Welding method for connecting molybdenum alloy and niobium alloy dissimilar materials

Abstract

The embodiment of the invention relates to the technical field of electron beam welding, in particular to a welding method for connecting molybdenum alloy and niobium alloy dissimilar materials, which comprises the following steps: S1, preparing a molybdenum alloy test sample and a niobium alloy test sample, the molybdenum alloy test sample and the niobium alloy test sample are subjected to beam deflection welding with the first beam deflection amount through the electron beam welding technology, and a welding test sample is obtained; s2, determining a molybdenum alloy side fusion line of the welding test sample, and determining an included angle between the butt joint surface of the molybdenum alloy test sample and the molybdenum alloy side fusion line of the welding test sample; s3, according to the included angle, the first beam deflection amount and the thickness of the molybdenum alloy test sample, actual welding parameters for conducting beam deflection welding on the molybdenum alloy actual sample and the niobium alloy actual sample through the electron beam welding technology are determined; and S4, according to the actual welding parameters, the molybdenum alloy actual sample and the niobium alloy actual sample are welded. The welding method provided by the embodiment of the invention is beneficial to improving the welding quality.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of electron beam welding, and in particular to a welding method for connecting dissimilar materials of molybdenum alloy and niobium alloy. Background Art

[0002] This section of content merely provides background information related to the present application and does not necessarily constitute prior art.

[0003] As refractory alloys, molybdenum alloys and niobium alloys are widely used in the fields of nuclear industry, aerospace, chemical metallurgy, and electronics due to their good high temperature resistance and corrosion resistance. In the process of molybdenum alloys and niobium alloys being used in the above fields, in some cases, it is necessary to weld the molybdenum alloys and niobium alloys.

[0004] Although electron beam welding has the advantages of high power density, large aspect ratio, and strong penetration ability, and is often used to weld refractory metals and dissimilar alloys, the welding process still has defects in the dissimilar fusion welding of molybdenum alloys and niobium alloys, resulting in poor welding quality. Summary of the invention

[0005] A brief overview of the present application is provided below in order to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify the key or important parts of the present application, nor is it intended to limit the scope of the present application. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0006] In order to solve the above technical problems, an embodiment of the present application provides a welding method for connecting dissimilar materials of molybdenum alloy and niobium alloy.

[0007] In a first aspect, an embodiment of the present application provides a welding method for connecting dissimilar materials of molybdenum alloy and niobium alloy, which may include: S1, preparing a molybdenum alloy test sample and a niobium alloy test sample, and using an electron beam welding process to perform offset beam welding on the molybdenum alloy test sample and the niobium alloy test sample to obtain a welded test sample; in the offset beam welding, the deflection amount of the electron beam from the butt surface of the molybdenum alloy test sample is a first deflection amount; S2, determining the fusion line on the molybdenum alloy side of the welding test sample, and determining the angle between the butt surface of the molybdenum alloy test sample and the fusion line on the molybdenum alloy side of the welding test sample as a first angle; S3, determining actual welding parameters for offset beam welding of the molybdenum alloy actual sample and the niobium alloy actual sample using the electron beam welding process based on the first angle, the first deflection amount and the thickness of the molybdenum alloy test sample; S4, welding the molybdenum alloy actual sample and the niobium alloy actual sample based on the actual welding parameters.

[0008] The welding method for connecting dissimilar materials of molybdenum alloy and niobium alloy provided in the embodiment of the present application determines the actual welding parameters for offset beam welding of the actual molybdenum alloy sample and the actual niobium alloy sample using the electron beam welding process according to the first angle, the first offset beam amount and the thickness of the molybdenum alloy test sample, which is beneficial to reducing the melting amount of the molybdenum alloy, reducing the generation of brittle oxides in the metallurgical reaction of the weld, and reducing the formation of pores in the weld area 40, thereby helping to improve the welding quality of the dissimilar materials of the molybdenum alloy and the niobium alloy, and improving the plasticity and toughness of the welded joint.

[0009] In a second aspect, an embodiment of the present application provides a welding method for connecting dissimilar materials of molybdenum alloy and niobium alloy, which may include: S10, preparing a molybdenum alloy test sample and a niobium alloy test sample, and performing offset beam welding on the molybdenum alloy test sample and the niobium alloy test sample using an electron beam welding process; S20, according to the result of the offset beam welding in step S10, determining the angle at which the electron beam is tilted relative to the molybdenum alloy actual sample and the niobium alloy actual sample when the electron beam welding process is used to perform offset beam welding on the molybdenum alloy actual sample and the niobium alloy actual sample, and a second offset beam amount by which the electron beam deviates from the butt joint surface of the molybdenum alloy actual sample; S30, welding the molybdenum alloy actual sample and the niobium alloy actual sample according to the angle and the second offset beam amount determined in step S20.

