Electron beam welding method for titanium alloy with transition intermediate layer

Abstract

The invention relates to the technical field of electron beam welding, in particular to a titanium alloy electron beam welding method with a transition middle layer, which comprises the following steps: assembling the transition middle layer prepared in advance in a welding seam of a titanium alloy butt-joint base material, the transition intermediate layer is prepared from the following raw materials in percentage by mass: 0 to 3 percent of aluminum element, 0.5 to 1.5 percent of boron element and 95.5 to 99.5 percent of titanium element; and a circular waveform deflection scanning electron beam is adopted for positioning spot welding, so that the transition middle layer and the titanium alloy butt-joint base material are fused, and the weld joint is filled with the transition middle layer. The welding quality of a titanium alloy welding joint structure can be improved, welding element burning loss is compensated, the titanium element content of a welding seam is increased, and the structure performance of the welding seam and the plasticity and toughness of the joint are improved.

Description

Technical Field

[0001] The present application relates to the technical field of electron beam welding, and in particular to a method for electron beam welding of a titanium alloy with a transition intermediate layer. Background Art

[0002] With the development of aviation manufacturing technology, vacuum electron beam welding technology has been widely used in the manufacture of thick titanium alloy structures such as frame beams. Since electron beam welding generally adopts a self-melting welding method without filler metal, it will cause the burnout of the alloy elements in the weld. Although the tensile strength of the titanium alloy welded joint reaches more than 90% of the base material and is equivalent to the base material, the tensile plasticity of the joint and the impact performance of the weld are still lower than the base material.

[0003] At present, the manufacturing of new aviation structures will continue to develop in the direction of large-scale, integrated, lightweight and low-cost, and electron beam welding will still be one of the research and development solutions for titanium alloy load-bearing structures. However, the comprehensive performance of the plasticity and toughness of titanium alloy welded joint structures needs to be improved urgently to meet the comprehensive performance indicators of aviation structures. In terms of plasticity and toughness regulation, the improvement effect of conventional electron beam welding process methods is limited. Therefore, it is urgent to adopt new welding technologies to achieve alloying of weld metal, improve weld microstructure and properties, and improve the plasticity and toughness of welds. Summary of the invention

[0004] (1) Technical issues to be solved

[0005] The present application provides a titanium alloy electron beam welding method with a transition intermediate layer, which solves the problem of how to improve the weld microstructure performance of the titanium alloy welded joint structure and enhance the plastic toughness of the weld.

[0006] (2) Technical solution

[0007] The present application provides a titanium alloy electron beam welding method with a transition intermediate layer, comprising:

[0008] Assembling a pre-prepared transition intermediate layer in the weld of the titanium alloy butt substrate, wherein the raw materials for preparing the transition intermediate layer include 0% to 3% by mass of aluminum, 0.5% to 1.5% by mass of boron and 95.5% to 99.5% by mass of titanium;

[0009] A circular waveform deflection scanning electron beam is used for positioning spot welding to melt the transition intermediate layer and the titanium alloy butt substrate, so that the transition intermediate layer fills into the weld.

[0010] Further, the transition intermediate layer comprises a semi-I-shaped foil strip intermediate layer;

[0011] The half-I-shaped foil strip middle layer comprises an upper edge strip, a middle web plate and a lower edge strip; the upper edge strip and the lower edge strip are respectively vertically connected to the middle web plate and face the same side of the middle web plate.

[0012] Furthermore, the width of the upper edge strip is greater than the width of the lower edge strip, and the height of the middle web is the same as the thickness of the titanium alloy butt-jointed substrate.

[0013] Furthermore, the number of the half-I-shaped foil strip middle layers is two, and the upper edge strips and the lower edge strips of the two half-I-shaped foil strip middle layers are respectively oriented toward the two sides of the weld.

[0014] Furthermore, the transition intermediate layer further comprises a straight rectangular foil intermediate layer, and the straight rectangular foil intermediate layer is superimposed on one side of the middle web.

