CN107498182A - A kind of compound molten bath concussion welding methods of laser scanning TIG - Google Patents

Abstract

The invention discloses a laser scanning-TIG composite molten pool oscillation welding method, which is realized by combining laser scanning and TIG welding, including: when welding, select the laser scanning groove in front, TIG welding torch welding behind, or TIG welding torch welding in The laser scans the two composite welding methods with the groove at the back, and the trajectory of the laser scanning molten pool has different methods according to different materials and welding requirements. The ranges on both sides of the laser scanning groove are the same or different, or the laser scans only On one side of the groove, the scanning trajectory can be circular, sinusoidal, triangular or selectively scan a specific area. The invention utilizes the mutual enhancement and coupling effect of laser and electric arc to increase penetration and improve efficiency, and scans the welding pool by laser to realize stirring of the pool, reduce temperature gradient, improve solidification and crystallization process, and improve performance of welded joints.

Description

A Laser Scanning-TIG Composite Melt Pool Oscillation Welding Method

technical field

The invention relates to the technical field of high-precision laser welding manufacturing, in particular to a laser scanning-TIG composite molten pool oscillation welding method.

Background technique

Due to its high energy density, low heat input, small welding deformation, high welding efficiency and good welding quality, laser welding has been widely used and promoted in important fields of the national economy such as automobiles, shipbuilding, aviation and aerospace, and nuclear power.

Laser-TIG hybrid welding can combine the advantages of laser welding and TIG welding to obtain better welding quality, and use the mutual attraction enhancement effect of laser and arc to obtain greater penetration and higher efficiency. However, due to the high energy density of the laser and the fast welding speed, the temperature gradient during the solidification of the weld seam is large, resulting in coarse grains, which affects the mechanical properties of the welded joint to a certain extent. However, laser-TIG welding has deep penetration, narrow fusion width, and weak wettability and spreadability to the edge of the weld. In the narrow gap welding of thick plates, it is easy to cause the problem of incomplete fusion of the side wall or incomplete fusion between layers. In addition, laser-TIG hybrid welding has a fixed position of the weld due to the action of the laser, which makes it difficult to control the heat distribution on both sides when welding two different weldments, and it is difficult to obtain good welding quality.

Invention patent CN101716701A proposes a laser-GMA arc hybrid welding device to achieve swing welding. During welding, the arc welding torch basically remains still, and the laser beam focusing welding torch swings back and forth in an "S" shape before the welding arc. Problems such as lack of fusion between layers and side walls of medium and thick plate welds, slag inclusions, pores and other defects. The dissertation of the Harbin Welding Research Institute "Research on Laser Scanning-CMT Composite Welding of Stainless Steel Pure Ar Protection" proposed a laser scanning-CMT composite welding method. Laser scanning in front of the arc prolongs the solidification time of the liquid metal at the edge of the molten pool, which is beneficial The molten pool metal spreads to the edge of the weld, and finally a regular and stable weld is obtained. It can be seen that in the prior art, only a combined welding method of laser scanning and GMA is proposed, and there is only an S-shaped swing trajectory. However, the combination of laser scanning and CMT is pointed out in the prior art, but only the symmetrical linear reciprocating scanning trajectory along the weld groove section is studied. Other welding methods and scanning trajectories are not involved.

In addition, the molten pool is usually stirred by means of ultrasonic, electromagnetic, electric arc, mechanical, etc., which can reduce the temperature gradient of the molten pool, improve the solidification and crystallization process, increase the nucleation rate and promote the formation of equiaxed crystals, reduce component segregation, and accelerate Pore overflow, suppression defects, etc. However, due to the need for additional auxiliary devices, the torch head part is often relatively large, which often limits the accessibility of the welding torch to a certain extent.

Contents of the invention

In view of the above technical problems, the object of the present invention is to provide a laser scanning-TIG hybrid welding method, which is efficient, can reduce the temperature gradient, improve the solidification and crystallization process, has good wetting and spreading properties and has selectable regionality Laser heating.

