A system for fabricating test specimens for chemical composition testing of welding wire

Abstract

This utility model discloses a system for fabricating a chemical composition test specimen for welding wire, including a sample preparation container. The sample preparation container includes an electrically insulated container body, and the interior of the container body forms a sample preparation cavity with an opening at the top. The sample preparation container also includes a cover detachably assembled to the opening, and the cover has a gas channel for communicating with the sample preparation cavity. The fabrication system also includes a medium-frequency induction heating device, including a medium-frequency induction power supply and an induction coil spirally wrapped around the outer periphery of the container body. The induction coil and the medium-frequency induction power supply form a closed circuit for heating the welding wire in the sample preparation cavity. The beneficial effects of this utility model are: using inert gas to protect the molten metal reduces sample oxidation and some element burn-off, effectively prevents the escape of volatile elements in the sample, ensures that the sample composition is consistent with the actual composition, and achieves rapid and low-cost sample preparation.

Description

Technical Field

[0001] This utility model belongs to the field of high-temperature alloy processing, specifically a system for manufacturing chemical composition test specimens for welding wire, and in particular a system for manufacturing chemical composition test specimens for welding wire based on crucible melting method that can ensure that the sample composition is consistent with the actual composition. This system reduces sample oxidation and some element loss by using inert gas protection, thereby obtaining sample composition consistent with the actual composition. Background Technology

[0002] Chemical composition analysis of welding wire is crucial for product quality verification, especially for stainless steel and nickel-based alloys. Currently, there are three main methods for obtaining samples used for chemical composition analysis:

[0003] 1. Direct sampling method: This method has a very low cost to obtain samples. A sample of appropriate length can be cut from the welding wire. ICP or wet method can be used. However, the detection efficiency is slow, the requirements for test personnel are very high, and the cost is very high for stainless steel and nickel-based alloys containing a lot of elements.

[0004] II. Multi-pass, multi-layer cladding method: This method involves performing multi-pass, multi-layer cladding on thick steel plates or test plates (usually at least ≥3 layers; the specific number of layers depends on the welding method, base plate material, and process parameters). After removing the surface oxide layer, a sample is taken from the center of the weld metal. Currently, the multi-pass cladding method is the most commonly used in practical applications. See [link to relevant documentation]. Figure 14 (In the figure, 1' represents the cladding metal, 2' represents the base plate, i.e., the parent material. The total weld height H1 of the sample is ≥8mm, which is related to the material of the base plate. The sample length L is ≥100mm, and the sample width W is ≥100mm.) The advantages of this method are as follows: 1) Simple operation: Only conventional welding equipment (welding machine, parent material) is required, and no special tooling is needed. 2) Low cost: The material is readily available (ordinary steel plate), suitable for routine laboratory analysis. 3) Compliant with standards: Meets the sampling requirements of standards such as AWS A5.01 for cladding metal. 4) Wide applicability: Applicable to most types of welding wire. However, there are also obvious disadvantages, the main disadvantages are as follows: 1) Dilution rate problem: The bottom weld is affected by the composition of the parent material (high dilution rate), which may lead to deviation in results (especially when sensitive to trace elements); 2) Oxidation risk: The surface of the weld layer needs to be mechanically ground to remove the oxide layer. If the grinding is insufficient, it will contaminate the sample; 3) Composition segregation: The thermal cycle of multi-layer welding may lead to uneven composition. Sampling should be done at the center of the weld to reduce the influence. 4) Low efficiency: Multiple layers of welding are required to ensure the purity of the deposited metal, which takes a long time.

[0005] III. Crucible Melting Method: This method involves melting the welding wire in a crucible, cooling it, and obtaining a cast weld metal sample. Currently, vacuum induction melting is widely used. Its main advantages are: 1) Purest composition: Completely avoids dilution and oxidation of the base material, and the composition is close to the theoretical value of the welding wire. 2) No risk of segregation: Rapid solidification reduces elemental segregation, making it suitable for high-precision analysis (such as scientific research and high-end alloys). The main disadvantages are: 1) Expensive equipment: Requires a vacuum melting furnace system, resulting in high investment costs; 2) Not suitable for materials containing easily lost elements (such as high nitrogen, high manganese, etc.).