[0015] Furthermore, the height of the intermediate layer of the straight rectangular foil strip is the same as the thickness of the titanium alloy butt-jointed substrate.

[0016] Furthermore, the number of the straight rectangular foil strip intermediate layers is one or two.

[0017] Furthermore, it also includes:

[0018] Applying upper pressing force and two-end pressing force to the titanium alloy butt joint substrate assembled with the transition intermediate layer, respectively, so that the welding assembly gap is smaller than the first preset value, the misalignment is smaller than the second preset value, and the lateral preload deformation is controlled within a preset range;

[0019] The welding auxiliary pad is installed below the weld, and a venting groove is provided in the center of the welding auxiliary pad; the venting groove is arranged along the welding direction, and the width is greater than twice the width of the lower edge strip.

[0020] Furthermore, when the circular waveform deflection scanning electron beam is used for positioning spot welding, the positioning welding beam spot width completely encompasses the transition intermediate layer, and the number of positioning welding points is 5 to 8 points;

[0021] After the positioning spot welding, segmented continuous positioning welding is used for secondary positioning. The number of segments is 2 to 3, and the length of each segment is 1 / 4 to 1 / 3 of the welding length and is spaced apart. The welding penetration reaches 1 / 4 to 1 / 3 of the thickness.

[0022] Furthermore, it also includes:

[0023] A medium welding speed of 600mm / min to 800mm / min is used, and deflection scanning welding is performed in the lower focusing state at the 1 / 3 to 1 / 2 thickness position. A modification welding method with increased penetration depth of 1 / 3 to 1 / 2 thickness is designed, and the upper metal is remelted for a second time.

[0024] (3) Beneficial effects

[0025] The above technical solution of the present application has the following advantages:

[0026] The present application provides a titanium alloy electron beam welding method with a transition intermediate layer, which comprises assembling a pre-prepared transition intermediate layer in the weld of the titanium alloy butt substrate, wherein the raw materials for preparing the transition intermediate layer include 0% to 3% by mass of aluminum, 0.5% to 1.5% by mass of boron and 95.5% to 99.5% by mass of titanium, and then using a circular waveform deflection scanning electron beam for positioning spot welding to melt the transition intermediate layer and the titanium alloy butt substrate so that the transition intermediate layer is filled into the weld, thereby compensating for welding element burnout, increasing the titanium content of the weld, refining the grain structure, and improving the structural properties, thereby achieving joint / weld strengthening and toughening, and improving the welding quality and joint plastic toughness of the titanium alloy welded joint structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 A schematic diagram of a half-I-shaped foil tape intermediate layer provided for this application;

[0029] Figure 2 A schematic diagram of a straight rectangular foil strip middle layer and a semi-I-shaped foil strip middle layer provided by the present application being superimposed;

[0030] Figure 3 A schematic diagram of the transition intermediate layer provided in the present application being assembled in the weld between a titanium alloy and a substrate.

[0031] Figure numerals: 1, titanium alloy butt-jointed substrate; 21, semi-I-shaped foil strip middle layer; 211, upper edge strip; 212, middle web; 213, lower edge strip; 22, straight rectangular foil strip middle layer; 31, upper clamping force; 32, two end clamping force; 4, welding auxiliary pad; 41, venting groove. DETAILED DESCRIPTION

[0032] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0033] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0034] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0035] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways. "Multiple" means "two or more".

[0036] The specific implementation methods of the present application are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but are not intended to limit the scope of the present application.

[0037] The embodiment of the present application provides a titanium alloy electron beam welding method with a transition intermediate layer, comprising: assembling a pre-prepared transition intermediate layer in the weld of the titanium alloy butt substrate, wherein the raw materials for preparing the transition intermediate layer include 0% to 3% by mass of aluminum, 0.5% to 1.5% by mass of boron and 95.5% to 99.5% by mass of titanium; using a circular waveform deflection scanning electron beam for positioning spot welding to melt the transition intermediate layer and the titanium alloy butt substrate, so that the transition intermediate layer fills into the weld.

