Welded joint tensile sample and preparation method thereof

Abstract

The invention relates to the field of welding, and provides a welded joint tensile sample and a preparation method thereof. The preparation method of the welded joint tensile sample comprises the following steps: inserting and welding an inserting plate at the end part of a honeycomb structure base material so as to prepare an end part structure at the end part of the base material; and preparing a tensile sample by taking the end part structure as a clamping end. According to the preparation method of the welded joint tensile sample, the insertion plate is welded at the end part of the base material, so that the strength of the clamping end is ensured, the sample can be normally subjected to a tensile test, the clamping end of the tensile sample can be ensured to be normally clamped without being damaged, and the stretchability of a honeycomb structure can be integrally evaluated. According to the tensile sample prepared by the method, the tensile sample with reliable strength can be prepared from the honeycomb structure base material, so that a normal tensile test can be carried out, and the mechanical property and failure behavior of the tensile sample under tensile force in the direction perpendicular to a welding line can be more conveniently researched.

Description

Technical Field

[0001] The invention relates to the field of welding and provides a welding joint tensile specimen and a preparation method thereof. Background Art

[0002] Honeycomb structure is the basic structure of a honeycomb, which is composed of regular hexagonal single rooms, with the room openings all facing downward or to one side, and arranged symmetrically back to back. This structure has excellent geometric mechanical properties, such as light weight, high strength, high stiffness, good thermal insulation and sound insulation. Honeycomb structure is widely used in material science. For example, in the field of rail vehicles, honeycomb structure is often used to make driver's cabs and car bodies. In the driver's cab structure, different honeycomb aluminums are connected by welding. During welding, there are problems such as arc welding easily penetrating the honeycomb aluminum top plate, and the internal brazing welds recrystallizing after secondary melting, and the welding quality is difficult to control.

[0003] The tensile test is a test that studies a series of properties of materials under tensile loads, and is also the most common test type for welded joints. For welded joints of honeycomb structures, if conventional tensile specimens are made by referring to the welds of metal materials, the clamping ends of the honeycomb structure welding structure are easily damaged by the tensile testing machine during the tensile test, making the test impossible. If upper and lower clamps are added to the honeycomb structure and processed separately into tensile specimens, the role of the honeycomb core will be ignored, and the test cannot reflect the actual condition of the honeycomb aluminum material under tensile force. In addition, this method is difficult to process and requires a large amount of processing. After being processed into tensile specimens, the parallelism is difficult to meet the test requirements. Summary of the invention

[0004] The invention provides a method for preparing a tensile test specimen of a welded joint, which is used to ensure that the clamping end of the tensile specimen can be normally clamped without being damaged, and to evaluate the tensile property of a honeycomb structure as a whole.

[0005] The invention also provides a welding joint tensile test specimen.

[0006] The present invention provides a method for preparing a welding joint tensile specimen, which comprises the following steps.

[0007] A plug-in plate is inserted and welded at the end of the honeycomb structure mother material to prepare an end structure at the end of the mother material.

[0008] The end structure is used as a clamping end to prepare a tensile test specimen.

[0009] According to the method for preparing a tensile specimen of a welded joint of the present invention, the step of inserting and welding a plug-in plate at the end of a honeycomb structure base material to prepare an end structure at the end of the base material further includes the following steps.

[0010] A top plate is welded on the upper surface and the lower surface of the honeycomb structure base material to construct a sandwich structure, and a plug-in channel is constructed at the end of the base material of the sandwich structure.

[0011] The end of the plug board is inserted into the plug channel, and the plug board is fixed to a pair of the top plates by welding.

[0012] According to the method for preparing a tensile specimen of a welded joint of the present invention, the step of welding a top plate on the upper and lower surfaces of the honeycomb structure base material to construct a sandwich structure, and constructing a plug-in channel at the end of the base material of the sandwich structure, further includes one of the following steps.

[0013] After the top plates are welded to the upper and lower surfaces of the honeycomb structure mother material, a portion of the honeycomb core is removed from the end of the mother material toward the center by machining to construct the insertion channel between a stack of the top plates.