[0006] Therefore, there is a need for a low-cost, rapid device that can ensure the sample composition is consistent with the actual composition for preparing welding wire chemical composition testing samples. Utility Model Content

[0007] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a low-cost, fast, and reliable welding wire chemical composition test piece manufacturing system that can ensure that the sample composition is consistent with the actual composition.

[0008] To solve the above problems, the technical solution adopted by this utility model is as follows:

[0009] A system for fabricating a chemical composition test specimen for welding wire includes a sample preparation container having a sample preparation cavity with a top opening; the system further includes:

[0010] A medium-frequency induction heating device includes a medium-frequency induction power supply and an induction coil spirally wound around the outer periphery of the sample preparation container. The induction coil and the medium-frequency induction power supply form a closed circuit for heating the welding wire inside the sample preparation chamber; and

[0011] A protective gas hood is located above the opening, and the protective gas hood is provided with a gas channel for supplying protective gas to the sample preparation chamber.

[0012] As a preferred embodiment of this application, the welding wire chemical composition test specimen fabrication system further includes a protective gas supply device, which includes a gas supply equipment and a gas delivery pipeline. One end of the gas delivery pipeline is connected to the gas supply equipment, and the other end is connected to the gas channel on the protective gas hood, for delivering protective gas into the sample preparation chamber.

[0013] As a preferred embodiment of this application, the opening of the sample preparation container is provided with an outwardly extending circumferential edge, and the lower surface of the circumferential edge away from the protective gas cover forms a blocking surface to prevent the induction coil from detaching.

[0014] As a preferred embodiment of this application, the sample preparation container may be a crucible with a lid.

[0015] As a preferred embodiment of this application, the protective gas cover includes a protective gas cover body and an annular baffle integrally formed on the lower end face of the protective gas cover body. The protective gas cover body is provided with a gas channel that axially penetrates the upper and lower end faces of the protective gas cover body. The lower end face of the protective gas cover body and the inner sidewall of the annular baffle together form a uniform air cavity.

[0016] As a preferred embodiment of this application, the protective air hood further includes an air distributor disposed within the air distribution cavity.

[0017] As a preferred embodiment of this application, the air distribution device includes an air distribution plate and an annular connector. The annular connector is fixed to the outer edge of the air distribution plate along the circumferential direction. The air distribution device is provided with a plurality of air distribution holes that penetrate the air distribution device along its thickness direction. The axis of each air distribution hole is parallel to the axis of the protective air cover body.

[0018] As a preferred embodiment of this application, the air distributor is installed inside the air distribution cavity by fastening bolts.

[0019] As a preferred embodiment of this application, the air distribution holes are arranged in multiple rows and columns on the air distribution device, and from the center to the two side edges, the center distance between adjacent rows of air distribution holes is either equal or in a decreasing manner.

[0020] As a preferred embodiment of this application, the end of the gas channel away from the annular baffle protrudes upward along the axis of the protective gas cover to form a connecting section protruding from the surface of the main body of the protective gas cover for connecting the gas transmission pipeline.

[0021] As a preferred embodiment of this application, the connecting section is equipped with a quick-connect interface, which can be conveniently and quickly connected to the gas pipeline.

[0022] As a preferred embodiment of this application, the longitudinal section of the sample preparation container is a trapezoid with a larger upper section and a smaller lower section.

[0023] As a preferred embodiment of this application, the angle α between the inner wall of the sample preparation container and the axial direction of the sample preparation container is 5°~10°.

[0024] As a preferred embodiment of this application, the fabrication system further includes a cutting machine for cutting the specimen. The cutting machine can be a manual metal specimen cutting machine or an automatic metal specimen cutting machine, as long as it can cut the resolidified metal specimen.

