阅读说明：本技术 低功率激光引导超高功率激光-电弧焊接的方法及应用 (Method for guiding ultrahigh-power laser-arc welding by low-power laser and application ) 是由 蒋平 李艳 耿韶宁 任良原 舒乐时 郭玲玉 于 2021-09-30 设计创作，主要内容包括：本发明属于焊接相关技术领域,其公开了一种低功率激光引导的超高功率激光-电弧焊接的方法及应用,所述方法包括在焊接的过程中采用低功率激光在前,超高功率激光在中间,电弧在后的方式进行焊接,其中,所述低功率激光的功率为3～7kW,所述超高功率激光的功率为20～30kW。本申请可以有效减小超高功率激光焊接时熔池、匙孔的不稳定现象,提高焊接过程的稳定性,同时显著缩短了焊接时间,提高了焊接效率。(The invention belongs to the technical field of welding, and discloses a low-power laser-guided ultrahigh-power laser-electric arc welding method and application thereof, wherein the method comprises the steps of welding in a mode that a low-power laser is arranged in front, an ultrahigh-power laser is arranged in the middle, and an electric arc is arranged behind, wherein the power of the low-power laser is 3-7 kW, and the power of the ultrahigh-power laser is 20-30 kW. The welding device can effectively reduce the unstable phenomena of the molten pool and the keyhole during the ultra-high power laser welding, improve the stability of the welding process, and meanwhile, obviously shorten the welding time and improve the welding efficiency.)

1. A method of low power laser guided ultra high power laser-arc welding, the method comprising:

in the welding process, welding is carried out in a mode that low-power laser is in front, ultrahigh-power laser is in the middle and electric arc is behind, wherein the power of the low-power laser is 3-7 kW, and the power of the ultrahigh-power laser is 20-30 kW.

2. The method of claim 1, wherein the low power laser spot diameter is 1-2 times the ultra high power laser spot diameter.

3. The method of claim 1, wherein the low power laser has a spot spaced from the ultra high power laser by 15-25 mm, and the ultra high power laser has a spot spaced from the end of the arc welding wire by 3-8 mm.

4. The method according to claim 1 or 3, wherein the ultra-high power laser is irradiated to a central position of the surface of the low power laser-formed melt pool.

5. The method according to claim 1, characterized in that the defocusing amount of the low-power laser relative to the surface of the workpiece to be welded is-2 to-5 mm, and the defocusing amount of the ultrahigh-power laser relative to the surface of the workpiece to be welded is-5 to-20 mm.

6. The method according to claim 1, characterized in that the low-power laser light is at an angle of 95-100 ° with respect to the surface of the workpiece to be welded, the ultra-high-power laser light is at an angle of 95-100 ° with respect to the surface of the workpiece to be welded, and the arc wire is at an angle of 125-140 ° with respect to the surface of the workpiece to be welded.

7. The method of claim 1, further comprising side blowing a shielding gas over the keyhole of the ultra-high power laser.

8. The application of the method for the ultrahigh-power laser-arc hybrid welding according to any one of claims 1 to 7, wherein the method is applied to welding of a Y-shaped groove, and the method further comprises the following treatment of the Y-shaped groove before welding:

the bottom of the Y-shaped groove is additionally provided with a platform with a certain width, and the width of the platform is 0.5-2 mm.

9. The use of claim 8, wherein the gap at the root of the Y-shaped groove is 0.5-2 mm, and the unilateral angle of the Y-shaped groove is 5-15 °.

10. Use according to claim 8, characterized in that the thickness of the work piece to be welded is 30 to 40 mm.

Technical Field

The invention belongs to the technical field of welding, and particularly relates to a method for guiding ultrahigh-power laser-arc welding by low-power laser and application of the method.

Background

With the high-speed development of heavy industry, the welding of thick plate members in the fields of ships, hydropower, petrochemical industry, bridge buildings, pressure containers and the like is urgently required. The ultrahigh-power laser has ultrahigh energy density, can realize large fusion depth welding of thick plates, and can realize high-quality and high-efficiency welding of the thick plates by combining the advantage of large spreadability of electric arcs.

When the myriawatt-level ultrahigh-power laser directly acts on the surface of a welding material due to ultrahigh energy density in the welding process, the material is quickly melted and vaporized to form a keyhole, the material in the keyhole is violently vaporized, the interaction between metal vapor plasma in the keyhole and the wall surface of the slender small hole is more complex, the fluctuation of an opening of the keyhole is large, the metal vapor pressure at the position of the keyhole is obviously increased, a liquid column is accelerated to rise, large drops of splashes are formed, and finally the instability of the welding process is caused. The keyhole opening can be increased to a certain extent by adding the electric arc, and the stability of the welding process is improved. However, the intense metal vapor generated by the ultra-high power laser strikes the arc, resulting in unstable combustion of the welding arc. In order to improve the stability of the welding process, the conventional method usually adopts pre-welding preheating, however, the method needs more time and has low welding efficiency.