[0014] Before welding the top plates to the upper and lower surfaces of the honeycomb structure base material, a pair of the top plates are first laid on the upper and lower surfaces of the honeycomb core of the base material, and both of the top plates can extend outward from the end edges of the honeycomb core to construct the insertion channel between the extended ends of the pair of top plates.

[0015] According to the method for preparing a tensile specimen for a welded joint of the present invention, the step of inserting the end of the plug-in plate into the plug-in channel and welding and fixing the plug-in plate to a pair of the top plates further includes the following steps.

[0016] The upper surface and the lower surface of the end of the plug board are cut respectively to form a protruding end at the end of the plug board, and the width of the protruding end is smaller than the width of the plug board.

[0017] The extended end of the plug board is inserted into the plug channel to form a plug-in structure.

[0018] The upper surface and the lower surface of the insert structure are respectively fixed to the grooves formed by a pair of top plates by welding.

[0019] According to the method for preparing a tensile test specimen for a welded joint of the present invention, a J-shaped groove is formed between the extended end surface of the plug-in plate and the corresponding top plate, and a flat gasket is provided on the J-shaped groove.

[0020] According to the method for preparing a tensile specimen of a welded joint of the present invention, the step of welding and fixing the upper surface and the lower surface of the inserted structure to the grooves formed by a pair of top plates, respectively, further includes: welding the grooves by metal inert gas shielded welding, the shielding gas of the metal inert gas shielded welding is argon, and the argon ratio of the shielding gas is 99.999%; during the welding process, the welding gun is pointed to the root of the groove, and the upper surface and the lower surface of the inserted structure are symmetrically welded; the welding parameters include welding current and welding speed, the welding current ranges from 140A to 160A, and the welding speed ranges from 9 mm / s to 11 mm / s.

[0021] According to the method for preparing a tensile specimen of a welded joint of the present invention, the step of preparing the tensile specimen using the end structure as a clamping end further includes the following steps.

[0022] The end structures are respectively prepared at both ends of the parent material.

[0023] The end structures at both ends of the parent material are used as the clamping ends to prepare the tensile test specimen.

[0024] According to the method for preparing a tensile specimen of a welded joint of the present invention, the step of preparing the tensile specimen using the end structure as a clamping end further includes the following steps.

[0025] The ends of the two parent materials far away from the end structures are welded to form a specimen assembly, and the end structures are respectively provided at both ends of the specimen assembly.

[0026] The end structures at both ends of the specimen assembly are used as the clamping ends at both ends of the tensile specimen to prepare the tensile specimen.

[0027] According to the method for preparing a tensile specimen of a welded joint of the present invention, the step of preparing the tensile specimen by using the end structures at both ends of the specimen assembly as the clamping ends at both ends of the tensile specimen, further comprises the following steps: cutting a plurality of the tensile specimens at intervals on the specimen assembly, and each of the tensile specimens is provided with the clamping ends at both ends.

[0028] The present invention provides a welding joint tensile specimen, which is prepared by using the welding joint tensile specimen preparation method as described above.

[0029] The weld joint tensile specimen includes a parallel section and a pair of clamping ends, wherein the pair of clamping ends are respectively connected to the two ends of the parallel section, the clamping end includes an end structure of a honeycomb structure base material, and the end structure includes a plug-in plate inserted into the end of the honeycomb structure base material.

[0030] According to the weld joint tensile specimen of the present invention, the end structure includes a honeycomb core and a pair of top plates, the pair of top plates are respectively laid flat and fixed to the upper surface and the lower surface of the honeycomb core, and the pair of top plates extend outward from the honeycomb core, and a plug-in channel is left between the protruding ends of the pair of top plates, and the plug-in plate is inserted and welded in the plug-in channel.

[0031] According to the weld joint tensile specimen of the present invention, the weld joint tensile specimen also includes a transition section, the clamping end is connected to the parallel section through the transition section, the width of the clamping end is greater than the width of the parallel section, and the transition section is arranged in an inwardly concave arc structure.

