Wire filling welding method in a high pressure environment

Abstract

The present disclosure discloses a wire filling welding method in a high pressure environment, comprising: S100: pretreating a workpiece to be welded, a welding wire and a target material; S200: arranging relative positions of the workpiece to be welded, the welding wire and the target material according to welding requirements; S300: heating and melting the welding wire by using a plasma as a heat source; and S400: forming a weld seam of the workpiece to be welded by using the heated and melted welding wire. The present disclosure uses the plasma as the heat source to perform welding, which can effectively avoid the shielding effect of the plasma on the laser in the high pressure environment, thereby improving the utilization rate of the laser energy.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of welding, and particularly relates to a filler wire welding method in a high-pressure environment. BACKGROUND

[0002] The filler wire welding technology is developed on the basis of the self-fusion welding technology. Compared with the self-fusion welding technology, the filler wire welding can reduce the requirement for the assembly precision of a workpiece and improve the welding efficiency by adding an external welding wire material. In addition, the filler wire welding can realize the regulation of the composition of a weld and ensure the forming quality of the weld by adding welding wires with different compositions. So far, based on the two advantages, the laser filler wire welding plays an irreplaceable role in many industrial fields. In the field of nuclear industry and electronic industry, devices need to work in a high-pressure environment. At present, there are many difficulties in welding and repairing the devices. The filler wire welding can effectively reduce the difficulty of welding in a high-pressure environment. In addition, the filler wire welding can effectively avoid the solidification cracks generated during the cooling of the weld. Therefore, the filler wire welding in a high-pressure environment has a good application prospect.

[0003] Generally, the filler wire welding is divided into two types: arc filler wire welding and laser filler wire welding. Both welding methods have good welding effects under normal pressure. However, existing researches show that the arc form is very unstable under high pressure, and the instability degree gradually increases with the increase of the environmental pressure, which eventually seriously affects the welding quality. Although the laser filler wire welding can usually complete the welding under high pressure, the plasma will be significantly enhanced when the environmental pressure is not lower than 1.0 MPa. The laser will be seriously energy shielded when passing through the plasma, which eventually causes energy loss and unstable weld forming. Therefore, it is necessary to propose a new filler wire welding method. SUMMARY

[0004] In view of the deficiencies in the prior art, the purpose of the present disclosure is to provide a filler wire welding method in a high-pressure environment. The method can reduce the energy attenuation of the laser beam caused by the plasma under high pressure and ensure the stability of the heat source, so that a well-formed weld can be obtained.

[0005] To achieve the above purpose, the present disclosure provides the following technical solutions.

[0006] A filler wire welding method in a high-pressure environment, comprising the following steps:

[0007] S100: pretreating a workpiece to be welded, a welding wire and a target material;

[0008] S200: arranging the relative positions of the workpiece to be welded, the welding wire and the target material according to the welding requirements;

[0009] S300: heating and melting the welding wire by using the plasma as a heat source;

[0010] S400: forming a weld seam on the workpiece to be welded by using the welding wire after heating and melting.

[0011] Preferably, the plasma is generated by irradiating a target or the workpiece to be welded by a laser beam.

[0012] Preferably, step S400 is implemented in a high-pressure environment.

[0013] Preferably, the high-pressure environment is 1 MPa-30 MPa.

[0014] Preferably, the angle between the axis of the laser beam and the axis of the plasma is greater than the divergence angle of the plasma.

[0015] Preferably, in step S100, the pre-treatment of the workpiece to be welded, the welding wire and the target includes grinding and cleaning the workpiece to be welded, the welding wire and the target.

[0016] Compared with the prior art, the present disclosure has the beneficial effects that: by generating plasma by laser irradiation and using plasma as a heat source for welding, the shielding effect of plasma on laser in a high-pressure environment can be effectively avoided, thereby improving the utilization rate of laser energy, and the plasma is more stable than directly using a laser beam or an electric arc. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a flowchart of a wire filling welding method in a high-pressure environment provided by one embodiment of the present disclosure;

[0018] Figure 2 is a vertical welding schematic diagram provided by another embodiment of the present disclosure;

[0019] Figure 3 is a horizontal welding schematic diagram provided by another embodiment of the present disclosure;

[0020] Figure 4 is a schematic diagram of the shape of plasma under different environmental pressures;

[0021] The markers in the drawings are explained as follows:

[0022] 1, welding workpiece; 2, welding wire; 3, target; 4, laser beam; 5, plasma. DETAILED DESCRIPTION

[0023] The following will be described with reference to the accompanying drawings Figures 1 to 4The specific embodiments of the present disclosure are described in detail. Although specific embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be accurately conveyed to those skilled in the art.