In the ultra-high power laser-electric arc hybrid welding process, unstable welding process can be caused by unstable plasma energy absorption in a keyhole, keyhole oscillation caused by violent evaporation of local metal, strong impact of violent erupted metal steam/plasma on electric arc, rising of a molten liquid column, splashing and the like, and the forming quality of a welding seam is directly influenced, such as air holes, undercut, splashing and the like can be generated, so that the welding quality can hardly meet the industrial requirements. Therefore, in order to ensure the penetration of the thick plate, improve the stability of the welding process and improve the welding efficiency, it is necessary to design a welding process which can realize high quality and high efficiency of the thick plate and has a stable welding process.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, the invention provides a method for guiding ultrahigh-power laser-arc welding by low-power laser and application thereof.

To achieve the above object, according to one aspect of the present invention, there is provided a method of low power laser guided ultra high power laser-arc welding, the method comprising: in the welding process, welding is carried out in a mode that low-power laser is in front, ultrahigh-power laser is in the middle and electric arc is behind, wherein the power of the low-power laser is 3-7 kW, and the power of the ultrahigh-power laser is 20-30 kW.

Preferably, the diameter of the low-power laser spot is 1-2 times of that of the ultrahigh-power laser spot.

Preferably, the distance between the light spot of the low-power laser and the light spot of the ultrahigh-power laser is 15-25 mm, and the distance between the ultrahigh-power laser and the end part of the arc welding wire is 3-8 mm.

Preferably, the ultrahigh-power laser is irradiated to a central position of the surface of the molten pool formed by the low-power laser.

Preferably, the defocusing amount of the low-power laser relative to the surface of the workpiece to be welded is-2 to-5 mm, and the defocusing amount of the ultrahigh-power laser relative to the surface of the workpiece to be welded is-5 to-20 mm.

Preferably, the included angle of the low-power laser relative to the surface of the workpiece to be welded is 95-100 degrees, the included angle of the ultrahigh-power laser relative to the surface of the workpiece to be welded is 95-100 degrees, and the included angle of the arc welding wire relative to the surface of the workpiece to be welded is 125-140 degrees.

Preferably, the method further comprises side blowing the spot of the ultrahigh-power laser by using a shielding gas.

According to another aspect of the present invention, there is provided an application of the method for low power laser guided ultra high power laser-arc welding as described above, the method being applied to welding of a Y-groove, the method further comprising the following steps of: the bottom of the Y-shaped groove is additionally provided with a platform with a certain width, and the width of the platform is 0.5-2 mm.

Preferably, the gap at the root of the Y-shaped groove is 0.5-2 mm, and the single-side angle of the Y-shaped groove is 5-15 degrees.

Preferably, the thickness of the workpiece to be welded is 30-40 mm.

In general, compared with the prior art, through the above technical solutions of the present invention, the method and application of low-power laser-guided ultra-high-power laser-arc welding provided by the present invention have the following beneficial effects:

1. in the method, a series welding mode is adopted, low-power laser is used as an auxiliary heat source to melt metal on the surface of a workpiece to be welded and form a molten metal layer with a certain thickness, the molten metal layer can inhibit violent fluctuation of a molten pool under ultrahigh-power laser welding, and then the height of a liquid column is reduced, splashing is reduced, and the stability of a welding process is improved.

2. The full penetration welding method is particularly suitable for full penetration welding of thick plates with large thickness and high truncated edges, the electric arc is arranged behind the ultrahigh-power laser, the ultrahigh-power laser can maintain stable combustion of a large-current electric arc in a high-speed welding state, the heat input of the electric arc enhances the surface fluidity of a molten pool, and the complete cover surface of a narrow gap is realized, so that single-pass full penetration stable welding of the welding seams of the thick plates can be realized, and good welding seam forming is guaranteed.

3. The low-power laser guide can realize preheating and melting and form a molten metal layer with a certain thickness, and compared with the traditional plate preheating, the metal layer can effectively reduce the instability of a molten pool and a keyhole under the action of ultrahigh-power laser and improve the stability of the welding process.

4. According to the method, the ultrahigh-power laser is directly acted on the molten metal layer, the laser absorption efficiency is improved, the penetration capacity is increased, the full penetration of the single-pass welding with the large truncated edge height of the thick plate is realized, and the welding quality is ensured.

