Manufacturing Method of Welding Porosity Defect Simulation Specimen and Simulation Specimen

Abstract

The present invention provides a method for manufacturing a simulation specimen with welding porosity defects and the simulation specimen. The manufacturing method uses a circumferential welding process to weld a first nozzle and a second nozzle to form the simulation specimen with welding porosity defects; the first nozzle and the second nozzle have the same diameter and the wall thickness of both is 2 mm to 3 mm; the nozzles are assembled with a stepped groove, and the assembly gap is 0.05 mm to 0.4 mm; the welding angle of the circumferential welding is 0° to 45° relative to the vertical direction. This manufacturing method can controllably form porosity defects at the welding position of the simulation specimen, effectively simulate the internal pores generated during welding, and improve the accuracy of the simulated flaw detection experiment.

Description

Technical Field

[0001] This specification relates to the field of welding technology, and particularly to a method for manufacturing a simulation specimen with welding porosity defects and the simulation specimen. Background Art

[0002] When welding pipe fittings, porosity defects will occur, affecting the quality and service life of the final welded product. Therefore, flaw detection experiments need to be carried out on the welded product. Before the experiment, it is first necessary to confirm that the flaw detection experiment process is feasible and the results are valid. Therefore, a simulation specimen with porosity defects needs to be used to simulate the flaw detection experiment to verify the feasibility and effectiveness of the experiment. The existing simulation methods for porosity defects mostly use physical means, such as using knocking, drilling and other methods to form holes or indentations on the specimen. However, these simulated traces are mostly on the surface and cannot simulate the internal pores of the workpiece, nor can they simulate the actual situation of welding, which will bring deviations to the results of the simulated flaw detection experiment. Summary of the Invention

[0003] In view of this, the embodiments of this specification provide a method for manufacturing a simulation specimen with welding porosity defects and the simulation specimen. Among them, the method for manufacturing a simulation specimen with welding porosity defects can controllably form porosity defects at the welding position of the simulation specimen, effectively simulate the internal pores generated under welding conditions, and improve the accuracy of the simulated flaw detection experiment.

[0004] The embodiments of this specification provide the following technical solutions:

[0005] A method for manufacturing a simulation specimen with welding porosity defects, using the circumferential welding process to weld the first nozzle and the second nozzle to form the simulation specimen with welding porosity defects;

[0006] The first nozzle and the second nozzle have the same diameter and the wall thickness of both is 2 mm to 3 mm;

[0007] The first nozzle and the second nozzle are assembled with a stepped groove, and the assembly gap is 0.05 mm to 0.4 mm;

[0008] The welding angle of the circumferential welding is 0° to 45° relative to the vertical direction.

[0009] In the above method for manufacturing a simulation specimen with welding porosity defects, during circumferential welding, by selecting appropriate nozzle wall thicknesses and groove shapes, controlling the assembly gap between the nozzles and the welding angle of the circumferential welding, simulated pores with predictable positions, quantities, and sizes can be controllably formed at the weld, effectively simulating the internal pores generated under welding conditions. The simulation specimen manufactured using this method is easy to confirm the effectiveness during simulated flaw detection in real time, ensuring the accuracy of subsequent flaw detection experiments.

[0010] In a preferred embodiment, the assembly gap at the first assembly position is 0.05 mm to 0.15 mm, the assembly gap at the second assembly position is 0.3 mm to 0.4 mm, and the first assembly position and the second assembly position are symmetrical about the axis of the first nozzle.

[0011] In a preferred embodiment, when performing circumferential seam welding, the arc is initiated at the first assembly position.

[0012] In a preferred embodiment, the root face length of the stepped groove is not greater than 2 mm, and the root face thickness of the stepped groove is not greater than 1 mm.

[0013] In a preferred embodiment, the base current of the circumferential seam welding is 30 A to 45 A, the peak current is 70 A to 90 A, the voltage is 10 V to 15 V, and the base and peak pulse ratio is 40:60.

[0014] In a preferred embodiment, the rotational speed of the circumferential seam welding is 90 mm / min to 120 mm / min.

[0015] In a preferred embodiment, the flow rate of the shielding gas for the circumferential seam welding is 15 L / min to 25 L / min.