[0010] These and other advantages of the present application will become more apparent through the following detailed description of the preferred embodiments of the present application in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to further illustrate the above and other advantages and features of the present application, the specific embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. The accompanying drawings together with the following detailed description are included in this specification and form a part of this specification. Elements with the same function and structure are represented by the same reference numerals. It should be understood that these drawings only describe typical examples of the present application and should not be regarded as limiting the scope of the present application.

[0012] Figure 1 is a schematic diagram of performing bias beam welding on a molybdenum alloy test sample and a niobium alloy test sample according to an embodiment of the present application;

[0013] Figure 2 is a schematic diagram of performing bias beam welding on an actual sample of a molybdenum alloy and an actual sample of a niobium alloy according to an embodiment of the present application;

[0014] Figure 3 yes Figure 2 The enlarged partial view of the weld formed by welding the actual sample of molybdenum alloy and the actual sample of niobium alloy shown;

[0015] Figure 4 is based on Figure 1Metallographic photograph of the weld cross section of the welding test sample obtained by the welding method shown;

[0016] Figure 5 is based on Figure 2 Metallographic photograph of the weld cross section of the actual welded sample obtained by the welding method shown.

[0017] It should be noted that the drawings are not necessarily drawn to scale, but are merely shown in a schematic manner that does not affect the reader's understanding.

[0018] Description of reference numerals:

[0019] 10. Molybdenum alloy test sample; 11. Molybdenum alloy actual sample;

[0020] 20. Niobium alloy test sample; 21. Niobium alloy actual sample;

[0021] 30. Electron beam;

[0022] 40. Welding area; 41. Butt joint; 42. Fusion line on the molybdenum alloy side;

[0023] 50. Pad;

[0024] h1, first beam deflection; h2, second beam deflection; d, thickness; y, electron beam direction. DETAILED DESCRIPTION

[0025] Exemplary embodiments of the present application will be described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual implementation are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the process of developing any such actual implementation in order to achieve the developer's specific goals, such as meeting those constraints related to the system and business, and these constraints may vary from implementation to implementation. In addition, it should be understood that although the development work may be very complex and time-consuming, it is only a routine task for those skilled in the art who benefit from the content of this application.

[0026] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, only the device structure and / or processing steps closely related to the scheme according to the present application are shown in the accompanying drawings, while other details that are not very relevant to the present application are omitted.

[0027] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in this application should have the common meanings understood by persons with ordinary skills in the field to which this application belongs.

[0028] In the description of the embodiments of the present application, “plurality” means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0029] The inventors of the present application have found that molybdenum alloy and niobium alloy, as refractory alloys, have large differences in physical properties such as melting point, thermal conductivity, linear expansion coefficient, etc. Direct welding of the two is prone to produce large welding stress, increasing the tendency of joint cracks. In addition, molybdenum alloy is easily oxidized at high temperature to form oxides such as MoO3 with low boiling point, which is easy to form pore defects, and react with impurity elements (O, N, C, etc.) to form brittle phases, resulting in reduced plastic toughness of welded joints.

[0030] For the dissimilar melting welding of molybdenum alloy / niobium alloy, reducing the melting amount of molybdenum alloy helps to reduce welding stress, control weld porosity defects, and improve joint plasticity and toughness. When using electron beam to weld dissimilar materials of molybdenum alloy / niobium alloy, the fusion ratio of molybdenum alloy / niobium alloy parent materials can be adjusted by using the offset beam welding method.

[0031] The inventors of the present application have found that there are still some problems in simply using the biased beam welding method to adjust the fusion ratio of the molybdenum alloy / niobium alloy, such as the inability to completely control the melting of the molybdenum alloy and the defect of greater brittleness of the welded joint.

[0032] Based on this, the embodiment of the present application provides a welding method for connecting dissimilar materials of molybdenum alloy and niobium alloy. Figure 1 and Figure 2 , Figure 1 is a schematic diagram of performing bias beam welding on a molybdenum alloy test sample and a niobium alloy test sample according to an embodiment of the present application; Figure 2 The present invention is a schematic diagram of performing offset beam welding on an actual molybdenum alloy sample and an actual niobium alloy sample according to an embodiment of the present application. The welding method provided by the embodiment of the present application may include: S1, preparing a molybdenum alloy test sample 10 and a niobium alloy test sample 20, and performing offset beam welding on the molybdenum alloy test sample 10 and the niobium alloy test sample 20 by an electron beam welding process to obtain a welded test sample; in the offset beam welding, the deflection amount of the electron beam 30 from the butt joint 41 of the molybdenum alloy test sample 10 is a first deflection amount h1; S2, determining a fusion line 42 on the molybdenum alloy side of the welded test sample, and determining that the angle between the butt joint 41 of the molybdenum alloy test sample 10 and the fusion line 42 on the molybdenum alloy side of the welded test sample is a first angle β; S3, determining actual welding parameters for performing offset beam welding on the molybdenum alloy actual sample 11 and the niobium alloy actual sample 21 by the electron beam welding process according to the first angle β, the first deflection amount h1 and the thickness of the molybdenum alloy test sample 10; S4, welding the molybdenum alloy actual sample 11 and the niobium alloy actual sample 21 according to the actual welding parameters.