[0032] The present invention provides a method for preparing a tensile specimen of a welded joint, comprising the following steps: inserting and welding a plug-in plate at the end of a honeycomb structure base material to prepare an end structure at the end of the base material; and preparing a tensile specimen using the end structure as a clamping end. The method for preparing a tensile specimen of a welded joint ensures the strength of the clamping end by welding a plug-in plate at the end of the base material, so that the specimen can undergo a normal tensile test, thereby ensuring that the clamping end of the tensile specimen can be clamped normally without being damaged, and evaluating the tensile properties of the honeycomb structure as a whole, and the manufacturing method is simple and reliable. The tensile specimen prepared by this method can use the honeycomb structure base material to manufacture a tensile specimen with reliable strength to conduct a normal tensile test, and it is more convenient to study its mechanical properties and failure behavior when subjected to tensile force perpendicular to the weld direction.

[0033] The present invention provides a welding joint tensile specimen, which is prepared by the above-mentioned welding joint tensile specimen preparation method; the welding joint tensile specimen includes a parallel section and a pair of clamping ends, the pair of clamping ends are respectively connected to the two ends of the parallel section, the clamping end includes an end structure of a honeycomb structure parent material, and the end structure includes a plug-in plate inserted into the end of the honeycomb structure parent material. The tensile specimen can perform a tensile test on the honeycomb structure parent material as a whole, effectively test various properties when a tensile load is applied in the direction perpendicular to the weld, and study its failure mode; and the tensile specimen has a simple structure, which effectively solves the problem that the traditional sandwich structure adhesive connection test method has low strength and is prone to debonding.

[0034] Furthermore, since the weld joint tensile specimen is prepared by using the above-mentioned weld joint tensile specimen preparation method, it can have all the advantages of the above-mentioned weld joint tensile specimen preparation method, and the details are not repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 It is a schematic flow chart of the method for preparing a tensile specimen of a welded joint provided by the present invention.

[0037] Figure 2 It is a structural schematic diagram of a sampling base material of a weld joint tensile test specimen provided by the present invention.

[0038] Figure 3 It is a schematic structural diagram of the base material end portion of the weld joint tensile specimen provided by the present invention.

[0039] Figure 4 It is a schematic structural diagram of the clamping end of the weld joint tensile specimen provided by the present invention.

[0040] Figure 5 It is a schematic structural diagram of the clamping weld of the weld joint tensile specimen provided by the present invention.

[0041] Figure 6 It is a structural schematic diagram of the sampling combination structure of the welding joint tensile specimen provided by the present invention.

[0042] Figure 7 It is a schematic diagram of the structure of the welding joint tensile specimen provided by the present invention.

[0043] Figure 8 and Fig. 9 It is a metallographic structure diagram of the welded joint tensile specimen provided by the present invention after a tensile test.

[0044] Figures 10 to 12 This is a state diagram of the welded joint tensile specimen provided by the present invention after fracture.

[0045] Reference numerals: 1. First end structure; 2. First parent material core; 3. Connecting weld; 4. Second parent material core; 5. Second end structure; 51. Top plate; 52. Honeycomb core; 6. Plug-in plate; 7. Plug-in groove; 8. Sample assembly; A. Clamping end; B. Parallel section; C. Transition section. DETAILED DESCRIPTION

[0046] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0047] Reference Figures 1 to 12 As shown, the embodiment of the present invention specifically proposes a method for preparing a tensile specimen of a welded joint (referred to as “preparation method” in the present invention), and a tensile specimen of a welded joint prepared by the preparation method (referred to as “tensile specimen” in the present invention).

[0048] like Figure 1 As shown, the method for preparing a tensile specimen of a welded joint described in an embodiment of the present invention includes an end structure preparation step and a tensile specimen preparation step.

[0049] End structure preparation step: inserting and welding a plug-in plate 6 at the end of the honeycomb structure mother material to prepare an end structure at the end of the mother material.

[0050] Steps for preparing the tensile specimen: Use the end structure as the clamping end A to prepare the tensile specimen.

[0051] The preparation method improves the connection strength of the end of the parent material by welding the plug plate 6 at the end of the parent material, thereby ensuring the strength of the clamping end A so that the sample can be normally subjected to the tensile test, thereby ensuring that the clamping end A of the tensile sample can be normally clamped without being damaged, and the tensile property of the honeycomb structure can be evaluated as a whole, and the preparation method is simple and reliable. The tensile specimen prepared by this method can use the honeycomb structure parent material to make a tensile specimen with reliable strength to conduct a normal tensile test, and it is more convenient to study its mechanical properties and failure behavior when subjected to tensile force perpendicular to the weld direction.