5. The concentration of metal steam/plasma generated by the ultrahigh-power laser can be reduced by side blowing the ultrahigh-power laser with the shielding gas, so that the effects of reflection or refraction and the like of the metal steam/plasma on the incident laser are reduced, and the problems of reducing the laser energy reaching a workpiece and the like are solved.

6. The combination of the large-current electric arc and the ultrahigh-power laser improves the stability of the electric arc, promotes the flow of a molten pool, realizes the cover surface, promotes the stability of the welding process, realizes the high-quality and high-efficiency welding of thick plates, and simultaneously shortens the welding time by more than 50 percent and obviously improves the welding efficiency by adopting the method.

Drawings

FIG. 1 is a schematic diagram of a low power laser beam/ultra high power laser beam, arc alignment in a method for low power laser guided ultra high power laser-arc welding according to the present embodiment;

FIG. 2 is a schematic view of the welding process of the present invention;

FIG. 3 is a groove design drawing in example 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 1 and 2, the present invention provides a method for guiding ultra-high power laser-arc welding by low power laser, wherein the method comprises welding with low power laser 1 in front, ultra-high power laser 3 in the middle, and arc 4 in back, wherein the power of the low power laser 1 is 3-7 kW, and the power of the ultra-high power laser 3 is 20-30 kW.

The diameter of the light spot of the low-power laser 1 is 1-2 times that of the light spot of the ultrahigh-power laser 3.

The distance 5 between the light spot of the low-power laser and the light spot of the ultrahigh-power laser is 15-25 mm, and the distance 6 between the ultrahigh-power laser and the end of the arc welding wire is 3-8 mm.

The ultrahigh-power laser is irradiated to the central position of the surface of the molten pool formed by the low-power laser. And adopting a protective gas 2 to blow the side of the upper part of the keyhole of the ultrahigh-power laser.

The defocusing amount of the low-power laser relative to the surface of the workpiece 7 to be welded is-2 to-5 mm, and the defocusing amount of the ultrahigh-power laser relative to the surface of the workpiece to be welded is-5 to-20 mm.

The included angle of the low-power laser relative to the surface of the workpiece to be welded is 95-100 degrees, the included angle of the ultrahigh-power laser relative to the surface of the workpiece to be welded is 95-100 degrees, and the included angle of the arc welding wire relative to the surface of the workpiece to be welded is 125-140 degrees.

In another aspect, the present application provides an application of the method for low power guided ultra-high power laser-arc welding as described above, wherein the method is applied to welding of a Y-groove, and the method further comprises the following steps of: the bottom of the Y-shaped groove is additionally provided with a platform with a certain width, and the width of the platform is 0.5-2 mm. The specific application process is as follows:

step 1: designing a groove, processing a groove with a truncated edge on a workpiece to be welded, wherein the groove is a single-side narrow-gap groove, the single-side narrow-gap groove is further optimized on a typical Y-shaped groove, a platform with a certain width is additionally arranged at the bottom of the oblique edge, and the width of the platform is preferably 0.5-2 mm.

The method in this application is particularly useful for the welding of the work piece of big thickness, and the thickness of waiting to weld the work piece in this embodiment is 30 ~ 40mm, and the chamfer height of blunt edge is 20 ~ 30mm, and the unilateral angle of groove is 5 ~ 15.

Step 2: pre-welding, namely performing laser cleaning on the surface of a workpiece to be welded, cleaning oil stains on the surface by using ethanol or acetone and the like, removing an oxidation film, and fixing the workpiece on a welding tool clamp. The gap of the root part of the groove of the workpiece to be welded is 0.5-2 mm. And the groove platform is fixed by spot welding at multiple positions, so that the problems of welding deformation, uneven groove root gap and the like caused by overlarge heat input in the welding process are solved.

And step 3: the welding is carried out by adopting a mode that low-power laser is used at the front, ultrahigh-power laser is used at the middle, and electric arc is used at the back.

The low-power laser with the power of 3-7 kW is used as a pre-heating melting heat source, the included angle between the low-power laser and a workpiece is 95-100 degrees and the defocusing amount is-2-5 mm, and the low-power laser is used for heating and melting metal with a part of thickness of the truncated edge to form molten metal, providing a molten state incident surface for the ultrahigh-power laser, enhancing the absorption efficiency of the ultrahigh-power laser, improving the stability of a keyhole under the action of an ultrahigh-energy-density laser beam, preventing the ultrahigh power from directly acting on a solid plate to form a violent upwelling liquid column and accompanying a large amount of splashing, and improving the stability of a welding process. The middle ultrahigh-power laser acts on the surface of the molten metal, the laser power is 20-30 kW, the included angle between the laser power and a workpiece is 80-85 degrees, and the defocusing amount is-5-20 mm. The distance between the light spots of the low-power laser and the ultrahigh-power laser is 15-25 mm, the ultrahigh-power laser beam irradiates the center of the surface of a welding seam formed by the low-power laser beam, and the diameter of the light spot of the low-power laser is 1-2 times that of the light spot of the ultrahigh-power laser.