[0033] The welding method for connecting dissimilar materials of molybdenum alloy and niobium alloy provided in the embodiment of the present application determines the actual welding parameters for offset beam welding of the molybdenum alloy actual sample 11 and the niobium alloy actual sample 21 using the electron beam welding process according to the first angle β, the first offset beam amount h1 and the thickness of the molybdenum alloy test sample 10, which is beneficial to reducing the melting amount of the molybdenum alloy, reducing the generation of brittle oxides in the metallurgical reaction of the weld, and reducing the formation of pores in the weld area 40, thereby helping to improve the welding quality of the dissimilar materials of the molybdenum alloy and the niobium alloy, and improving the plasticity and toughness of the welded joint.

[0034] In some embodiments, the molybdenum alloy test sample 10, the niobium alloy test sample 20, the molybdenum alloy actual sample 11 and the niobium alloy actual sample 21 are all plate-like samples, and the thickness d of the plate-like samples is 2 to 3 mm. It is easy to understand that since molybdenum and niobium are refractory metals, thicker samples are difficult to be penetrated by the electron beam 30 during welding. Therefore, a thinner plate-like sample of 2 to 3 mm is used in this embodiment. Such a thickness is conducive to the electron beam 30 penetrating the sample, so that heat can be quickly transferred to the weld area 40, and at the same time it is conducive to reducing the pores and cracks of the weld.

[0035] The thicknesses of the molybdenum alloy test sample 10, the niobium alloy test sample 20, the molybdenum alloy actual sample 11, and the niobium alloy actual sample 21 are all the same.

[0036] In some embodiments, the molybdenum content in the molybdenum alloy may be 100%, that is, metallic molybdenum.

[0037] In some embodiments, the niobium content in the niobium alloy may be 100%, ie, metallic niobium.

[0038] In some embodiments, in step S1, before welding, the butting surfaces 41 of the molybdenum alloy test sample 10 and the niobium alloy test sample 20 to be welded may be mechanically polished, and cleaned to obtain the molybdenum alloy test sample 10 and the niobium alloy test sample 20.

[0039] In some embodiments, in step S1, a fixture may be used to fix the molybdenum alloy test sample 10 and the niobium alloy test sample 20 so that the butt surfaces 41 of the molybdenum alloy test sample 10 and the niobium alloy test sample 20 are butted against each other to facilitate bias beam welding, and the fixture may be used to constrain the surfaces of the molybdenum alloy test sample 10 and the niobium alloy test sample 20 to prevent warping deformation during welding.

[0040] In some embodiments, in step S1 , the molybdenum alloy test sample 10 and the niobium alloy test sample 20 may be fixed on a backing plate 50 , thereby facilitating improving stability during welding.

[0041] In some embodiments, the backing plate 50 may be made of metal molybdenum or metal niobium, which is beneficial for reducing stress and deformation caused by the difference in thermal expansion coefficients of different materials during the welding process.

[0042] The molybdenum alloy actual sample 11 and the niobium alloy actual sample 21 are welded to obtain a welded actual sample.

[0043] In some embodiments, in step S3, the actual welding parameters may include the angle at which the electron beam 30 is tilted relative to the actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy, and the second beam deflection amount h2 of the electron beam 30 from the butt joint surface 41 of the actual sample 11 of the molybdenum alloy. The inventors of the present application have found that increasing the beam deflection amount of the electron beam 30 from the butt joint surface 41 of the molybdenum alloy sample is beneficial to reducing the amount of melting of the molybdenum alloy, but the bottom end of the butt joint surface of the molybdenum alloy sample in the welded actual sample may not melt. The embodiment of the present application tilts the electron beam 30 relative to the actual sample 11 of the molybdenum alloy and the actual sample 21 at a preset angle, and still uses the electron beam welding process to perform beam deflection welding on the actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy. Such a welding process is beneficial to reducing the amount of melting of the molybdenum alloy, and is also beneficial to complete fusion of the molybdenum alloy and the niobium alloy, avoiding the phenomenon that the bottom of the weld area 40 is not fused.