[0038] Considering the loss of elemental components caused by the melting, gasification, and evaporation of weld metal during electron beam welding, the transition intermediate layer is designed to add compensating elements such as Ti and Al to increase the titanium content and the plastic toughness of the weld. At the same time, in order to activate the titanium alloy material, the transition intermediate layer is also designed to add B elements, which can also refine the weld grains and structure and improve the stability of the weld structure. The mass percentage of the elemental composition of the transition intermediate layer is designed as follows: Al content 0% to 3%; B content 0.5% to 1.5%, Ti content 95.5% to 99.5%. The intermediate layer foil is prepared by hot rolling or other preparation methods.

[0039] Based on the performance requirements of the welded joint, the transition intermediate layer composition is designed with Ti as the main element and B and Al as the auxiliary elements to compensate for the burning of welding elements, increase the titanium content of the weld, refine the grain structure, and improve the organizational properties, thereby achieving joint / weld strengthening and toughening.

[0040] In some embodiments, the transition intermediate layer includes a semi-I-shaped foil intermediate layer; the semi-I-shaped foil intermediate layer includes an upper edge strip, a middle web plate and a lower edge strip; the upper edge strip and the lower edge strip are respectively vertically connected to the middle web plate and face the same side of the middle web plate.

[0041] In some embodiments, the width of the upper edge strip is greater than the width of the lower edge strip, and the height of the middle web is the same as the thickness of the titanium alloy butt substrate.

[0042] In some embodiments, the number of the half-I-shaped foil strip middle layers is two, and the upper edge strips and the lower edge strips of the two half-I-shaped foil strip middle layers face the two sides of the weld respectively.

[0043] In some embodiments, the transition intermediate layer further comprises a straight rectangular foil intermediate layer, and the straight rectangular foil intermediate layer is superimposed on one side of the middle web.

[0044] In some embodiments, the height of the straight rectangular foil intermediate layer is the same as the thickness of the titanium alloy butting substrate.

[0045] In some embodiments, the number of the straight rectangular foil intermediate layer is one or two.

[0046] In some embodiments, it also includes: applying upper pressing force and two end pressing force to the titanium alloy butt joint substrate assembled with the transition intermediate layer, so that the welding assembly gap is smaller than a first preset value, the misalignment is smaller than a second preset value, and the lateral preload deformation is controlled within a preset range; installing a welding auxiliary pad under the weld, and a venting groove is provided in the center of the welding auxiliary pad; the venting groove is arranged along the welding direction, and the width is greater than twice the width of the lower edge strip.

[0047] In some embodiments, when the circular waveform deflection scanning electron beam is used for positioning spot welding, the positioning welding beam spot width completely encompasses the transition intermediate layer, and the number of positioning welds is 5 to 8 points; after the positioning spot welding, segmented continuous positioning welding is used for secondary positioning, the number of segments is 2 to 3, the length of each segment is 1 / 4 to 1 / 3 of the welding length and is spaced apart, and the welding penetration reaches 1 / 4 to 1 / 3 of the thickness.

[0048] In some embodiments, it also includes: using a medium welding speed of 600mm / min to 800mm / min, performing yaw scanning welding in a lower focusing state at a 1 / 3 to 1 / 2 thickness position, designing a 1 / 3 to 1 / 2 thickness increased penetration modification welding method, and performing a secondary remelting of the upper metal.

[0049] Taking the electron beam welding of TC4 titanium alloy with large thickness and uniform cross section of 90-100 mm as an example, in order to match the weld joint, a semi-I-shaped foil strip intermediate layer 21 bent into a shape is designed in combination with the weld morphology characteristics. Figure 1 As shown, it includes the upper edge strip 211, the middle web 212 and the lower edge strip 213, etc., with a thickness of 0.2 to 1 mm. Since the upper width of the weld is greater than the root width, the width of the upper edge strip 211 is larger than that of the lower edge strip 213, and the widths are 5 to 10 mm and 1 to 3 mm respectively. The internal height of the middle web 212 is consistent with the thickness of the titanium alloy butt substrate 1 to be welded. That is, the design of the upper edge strip 211, the middle web 212 and the lower edge strip 213 of the semi-I-shaped foil strip intermediate layer 21 respectively meets the filler metal requirements of the upper, middle and root of the weld. Through electron beam welding, the semi-I-shaped foil strip intermediate layer 21 is fully filled and melted into the weld to improve the weld structure and performance.