To achieve the above object, the present invention is achieved according to the following technical solutions:

A laser scanning-TIG composite molten pool oscillation welding method, which is realized by combining laser scanning and TIG welding, is characterized in that it includes:

When welding, choose the laser scanning groove in front, TIG torch welding behind, or TIG welding torch welding in front, laser scanning groove behind two composite welding methods, and the trajectory of the laser scanning molten pool depends on different materials and welding Different methods are required, the range of laser scanning on both sides of the groove is the same or different, or the laser scans only one side of the groove.

In the above technical solution, the angle range between the laser and the TIG welding torch is 15-60 degrees.

In the above technical solution, the distance between the center of the laser and the center of the molten pool of the arc electrode of the TIG torch is 1-6 mm.

In the above technical solution, the distance from the electrode tip of the TIG welding torch to the workpiece is in the range of 1-5 mm.

In the above technical solution, the laser power range is set to 20-6000W, the arc power range is 500-5KW, and the laser scanning frequency range is 2-200Hz, and the scanning range is 0-10mm.

In the above technical solution, the trajectory of the laser scanning weld pool is circular, elliptical, sinusoidal, triangular or a scanning trajectory of a selectively specified area.

In the above technical solution, the trajectory of the laser scanning the weld pool is a scanning trajectory of linear reciprocation or lateral swinging back and forth.

Compared with the prior art, the present invention has the following beneficial effects:

Compared with laser-TIG hybrid welding, in addition to the mutual coupling enhancement effect of arc and laser, the penetration depth is increased, and at the same time, through high-speed scanning of the molten pool, the agitation of the molten pool is realized, the solidification and crystallization process is improved, and the grains are refined. , Improve the organization, suppress the defects such as stomata.

Compared with electromagnetic stirring, ultrasonic stirring and other stirring forms, it is more flexible, and can easily change the scanning frequency, amplitude, scanning trajectory, scanning area, etc., which is more beneficial for improving the solidification and crystallization process and suppressing welding defects.

The laser is a non-contact heat source, which can scan the molten pool from a long distance, so it has better accessibility than electromagnetic stirring, which requires additional devices.

While stirring the molten pool, due to the mutual coupling enhancement effect between the laser and the arc, it can also significantly increase the penetration depth and improve the welding efficiency.

For the connection of two different materials, you can scan by selecting a specific range and area, which has a great advantage for the connection of different materials. Through selective scanning, the thermal difference between the two metals is reduced and balanced, thereby improving the welding adaptability of difficult-to-solder materials.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the schematic diagram of the laser scanning-TIG hybrid welding method of the embodiment of the present invention;

Figures 2(a)-2(c) are schematic diagrams showing the coupling relationship between various scanning modes of laser and TIG arc.

Wherein, reference signs: 1-laser, 2-TIG welding torch, 3-scanning trajectory, 31-triangular scanning trajectory, 32-sine scanning trajectory, 33-circular scanning trajectory.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments.

A laser scanning-TIG composite molten pool oscillation welding method, which is realized by combining laser scanning and TIG welding, is characterized in that it includes:

When welding, choose the laser scanning groove in front, TIG torch welding behind, or TIG welding torch welding in front, laser scanning groove behind two composite welding methods, and the trajectory of the laser scanning molten pool depends on different materials and welding Different methods are required, the range of laser scanning on both sides of the groove is the same or different, or the laser scans only one side of the groove.

In the technical solution of the present invention, the angle range between the laser and the TIG welding torch is 15-60 degrees. The distance between the laser center point and the molten pool center of the arc electrode of the TIG welding torch is in the range of 1-6mm. The distance from the electrode tip of the TIG welding torch to the workpiece is in the range of 1-5mm. Set the laser power range from 20-6000W, the arc power range from 500-5KW, the laser scanning frequency range from 2-200Hz, and the scanning range from 0-10mm.