[0044] In some embodiments, in step S3, the actual welding parameters may also include: vacuum degree, acceleration voltage, focusing current, welding beam, and welding speed. These welding parameters may be the same as the welding parameters for the offset beam welding of the molybdenum alloy test sample 10 and the niobium alloy test sample 20 using the electron beam welding process in step S1.

[0045] In some embodiments, the vacuum degree can be 10 -3 ~10 -1 Pa, the acceleration voltage can be 50kV~70kV, the focusing current can be 680~700mA, the welding beam current can be 25mA~45mA, and the welding speed can be 500mm / min~1000mm / min.

[0046] In some embodiments, in step S3, the electron beam 30 is tilted at the same angle as the first angle β relative to the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21. The inventors of the present application have found that the fusion line 42 on the molybdenum alloy side of the welding test sample is substantially a straight line, so that when the tilt angle of the electron beam 30 or the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21 is made the same as the first angle β, the fusion line 42 on the molybdenum alloy side is substantially coincident with the butt joint 41, so that by adjusting the second deflection amount h2, the melting amount of the molybdenum alloy can be reduced, and at the same time, it is also beneficial to uniformly fuse the molybdenum alloy and the niobium alloy, effectively adjusting the fusion ratio of the molybdenum alloy and the niobium alloy, and thus improving the welding quality of the molybdenum alloy and the niobium alloy.

[0047] In some embodiments, when welding is performed using a fixed-gun electron beam welding device, in order to achieve the above-mentioned inclination angle of the electron beam 30 relative to the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21, the inclination angle of the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21 can be adjusted.

[0048] In some embodiments, in step S3, the butt joint surfaces 41 of the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21 to be welded may be mechanically polished, respectively, and cleaned to obtain the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21.

[0049] In some embodiments, in step S3, a clamp can be used to fix the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21 so that the mating surfaces 41 of the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21 are butted together to facilitate offset beam welding; the clamp can also be used to constrain the upper surfaces of the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21 to prevent warping and deformation during welding; after the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21 are loaded on the clamp, the inclination angle of the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21 can be adjusted so that the inclination angle of the electron beam 30 relative to the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21 is the same as the first angle β.

[0050] In some embodiments, in step S3, the actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy may be fixed on the backing plate 50, so as to improve the stability during the welding process.

[0051] See also Figure 3 , Figure 3 yes Figure 2 The enlarged local view of the weld formed by welding the actual molybdenum alloy sample and the actual niobium alloy sample is shown. The endpoints a1 and a2 in the figure correspond to the lower endpoint and the upper endpoint of the butt joint 41 of the actual molybdenum alloy sample 11. In the figure, y represents the direction of the electron beam 30, y1 is the foot of the perpendicular line passing through the endpoint a1 and perpendicular to the direction y of the electron beam 30, and y2 is the foot of the perpendicular line passing through the endpoint a2 and perpendicular to the direction y of the electron beam 30. Connect the endpoint a1, the endpoint a2, the foot of the perpendicular y2 and the foot of the perpendicular y1 to form a right-angled trapezoid. Among them, the line between the endpoint a1 and the foot of the perpendicular y1 is the first deflection amount h1, the line between the endpoint a2 and the foot of the perpendicular y2 is the second deflection amount h2, the length of the line between the endpoints a1 and a2 is the thickness d of the molybdenum alloy test sample 10, and the angle between the line between the endpoints a1 and a2 and the y direction is the angle α at which the electron beam 30 is tilted relative to the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21.

[0052] It can be seen that in step S3, the second beam deflection amount h2 of the electron beam 30 from the butt joint surface 41 of the actual molybdenum alloy sample 11 can be determined by the following expression:

[0053] h2=h1+d×sinα.

[0054] Wherein, h2 is the second deflection amount, h1 is the first deflection amount; d is the thickness of the molybdenum alloy test sample 10; α is the angle at which the electron beam 30 is tilted relative to the molybdenum alloy actual sample 11 and the niobium alloy actual sample 21. Since the value of α is equal to the first angle β, the second deflection amount h2 of the electron beam 30 during actual welding can be determined according to the thickness d of the molybdenum alloy test sample 10, the first deflection amount h1 and the first angle β. Through the above method, the deflection amount of the electron beam 30 can be adjusted to the maximum deflection amount, further reducing the melting amount of the molybdenum alloy, while ensuring that the molybdenum alloy and the niobium alloy are completely fused, avoiding the phenomenon of unfused bottom of the weld area 40, and improving the quality of the dissimilar welding joints of the molybdenum alloy and the niobium alloy.