[0050] According to the requirements for improving the organizational performance, the intermediate layer can be expanded, the amount of the filling transition intermediate layer can be determined, and an embedded transition intermediate layer can be added to the inner or outer side of the middle web 212 of the semi-I-shaped foil intermediate layer 21, such as Figure 2 As shown, a straight rectangular foil strip intermediate layer 22 of shape I is used, with a thickness of 0.2 to 1 mm and a height consistent with the thickness of the titanium alloy butt substrate 1 to be welded, and can form intermediate layers in various combinations such as ]+[, Ⅰ+]+[, Ⅰ+]+[+Ⅰ, ]+Ⅰ+[, etc. This transition intermediate layer structure design can not only provide sufficient alloying element components for the weld, but also facilitate assembly with the joint and ensure assembly accuracy.

[0051] During assembly, the upper part is pressed tightly and the two ends are tightened to ensure that the welding assembly gap is less than 0.1mm and the misalignment is less than 0.1mm. The overall structure is as follows: Figure 3As shown. In order to be suitable for the assembly of the lower edge strip, a venting groove 41 with a width of 3 to 6 mm is designed at the central position of the front of the welding auxiliary pad strip 4, and is arranged along the welding direction. It not only provides assembly space for the lower edge strip 213 of the I-shaped middle layer, but also can discharge metal vapor and reduce the probability of pore defects. Upper, middle and lower transverse tightening parts are added at both ends of the substrate in the thickness direction. The tightening device is used to increase the pre-tightening force and make it uniform. The transverse pre-tightening deformation is controlled at 0.1 to 0.2 mm to compensate for welding shrinkage deformation and reduce welding stress.

[0052] Due to the assembly and filling of the intermediate layer, the width of the welding weld needs to be increased to fully contain and melt the transition metal and the substrate. On the basis of focusing state control, the deflection scanning electron beam is used for positioning spot welding. The positioning welding beam spot width is 1-2mm larger than the conventional beam spot, which completely contains the transition intermediate layer, and the number of positioning welds is 5-8 points. In order to avoid the change of assembly accuracy during welding due to the influence of multiple interfaces and thermal stress, segmented continuous positioning welding is adopted for secondary positioning after positioning spot welding. The number of segments is 2-3, and the length of each segment is 1 / 4-1 / 3 of the welding length and is spaced. The welding penetration reaches 1 / 4-1 / 3 of the thickness. A medium welding speed of 600mm / min-800mm / min is used, and deflection scanning welding is performed in the lower focusing state of 1 / 3-1 / 2 thickness position. A welding method with increased penetration modification of 1 / 3-1 / 2 thickness is designed, and the upper metal is remelted for a second time to improve the uniformity of the organization.

[0053] The titanium alloy electron beam welding method with a transition intermediate layer provided in the embodiment of the present application, through the analysis of the butt joint form and weld morphology characteristics, proposes a bent semi-I-shaped foil transition intermediate layer and its superimposed expansion design, which respectively meets the needs of filling metal in different parts such as the upper, middle and lower parts of the weld, meets the assembly matching needs with the welded joint, provides sufficient alloying filling material for the weld, and is beneficial to improving the welding assembly accuracy.

[0054] For butt joints with transitional intermediate layers, the assembly method of upper compression and two-end tightening is adopted, and the size design of the welding pad air release groove is supplemented and improved to provide assembly space for the lower edge strip of the intermediate layer, increase the preload force, set the pre-deformation, realize the control of welding assembly gap and misalignment precision, improve the discharge of lower metal vapor, compensate for welding shrinkage deformation, and reduce welding stress.