The trajectory of the laser scanning molten pool can be in any form, and there are different ways according to different materials and welding requirements. The trajectory of the laser scanning welding molten pool can be circular, elliptical, sinusoidal or triangular scanning trajectory or linear reciprocating or horizontal The scan track that oscillates back and forth can even be a weld pool that only has high-frequency pulses acting on it, or a scan track that selectively specifies a region.

During TIG welding, the laser scans the welding pool at the same time. On the one hand, the mutual enhancement coupling between the laser and the arc is used to increase the penetration depth and efficiency. On the other hand, the stirring effect of the laser scanning on the molten pool is used to reduce the temperature gradient of the molten pool. , Improve the solidification and crystallization process, refine grains, and reduce defects. There are many ways to stir the molten pool by scanning the laser during welding, such as pulse, circular, sine wave, triangular wave and other methods. Of course, it is also possible to choose directional and selective scanning for the connection of two different materials to reduce and balance the thermal difference of the two metals, thereby improving the welding adaptability of difficult-to-solder metals.

FIG. 1 is a schematic diagram of a laser scanning-TIG hybrid welding method according to an embodiment of the present invention; Embodiment 1 adopts a laser scanning-TIG hybrid welding method, and the relative positional relationship shown in FIG. 1 . The distance between the center of the laser 1 and the center of the arc electrode welding pool of the TIG welding torch 2 D _LA is 2 mm; the angle between the TIG welding torch 2 and the center of the laser 1 is 30 degrees; the distance h between the electrode tip of the TIG welding torch 2 and the workpiece surface is 2mm. The average laser power is 150W, the laser scanning frequency is 100Hz, the welding pulse current is 100A, the base value current is 20A, the pulse frequency is 40Hz, the shielding gas flow rate is 15L/min, the welding material is 3mm stainless steel butt joint, and the welding speed is 0.6m/min. TIG welding is carried out with a TIG welding torch, and at the same time a laser scanning head is used for laser scanning of the weld pool. The scanning trajectory 3 can have different shapes.

Figure 2(a)-2(c) is a schematic diagram of the coupling relationship between various laser scanning forms and TIG arc, and Figure 2(a)-2(c) respectively show a triangular scanning trajectory 31, a sinusoidal scanning trajectory 32, and a circular scanning trajectory 33 .

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. In the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims (7)

1. A laser scanning-TIG composite melt pool oscillation welding method, which is realized by combining laser scanning and TIG welding, is characterized in that, comprising: When welding, choose the laser scanning groove in front, TIG torch welding behind, or TIG welding torch welding in front, laser scanning groove behind two composite welding methods, and the trajectory of the laser scanning molten pool depends on different materials and welding Different methods are required, the range of laser scanning on both sides of the groove is the same or different, or the laser scans only one side of the groove. 2. A laser scanning-TIG composite molten pool oscillation welding method according to claim 1, characterized in that: the angle range between the laser and the TIG welding torch is 15-60 degrees. 3. A laser scanning-TIG composite molten pool oscillation welding method according to claim 1, characterized in that: the distance between the laser center point and the molten pool center of the arc electrode of the TIG welding torch is 1-6 mm. 4. A laser scanning-TIG composite molten pool oscillation welding method according to claim 1, characterized in that the distance from the electrode tip of the TIG welding torch to the workpiece is in the range of 1-5mm. 5. A laser scanning-TIG composite molten pool oscillation welding method according to claim 1, characterized in that: the laser power range is set at 20-6000W, the arc power range is at 500-5KW, and the laser scanning frequency range is at 2 -200Hz, the scanning range is 0-10mm. 6. A laser scanning-TIG composite molten pool oscillation welding method according to claim 1, characterized in that: the trajectory of the laser scanning welding molten pool is circular, elliptical, sinusoidal, triangular or selectively specified The scan track of the area. 7 . The laser scanning-TIG composite molten pool oscillation welding method according to claim 1 , further characterized in that: the trajectory of the laser scanning welding molten pool is a linear reciprocating or laterally reciprocating scanning trajectory. 8 .