[0016] The embodiments of this specification also provide a welding porosity defect simulation specimen. The welding porosity defect simulation specimen is prepared by using the manufacturing method of the welding porosity defect simulation specimen of any one of the above, and the welding porosity defect simulation specimen is a hollow circular tube with a wall thickness of 2 mm to 3 mm and has 1 to 12 simulated pores for flaw detection experiments.

[0017] The simulated pores are located at a position on the reverse side of the welding at a circumferential angle of 10° to 50° from the arc initiation position, and the diameter is 0.3 mm to 0.9 mm.

[0018] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted in the embodiments of this specification at least include: The manufacturing method of the welding porosity defect simulation specimen disclosed in the present invention uses the circumferential seam welding process of the nozzle. By setting a specific wall thickness and groove shape, controlling the assembly gap and welding angle, it is possible to controllably form porosity defects at the welding position of the simulation specimen, effectively simulate the internal pores generated during welding, and improve the accuracy of the simulated flaw detection experiment. Description of the Drawings

[0019] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0020] Figure 1 is an assembly schematic diagram of the first nozzle and the second nozzle;

[0021] Figure 2 is the radiographic film of the simulation specimen with welding porosity defects (where, Figure 2 (a) is the radiographic film containing 1 simulated pore, Figure 2 (b) is the radiographic film containing 2 simulated pores, Figure 2 (c) is the radiographic film containing 3 simulated pores, Figure 2 (d) is the radiographic film containing 4 simulated pores, Figure 2 (e) is the radiographic film containing 6 simulated pores;

[0022] Figure 3 is the schematic diagram of the positions of the simulated pores;

[0023] The reference numerals used in the accompanying drawings are as follows:

[0024] 1, the first nozzle; 2, the second nozzle; 3, the stepped groove. Specific embodiments

[0025] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0026] The following illustrates the implementation manners of the present application through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope protected by the present application.

[0027] It should be noted that the following description relates to various aspects of embodiments within the scope of the appended claims. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is for illustrative purposes only. Based on this application, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects described herein can be used to implement a device and / or practice a method. Additionally, this device can be implemented and this method can be practiced using other structures and / or functionality in addition to one or more of the aspects described herein.

[0028] It should also be noted that the drawings provided in the following embodiments only schematically illustrate the basic concept of this application. The components shown in the drawings only relate to those relevant to this application and are not drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and proportion of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0029] It should be understood that the "connection between component A and component B" means that component A is directly in contact with component B, or component A is indirectly connected to component B through other components. The orientation terms such as "upper", "lower", "inner", "outer", "side", etc. described in the exemplary embodiments of this specification are described from the angle shown in the drawings and should not be construed as a limitation on the exemplary embodiments of this specification.

[0030] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the aspects described herein can be practiced without these specific details.

[0031] The current tube-to-tube butt welding process may produce porosity defects. Porosity defects are spherical holes generated at the welding position (weld seam) due to the release of gas during the cooling and solidification of the metal, or the intrusion of gas during the welding process and the failure to escape in time. The porosity defects generated inside the welded part will become the initiation positions of cracks, reducing the mechanical properties of the material and seriously affecting the quality and service life of the component. Therefore, it is a welding defect that needs to be avoided during the welding process.

[0032] Porosity defects can be detected by means of metal flaw detection, such as ultrasonic testing (UT) or radiographic testing (RT). To ensure the feasibility of flaw detection operations and verify the effectiveness of flaw detection results, simulation experiments need to be carried out on metal flaw detection. In the experiments, simulation specimens are required. In the prior art, physical damage methods such as knocking and drilling are mostly used to form holes or indentations on the specimens, which cannot simulate pores inside the workpiece or the actual situation of welding. The applicability of the specimens is poor, affecting the results of the simulation experiments.

[0033] The present invention provides a method for manufacturing a simulation specimen of welding porosity defects and the simulation specimen. The simulation specimen is made by actual welding. The inventor found through numerous experiments that by using a nozzle with the same diameter and wall thickness within a certain range as the component to be welded, adopting a stepped groove assembly method, controlling the assembly gap within a certain range, using a circumferential welding process and controlling the welding angle within a certain range, a certain number and size of simulated pores can be formed within a certain angular range from the starting point of the weld in the weld, thus forming a simulation specimen that can simulate the real welding process and the simulated pores are located inside the workpiece, thereby improving the accuracy of the simulated metal flaw detection experiment and expanding the applicability of the simulation specimen.