[0055] Based on the welding process matching design of the transition intermediate layer, large beam spot welding is adopted, segmented continuous positioning welding is designed for secondary positioning, and a medium speed, downward focusing state deflection scanning welding process is adopted. After welding, a large penetration modification welding method is used to avoid changes in assembly accuracy during welding, fully contain and melt transition metal and substrate, and improve the uniformity of weld structure and the plastic toughness of the joint.

[0056] The following is described by means of specific examples.

[0057] Example

[0058] Take the TC4 titanium alloy joint with a thickness of 100 mm and a welding length of 300 mm as an example, electron beam welding is performed. Figures 1 to 3 As shown:

[0059] (1) Design and preparation of alloy element composition of intermediate layer: element composition ratio Al element content 1%, B element content 1%, Ti element content 98%. The intermediate layer is prepared by hot rolling method.

[0060] (2) Design and preparation of the structure of the intermediate layer: A semi-I-shaped foil intermediate layer 21 and a straight rectangular foil intermediate layer 22 with a thickness of 0.2 mm were designed. The widths of the upper edge strip 211 and the lower edge strip 213 of the semi-I-shaped foil intermediate layer 21 were 8 mm and 2 mm respectively. The inner height of the middle web 212 was the same as 100 mm. The intermediate layer structure of the combination of Ⅰ+]+[ was adopted to provide sufficient intermediate layer metal addition for welding.

[0061] (3) Welding assembly control: The assembly method of upper clamping force 31 and two-end tightening force 32 is adopted to ensure that the welding assembly gap is less than 0.1mm and the misalignment is less than 0.1mm. A 5mm wide air release groove 41 is designed at the central position of the front of the welding auxiliary pad 4; the two-end tightening force 32 is used to increase the pre-tightening force and make it uniform, and the lateral pre-tightening deformation is controlled at 0.2mm.

[0062] (4) Welding process matching:

[0063] 1) Positioning welding design: circular waveform deflection scanning electron beam is used for positioning spot welding, welding high voltage is 150kV, scanning amplitude and scanning frequency are 2mm and 300HZ respectively, current is 12mA, positioning welding beam spot width is 2mm larger than conventional spot welding beam spot, 5 positioning welding points are set; secondary segmented continuous positioning welding current is 60mA, number of segments is 3, each segment length is 75mm, and penetration is 25mm.

[0064] 2) Welding process optimization: Use a welding speed of 600 mm / min, perform deflection scanning welding in the lower focusing state at the 1 / 3 thickness position, and a welding current of 280 mA; after welding, use a modified welding method with a 30 mm penetration depth, perform a secondary remelting of the upper metal, and a welding current of 70 mA to improve the uniformity of the structure.

[0065] (5) Welding inspection: After welding, the welding penetration meets 100mm, the welding quality meets the first-level standard, and the structure tends to be uniform. The room temperature tensile strength of the joint reaches 939-953MPa, and the elongation after fracture reaches 12-13%. Compared with conventional welded joints, the joint strength and plasticity are improved.

[0066] The titanium alloy electron beam welding method with transition intermediate layer provided in the embodiment of the present application adopts the transition intermediate layer composition design mainly composed of Ti elements and supplemented by B elements and Al elements, and adopts the half-I-shaped foil intermediate layer formed by bending and its superimposed expansion structure, and increases the pre-tightening force and sets the pre-deformation through the assembly method of pressing the upper part and tightening the two ends, so as to meet the assembly requirements of the transition intermediate layer joint, meet the requirements of the upper, middle and lower filling metals of the weld, provide sufficient alloying element components, reduce welding stress, and compensate for welding shrinkage deformation. Through the process matching design of large beam spot welding, secondary positioning welding, medium speed deflection scanning welding, large penetration depth modification welding, etc., the transition intermediate layer metal and the substrate are fully contained and melted, the welding quality is improved, the welding element burnout is compensated, the titanium element content of the weld is increased, and the weld microstructure performance and joint plastic toughness are improved.