[0052] In some embodiments, Figure 1 and Figure 2 As shown, the above-mentioned end structure preparation step further includes a plug-in channel preparation step and a welding and fixing step.

[0053] Preparation steps of the plug-in channel: welding a top plate 51 on the upper surface and the lower surface of the honeycomb structure base material to construct a sandwich structure, and constructing a plug-in channel at the end of the base material of the sandwich structure.

[0054] Welding and fixing step: insert the end of the plug-in board 6 into the plug-in channel, and weld and fix the plug-in board 6 and a pair of top plates 51.

[0055] The sandwich structure of the honeycomb structure parent material can strengthen the strength of the honeycomb structure and effectively prevent arc welding from penetrating the top plate 51 of the aluminum honeycomb core 52 (i.e., the honeycomb aluminum core) during welding. The sandwich structure can usually be applied to the driver's cab in the field of rail transit. In the embodiment of the present invention, a sandwich structure is preferably set for the brazed honeycomb aluminum, and the top plates 51 welded to the upper and lower surfaces of the honeycomb core 52 are both aluminum alloy plates. The honeycomb core 52 is made of a honeycomb aluminum ultra-thin plate, and the honeycomb core 52 is connected to a pair of top plates 51 by brazing. However, for the honeycomb structure parent material of the sandwich structure, there are still the above-mentioned problems such as arc welding easily penetrating the honeycomb aluminum top plate 51 during welding, and the internal brazing weld seam recrystallization after secondary melting. The welding quality is difficult to control, so it is necessary to use the plug-in and welding of the plug-in plate 6 and the plug-in channel in combination with the welding fixing step to implement the end reinforcement of the honeycomb structure parent material.

[0056] It should be noted that, in the embodiment of the present invention, the preparation of the above sandwich structure is completed based on the honeycomb aluminum material joint form and welding parameters to be studied.

[0057] In some specific embodiments, the above-mentioned plug-in channel preparation step further includes one of the following steps. That is, after welding the top plate 51 on the upper surface and the lower surface of the honeycomb structure mother material, a part of the honeycomb core 52 is removed from the end of the mother material to the center by machining to construct a plug-in channel between a pile of top plates 51; or, before welding the top plate 51 on the upper surface and the lower surface of the honeycomb structure mother material, a pair of top plates 51 is first laid on the upper surface and the lower surface of the honeycomb core 52 of the mother material, and the pair of top plates 51 can both extend outward from the end edge of the honeycomb core 52 to construct a plug-in channel between the extended ends of the pair of top plates 51.

[0058] In this embodiment, Figure 2 As shown, at least 20 mm of the honeycomb core 52 is machined inward from the end of the sandwich structure along the position between the pair of top plates 51, so that only the insertion channel of the upper and lower top plates 51 is retained at the end of the parent material of the sandwich structure. This preparation method is more efficient and does not damage the connection strength of the top plate 51, ensuring smooth preparation of subsequent steps.

[0059] In some specific embodiments, the welding and fixing step further includes a cutting step, an insert structure preparation step, and a welding step.

[0060] Cutting step: Cut the upper surface and the lower surface of the end of the plug board 6 respectively to form a protruding end at the end of the plug board 6, and the width of the protruding end is smaller than the width of the plug board 6.

[0061] Preparation step of the plug-in structure: insert the extended end of the plug-in board 6 into the plug-in channel to form the plug-in structure.

[0062] Welding step: The upper surface and the lower surface of the plug-in structure are respectively fixed to the grooves formed by a pair of top plates 51 by welding.

[0063] The above-mentioned cutting step can reliably prepare for forming a J-shaped groove between the extended end surface of the plug-in board 6 and the corresponding top plate 51. In the plug-in structure preparation step, it is preferred to use a 5083 aluminum plate with the same thickness as the honeycomb structure base material as the plug-in board 6, and to make the clamping end A by plugging, assembling and welding. Specifically, it is preferred to insert the processed plug-in board 6 into the above-mentioned plug-in channel to form an plug-in structure, such as Figure 4 The joint formed by this plug-in structure is more structurally stable and has less deformation during welding.

