Step loading bi-directional electromagnetic force pipe gradual electromagnetic welding method

Abstract

The application relates to a step-by-step loading type pipe gradual electromagnetic welding method of bidirectional electromagnetic force, and belongs to the field of electromagnetic forming of metal workpieces. The welding method comprises pretreatment before welding, a gradual welding process and a repair welding process. In the gradual welding process, a gradual conduction type is adopted to load electromagnetic force on the welding areas of the inner pipe and the outer pipe by using an expanding coil in the inner pipe and a compression coil outside the outer pipe. The application realizes pipe welding from a line to a plane, facilitates accurate control of the pipe welding process, improves the pipe welding effect and quality, adopts multiple end coils, compression coils and expanding coils to realize diversified electromagnetic force application modes, improves the pipe welding strength, and makes the pipe welding part more firm.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of electromagnetic forming of metal workpieces, and particularly relates to a pipe gradual electromagnetic welding method with step-by-step loading of bidirectional electromagnetic force. BACKGROUND

[0002] Pipe electromagnetic pulse welding belongs to a kind of solid-state welding collision welding, and this process does not have a melting process in the welding process, thus not causing problems such as beneficial alloy element burning loss and harmful element invasion into the weld, simplifying the welding process, improving the welding quality, and having low cost, high production efficiency, small energy consumption pollution, simple production process, and easy automatic control, thus having a very good development prospect. However, the existing pipe electromagnetic pulse welding has some technical problems that limit the development of this technology.

[0003] In the traditional pipe electromagnetic welding technology, a single coil is placed outside the outer pipe, a capacitor power supply is discharged through a discharge switch to generate a pulse current in the coil, and the radial electromagnetic force between the coil and the pipe causes high-speed collision between the inner and outer pipes to achieve welding. This single-coil loading pipe welding method has a single electromagnetic force application mode, and the electromagnetic welding strength is not enough, which easily leads to an unstable welded part.

[0004] The Chinese invention patent with the publication number CN 101905375 A, "Thin-walled metal pipe magnetic pulse connection method and joint structure", discloses a thin-walled metal pipe magnetic pulse connection method, which uses a coil-magnetic collector composite inductor or a coil inductor connected with an electromagnetic pulse forming device to perform magnetic pulse connection on pipes made of various metal materials and having various structural shapes. This electromagnetic pulse welding method still has the problems of single electromagnetic force application mode and insufficient electromagnetic welding strength, as the single coil is placed outside the outer pipe to provide radial electromagnetic force to the outer pipe to compress the outer pipe and the inner pipe to collide and achieve welding.

[0005] The utility model patent with the publication number CN 206839400 U, "Bidirectional loading type pipe electromagnetic welding device", discloses a bidirectional loading type pipe electromagnetic welding method, which proposes to place an expanding coil inside the inner pipe and a compression coil outside the outer pipe on the basis of the traditional welding, and the compression and expansion are performed at the same time to solve the problem of insufficient radial electromagnetic force strength. However, this electromagnetic welding device, like the traditional pipe welding, is for one-time welding, and the uniform welding will also lead to an unstable welded part. SUMMARY

[0006] The present application aims to solve the above problems, and provides a pipe gradual electromagnetic welding method with step-by-step loading of bidirectional electromagnetic force, which uses a gradual conductive coil and a gradual electromagnetic force loading mode for the inner and outer pipe welding areas to achieve accurate control of the pipe welding process and improve the pipe welding effect.

[0007] The technical solution of the present invention is a stepwise electromagnetic welding method for pipe fittings with bidirectional electromagnetic force applied in stages. The method uses a first end coil and a second end coil to apply axial electromagnetic force to the inner and outer pipe fittings; uses an expansion coil to apply radially outward electromagnetic force to the inner pipe fitting; uses a compression coil to apply radially inward electromagnetic force to the outer pipe fitting; and aligns the axes of the inner and outer pipe fittings so that the welding areas of the inner and outer pipe fittings overlap axially.

[0008] The progressive electromagnetic welding method for pipe fittings includes:

[0009] Gradual welding process:

[0010] (1) The first end coil, the first compression coil and the first expansion coil are connected to the coil power supply through a switch and energized. Induction current is generated in the welding area of ​​the inner tube and the welding area of ​​the outer tube between the first compression coil and the first expansion coil, and local welding is performed under the action of axial electromagnetic force, radial outward electromagnetic force and radial inward electromagnetic force.

[0011] (2) Connect the second compression coil and the second expansion coil to the coil power supply via a switch and energize them. Induction current is generated in the welding area of ​​the inner pipe and the welding area of ​​the outer pipe located between the second compression coil and the second expansion coil. Local welding is performed under the action of axial electromagnetic force, radial outward electromagnetic force, and radial inward electromagnetic force.