[0067] It should be clear that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. The present application is not limited to the specific structures described above and shown in the figures. In addition, for the sake of simplicity, detailed descriptions of known methods and technologies are omitted here.

[0068] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for electron beam welding of titanium alloy with a transition intermediate layer, characterized in that: include: Assembling a pre-prepared transition intermediate layer in the weld of the titanium alloy butt substrate, wherein the raw materials for preparing the transition intermediate layer include 0% to 3% by mass of aluminum, 0.5% to 1.5% by mass of boron and 95.5% to 99.5% by mass of titanium; A circular waveform deflection scanning electron beam is used for positioning spot welding to melt the transition intermediate layer and the titanium alloy butt substrate, so that the transition intermediate layer fills into the weld.

2. The method for electron beam welding of titanium alloy with a transition intermediate layer according to claim 1, characterized in that: The transition intermediate layer comprises a semi-I-shaped foil tape intermediate layer; The half-I-shaped foil strip middle layer comprises an upper edge strip, a middle web plate and a lower edge strip; the upper edge strip and the lower edge strip are respectively vertically connected to the middle web plate and face the same side of the middle web plate.

3. The method for electron beam welding of titanium alloy with a transition intermediate layer according to claim 2, characterized in that: The width of the upper edge strip is greater than that of the lower edge strip, and the height of the middle web is the same as the thickness of the titanium alloy butt-jointed substrate.

4. The method for electron beam welding of titanium alloy with a transition intermediate layer according to claim 2, characterized in that: The number of the half-I-shaped foil strip middle layers is two, and the upper edge strips and the lower edge strips of the two half-I-shaped foil strip middle layers are respectively oriented toward the two sides of the weld.

5. The method for electron beam welding of titanium alloy with a transition intermediate layer according to claim 2, characterized in that: The transition intermediate layer further comprises a straight rectangular foil intermediate layer, and the straight rectangular foil intermediate layer is superimposed on one side of the middle web.

6. The method for electron beam welding of titanium alloy with a transition intermediate layer according to claim 5, characterized in that: The height of the intermediate layer of the straight rectangular foil strip is the same as the thickness of the titanium alloy butt-jointed substrate.

7. The method for electron beam welding of titanium alloy with a transition intermediate layer according to claim 5, characterized in that: The number of the intermediate layers of the straight rectangular foil strip is one or two.

8. The method for electron beam welding of titanium alloy with a transition intermediate layer according to claim 2, characterized in that: Also includes: Applying upper pressing force and two-end pressing force to the titanium alloy butt joint substrate assembled with the transition intermediate layer, respectively, so that the welding assembly gap is smaller than the first preset value, the misalignment is smaller than the second preset value, and the lateral preload deformation is controlled within a preset range; The welding auxiliary pad is installed below the weld, and a venting groove is provided in the center of the welding auxiliary pad; the venting groove is arranged along the welding direction, and the width is greater than twice the width of the lower edge strip.

9. The method for electron beam welding of titanium alloy with a transition intermediate layer according to claim 1, characterized in that: When the circular waveform deflection scanning electron beam is used for positioning spot welding, the positioning welding beam spot width completely encompasses the transition intermediate layer, and the number of positioning welding points is 5 to 8 points; After the positioning spot welding, segmented continuous positioning welding is used for secondary positioning. The number of segments is 2 to 3, and the length of each segment is 1 / 4 to 1 / 3 of the welding length and is spaced apart. The welding penetration reaches 1 / 4 to 1 / 3 of the thickness.

10. The method for electron beam welding of titanium alloy with a transition intermediate layer according to claim 1, characterized in that: Also includes: A medium welding speed of 600mm / min to 800mm / min is used, and deflection scanning welding is performed in the lower focusing state at the 1 / 3 to 1 / 2 thickness position. A modification welding method with increased penetration depth of 1 / 3 to 1 / 2 thickness is designed, and the upper metal is remelted for a second time.

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