[0055] In some embodiments, in step S3, the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21 are set to be inclined at a first angle β relative to the electron beam 30; the distance between the electron beam 30 and the upper end of the butt joint 41 of the actual molybdenum alloy sample 11 is adjusted to the second beam deflection amount h2. In such an embodiment, the distance from the end point a1 to the foot of the perpendicular y1 is the first beam deflection amount h1, the distance from the end point a2 to the foot of the perpendicular y2 is the second beam deflection amount h2, the distance from the end point a1 to the end point a2 is the thickness d of the actual molybdenum alloy sample 11, and the angle between the butt joint 41 and the fusion line 42 on the molybdenum alloy side is the first angle β, so that the second beam deflection amount h2 can be calculated according to the expression h2=h1+d×sinα.

[0056] In some embodiments, in step S1, multiple groups of molybdenum alloy test samples 10 and niobium alloy test samples 20 are prepared; the molybdenum alloy test samples 10 and the niobium alloy test samples 20 of each group are subjected to biased beam welding by an electron beam welding process to obtain multiple groups of welding test samples, wherein the deflection amount of the electron beam 30 from the butt joint 41 of the molybdenum alloy test sample 10 is different in different groups of biased beam welding; and the first biased beam amount h1 is determined according to the welding quality of the multiple groups of welding test samples. This embodiment can determine the first biased beam amount h1 based on the welding quality, and provide an optimized parameter basis for the subsequent determination of the second biased beam amount h2, thereby facilitating the improvement of the welding quality of the molybdenum alloy and the niobium alloy.

[0057] In some embodiments, in step S1, for different groups of offset beam welding, the offset beam amount can be adjusted from a range of 0 to 0.9 mm.

[0058] In some embodiments, the welding quality includes the microstructure at the weld of the welding test sample and the mechanical properties of the welding test sample. In such an embodiment, an optical microscope can be used to observe the crystal phase, pores and microcracks at the weld; a mechanical testing machine can be used to test the tensile strength of the welding test sample. If the crystal phase structure in the weld microstructure is dense, the number of pores and microcracks is small, and the tensile strength is high, the welding quality is good; if the crystal phase structure is loose, the number of pores and microcracks is large, and the tensile strength is low, the welding quality is poor.

[0059] In some embodiments, in step S2, the fusion line 42 on the molybdenum alloy side of the welding test sample may be determined based on a metallographic photograph of a weld cross section of the welding test sample.

[0060] See also Figure 4 and Figure 5 , Figure 4 is based on Figure 1 Metallographic photograph of the weld cross section of the welding test sample obtained by the welding method shown; Figure 5 is based on Figure 2 The cross-sectional metallographic photograph of the weld of the actual sample obtained by the welding method shown. Figure 4 and Figure 5 It can be seen that the cross section of the weld between the molybdenum alloy sample and the niobium alloy sample is bowl-shaped, the fusion line 42 on the molybdenum alloy side is close to a straight line, and there is a first angle β between the fusion line 42 on the molybdenum alloy side and the butt surface 41. Figure 5 After the electron beam 30 is tilted at a first angle β relative to the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21, and the beam deflection amount is determined according to the above expression, the fusion line 42 on the molybdenum alloy side can be basically overlapped with the butt surface 41, which is beneficial to reduce the melting amount of the molybdenum alloy.

[0061] In some embodiments, in step S3, when the electron beam welding process is used to perform bias beam welding on the actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy, the value range of the second bias beam amount h2 can be: h1<h2≤h1+d×sinα, so that the melting amount of the molybdenum alloy can be adjusted by selecting different second bias beam amounts h2.

[0062] The embodiments of the present application also provide a welding method for connecting dissimilar materials of molybdenum alloy and niobium alloy, which may include: S10, preparing a molybdenum alloy test sample 10 and a niobium alloy test sample 20, and performing offset beam welding on the molybdenum alloy test sample 10 and the niobium alloy test sample 20 using an electron beam welding process; S20, according to the result of the offset beam welding in step S10, determining the angle at which the electron beam 30 is inclined relative to the molybdenum alloy actual sample 11 and the niobium alloy actual sample 21 when the electron beam welding process is used to perform offset beam welding on the molybdenum alloy actual sample 11 and the niobium alloy actual sample 21, and a second offset beam amount h2 of the electron beam 30 deviating from the butt surface 41 of the molybdenum alloy actual sample 11; S30, welding the molybdenum alloy actual sample 11 and the niobium alloy actual sample 21 according to the angle and the second offset beam amount h2 determined in step S20.

[0063] The welding method for connecting dissimilar materials of molybdenum alloy and niobium alloy provided in the embodiment of the present application determines the inclination angle and the second deflection beam amount h2 during actual welding according to the results of the deflection beam welding test, which is beneficial to reducing the melting amount of the molybdenum alloy, reducing the generation of brittle oxides in the metallurgical reaction of the weld, and reducing the formation of pores in the weld area 40, thereby helping to improve the welding quality of the dissimilar materials of the molybdenum alloy and the niobium alloy, and improving the plasticity and toughness of the welded joint.