[0064] In some specific embodiments, a J-shaped groove is formed between the extended end surface of the plug-in board 6 and the corresponding top plate 51. The J-shaped groove is provided with a flat gasket. That is, the joint form of the plug-in groove 7 of the plug-in structure is a J-shaped groove with a flat gasket. Figure 5 As shown, the specific joint details are that the straight spacing b between the top plate 51 of the end structure and the arc segment of the J-shaped groove ranges from 2mm to 3mm, the radius R of the arc segment ranges from 4mm to 6mm, and the slope angle β of the J-shaped groove ranges from 10 degrees to 20 degrees. Since the plug-in groove 7 is the welding of the top plate 51 (thin plate) and the extended end of the plug-in plate 6 (super thick plate), the difference in material thickness leads to a very large difference in heat dissipation, and quality defects such as burn-through at the thin plate and unmelted at the thick plate are prone to occur during welding. The design of the J-shaped groove with a flat gasket can ensure that the root of the weld is effectively filled, improve the welding quality, and ensure the strength of the clamping end A; in addition, the filling amount of the J-shaped groove is smaller than that of the V-shaped groove, and the welding deformation is smaller.

[0065] It should be noted that the above-mentioned welding and fixing steps further include: welding the groove using a metal inert gas shielded welding, the shielding gas of the metal inert gas shielded welding is argon, and the argon ratio of the shielding gas is 99.999%. The preferred welding wire is a welding wire of model ER5356. During the welding process, the welding gun points to the root of the groove, and the upper and lower surfaces of the plug-in structure are welded symmetrically. That is, after welding the plug-in groove 7 on the upper surface, the plug-in groove 7 on the lower surface of the same end structure is immediately welded. The welding parameters include welding current and welding speed, the welding current ranges from 140A to 160A, and the welding speed ranges from 9 mm / s to 11 mm / s.

[0066] In some embodiments, the tensile specimen preparation step further includes: preparing end structures at both ends of the parent material; and preparing the tensile specimen using the end structures at both ends of the parent material as the clamping ends A. The tensile specimen preparation step can directly prepare the tensile specimen on a set of parent materials. That is, the tensile specimen preparation step is applied to the overall preparation method, which is to first take the tensile specimen and then weld the clamping ends A.

[0067] In some embodiments, Figure 1 , Figure 6 and Figure 7 As shown, another tensile specimen preparation step can also be adopted. Specifically, the above tensile specimen preparation step further includes a specimen assembly preparation step and a tensile specimen cutting step.

[0068] The test piece assembly preparation steps are as follows: welding the ends of two base materials away from the end structures to form a test piece assembly, and the end structures are respectively provided at both ends of the test piece assembly.

[0069] Steps for cutting the tensile specimen: Use the end structures at both ends of the specimen assembly as the clamping ends A at both ends of the tensile specimen to prepare the tensile specimen.

[0070] The tensile specimen preparation step can weld two groups of parent materials together, thereby expanding the preparation size of the tensile specimen, and making the preparation of the test tensile specimen more convenient and efficient.

[0071] In some specific embodiments, the above-mentioned tensile specimen cutting step further includes the following steps: cutting a plurality of tensile specimens at intervals on the specimen assembly, and each tensile specimen is provided with a clamping end A at both ends.

[0072] That is, if Figure 6 As shown, two groups of honeycomb structure base materials that are respectively inserted and welded with the first end structure 1 and the second end structure 5 are first welded to form an integral test piece assembly, and then a plurality of tensile specimens are cut from the test piece assembly. Compared with the tensile specimen preparation steps of first taking the tensile specimen and then welding the clamping end A, this method can cut more tensile specimens from the honeycomb structure base material, and this method also has the advantages of fewer welding passes and can effectively avoid welding defects caused by frequent arc starting and closing.

[0073] The embodiment of the present invention also provides a welding joint tensile test specimen. Figures 7 to 12 As shown, the tensile specimen is prepared using the above-mentioned method for preparing a welded joint tensile specimen.