[0025] Preferably, the protective gas is an inert gas. More preferably, it is argon.

[0026] As a preferred embodiment of this application, the welding wire chemical composition test specimen fabrication system further includes a pressure gauge and a flow meter, which are installed on the gas transmission pipeline to facilitate control of the pressure inside the sample preparation container.

[0027] The protective gas shield described in this application is suspended directly above the opening of the sample preparation container, with a gap of 2-5mm between them. This ensures that the pressure inside the sample preparation container meets the requirements while preventing excessive pressure inside the container.

[0028] This application also provides a method for preparing a test specimen for chemical composition testing of welding wire, including the following steps:

[0029] Step 1, Feeding: Cut the welding wire to be tested into an appropriate length and put it into the sample preparation chamber of the sample preparation container, and suspend the protective gas cover above the opening of the sample preparation container.

[0030] Step 2, Ventilation: Continuously introduce protective gas into the sample preparation chamber to remove the air inside the chamber;

[0031] Step 3, Melting: The medium-frequency induction heating device starts working and heats the welding wire in the sample preparation chamber under a protective gas atmosphere until the welding wire is completely melted and then stops working;

[0032] Step 4, Cooling: Cool the molten metal in the sample preparation chamber under a protective atmosphere to obtain a steel ingot;

[0033] Step 5: Steel ingot surface processing: Cut the upper and lower surfaces of the steel ingot and process and flatten the cut surfaces to obtain a test piece for testing the chemical composition of the welding wire.

[0034] As a preferred embodiment of this application, the ventilation time in step 2 is at least 1 minute to ensure that the sample preparation chamber is filled with protective gas.

[0035] As a preferred embodiment of this application, protective gas needs to be continuously introduced into the sample preparation container in steps 2, 3 and 4, with a gas flow rate greater than 20 L / min.

[0036] As a preferred embodiment of this application, the pressure inside the sample preparation chamber must be maintained >0.4 MPa during heating and cooling of the molten metal. More preferably, it is 0.4 MPa to 0.6 MPa. Under this pressure, the escape of volatile elements in the sample can be effectively prevented, ensuring that the sample composition is consistent with the actual composition.

[0037] Compared with the prior art, the beneficial effects of this utility model are:

[0038] 1. The sample preparation system of this application uses inert gas to protect the molten metal, reducing sample oxidation and some element loss, and ensuring that the sample composition is consistent with the actual composition.

[0039] 2. The sample preparation system of this application fills the sample preparation chamber with inert protective gas so that the pressure inside the sample preparation chamber is >0.4Mpa, which can effectively prevent volatile elements (such as manganese, nitrogen and other elements) in the sample from escaping, and ensure that the sample composition is consistent with the actual composition.

[0040] 3. The sample preparation system of this application adds a gas homogenizer to the protective gas hood to ensure that the gas flow and pressure delivered by the gas homogenizer are more uniform and stable, which can better protect the molten metal in the crucible and make the sample more homogeneous.

[0041] 4. The sample preparation system of this application has a simple structure, low overall equipment cost, convenient operation, and simple sample preparation process, realizing rapid and low-cost sample preparation. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure of this utility model.

[0043] Figure 2 This is a structural diagram of the sample preparation container of this utility model.

[0044] Figure 3 This is a dimensioned diagram of the sample preparation container of this utility model.

[0045] Figure 4 This is a top view of the sample preparation container of this utility model.

[0046] Figure 5 This is a schematic diagram of the protective air cover of this utility model.

[0047] Figure 6 This is a schematic diagram of the structure of the wind-distributing plate of this utility model.

[0048] Figure 7 This is a top view of the protective air shield of this utility model.

[0049] Figure 8 This is a schematic diagram of the sample preparation system in another embodiment of the present invention.

[0050] Figure 9 A schematic diagram of the welding wire being loaded into the manufacturing system of this utility model (the arrow direction indicates the air intake direction).