[0064] The embodiments of the present application use tilted biased beam welding and select reasonable welding process parameters, which is conducive to obtaining electron beam welded joints with high strength and good plasticity.

[0065] In some embodiments, step S10 may include: S101, preparing multiple groups of molybdenum alloy test samples 10 and niobium alloy test samples 20; S102, using electron beam welding technology to perform biased beam welding on each group of molybdenum alloy test samples 10 and niobium alloy test samples 20, to obtain multiple groups of welding test samples, wherein the deflection amount of the electron beam 30 deviating from the butt joint 41 of the molybdenum alloy test sample 10 in the biased beam welding of different groups is different; S103, determining the optimal deflection amount h1 of the electron beam 30 deviating from the butt joint 41 of the molybdenum alloy test sample 10 in the biased beam welding according to the welding quality of the multiple groups of welding test samples. In this embodiment, by preparing multiple groups of molybdenum alloy test samples 10 and niobium alloy test samples 20, and performing biased beam welding with different deflection amounts on each group of samples, the influence of different deflection amounts on the welding quality can be evaluated, which is helpful to determine the optimal deflection amount h1 of the electron beam 30 deviating from the butt joint 41 of the molybdenum alloy test sample 10 in the biased beam welding, and provides optimized welding parameters for subsequent welding of actual samples, thereby facilitating improving welding quality.

[0066] In some embodiments, step S20 may include: S201, determining the molybdenum alloy side fusion line 42 of the welding test sample obtained by bias beam welding using the optimal bias beam amount h1, and determining that the angle between the butt surface 41 of the molybdenum alloy test sample 10 and the molybdenum alloy side fusion line 42 of the welding test sample is a first angle β; S202, determining the angle α at which the electron beam 30 is inclined relative to the molybdenum alloy actual sample 11 and the niobium alloy actual sample 21 and the second bias beam amount h2 when bias beam welding is performed on the molybdenum alloy actual sample 11 and the niobium alloy actual sample 21 using the electron beam welding process based on the first angle β, the optimal bias beam amount h1 and the thickness d of the molybdenum alloy test sample 10. In such an embodiment, the angle α at which the electron beam 30 is tilted relative to the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21 and the second deflection amount h2 are determined by the above method when the deflection beam welding is performed on the actual molybdenum alloy sample 11 and the actual niobium alloy sample 21, which is beneficial to reducing the melting amount of the molybdenum alloy in the actual welding and reducing the generation of brittle oxides in the metallurgical reaction of the weld, thereby facilitating improving the welding quality of dissimilar materials of the molybdenum alloy and the niobium alloy and improving the plasticity and toughness of the weld joint.

[0067] The welding method for connecting dissimilar materials of molybdenum alloy and niobium alloy in the embodiments of the present application is further described below with reference to specific embodiments.

[0068] (1) Prepare the molybdenum alloy test sample 10 and the niobium alloy test sample 20

[0069] Three groups of molybdenum alloy test samples 10 and niobium alloy test samples 20 were prepared, each group of samples was in plate shape, and the thickness d was 2 mm; the butt joint surfaces 41 of the molybdenum alloy test samples 10 and the niobium alloy test samples 20 were mechanically polished with sandpaper to ensure that the butt joint surfaces 41 were flat; the polished molybdenum alloy test samples 10 and the niobium alloy test samples 20 were cleaned with ethanol to remove oil stains and impurities, and clean molybdenum alloy test samples 10 and niobium alloy test samples 20 were obtained; the molybdenum alloy test samples 10 and the niobium alloy test samples 20 were fixed with a clamp to make the butt joint surfaces 41 of the molybdenum alloy test samples 10 and the niobium alloy test samples 20 butt joint to ensure that the butt joint surfaces 41 were tightly fitted without gaps; the molybdenum alloy test samples 10 and the niobium alloy test samples 20 were fixed on a backing plate 50, the backing plate 50 was made of metal niobium, and the thickness of the backing plate 50 was 2 mm; the clamp was adjusted to constrain the upper surfaces of the molybdenum alloy test samples 10 and the niobium alloy test samples 20 to prevent warping and deformation during welding.