[0074] like Figure 7As shown, the weld joint tensile test specimen includes a parallel section B and a pair of clamping ends A. The pair of clamping ends A are respectively connected to the two ends of the parallel section B. The clamping end A includes an end structure of the honeycomb structure base material. The end structure includes a plug-in plate 6 inserted into the end of the honeycomb structure base material. The tensile test specimen can perform a tensile test on the honeycomb structure base material as a whole, effectively test various properties when a tensile load is applied in the direction perpendicular to the weld, and study its failure mode; and the tensile test specimen has a simple structure, which effectively solves the problem that the traditional sandwich structure adhesive connection test method has low strength and is prone to debonding.

[0075] Furthermore, since the weld joint tensile specimen is prepared by using the above-mentioned weld joint tensile specimen preparation method, it can have all the advantages of the above-mentioned weld joint tensile specimen preparation method, and the details are not repeated here.

[0076] In some embodiments, Figure 3 and Figure 7 As shown, the above-mentioned end structure includes a honeycomb core 52 and a pair of top plates 51. The pair of top plates 51 are respectively laid flat and fixed on the upper surface and the lower surface of the honeycomb core 52, and the pair of top plates 51 extend outward from the honeycomb core 52. A plug-in channel is left between the extended ends of the pair of top plates 51. Figure 4 As shown, the plug board 6 is inserted and welded in the plug channel. The specific advantages of the structural arrangement of the end structure have been described in detail in the above content, and will not be repeated here.

[0077] In some embodiments, Figure 7 As shown, the weld joint tensile test specimen also includes a transition section C. The clamping end A is connected to the parallel section B through the transition section C. In order to facilitate reliable clamping of the tensile test, the width of the clamping end A is greater than the width of the parallel section B, and the transition section C is correspondingly configured as an inwardly concave arc structure.

[0078] The specific structure of the tensile specimen prepared in the test example corresponding to the embodiment of the present invention is as follows: Figure 7 As shown, the length of the parallel section B (the sum of the widths of the two sets of parent materials) is ≥ 100 mm + the width of the joint weld Ls. Preferably, the width of the parallel section B is b = 25 mm, the width of the clamping end A is b1 = 37 mm, and the arc radius r of the transition section C is ≥ 25°.

[0079] It can be seen that in the tensile specimen of this test example prepared by the above preparation method, the J-shaped groove welding effect is as follows Figure 7 As shown. The tensile specimen has the advantages of good welding fusion and no defects. According to the above preparation method, the tensile specimen is prepared and the tensile test is carried out. The tensile specimen after fracture is as shown in Figure 8 and Fig. 9 As shown. Figures 10 to 12As shown, after the tensile test, all fractures occurred in the honeycomb structure base material or the joint welds of two groups of honeycomb structure base materials, while the clamping end A of the tensile specimen was not damaged. It can be seen that the tensile specimen of the present invention can be successfully applied to the tensile test of the honeycomb aluminum welded joint.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these 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 invention.

Claims

1. A method for preparing a tensile specimen of a welded joint, characterized in that: The following steps are involved: Inserting and welding a plug-in plate at the end of the honeycomb structure mother material to prepare an end structure at the end of the mother material; The end structure is used as a clamping end to prepare a tensile test specimen.

2. The method for preparing a tensile test specimen for a welded joint according to claim 1, characterized in that: The step of inserting and welding a plug-in plate at the end of the honeycomb structure mother material to prepare an end structure at the end of the mother material further includes the following steps: Welding top plates on the upper and lower surfaces of the honeycomb structure base material to construct a sandwich structure, and constructing a plug-in channel at the end of the base material of the sandwich structure; The end of the plug board is inserted into the plug channel, and the plug board is fixed to a pair of the top plates by welding.