[0024] It should be noted that some terms are used in the specification and claims to refer to specific components. Those skilled in the art should understand that the same component can be referred to by different terms. The specification and claims of this specification do not distinguish components based on differences in terminology, but rather on differences in function. As mentioned throughout the specification and claims, "including" or "including" is an open term, and should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present disclosure, and is intended to illustrate the general principles of the specification, and not to limit the scope of the present disclosure. The scope of protection of the present disclosure is defined by the appended claims.

[0025] To facilitate the understanding of the embodiments of the present disclosure, the following will be further explained and described with specific embodiments as examples in conjunction with the drawings, and each drawing does not constitute a limitation of the embodiments of the present disclosure.

[0026] In one embodiment, as shown in Figure 1 The present disclosure provides a wire filling welding method in a high pressure environment, comprising the following steps:

[0027] 1. A stainless steel plate with a size of 100*60*5mm and a "V" type groove with a width of 4mm and a depth of 2mm is used as a workpiece to be welded, and a wire with a diameter of 1.2mm is used as a welding wire, and a stainless steel plate with a size of 70*20*10mm is used as a target material, and a movable sliding table is provided for the target material to adjust the moving speed of the target material.

[0028] 2. The workpiece to be welded, the welding wire and the target material are polished and cleaned between welding, and then the wire filling welding is carried out according to Figure 2The placement constraints are shown below. When the workpiece to be welded is placed vertically, the angle θ1 between the welding wire and the workpiece is 45°, and the incident angle θ2 between the laser beam 4 and the target is 45°. The laser beam irradiates the target to generate photo-induced plasma 5, and the angle between the photo-induced plasma and the welding wire is 90°. Furthermore, existing research has found that the laser's travel within the plasma causes attenuation of the laser energy, with the travel distance being proportional to the energy shielding. However, the generation of photo-induced plasma requires interaction between the laser and the target, meaning the contact point must be within the plasma. The laser beam inevitably travels within the plasma. If the angle between the laser beam's axis and the photo-induced plasma's axis is equal to or less than the plasma's divergence angle, the laser beam's travel distance within the plasma will greatly increase, resulting in severe attenuation of the laser beam's energy. To address this problem, according to experiments... Figure 2 As shown, in this embodiment, the angle θ3 between the axis of the laser beam and the axis of the photoinduced plasma is adjusted to be greater than the divergence angle θ4 of the photoinduced plasma. This can shorten the travel distance of the laser beam in the plasma, thereby greatly reducing the shielding effect of the plasma on the energy of the laser beam and improving the energy utilization rate of the laser.

[0029] 3. Place the workpiece to be welded, the welding wire, and the target material in an internal environment with a pressure of 1.0 MPa to 30 MPa (e.g., Figure 4 As shown, welding is performed in a high-pressure vessel (where plasma is significantly enhanced at pressures above 1.0 MPa). It should be noted that in the prior art, high-pressure environments ranging from 1.0 MPa to 30 MPa can be created through various means; this is not within the scope of this disclosure. Therefore, this document does not describe the design method of such a high-pressure environment or the apparatus involved in achieving it.