[0051] Figure 10 This is a schematic diagram of the manufacturing system of this utility model, which manufactures steel ingots after heating and cooling (the arrow direction represents the air intake direction).

[0052] Figure 11 A top view of the steel ingot manufactured using the production system of this utility model.

[0053] Figure 12 This is a process diagram of the steel ingot of this utility model being cut into a sample (A and B represent the cutting lines).

[0054] Figure 13 This is a top view of the sample prepared according to this invention.

[0055] Figure 14 This is a schematic diagram of the surface weld metal.

[0056] Wherein: 1-Sample preparation container; 11-Ring edge; 2-Medium frequency induction heating device; 21-Medium frequency induction power supply; 22-Induction coil; 3-Protective gas supply device; 31-Gas supply equipment; 32-Gas pipeline; 4-Protective gas cover; 41-Protective gas cover body; 411-Gas channel; 42-Ring edge; 43-Air distributor; 431-Air distributor plate; 432-Ring connector; 5-Steel ingot; 6-Protective gas; 7-Sample; 8-Welding wire. Detailed Implementation

[0057] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application.

[0058] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0059] Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the combined connection relationship between one or more devices / apparatus mentioned in this application does not preclude the existence of other devices / apparatus before or after the combined devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or limiting the scope of implementation of this application. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of implementation of this application.

[0060] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0061] In the description of this application, it should be understood that the terms "upper," "lower," "left," "right," "inner," "outer," "axial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0062] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0063] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0064] The present application will be further described below with reference to specific embodiments, but the scope of protection of the present application is not limited thereto.

[0065] like Figure 1 As shown, the present invention discloses a system for fabricating a chemical composition test specimen for welding wire, comprising a sample preparation container 1 having a sample preparation cavity with a top opening. The system further comprises:

[0066] The intermediate frequency induction heating device 2 includes an intermediate frequency induction power supply 21 and an induction coil 22 spirally wound around the outer periphery of the sample preparation container 1. The induction coil 22 and the intermediate frequency induction power supply 21 form a closed circuit for heating the welding wire 8 inside the sample preparation chamber; and

[0067] A protective gas hood 4 is located above the opening. The protective gas hood 4 is provided with a gas channel for supplying protective gas to the sample preparation chamber.

[0068] like Figure 8 As shown, the manufacturing system also includes a protective gas supply device 3, which includes a gas supply device 31 and a gas delivery pipe 32. One end of the gas delivery pipe 32 is connected to the gas supply device 31, and the other end is connected to the gas channel 411 on the protective gas cover 4, for delivering protective gas into the sample preparation chamber.

[0069] like Figure 2 and Figure 3 As shown, the sample preparation container 11 has an outwardly extending ring edge 11 at its opening, and the lower surface of the ring edge 11 away from the protective gas cover forms a blocking surface to prevent the induction coil 22 from detaching.

[0070] like Figure 5 , Figure 7 As shown, the protective gas cover 4 includes a protective gas cover body 41 and an annular baffle 42 integrally formed on the lower end face of the protective gas cover body 41. The protective gas cover body 41 is provided with a gas channel 411 that axially penetrates the upper and lower end faces of the protective gas cover body 41. The lower end face of the protective gas cover body 41 and the inner sidewall of the annular baffle 42 together form a uniform air cavity.

[0071] like Figure 5 As shown, the protective air cover 4 also includes an air distributor 43 disposed in the air distribution cavity.

[0072] like Figure 5 As shown, the air distribution device 43 includes an air distribution plate 431 and an annular connector 432. The annular connector 432 is fixed to the outer edge of the air distribution plate 431 along the circumferential direction. The air distribution plate 431 is provided with a plurality of air distribution holes that penetrate the air distribution device 43 along its thickness direction. The axis of each air distribution hole is parallel to the axis of the protective air cover body 41.

[0073] like Figure 5 As shown, the air distributor 43 is installed in the air distribution chamber by fastening bolts 44. This facilitates the replacement of air distributors 43 with different orifice diameters and arrangements.