3. The method for preparing a tensile test specimen for a welded joint according to claim 2, characterized in that: The step of welding top plates on the upper and lower surfaces of the honeycomb structure base material to construct a sandwich structure, and constructing a plug-in channel at the end of the base material of the sandwich structure, further includes one of the following steps: After the top plates are welded to the upper and lower surfaces of the honeycomb structure mother material, a portion of the honeycomb core is removed from the end of the mother material toward the center by machining to construct the insertion channel between a stack of the top plates; Before welding the top plates to the upper and lower surfaces of the honeycomb structure base material, a pair of the top plates are first laid on the upper and lower surfaces of the honeycomb core of the base material, and both of the top plates can extend outward from the end edges of the honeycomb core to construct the insertion channel between the extended ends of the pair of top plates.

4. The method for preparing a tensile test specimen for a welded joint according to claim 2, characterized in that: The step of inserting the end of the plug board into the plug channel and welding the plug board to a pair of top plates further includes the following steps: Cutting the upper surface and the lower surface of the end of the plug board respectively to form a protruding end at the end of the plug board, wherein the width of the protruding end is smaller than the width of the plug board; Inserting the extended end of the plug board into the plug channel to form a plug-in structure; The upper surface and the lower surface of the inserting structure are respectively fixed to the grooves formed by a pair of top plates by welding.

5. The method for preparing a tensile test specimen for a welded joint according to claim 4, characterized in that: A J-shaped groove is formed between the extended end surface of the plug board and the corresponding top plate, and a flat gasket is provided on the J-shaped groove.

6. The method for preparing a tensile test specimen for a welded joint according to claim 4, characterized in that: The step of welding and fixing the upper surface and the lower surface of the plug-in structure to the grooves formed by the pair of top plates respectively further comprises: The groove is welded by using metal inert gas shielded welding, the shielding gas of the metal inert gas shielded welding is argon, and the argon ratio of the shielding gas is 99.999%; During the welding process, the welding gun is pointed at the root of the groove, and the upper and lower surfaces of the inserted structure are symmetrically welded; the welding parameters include welding current and welding speed, the welding current ranges from 140A to 160A, and the welding speed ranges from 9mm / s to 11mm / s.

7. The method for preparing a tensile test specimen for a welded joint according to any one of claims 1 to 6, characterized in that: The step of preparing a tensile specimen using the end structure as a clamping end further comprises the following steps: preparing the end structures at both ends of the parent material respectively; The end structures at both ends of the parent material are used as the clamping ends to prepare the tensile test specimen.

8. The method for preparing a tensile test specimen for a welded joint according to any one of claims 1 to 6, characterized in that: The step of preparing a tensile specimen using the end structure as a clamping end further comprises the following steps: Welding two ends of the parent materials away from the end structures to form a specimen assembly, wherein the end structures are respectively provided at both ends of the specimen assembly; The end structures at both ends of the specimen assembly are used as the clamping ends at both ends of the tensile specimen to prepare the tensile specimen.

9. The method for preparing a tensile test specimen for a welded joint according to claim 8, characterized in that: The step of preparing the tensile specimen by using the end structures at both ends of the specimen assembly as the clamping ends at both ends of the tensile specimen, further comprises the following steps: A plurality of tensile specimens are cut from the specimen assembly at intervals, and the clamping ends are respectively provided at both ends of each tensile specimen.

10. A weld joint tensile test specimen, characterized in that: Prepared by the method for preparing a weld joint tensile specimen according to any one of claims 1 to 9; The weld joint tensile specimen includes a parallel section and a pair of clamping ends, wherein the pair of clamping ends are respectively connected to the two ends of the parallel section, the clamping end includes an end structure of a honeycomb structure base material, and the end structure includes a plug-in plate inserted into the end of the honeycomb structure base material.

11. The weld joint tensile test specimen according to claim 10, characterized in that: The end structure includes a honeycomb core and a pair of top plates, wherein the pair of top plates are respectively laid flat and fixed to the upper surface and the lower surface of the honeycomb core, and the pair of top plates extend outward from the honeycomb core, and a plug-in channel is left between the extended ends of the pair of top plates, and the plug-in plate is inserted and welded in the plug-in channel.

12. The weld joint tensile test specimen according to claim 10, characterized in that: The weld joint tensile test specimen further includes a transition section, the clamping end is connected to the parallel section via the transition section, the width of the clamping end is greater than the width of the parallel section, and the transition section is arranged in an inwardly concave arc structure.

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