[0030] 4. Existing research indicates that laser filler wire welding typically uses either a laser beam or an electric arc as the heat source. However, both of these heat sources have significant drawbacks under the high-pressure environment specified above. When using a laser beam as the heat source, the plasma is enhanced under high pressure, which also strengthens the shielding effect on the laser, causing laser energy attenuation and resulting in poor welding quality. Moreover, the higher the pressure, the stronger the plasma, and the worse the effect. When using an electric arc as the heat source, there are difficulties in arc ignition and arc instability under high pressure, leading to unstable heat input during welding and also resulting in poor weld formation. Compared to laser beams, the advantage of using photo-induced plasma as a heat source is that—only plasma stability needs to be ensured, and the shielding effect of plasma on lasers is no longer a significant factor affecting stability (however, to reduce unnecessary energy consumption, the travel distance of the laser beam in the plasma should be minimized as much as possible); compared to electric arcs, the advantage of using photo-induced plasma as a heat source is that—in ordinary arc welding, the degree of arc ionization decreases in a high-pressure environment, the proportion of charged particles that conduct electricity in space decreases, and the conductivity of the arc decreases, resulting in a decrease in arc stability. However, by using photo-induced plasma, the gas is ionized through high temperature, which can ensure the proportion of charged particles, so it can be more durable and stable, and thus can obtain continuous and stable high-quality welds.

[0031] It should be noted that the purpose of constraining the position of each welding component in step 2 is to ensure stable output of the laser plasma heat source and improve the utilization rate of laser energy, thereby obtaining a better weld.

[0032] In another embodiment, this disclosure also provides a method for filler wire welding in a high-pressure environment, comprising the following steps:

[0033] 1. For a stainless steel plate with dimensions of 100*60*5mm and a U-shaped bevel of 4mm width and 2mm depth as the workpiece to be welded, filler wire of the same material with a diameter of 1.2mm is used for filler welding. In this example, it is not necessary to use a target material as the photo-induced plasma source. The laser beam can directly act on the surface of the workpiece to generate photo-induced plasma, and then use the photo-induced plasma as a heat source to heat and melt the welding wire.

[0034] 2. Assemble the welding components according to... Figure 3 The placement constraints are shown, wherein when the workpiece to be welded is placed horizontally, the angle θ1 between the workpiece and the welding wire is 45°, and the laser beam is perpendicular to the welding wire. Simultaneously, the angle θ3 between the laser beam axis and the plasma axis is 45°. Similarly, in this embodiment, the angle θ3 between the laser beam axis and the photo-induced plasma axis is adjusted to be greater than the divergence angle θ4 of the photo-induced plasma, thereby shortening the travel distance of the laser beam within the plasma and significantly reducing the energy attenuation of the laser beam caused by the plasma.

[0035] 3. The welding assembly is placed in a high-pressure container with an internal environment pressure of 1.0 MPa to 30 MPa for welding.

[0036] It should be noted that the fillet welding of the vertically or horizontally placed workpiece to be welded is only exemplary, and when the workpiece to be welded is placed at an arbitrary angle, the relative positions of the welding wire and the target material and the workpiece to be welded can be adjusted appropriately.

[0037] The above describes the present disclosure by using specific embodiments, which is only used to help understand the present disclosure and does not limit the present disclosure. Any modification or replacement within the technical scope disclosed by the present disclosure by any person skilled in the art should be covered within the scope of the present disclosure.

Claims

1. A wire filling welding method in a high pressure environment, comprising the following steps: S100: pretreating the workpiece to be welded, the welding wire and the target material, including polishing and cleaning the workpiece to be welded, the welding wire and the target material; S200: arranging the relative positions of the workpiece to be welded, the welding wire and the target material according to the welding requirements, when the workpiece to be welded is vertically placed, the angle θ1 between the welding wire and the workpiece to be welded is 45°, the incident angle θ2 between the laser beam and the target material is 45°, the laser beam irradiates the target material to generate photo-induced plasma, and the angle between the photo-induced plasma and the welding wire is 90°; the included angle θ3 between the axis of the laser beam and the axis of the photo-induced plasma is greater than the divergence angle θ4 of the photo-induced plasma, so as to shorten the travel distance of the laser beam in the plasma, thereby greatly reducing the shielding amount of the plasma to the energy of the laser beam, and further improving the energy utilization rate of the laser; S300: heating and melting the welding wire by using the plasma as a heat source; S400: forming a weld seam of the workpiece to be welded by using the heated and melted welding wire in a high pressure environment of 1 MPa-30 MPa; The method can reduce the energy attenuation of the laser beam by the plasma while ensuring the stability of the heat source in a high pressure environment, so as to obtain a well-formed weld seam.

2. The method of claim 1, wherein, The plasma is generated by irradiating the target material or the workpiece to be welded by the laser beam.

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