[0074] like Figure 6 As shown, the air distribution holes are arranged in multiple rows and columns on the air distribution device 43, and from the center to the two side edges, the center distance between adjacent rows of air distribution holes is either equal or in a decreasing manner.

[0075] like Figure 5 , Figure 9 , Figure 10 As shown, the end of the gas channel 411 away from the annular baffle extends upward along the axis of the protective gas cover to form a connecting section protruding from the surface of the main body of the protective gas cover for connecting the gas pipeline 32.

[0076] In some embodiments of this application, the connecting segment is equipped with a quick-connect interface, which can be conveniently and quickly connected to the gas pipeline.

[0077] like Figure 3 As shown, the longitudinal section of the sample preparation container 11 is a trapezoid with a larger top and a smaller bottom.

[0078] like Figure 3 As shown, the angle α between the inner wall of the sample preparation container and the axial direction of the sample preparation container is 5°~10°.

[0079] In some embodiments of this application, the fabrication system further includes a cutting machine for cutting the specimen. The cutting machine can be a manual metal specimen cutting machine or an automatic metal specimen cutting machine, as long as it can cut the resolidified metal specimen.

[0080] In some embodiments of this application, the protective gas is an inert gas, preferably high-purity argon.

[0081] like Figure 3 , Figure 4 , Figure 6 , Figure 7 As shown, the sample preparation container dimensions are: OD1 = 30~50mm, OD2 = OD1 + (5~10)mm, the outer diameter of the ring edge of the sample preparation container OD3 = outer diameter of the induction coil + (10~20)mm, usually 80~120mm; H = 60-120mm, α = 5-10°; the protective gas cover dimensions are: OD4 = OD3, OD5 = 12~16mm, d = 1.5~2.0mm; where OD1 is the minimum inner diameter of the sample preparation container; OD2 is the maximum inner diameter of the sample preparation container; OD3 is the outer diameter of the ring edge of the sample preparation container; OD4 is the outer diameter of the annular baffle; OD5 is the inner diameter of the gas channel; H is the distance between the upper surface of the ring edge and the inner bottom surface of the sample preparation container; d is the diameter of the uniform air hole.

[0082] This application also provides a method for preparing a test specimen for chemical composition testing of welding wire, including the following steps:

[0083] Step 1, Feeding: Cut the welding wire 8 to be tested into a suitable length and put it into the sample preparation container, and suspend the protective gas cover above the opening of the sample preparation container.

[0084] Step 2, Ventilation: Continuously introduce protective gas into the sample preparation chamber for at least 1 minute to ensure that the sample preparation chamber is filled with protective gas to remove air from the sample preparation chamber; the gas flow rate should be greater than 20 L / min.

[0085] Step 3, Melting: Continuously introduce protective gas into the sample preparation chamber, and the medium frequency induction heating device starts to work, heating the welding wire in the sample preparation chamber under the protective gas atmosphere;

[0086] Step 4, Cooling: Continuously introduce protective gas into the sample preparation chamber to cool the molten metal in the sample preparation chamber under the protective gas atmosphere, and obtain steel ingot 6;

[0087] Step 5, Steel Ingot Surface Processing: Cut the upper and lower surfaces of the steel ingot and process and level the cut surfaces to obtain specimen 7 for testing the chemical composition of the welding wire.

[0088] In some embodiments of this application, protective gas needs to be continuously introduced into the sample preparation container in steps 2, 3 and 4.

[0089] In some embodiments of this application, the pressure inside the sample preparation chamber is >0.4 MPa during the heating and cooling of the molten metal.

[0090] This application utilizes a proprietary welding wire chemical composition testing specimen preparation system for sample preparation. Through feeding → ventilation → melting → cooling → steel ingot surface processing → specimen preparation, it is possible to quickly prepare a specimen that meets the requirements and whose composition is consistent with the actual composition. Figure 9 , Figure 10 , Figure 11 A schematic diagram showing the process of feeding, melting, and cooling to prepare steel ingots is presented. Figure 12 , Figure 13 The diagram shows a process for preparing a sample by cutting a steel ingot. The sample needs to have at least 5 mm removed from both the upper and lower surfaces and then be machined flat to obtain the final sample, which can be used for subsequent chemical composition analysis.