[0012] (3) The first i The compression coil and the first i The first expanded coil is connected to the coil power supply via a switch and is energized, located at the... i The compression coil and the first i Induced currents are generated in the welding areas of the inner and outer tubing components between the expansion coils, and local welding is performed under the action of axial electromagnetic force, radially outward electromagnetic force, and radially inward electromagnetic force, 2 ≤ i < n , n This refers to the number of compression coils;

[0013] i = i +1;

[0014] (4) Judgment i < n If the condition is met, repeat step (3); otherwise, proceed to step (5).

[0015] (5) The first n The compression coil, the first nThe first expanded coil and the second end coil are connected to the coil power supply via a switch and are energized, located at the first... n The compression coil, the first n Induced currents are generated in the welding areas of the inner and outer pipe fittings between the expansion coils, and welding is performed under the action of axial electromagnetic force, radial outward electromagnetic force, and radial inward electromagnetic force, thus completing the welding of the pipe fittings and the outer pipe fittings.

[0016] Preferably, the pipe fittings progressive electromagnetic welding method further includes a pretreatment process before welding:

[0017] (a) Clean and polish the outer surface of the welding area of ​​the inner pipe fitting;

[0018] (b) Clean and polish the surface of the welding area of ​​the outer pipe fitting.

[0019] Preferably, the progressive electromagnetic welding method for pipe fittings further includes a repair welding process: checking whether there are any incomplete welds or empty welds in the welding areas of the inner and outer pipe fittings; if there are incomplete welds or empty welds, connecting the compression coil and expansion coil at the incomplete weld or empty weld to the coil power supply and energizing them, and then performing local welding on the incomplete weld or empty weld again.

[0020] Preferably, in step (3) of the progressive welding process, the first... i -1 compression coil and the first i The compression coil and the first i All the expanded coils are energized simultaneously, increasing the number of coils. i The axial and radial electromagnetic forces acting on the welding area of ​​the inner tube between the compression coil and the i-th expansion coil improve the weld density.

[0021] Preferably, the distance between the compression coil and the outer tube is no more than 4 mm.

[0022] Preferably, the distance between the bulging coil and the inner tube is no more than 3.5 mm.

[0023] Compared with the prior art, the beneficial effects of the present invention include:

[0024] 1) This invention uses a progressive conducting coil and a progressive electromagnetic force applied to the welding area of ​​the inner and outer pipe fittings to realize pipe fitting welding from line to surface, which facilitates precise control of the pipe fitting welding process and improves the welding effect and quality of the pipe fittings;

[0025] 2) This invention uses multiple end coils, compression coils and expansion coils to achieve diverse electromagnetic force application methods, which improves the welding strength of pipe fittings and makes the welded parts of pipe fittings more robust. Attached Figure Description

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] Figure 1 A schematic diagram of a pipe gradual electromagnetic welding process according to an embodiment of the present application.

[0028] Figure 2 A schematic diagram of a pipe gradual electromagnetic welding process according to another embodiment of the present application.

[0029] Figure 3 An effect diagram of step (1) of a gradual welding process according to an embodiment of the present application.

[0030] Figure 4 An effect diagram of a gradual welding process according to an embodiment of the present application when completed.

[0031] Legend: first end coil 1, second end coil 2, compression coil 3, bulging coil 4, inner pipe 5, welding zone 501 of inner pipe, outer pipe 6, welding zone 601 of outer pipe. DETAILED DESCRIPTION

[0032] Embodiment One

[0033] As shown in the figure, the electromagnetic welding device in the embodiment includes a first end coil 1, a second end coil 2, a plurality of compression coils 3, a plurality of bulging coils 4, an inner pipe 5, and an outer pipe 6. Figure 1 The first end coil 1 and the second end coil 2 are used to apply axial electromagnetic force to the inner pipe 5 and the outer pipe 6.

[0034] The bulging coil 4 is used to apply electromagnetic force radially outward to the inner pipe 5; the compression coil 5 is used to apply electromagnetic force radially inward to the outer pipe 6.

[0035] In the embodiment, in order to make the pipe receive sufficient electromagnetic force to complete the welding process, the distance between the compression coil 3 and the outer pipe 6 is less than 2 mm. The distance between the bulging coil 4 and the inner pipe 5 is less than 1.5 mm.

[0036] As shown in the figure, the step-by-step loading two-way electromagnetic force pipe gradual electromagnetic welding method of the embodiment includes:

[0037] Figure 1 Pre-treatment process:

[0038] (a) Clean and polish the outer surface of the welding zone 501 of the inner pipe;

[0039] (b) Clean and polish the inner surface of the welding zone 601 of the outer pipe.