And (3) laterally blowing protective gas by using the ultrahigh-power laser beam, wherein the direction of the protective gas is in the same line with the laser beam, the flow of the protective gas is 25-35L/min, and the refraction and scattering degree of the violent-eruption large-density metal steam and high-concentration composite plasma on the laser energy is reduced.

And arc welding is carried out at the rear, the diameter of the welding wire is 1.0-1.6 mm, the included angle between the welding wire and the surface of the workpiece to be welded is 125-140 degrees, and the welding current is 200-380A. The protective gas flow is 25-35L/min, and the distance between the ultrahigh-power laser and the end part of the welding wire is 3-8 mm.

The low-power laser, the ultrahigh-power laser and the electric arc are arranged in a series mode, the welding speed is consistent, and the welding speed is 1-3 m/min. The ultra-high power laser and the large current arc are compounded, so that the stability of the arc can be effectively improved, and the arc can still stably strike at a higher welding speed. Under the action of the electric arc, the surface flow of the molten metal is promoted, the groove area is filled, the stability of the welding process is improved, and the high-quality and high-efficiency welding of the thick plate is realized.

Example 1

The material of the workpiece to be welded is Q460ME low-alloy high-strength steel, the section is in a hot rolling state, the plate specification is 500 x 200 x 35mm, the joint is in a narrow gap groove butt joint mode, as shown in figure 3, an 8-degree groove is formed, the height h of a truncated edge is 30mm, the width w of a groove platform is 1mm, the gap d at the root of the groove is 0.7mm, and a THT80-1 welding wire with the diameter of 1.2mm is selected. The groove is cleaned and clamped before welding, and the groove platform is fixed by spot welding at multiple positions, so that welding deformation caused by overlarge heat input in the welding process is prevented, and the gap at the root of the groove is not uniform.

The method adopts a preposed low-power laser beam to preheat and melt the surface of the groove platform to form a molten metal layer with a certain depth, so that the middle ultrahigh-power laser directly acts on the molten metal layer to enhance the laser absorption efficiency and improve the stability of the welding process. In the implementation process, the power of the low-power laser is 7kw, the included angle between the low-power laser and the workpiece is 95 degrees, the defocusing amount is minus 5mm, and the welding speed is 1.0 m/min. The middle ultrahigh-power laser mainly has the main functions of realizing full penetration of the large-thickness truncated edge, the laser power is 30kW in the implementation process, the included angle between the laser power and a workpiece is 95 degrees, the defocusing amount is-15 mm, and the welding speed is 1.0 m/min. The ultrahigh-power laser beam blows protective gas, the direction of the protective gas is in a straight line with the laser beam, the protective gas adopts pure argon, the flow rate is 35L/min, and the refraction and scattering degree of the violent-eruption large-density metal steam and high-concentration composite plasma to the laser energy is reduced. The spot spacing 5 between the low-power laser and the ultrahigh-power laser is 25mm, the ultrahigh-power laser beam irradiates the central position of the surface of a molten pool formed by the low-power laser beam, and the diameter of the spot of the low-power laser is 2 times that of the spot of the ultrahigh-power laser. The distance between the ultrahigh-power laser and the end of the arc welding wire is 5mm, the post arc welding and the ultrahigh-power laser are compounded, the welding current is 300A, the shielding gas is pure argon, the flow is 25L/min, and the welding speed is 1.0 m/min.

Example 2

The material of a workpiece to be welded is Q460ME low-alloy high-strength steel, the shape is in a hot rolling state, the specification of a plate is 500 x 200 x 30mm, the joint is in a form of narrow gap groove butt joint, a groove with 5 degrees is formed, the height of a truncated edge is 25mm, the width of a groove platform is 1mm, the gap of the root part of the groove is 0.7mm, and a welding wire of THT80-1 with the diameter of 1.2mm is selected. The groove is cleaned and clamped before welding, and the groove platform is fixed by spot welding at multiple positions, so that welding deformation caused by overlarge heat input in the welding process is prevented, and the gap at the root of the groove is not uniform.

