape. Its composition is shown in Table 7. The parent material TaW2.5 tantalum alloy and the metal transition section vanadium-based alloy have good chemical compatibility, and the melting point of the metal transition section vanadium-based alloy is greater than the melting point of the parent material Inconel625 nickel-based alloy. The metal transition section vanadium-based alloy is prepared;

[0114] (2) According to the composition, components, physical and chemical properties of the base material TaW2.5 tantalum alloy and the metal transition section vanadium-based alloy to be connected, a welding wire 1 having good chemical compatibility with the base material TaW2.5 tantalum alloy and the metal transition section vanadium-based alloy is designed, and the type, composition and content of the welding wire 1 are shown in Table 7, and the welding wire 1 is prepared;

[0115] (3) The spacing between the connected end face of the parent material TaW2.5 tantalum alloy and the connected end face of the metal transition section vanadium-based alloy is set to 0.6 mm, the gas shielded arc welding type is determined to be metal-metal gas shielded arc welding, the gas shielded arc welding mode is set to CMT mode, and the metal-metal gas shielded arc welding process parameters are set to: average welding current is 190 A, average arc voltage is 17 V, welding speed is 3.8 m / min, wire dry extension length is 19 mm, wire diameter is 1.6 mm, shielding gas is a mixed gas of Ar and CO2, gas flow rate is 27 L / min, welding gas supply system and welding equipment are started, the axial extension line of welding wire 1 is pointed to the connected end face, and metal-metal gas shielded arc welding is performed;

[0116] (4) According to the composition, components, physical and chemical properties of the parent material Inconel625 nickel-based alloy and the metal transition section vanadium-based alloy to be connected, a welding wire 2 having good chemical compatibility with the parent material Inconel625 nickel-based alloy and the metal transition section vanadium-based alloy is designed. The type, composition and content of the welding wire 2 are shown in Table 7, and the welding wire 2 is prepared;

[0117] (5) The spacing between the connected end face of the parent material Inconel625 nickel-based alloy and the connected end face of the metal transition section vanadium-based alloy is set to 1.2 mm, the gas shielded arc welding type is determined to be metal-metal gas shielded arc welding, the gas shielded arc welding mode is set to CMT mode, and the metal-metal gas shielded arc welding process parameters are set to: average welding current is 150 A, average arc voltage is 14 V, welding speed is 1.9 m / min, wire dry extension length is 15 mm, wire diameter is 1.2 mm, shielding gas is a mixed gas of Ar and N2, gas flow rate is 22 L / min, welding gas supply system and welding equipment are started, and the distance between the intersection of the axial extension line of welding wire 2 and the surface of the metal transition section vanadium-based alloy and the point closest to the connected end face of the metal transition section niobium-based alloy is set to 0.4 mm, and the distance is kept unchanged during the welding process, and metal-metal gas shielded arc welding is implemented.

[0118] Table 7 Type, composition and content of metal transition section and welding wire

[0119]

[0120] Example 8

[0121] A gas shielded arc welding method for connecting ultra-thin plate W1 tungsten alloy and 304 stainless steel dissimilar metals, wherein the connecting parent materials are W1 tungsten alloy and 304 stainless steel, the thickness of the W1 tungsten alloy is 1.0 mm, the thickness of the 304 stainless steel is 1.1 mm, and the shapes are both circular ring planes. The two materials have poor chemical compatibility, and the W element in the W1 tungsten alloy and the Fe, Ni, and Cr elements in the 304 stainless steel are prone to generate brittle structures. The linear expansion coefficient, thermal conductivity, specific heat capacity and other physical properties of the W1 tungsten alloy and the 304 stainless steel are also quite different. In order to implement the connection of ultra-thin plate W1 tungsten alloy and 304 stainless steel dissimilar metals, the method specifically comprises the following steps:

[0122] (1) According to the composition, components, physical and chemical properties and shape characteristics of the parent materials W1 tungsten alloy and 304 stainless steel in the dissimilar metals to be connected, the metal transition section is designed to be a niobium-based alloy with a thickness of 1.0 mm and a circular plane shape. Its composition is shown in Table 8. The parent material W1 tungsten alloy and the niobium-based alloy of the metal transition section have good chemical compatibility. The melting point of the niobium-based alloy of the metal transition section is greater than the melting point of the parent material 304 stainless steel. The niobium-based alloy of the metal transition section is prepared;

[0123] (2) According to the composition, components, physical and chemical properties of the base material W1 tungsten alloy and the metal transition section niobium-based alloy to be connected, a welding wire 1 having good chemical compatibility with the base material W1 tungsten alloy and the metal transition section niobium-based alloy is designed. The type, composition and content of the welding wire 1 are shown in Table 8, and the welding wire 1 is prepared;

[0124] (3) The distance between the connected end face of the base material W1 tungsten alloy and the connected end face of the metal transition section niobium-based alloy is set to 2 mm, the gas shielded arc welding type is determined to be non-melting electrode gas shielded arc welding, the gas shielded arc welding mode is set to AC mode, and the non-melting electrode gas shielded arc welding process parameters are set to: average welding current is 150 A, average arc voltage is 15 V, welding speed is 1.8 m / min, wire diameter is 1.2 mm, shielding gas is a mixed gas of Ar and CO2, gas flow rate is 16 L / min, the welding gas supply system and welding equipment are started, the axial extension line of the welding wire 1 is pointed to the connected end face, and non-melting electrode gas shielded arc welding is performed;

[0125] (4) According to the composition, components, physical and chemical properties of the base material 304 stainless steel and the niobium-based alloy in the metal transition section to be connected, a welding wire 2 having good chemical compatibility with the base material 304 stainless steel and the niobium-based alloy in the metal transition section is designed. The type, composition and content of the welding wire 2 are shown in Table 8, and the welding wire 2 is prepared;

[0126] (5) The spacing between the connected end face of the base material 304 stainless steel and the connected end face of the niobium-based alloy in the metal transition section is set to 2 mm, the gas shielded arc welding type is determined to be non-melting electrode gas shielded arc welding, the gas shielded arc welding mode is set to DC mode, and the non-melting electrode gas shielded arc welding process parameters are set to: average welding current is 130 A, average arc voltage is 13 V, welding speed is 1.6 m / min, welding wire diameter is 1.6 mm, shielding gas is a mixed gas of Ar and O2, gas flow rate is 24 L / min, welding gas supply system and welding equipment are started, and the distance between the intersection of the axial extension line of the welding wire 2 and the surface of the niobium-based alloy in the metal transition section and the point closest to the connected end face of the niobium-based alloy in the metal transition section is set to 0.6 mm, and the distance is kept unchanged during the welding process to implement non-melting electrode gas shielded arc welding.

[0127] Table 8 Type, composition and content of metal transition section and welding wire

[0128]

[0129] Example 9

[0130] A gas shielded arc welding method for connecting ultra-thin TA2 pure titanium and 304 stainless steel dissimilar metals, wherein the connecting base materials are TA2 pure titanium and 304 stainless steel, the thickness of TA2 pure titanium is 0.5 mm, the thickness of 304 stainless steel is 0.5 mm, and the shapes are both rectangular ring planes. The two materials have poor chemical compatibility, and the Ti element in TA2 pure titanium and the Fe, Ni, and Cr elements in 304 stainless steel are prone to generate brittle structures. The linear expansion coefficient, thermal conductivity, specific heat capacity and other physical properties of TA2 pure titanium and 304 stainless steel are also quite different. In order to implement the connection of ultra-thin TA2 pure titanium and 304 stainless steel dissimilar metals, the method specifically includes the following steps:

[0131] (1) According to the composition, components, physical and chemical properties and shape characteristics of the parent materials TA2 pure titanium and 304 stainless steel in the dissimilar metals to be connected, the metal transition section is designed to be pure niobium, with a thickness of 0.5 mm and a rectangular ring plane shape. Its composition is shown in Table 9. The parent material TA2 pure titanium and the metal transition section pure niobium have good chemical compatibility, and the melting point of the metal transition section pure niobium is greater than the melting point of the parent material 304 stainless steel. The metal transition section pure niobium is prepared;

[0132] (2) According to the composition, components, physical and chemical properties of the base material TA2 pure titanium and the metal transition section pure niobium to be connected, a welding wire 1 having good chemical compatibility with the base material TA2 pure titanium and the metal transition section pure niobium is designed. The type, composition and content of the welding wire 1 are shown in Table 9, and the welding wire 1 is prepared;

[0133] (3) The spacing between the connected end face of the base material TA2 pure titanium and the connected end face of the metal transition section pure niobium is set to 0.4 mm, the gas shielded arc welding type is determined to be metal-metal gas shielded arc welding, the gas shielded arc welding mode is set to CMT mode, and the metal-metal gas shielded arc welding process parameters are set to: average welding current is 65 A, average arc voltage is 11 V, welding speed is 0.8 m / min, wire dry extension length is 12 mm, wire diameter is 1.0 mm, shielding gas is Ar gas, gas flow rate is 20 L / min, welding gas supply system and welding equipment are started, the axial extension line of welding wire 1 is pointed to the connected end face, and metal-metal gas shielded arc welding is performed;

[0134] (4) According to the composition, components, physical and chemical properties of the base material 304 stainless steel and the pure niobium in the metal transition section to be connected, a welding wire 2 having good chemical compatibility with the base material 304 stainless steel and the pure niobium in the metal transition section is designed. The type, composition and content of the welding wire 2 are shown in Table 9, and the welding wire 2 is prepared;

[0135] (5) The spacing between the connected end face of the base material 304 stainless steel and the connected end face of the pure niobium in the metal transition section is set to 0.1 mm, the gas shielded arc welding type is determined to be metal-metal gas shielded arc welding, the gas shielded arc welding mode is set to CMT mode, and the metal-metal gas shielded arc welding process parameters are set to: average welding current is 54 A, average arc voltage is 8.8 V, welding speed is 0.9 m / min, wire dry extension length is 12 mm, wire diameter is 1.0 mm, shielding gas is a mixed gas of Ar and He, gas flow rate is 25 L / min, welding gas supply system and welding equipment are started, and the distance between the intersection of the axial extension line of welding wire 2 and the surface of the pure niobium in the metal transition section and the point closest to the connected end face of the pure niobium in the metal transition section is set to 1 mm, and the distance is kept unchanged during the welding process, and metal-metal gas shielded arc welding is implemented.

[0136] Table 9 Type, composition and content of metal transition section and welding wire

[0137]

[0138] The above embodiments design and adopt suitable metal transition sections and matching welding wires, adopt suitable connected end face spacing, optimally arrange the welding wire positions, select suitable gas shielded welding methods, welding modes and welding process parameters, and perform effective welding gas protection, thereby solving the connection problems of ultra-thin plate dissimilar metals due to large differences in physical properties, poor chemical compatibility and excessively thin plates, large stress and deformation, easy formation of brittle structure in welds, poor performance of welded joints and easy penetration. The welding method has simple welding process, good welding flexibility, high welding efficiency, low welding cost, precise controllable heat input and temperature in the connection zone, avoids coarse grains in the heat affected zone, avoids the formation of brittle structures such as intermetallic compounds, and avoids the formation of brazing. The welding stress and deformation are small, the weld formation is excellent, the weld joint structure and performance are easy to regulate, the internal quality of the weld is excellent, and defects such as pores, cracks, penetration, incomplete fusion and incomplete penetration are eliminated. The connection joint has excellent comprehensive performance and meets the technical requirements.