[0040] Gradual welding process:

[0041]

[0042] ​​(1) The first end coil 1, the first compression coil 3, and the first expansion coil 4 are connected to the coil power supply via a switch and energized. Induced currents are generated in the welding area 501 of the inner pipe fitting and the welding area 601 of the outer pipe fitting located between the first compression coil 3 and the first expansion coil 4. Local welding is performed under the action of axial electromagnetic force, radial outward electromagnetic force, and radial inward electromagnetic force, such as Figure 1 Setp in As shown, the welding effect is as follows Figure 3 As shown;

[0043] (2) The second compression coil 3 and the second expansion coil 4 are connected to the coil power supply via a switch and energized. Induced currents are generated in the welding area 501 of the inner pipe fitting and the welding area 601 of the outer pipe fitting located between the second compression coil 3 and the second expansion coil 4. Local welding is performed under the action of axial electromagnetic force, radial outward electromagnetic force, and radial inward electromagnetic force, such as... Figure 1 Setp in As shown;

[0044] (3) The first i The third compression coil and the i The expansion coil 4 is connected to the coil power supply via a switch and energized, located at the... i The third compression coil and the i Induced currents are generated in the welding area 501 of the inner tube and the welding area 601 of the outer tube between the expansion coils 4, and local welding is performed under the action of axial electromagnetic force, radial outward electromagnetic force, and radial inward electromagnetic force, such as... Figure 1 Setp in i As shown, 2 ≤ i < n ;

[0045] i = i +1;

[0046] (4) Judgment i < n If the condition is met, repeat step (3); otherwise, proceed to step (5).

[0047] (5) The first n The third compression coil n The first expansion coil 4 and the second end coil 2 are connected to the coil power supply via a switch and energized. n The third compression coil n Induced currents are generated in the welding area 501 of the inner tube and the welding area 601 of the outer tube between the expansion coils 4, and welding is performed under the action of axial electromagnetic force, radial outward electromagnetic force, and radial inward electromagnetic force, such as... Figure 1Setp in n As shown, the welding of fitting 5 and outer fitting 6 is completed, and the welding effect is as follows. Figure 4 As shown.

[0048] Example 2

[0049] The electromagnetic welding device in Example 2 is the same as that in Example 1.

[0050] like Figure 2 As shown, the stepwise electromagnetic welding method for pipe fittings with bidirectional electromagnetic force applied in Embodiment 2 includes a pretreatment process, a stepwise welding process, and a repair welding process.

[0051] The pretreatment process in Example 2 is the same as that in Example 1.

[0052] Gradual welding process:

[0053] (1) The first end coil 1, the first compression coil 3, and the first expansion coil 4 are connected to the coil power supply via a switch and energized. Induced current is generated in the welding area 501 of the inner pipe fitting and the welding area 601 of the outer pipe fitting located between the first compression coil 3 and the first expansion coil 4. Under the action of axial electromagnetic force, radial outward electromagnetic force, and radial inward electromagnetic force, the welding area 501 of the inner pipe fitting and the welding area 601 of the outer pipe fitting deform and impact contact, realizing local welding, such as Figure 2 As shown in Step ①, the welding effect is as follows: Figure 3 As shown.

[0054] (2) The second compression coil 3 and the second expansion coil 4 are connected to the coil power supply via a switch and energized. Induced current is generated in the welding area 501 of the inner pipe fitting and the welding area 601 of the outer pipe fitting located between the second compression coil 3 and the second expansion coil 4. Under the action of axial electromagnetic force, radial outward electromagnetic force, and radial inward electromagnetic force, the welding area 501 of the inner pipe fitting and the welding area 601 of the outer pipe fitting deform and impact contact, realizing local welding, such as Figure 2 As shown in Step ②.

[0055] (3) The first i -1 compression coil 3, the first i The third compression coil and the i The expansion coil 4 is connected to the coil power supply via a switch and energized, located at the... i The third compression coil and the i Induced currents are generated in the welding areas 501 of the inner tube and 601 of the outer tube between the expansion coils 4. Under the action of axial electromagnetic force, radially outward electromagnetic force, and radially inward electromagnetic force, the welding areas 501 and 601 of the outer tube deform and impact into contact, achieving localized welding. 2≤ i <n ;

[0056] i = i +1.

[0057] (4) judge i n if it is established, if established, repeat step (3); otherwise, step (5) is executed.

[0058] (5) the first n Compression coil 3, the first n Expansion coil 4 and the second end coil 2 are connected with the coil power supply through the switch and powered on, the welding area 501 of the inner pipe and the welding area 601 of the outer pipe between the first n Compression coil 3, the first n Expansion coil 4 generates induced current, and the welding area 501 of the inner pipe and the welding area 601 of the outer pipe are deformed and impacted under the action of axial electromagnetic force and radial outward electromagnetic force, radial inward electromagnetic force, and the welding of the pipe 5 and the outer pipe 6 is completed, as shown in Figure 4 .