The method adopts a preposed low-power laser beam to preheat and melt the surface of the groove platform to form a molten metal layer with a certain depth, so that the middle ultrahigh-power laser directly acts on the molten metal layer to enhance the laser absorption efficiency and improve the stability of the welding process. In the implementation process, the power of the low-power laser is 3kw, the included angle between the low-power laser and the workpiece is 100 degrees, the defocusing amount is minus 2mm, and the welding speed is 1.0 m/min. The middle ultrahigh-power laser mainly has the main function of realizing full penetration of the large-thickness truncated edge, the laser power is 20kW in the implementation process, the included angle between the laser power and a workpiece is 100 degrees, the defocusing amount is-20 mm, and the welding speed is 1.0 m/min. The ultrahigh-power laser beam blows protective gas, the direction of the protective gas is in a straight line with the laser beam, the protective gas adopts pure argon, the flow rate is 35L/min, and the refraction and scattering degree of the violent-eruption large-density metal steam and high-concentration composite plasma to the laser energy is reduced. The spot space between the low-power laser and the ultrahigh-power laser is 15mm, the ultrahigh-power laser beam irradiates the central position of the surface of a molten pool formed by the low-power laser beam, and the diameter of a low-power laser spot is 1 time that of the ultrahigh-power laser spot. The post-arc welding and the ultrahigh power laser are compounded, the welding current is 300A, the shielding gas is pure argon, the flow is 25L/min, and the welding speed is 1.0 m/min.

Example 3

The material of a workpiece to be welded is Q460ME low-alloy high-strength steel, the shape is in a hot rolling state, the specification of a plate is 500 x 200 x 40mm, the joint is in a form of narrow gap groove butt joint, a 15-degree groove is formed, the height of a truncated edge is 35mm, the width of a groove platform is 1mm, the gap of the root part of the groove is 0.7mm, and a THT80-1 welding wire with the diameter of 1.2mm is selected. The groove is cleaned and clamped before welding, and the groove platform is fixed by spot welding at multiple positions, so that welding deformation caused by overlarge heat input in the welding process is prevented, and the gap at the root of the groove is not uniform.

The method adopts a preposed low-power laser beam to preheat and melt the surface of the groove platform to form a molten metal layer with a certain depth, so that the middle ultrahigh-power laser directly acts on the molten metal layer to enhance the laser absorption efficiency and improve the stability of the welding process. In the implementation process, the power of the low-power laser is 5kw, the included angle between the low-power laser and the workpiece is 98 degrees, the defocusing amount is minus 4mm, and the welding speed is 1.0 m/min. The middle ultrahigh-power laser mainly has the main functions of realizing full penetration of the large-thickness truncated edge, the laser power is 25kW in the implementation process, the included angle between the laser power and a workpiece is 98 degrees, the defocusing amount is minus 5mm, and the welding speed is 1.0 m/min. The ultrahigh-power laser beam blows protective gas, the direction of the protective gas is in a straight line with the laser beam, the protective gas adopts pure argon, the flow rate is 35L/min, and the refraction and scattering degree of the violent-eruption large-density metal steam and high-concentration composite plasma to the laser energy is reduced. The spot spacing between the low-power laser and the ultrahigh-power laser is 20mm, the ultrahigh-power laser beam irradiates the central position of the surface of a molten pool formed by the low-power laser beam, and the diameter of a low-power laser spot is 1.5 times that of the ultrahigh-power laser spot. The post-arc welding and the ultrahigh power laser are compounded, the welding current is 300A, the shielding gas is pure argon, the flow is 25L/min, and the welding speed is 1.0 m/min.

In the above embodiment, the welding process is very stable, no obvious spatter is generated on the surface of the weld, the weld is uniformly spread, the industrial requirements are met by X-ray flaw detection, compared with the traditional method for improving the stability by preheating, the welding time is shortened by more than 50%, the welding efficiency is obviously improved, and the specific and obvious industrial application value is achieved.

In conclusion, the low-power laser is used as an auxiliary heat source to melt the metal on the surface of the platform of the workpiece to be welded to form a molten metal layer with a certain thickness, and the molten metal layer can inhibit the violent fluctuation behavior of a molten pool under the ultrahigh-power laser welding, so that the height of a liquid column is reduced, the formation of splashing is reduced, and the stability of the welding process is improved. The ultra-high power laser realizes full penetration of the thick plate with large truncated edge height. The electric arc is arranged behind the ultrahigh-power laser, the ultrahigh-power laser can maintain stable combustion of a large-current electric arc in a high-speed welding state, the heat input of the electric arc enhances the surface fluidity of a molten pool, and the complete cover surface of a narrow gap is realized.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.