[0034] The following describes the technical solutions provided by the embodiments of the present application with reference to the accompanying drawings.

[0035] An embodiment of this specification provides a method for manufacturing a simulation specimen of welding porosity defects. The circumferential welding process is used for welding the nozzles, and the workpiece thus manufactured is the above-mentioned simulation specimen of welding porosity defects. Specifically, the welded workpiece includes two hollow round tubes with the same diameter, such as Figure 1 the first nozzle 1 and the second nozzle 2 shown. The wall thicknesses of the first nozzle 1 and the second nozzle 2 are both within the range of 2 mm to 3 mm. The assembly between the nozzles adopts a stepped welding groove. For example, Figure 1 as shown in, a stepped groove 3 is machined on the circular tube end face of the first nozzle 1 facing the second nozzle 2. Correspondingly, a recess structure matching the stepped groove 3 is machined on the circular tube end face of the second nozzle 2 facing the first nozzle 1. During assembly, the central axes of the first nozzle 1 and the second nozzle 2 are aligned. The stepped groove 3 of the first nozzle 1 is sleeved in the recess structure of the second nozzle 2, and the assembly gap between the two is controlled to be 0.05 mm to 0.4 mm. Subsequently, the first nozzle 1 and the second nozzle 2 are welded using the circumferential welding process, and the welding angle is controlled to be 0° to 45° relative to the vertical direction.

[0036] It should be noted that the diameters of the first nozzle 1 and the second nozzle 2 are not limited by Figure 1 the diameter dimensions inFigure 1 The diameters of the two nozzles in [[ ]] are only for example. In actual applications, nozzles with other diameters can be flexibly selected to make simulation specimens, as long as the wall thickness is ensured to be 2 mm to 3 mm, and the nozzle diameter is not limited.

[0037] Using the above welding method can produce simulation specimens with simulated pores, effectively simulating the internal pores generated during welding, and the formation of pores in terms of position, quantity, and size can be controlled within a certain range. Specifically, as Figure 2 shown, the diameter of the prefabricated simulated pores is 0.3 mm to 0.9 mm, located at a position of 10° to 50° of the circumferential angle with reference to the outer wall circumferential surface of the first nozzle 1 or the second nozzle 2 in the reverse direction of welding from the starting arc point, and the quantity is 1 to 12, thereby improving the accuracy of the simulated flaw detection experiment.

[0038] In some embodiments, when assembling the first nozzle 1 and the second nozzle 2, control the assembly spacing on both symmetric sides to achieve a better welding effect. Specifically, the assembly gap at the first assembly position on one side is 0.05 mm to 0.15 mm, and the assembly gap at the second assembly position on the other side is 0.3 mm to 0.4 mm. The first assembly position and the second assembly position differ by a circumferential angle of 180°, that is, the first assembly position and the second assembly position are symmetric about the axis of the first nozzle 1 (or the second nozzle 2).

[0039] Preferably, the above first assembly position is used as the starting arc point, that is, when performing circumferential welding, start the arc at the first assembly position.

[0040] In some embodiments, when machining the welding groove, control the root face length of the stepped groove 3 ( Figure 1 the distance along the horizontal direction of the stepped groove 3 in [[ ]]) not to be greater than 2 mm, and the root face thickness of the stepped groove ( Figure 1 the distance along the vertical direction of the stepped groove 3 in [[ ]]) not to be greater than 1 mm.

[0041] In some embodiments, control the welding current, welding voltage, and welding pulse of the welding machine. Specifically, control the base current to be 30 A to 45 A, the peak current to be 70 A to 90 A, the voltage to be 10 V to 15 V, and the base and peak pulse ratio to be 40:60, and perform circumferential welding on the above two nozzles.

[0042] In some embodiments, control the rotation speed of the circumferential welding to be 90 mm / min to 120 mm / min.

[0043] In some embodiments, the flow rate of the shielding gas for circumferential welding is 15 L / min to 25 L / min. Specifically, the flow rate of the main shielding gas is 15 L / min to 25 L / min, and the flow rate of the back shielding gas is 15 L / min to 25 L / min.