[0059] Repair welding process: check whether the welding area 501 of the inner pipe and the welding area 601 of the outer pipe have virtual welding or empty welding, if there is virtual welding or empty welding, the compression coil 3 and the expansion coil 4 at the virtual welding or empty welding are connected with the coil power supply and powered on, and the virtual welding or empty welding is welded again.

[0060] The results show that the gradual conductive coil and the method of gradually loading electromagnetic force on the welding area of the inner and outer pipes are adopted, the welding process utilizes the end coil, the expansion coil and the compression coil to realize the expansion of the inner pipe and the compression of the outer pipe at the same time, which can make the welding point more firm, and the welding form becomes non-uniform, which is convenient for accurate control of the pipe welding process, and improves the welding effect and quality of the pipe.​

Claims

1. A method of progressive electromagnetic welding of pipe fittings by means of a step loading bi-directional electromagnetic force, characterized in that, The first end coil and the second end coil are used to apply axial electromagnetic force to the inner tube and the outer tube; the bulging coil is used to apply electromagnetic force outward in the radial direction to the inner tube; and the compression coil is used to apply electromagnetic force inward in the radial direction to the outer tube; The inner tube and the outer tube are aligned along the axis, and the welding area of the inner tube and the welding area of the outer tube are axially overlapped; The first, second, …, and nth compression coils are sequentially and spacedly arranged along the outer surface of the welding area of the outer tube, and the second end coil and the nth compression coil are adjacently arranged; and the first, second, …, and nth bulging coils are sequentially and spacedly arranged along the inner surface of the welding area of the inner tube, and the first end coil and the first bulging coil are adjacently arranged; The tube gradual electromagnetic welding method comprises: The gradual welding process: (1) The first end coil, the first compression coil, and the first bulging coil are connected to the coil power supply through the switch and are powered on, the welding area of the inner tube and the welding area of the outer tube located between the first compression coil and the first bulging coil generate induced current, and are locally welded under the action of axial electromagnetic force and electromagnetic force outward in the radial direction and electromagnetic force inward in the radial direction; (2) The second compression coil and the second bulging coil are connected to the coil power supply through the switch and are powered on, the welding area of the inner tube and the welding area of the outer tube located between the second compression coil and the second bulging coil generate induced current, and are locally welded under the action of axial electromagnetic force and electromagnetic force outward in the radial direction and electromagnetic force inward in the radial direction; (3) The first i The compression coil and the first i The first expanded coil is connected to the coil power supply via a switch and is energized, located at the... i The compression coil and the first i Induced currents are generated in the welding areas of the inner and outer tubing components between the expansion coils, and local welding is performed under the action of axial electromagnetic force, radially outward electromagnetic force, and radially inward electromagnetic force, 2 ≤ i < n , n This refers to the number of compression coils; i = i +1； (4) judging i n whether it is true or not. If it is true, step (3) is repeated. Otherwise, step (5) is executed.​ (5) The first n The compression coil, the first n The first expanded coil and the second end coil are connected to the coil power supply via a switch and are energized, located at the first... n The compression coil, the first n Induced currents are generated in the welding areas of the inner and outer pipe fittings between the expansion coils, and welding is performed under the action of axial electromagnetic force, radial outward electromagnetic force, and radial inward electromagnetic force, thus completing the welding of the inner and outer pipe fittings.

2. The pipe progressive electromagnetic welding method of claim 1, wherein, The tube gradual electromagnetic welding method further comprises a pretreatment process before welding: (a) The outer surface of the welding area of the inner tube is cleaned and polished smooth; (b) The inner surface of the welding area of the outer tube is cleaned and polished smooth.

3. The pipe progressive electromagnetic welding method of claim 1, wherein, The tube gradual electromagnetic welding method further comprises a repair welding process: checking whether there is virtual welding or empty welding in the welding area of the inner tube and the welding area of the outer tube, if there is virtual welding or empty welding, the compression coil and the bulging coil at the virtual welding or empty welding are connected to the coil power supply and are powered on, and the virtual welding or empty welding is locally welded again.

4. The pipe progressive electromagnetic welding method of claim 1, wherein, In step (3) of the gradual welding process, the first i -1 compression coil is energized together with the first i -1 compression coil and the first i -1 bulging coil to increase the axial and radial electromagnetic force on the weld zone of the inner tube between the first i -1 compression coil and the first -1 bulging coil, thereby improving the weld density.

5. The pipe progressive electromagnetic welding method of claim 1 wherein, The distance between the compression coil and the outer tube is not greater than 4 mm.

6. The pipe progressive electromagnetic welding method of claim 1, wherein, The distance between the bulging coil and the inner tube is not greater than 3.5 mm.

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