[0091] The above embodiments are for illustrating the implementation schemes disclosed in this utility model and should not be construed as limiting the utility model. Furthermore, various modifications listed herein, as well as variations in the methods and compositions of the utility model, will be apparent to those skilled in the art without departing from the scope and spirit of this utility model. Although this utility model has been specifically described in conjunction with various specific preferred embodiments, it should be understood that this utility model should not be limited to these specific embodiments. In fact, various modifications as described above that are obvious to those skilled in the art to obtain the utility model should be included within the scope of this utility model.

Claims

1. A system for producing a test piece for chemical composition inspection of a welding wire, comprising a sample preparation container (1) having a sample preparation cavity with an open top, characterized in that, The manufacturing system also includes: The intermediate frequency induction heating device (2) includes an intermediate frequency induction power supply (21) and an induction coil (22) spirally surrounding the outer periphery of the sample preparation container (1). The induction coil (22) and the intermediate frequency induction power supply (21) form a closed circuit for heating the welding wire (8) in the sample preparation chamber; and A protective gas hood (4) is located above the opening. The protective gas hood (4) is provided with a gas channel for supplying protective gas to the sample preparation chamber.

2. The system for manufacturing a test piece for chemical composition of a welding wire according to claim 1, wherein The manufacturing system also includes a protective gas supply device (3), which includes a gas supply device (31) and a gas delivery pipe (32). One end of the gas delivery pipe (32) is connected to the gas supply device (31), and the other end is connected to the gas channel (411) on the protective gas cover (4), for delivering protective gas into the sample preparation chamber.

3. The system for fabricating welding wire chemical composition test specimens according to claim 1, characterized in that, The sample preparation container (1) has an outwardly extending ring edge (11) at its opening, and the lower surface of the ring edge (11) away from the protective gas cover forms a blocking surface to prevent the induction coil (22) from coming off.

4. The system for fabricating welding wire chemical composition test specimens according to claim 1, characterized in that, The protective gas cover (4) includes a protective gas cover body (41) and an annular baffle (42) integrally formed on the lower end face of the protective gas cover body (41). The protective gas cover body (41) is provided with a gas channel (411) that runs through the upper and lower end faces of the protective gas cover body (41) along its thickness direction. The lower end face of the protective gas cover body (41) and the inner wall of the annular baffle (42) together form a uniform air cavity.

5. The system for fabricating welding wire chemical composition test specimens according to claim 4, characterized in that, The protective air cover (4) also includes an air distributor (43) disposed in the air distribution cavity.

6. The system for fabricating welding wire chemical composition test specimens according to claim 5, characterized in that, The air distribution device (43) includes an air distribution plate (431) and an annular connector (432). The annular connector (432) is fixed to the outer edge of the air distribution plate (431) along the circumferential direction. The air distribution plate (431) is provided with a plurality of air distribution holes that penetrate the air distribution device (43) along its thickness direction. The axis of each air distribution hole is parallel to the axis of the protective air cover body (41).

7. The system for fabricating welding wire chemical composition test specimens according to claim 6, characterized in that, The air distribution holes are arranged in multiple rows and columns on the air distribution device (43), and the center distance between adjacent rows of air distribution holes is either equal or decreasing from the center to the two side edges.

8. The system for fabricating welding wire chemical composition test specimens according to claim 4, characterized in that: The end of the gas passage (411) away from the annular baffle extends upward along the axis of the protective gas cover to form a connecting section protruding from the surface of the main body of the protective gas cover for connecting the gas pipeline (32).

9. The system for fabricating welding wire chemical composition test specimens according to claim 1, characterized in that: The longitudinal section of the sample preparation container (1) is a trapezoid with a larger top and a smaller bottom.

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