[0139] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A gas shielded arc welding method for ultra-thin plate dissimilar metal connection, characterized in that: The following steps are involved: (1) Designing and preparing a metal transition section C according to the composition, components, physical and chemical properties and shape characteristics of the base material A and base material B in the dissimilar metals to be connected, wherein the base material A and the metal transition section C have good chemical compatibility, the melting point of the metal transition section C is greater than the melting point of the base material B, and the thickness of the base material A, the base material B and the metal transition section C is 0.2 to 1.5 mm; (2) designing the type, composition and content of the welding wire 1 having good chemical compatibility with the base material A and the metal transition section C according to the composition, components, physical and chemical properties of the base material A and the metal transition section C to be connected, and preparing the welding wire 1; (3) The connected end face of the base material A and the connected end face of the metal transition section C have a suitable spacing, the type of gas shielded arc welding is determined, the gas shielded arc welding mode and welding process parameters are set, the welding gas supply system and welding equipment are started, the axial extension line of the welding wire 1 is directed to the connected end face, and gas shielded arc welding is performed; (4) according to the composition, components, physical and chemical properties of the base material B and the metal transition section C to be connected, the type, composition and content of the welding wire 2 having good chemical compatibility with the base material B and the metal transition section C are designed, and the welding wire 2 is prepared, and the melting point of the base material B is greater than the melting point of the welding wire 2; (5) The distance between the connected end face of the base material B and the connected end face of the metal transition section C is 0.1 to 2 mm. The type of gas shielded arc welding is determined, the gas shielded arc welding mode and welding process parameters are set, the welding gas supply system and welding equipment are started, and the distance between the intersection of the axial extension line of the welding wire 2 and the surface of the metal transition section C and the point closest to the connected end face of the metal transition section C is 0.1 to 2 mm. This distance is kept unchanged during the welding process, and gas shielded arc welding is implemented.

2. A gas shielded arc welding method for ultra-thin plate dissimilar metal connection as claimed in claim 1, characterized in that: The shapes of the base material A, base material B and metal transition section C include planar and three-dimensional shapes.

3. A gas shielded arc welding method for ultra-thin plate dissimilar metal connection as claimed in claim 1, characterized in that: The types of welding wire include solid welding wire and flux-cored welding wire.

4. A gas shielded arc welding method for ultra-thin plate dissimilar metal connection as claimed in claim 1, characterized in that: The distance between the connected end surface of the base material A and the connected end surface of the metal transition section C is 0 to 2 mm.

5. A gas shielded arc welding method for ultra-thin plate dissimilar metal connection as claimed in claim 1, characterized in that: The gas shielded arc welding types include metal-electrode gas shielded arc welding and non-metal-electrode gas shielded arc welding, and the shielding gas of the welding gas supply system is at least one of Ar, He, CO2, O2, and N2.

6. A gas shielded arc welding method for ultra-thin plate dissimilar metal connection as claimed in claim 5, characterized in that: The welding mode of the metal-metal gas shielded arc welding is a CMT mode, a DC mode or an AC mode, and the welding mode of the non-metal-metal gas shielded arc welding is a DC mode or an AC mode.

7. A gas shielded arc welding method for ultra-thin plate dissimilar metal connection as claimed in claim 5, characterized in that: The welding mode of the metal-metal gas shielded arc welding is a pulse mode, and the welding mode of the non-metal-metal gas shielded arc welding is a pulse mode.

8. A gas shielded arc welding method for ultra-thin plate dissimilar metal connection as claimed in claim 5, characterized in that: The welding process parameters of the consumable electrode gas shielded arc welding are: average welding current of 20-200A, average arc voltage of 6-20V, welding speed of 0.3-4m / min, wire extension length of 6-20mm, wire diameter of 0.6-1.6mm, and gas flow rate of 5-30L / min.

9. A gas shielded arc welding method for ultra-thin plate dissimilar metal connection as claimed in claim 5, characterized in that: The non-melting electrode gas shielded arc welding process parameters are: average welding current of 20-150A, average arc voltage of 6-15V, welding speed of 0.3-2m / min, welding wire diameter of 0.6-1.6mm, and gas flow rate of 5-30L / min.

Images