[0070] (2) Biased beam welding test on molybdenum alloy test sample 10 and niobium alloy test sample 20

[0071] The three groups of molybdenum alloy test samples 10 and niobium alloy test samples 20 were placed in an electron beam welding machine and vacuumed to 3×10 -2Pa; set the parameters of electron beam welding: acceleration voltage of 60 kV, focusing current of 691 mA, welding beam current of 36 mA, welding speed of 600 mm / min; perform offset beam welding on the first group of molybdenum alloy test samples 10 and niobium alloy test samples 20, and the deflection amount of the electron beam 30 from the butt joint surface 41 of the molybdenum alloy test sample 10 is set to 0.2 mm; perform offset beam welding on the second group of molybdenum alloy test samples 10 and niobium alloy test samples 20, and the deflection amount of the electron beam 30 from the butt joint surface 41 of the molybdenum alloy test sample 10 is set to 0.4 mm; perform offset beam welding on the third group of molybdenum alloy test samples 10 and niobium alloy test samples 20, and the deflection amount of the electron beam 30 from the butt joint surface 41 of the molybdenum alloy test sample 10 is set to 0.8 mm; take out the welding test samples after cooling in the furnace for 15 minutes.

[0072] (3) Evaluate the quality of welding test samples

[0073] An optical microscope was used to observe the crystal phase, pores and microcracks of each group of welding test samples. A mechanical testing machine was used to test the tensile strength of each group of welding test samples. The welding quality was comprehensively evaluated. When the deflection amount was 0.4 mm, the crystal phase structure in the weld microstructure was dense, the number of pores and microcracks was small, the tensile strength was high, and the welding quality was optimal.

[0074] (4) Observe the metallographic photograph of the weld cross section of the welding test sample

[0075] An optical microscope was used to observe the weld cross-section metallographic photograph of the welding test sample with a beam deflection of 0.4 mm to determine the molybdenum alloy side fusion line 42, and the first angle β between the butt surface 41 of the molybdenum alloy test sample 10 and the molybdenum alloy side fusion line 42 was measured to be 8°.

[0076] (5) Calculate the second beam deflection amount h2

[0077] According to the expression h2=h1+d×sinα, the second deflection amount h2 is calculated, where h1 is the first deflection amount (0.4mm), d is the thickness of the molybdenum alloy test sample 10 (2mm), α is the same as the first angle β (8°), and the second deflection amount h2=0.4mm+2mm×sin8°≈0.68mm is calculated.

[0078] (6) Preparing actual molybdenum alloy sample 11 and actual niobium alloy sample 21

[0079] The actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy are both in plate shape, and the thickness d is 2 mm. The butt joint surface 41 of the actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy are mechanically polished with sandpaper to ensure that the butt joint surface 41 is flat. The actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy are cleaned with ethanol to remove oil and impurities, and the clean actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy are obtained. The actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy are fixed with a clamp to make the butt joint surface 41 of the actual sample 11 of the molybdenum alloy and the actual sample 21 butt joint to ensure that the butt joint surface 41 is tightly fitted without gap. The actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy are fixed on a pad 50, and the pad 50 is made of metal niobium, and the thickness d of the pad 50 is 2 mm. The clamp is adjusted to constrain the upper surface of the actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy to prevent warping and deformation during welding.

[0080] (7) Biased beam welding test on actual molybdenum alloy sample 11 and actual niobium alloy sample 21

[0081] The molybdenum alloy actual sample 11 and the niobium alloy actual sample 21 were placed in an electron beam welding machine and vacuumed to 3×10 - 2 Pa; set the parameters of electron beam welding: acceleration voltage of 60 kV, focusing current of 691 mA, welding beam current of 36 mA, welding speed of 600 mm / min; adjust the inclination angle of the actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy so that the angle between them and the horizontal plane is 8°; set the second deflection amount h2 of the electron beam 30 from the docking surface 41 of the molybdenum alloy test sample 10 to 0.68 mm; perform deflection beam welding on the actual sample 11 of the molybdenum alloy and the actual sample 21 of the niobium alloy; take out the welded actual sample after cooling in the furnace for 15 minutes.

[0082] (8) Observe the metallographic photograph of the weld cross section of the actual welded sample

[0083] The metallographic photograph was observed using an optical microscope. At this time, the fusion line 42 on the molybdenum alloy side and the butt surface 41 of the molybdenum alloy test sample 10 were substantially coincident.

[0084] Regarding the embodiments of the present application, it should also be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other to obtain new embodiments.

[0085] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A welding method for connecting dissimilar materials of molybdenum alloy and niobium alloy, characterized in that: include: S1. preparing a molybdenum alloy test sample and a niobium alloy test sample, and performing offset beam welding on the molybdenum alloy test sample and the niobium alloy test sample by an electron beam welding process to obtain a welded test sample; wherein, in the offset beam welding, the offset amount of the electron beam from the butt joint surface of the molybdenum alloy test sample is a first offset beam amount; S2, determining the fusion line on the molybdenum alloy side of the welding test sample, and determining the angle between the butt surface of the molybdenum alloy test sample and the fusion line on the molybdenum alloy side of the welding test sample as a first angle; S3, determining actual welding parameters for performing offset beam welding on the actual molybdenum alloy sample and the actual niobium alloy sample using an electron beam welding process according to the first angle, the first offset beam amount, and the thickness of the molybdenum alloy test sample; S4. Welding the actual molybdenum alloy sample and the actual niobium alloy sample according to the actual welding parameters.