[0044] The following specific examples are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0045] Example 1

[0046] As Figure 1 shown, the first nozzle 1 and the second nozzle 2 with a diameter of and a wall thickness of 3 mm are used. A stepped groove 3 is provided on the first nozzle 1, with a root face length of 1 mm and a thickness of 0.5 mm. Using the circumferential welding process, during the welding process, the second nozzle 2 is assembled with the stepped groove 3 of the first nozzle 1, and the assembly gap is controlled within 0.05 - 0.4 mm, where the assembly gap at the starting arc position is controlled within 0.05 - 0.15 mm, and the assembly gap at the position 180° adjacent to the starting arc position is controlled within 0.3 - 0.4 mm. The welding angle is 0° - 45° relative to the vertical direction. The selected welding process parameters are shown in Table 1, and multiple simulation specimens with welding porosity defects are made, as Figure 2 shown.

[0047] Table 1 Welding process parameters for nozzle butt welding

[0048]

[0049] Based on the same inventive concept, the embodiments of the present invention also provide a simulation specimen for welding porosity defects. The simulation specimen for welding porosity defects is prepared by using the manufacturing method of the simulation specimen for welding porosity defects of any one of the above, and the simulation specimen for welding porosity defects is a hollow circular tube with a wall thickness of 2 mm - 3 mm and has 1 - 12 simulated pores for flaw detection experiments;

[0050] Among them, the simulated pores are located at a position on the reverse side of welding at a circumferential angle of 10° - 50° from the starting arc position, with a diameter of 0.3 mm - 0.9 mm.

[0051] The simulation specimen for welding porosity defects can be used for metal flaw detection, such as UT and RT flaw detection experiments. It has simulated porosity defects formed during the welding process, can effectively simulate internal pores generated during welding, and improves the accuracy of simulated flaw detection experiments.

[0052] In this specification, for the same or similar parts among various embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the simulation sample embodiment described later, since it corresponds to the manufacturing method and the description is relatively simple, reference can be made to the partial description of the system embodiment for relevant parts.

[0053] As described above, the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for fabricating a simulation specimen of welding porosity defects, characterized in that, The first nozzle and the second nozzle are welded by circumferential seam welding process to form the simulation specimen of the welded porosity defect; The first nozzle and the second nozzle have the same diameter and the wall thickness is 2mm - 3mm; The first nozzle and the second nozzle are assembled with a stepped groove, and the assembly gap is 0.05mm - 0.4mm; The welding angle of circumferential seam welding is 0° - 45° relative to the vertical direction; Among them, the assembly gap at the first assembly position is 0.05mm - 0.15mm, and the assembly gap at the second assembly position is 0.3mm - 0.4mm. The first assembly position and the second assembly position are symmetrical about the axis of the first nozzle; When performing circumferential seam welding, starting arc at the first assembly position; The root face length of the stepped groove is not greater than 2mm, and the root face thickness of the stepped groove is not greater than 1mm; The base current of the circumferential seam welding is 30A - 45A, the peak current is 70A - 90A, the voltage is 10V - 15V, and the base and peak pulse ratio is 40:60; The rotational speed of the circumferential seam welding is 90mm / min - 120mm / min; The flow rate of the shielding gas for the circumferential seam welding is 15L / min - 25L / min; Among them, the specimen has 1 - 12 simulated pores for flaw detection experiments; the simulated pores are located at a position in the welding reverse direction and away from the starting arc position, satisfying a circumferential angle of 10° - 50°, and the diameter is 0.3mm - 0.9mm.

2. A simulation specimen for welding porosity defects, characterized in that, The simulation specimen of the welded porosity defect is prepared by the manufacturing method of the simulation specimen of the welded porosity defect as claimed in claim 1. The simulation specimen of the welded porosity defect is a hollow circular tube with a wall thickness of 2mm - 3mm and has 1 - 12 simulated pores for flaw detection experiments; The simulated pores are located at a position in the welding reverse direction and away from the starting arc position, satisfying a circumferential angle of 10° - 50°, and the diameter is 0.3mm - 0.9mm.

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