2. The welding method according to claim 1, characterized in that: In step S3, the actual welding parameters include an inclination angle of the electron beam relative to the actual molybdenum alloy sample and the actual niobium alloy sample, and a second beam deflection amount of the electron beam from the butting surface of the actual molybdenum alloy sample.

3. The welding method according to claim 2, characterized in that: In step S3, the electron beam is tilted at an angle that is the same as the first angle relative to the actual molybdenum alloy sample and the actual niobium alloy sample.

4. The welding method according to claim 2, characterized in that: In step S3, the second beam deflection amount of the electron beam from the butt joint surface of the actual molybdenum alloy sample is determined by the following expression: h2=h1+d×sinα; Among them, h2 is the second beam deflection amount, h1 is the first beam deflection amount; d is the thickness of the molybdenum alloy test sample; α is the angle at which the electron beam is tilted relative to the molybdenum alloy actual sample and the niobium alloy actual sample.

5. The welding method according to claim 2, characterized in that: In the S3 step, Disposing the actual sample of the molybdenum alloy and the actual sample of the niobium alloy to be inclined at the first angle relative to the electron beam; The distance between the electron beam and the upper end of the butting surface of the actual molybdenum alloy sample is adjusted to the second beam deflection amount.

6. The welding method according to claim 1, characterized in that: In step S1, Preparing a plurality of groups of molybdenum alloy test samples and niobium alloy test samples; performing offset beam welding on the molybdenum alloy test samples and the niobium alloy test samples of each group using an electron beam welding process to obtain a plurality of groups of welded test samples, wherein in the offset beam welding of different groups, the electron beam deviates from the butt joint surface of the molybdenum alloy test samples by different amounts; The first beam deflection amount is determined according to the welding qualities of the plurality of groups of welding test samples.

7. The welding method according to claim 6, characterized in that: The welding quality includes the microstructure at the weld of the welding test sample and the mechanical properties of the welding test sample.

8. The welding method according to claim 1, characterized in that: In step S2, the fusion line on the molybdenum alloy side of the welding test sample is determined based on the metallographic photograph of the weld cross section of the welding test sample.

9. The welding method according to claim 1, characterized in that: The molybdenum alloy test sample, the niobium alloy test sample, the molybdenum alloy actual sample and the niobium alloy actual sample are all plate-shaped samples, and the thickness of the plate-shaped sample is 2 to 3 mm.

10. A welding method for connecting dissimilar materials of molybdenum alloy and niobium alloy, characterized in that: include: S10, preparing a molybdenum alloy test sample and a niobium alloy test sample, and performing partial beam welding on the molybdenum alloy test sample and the niobium alloy test sample by using an electron beam welding process; S20, according to the result of the offset beam welding in step S10, determining the angle at which the electron beam is tilted relative to the actual molybdenum alloy sample and the actual niobium alloy sample when the electron beam welding process is used to perform offset beam welding on the actual molybdenum alloy sample and the actual niobium alloy sample, and the second offset beam amount by which the electron beam deviates from the butt joint surface of the actual molybdenum alloy sample; S30. Welding the actual molybdenum alloy sample and the actual niobium alloy sample according to the angle determined in step S20 and the second beam deflection amount.

11. The welding method according to claim 10, characterized in that: Step S10 includes: S101. Prepare multiple groups of molybdenum alloy test samples and niobium alloy test samples; S102, performing offset beam welding on each group of the molybdenum alloy test sample and the niobium alloy test sample using an electron beam welding process to obtain multiple groups of welded test samples, wherein in the offset beam welding of different groups, the electron beam deviates from the butt joint surface of the molybdenum alloy test sample by different amounts; S103, determining the optimal deflection amount of the electron beam from the butt joint surface of the molybdenum alloy test sample in deflection welding according to the welding qualities of the multiple groups of welding test samples.

12. The welding method according to claim 11, characterized in that: The S20 step includes: S201, determining a fusion line on the molybdenum alloy side of the welding test sample obtained by bias beam welding using an optimal bias beam amount, and determining an angle between a butt joint surface of the molybdenum alloy test sample and the fusion line on the molybdenum alloy side of the welding test sample as a first angle; S202. Determine, based on the first angle, the optimal beam deflection amount, and the thickness of the molybdenum alloy test sample, the inclination angle of the electron beam relative to the actual molybdenum alloy sample and the actual niobium alloy sample when the electron beam welding process is used to perform beam deflection welding on the actual molybdenum alloy sample and the actual niobium alloy sample, and the second beam deflection amount.

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