WO2018145544A1

WO2018145544A1 - Welding torch used for laser beam-plasma arc hybrid welding

Info

Publication number: WO2018145544A1
Application number: PCT/CN2018/000064
Authority: WO
Inventors: 王长春; 陈卓勤
Original assignee: 王长春
Priority date: 2017-02-07
Filing date: 2018-02-05
Publication date: 2018-08-16
Also published as: CN106735909A

Abstract

A multifunctional laser beam-plasma arc hybrid welding torch (100), provided with a cavity (113) for laser beams to pass through; a constriction nozzle (120) is provided at the lower end of the cavity of the welding torch; a slit is formed, by a plasma electrode, above the constriction nozzle (120) of the welding torch (100); and a part of laser beams are incident on the slit edge of the electrode, and the other part of the laser beams pass through the slit to focus on a workpiece. The multifunctional laser beam-plasma arc hybrid welding torch eliminates the defects of laser beam welding and plasma welding and has higher hybrid heating source coupling efficiency.

Description

Welding torch for laser beam and plasma arc hybrid welding

Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a welding torch apparatus for welding and coating metal materials, and more particularly to a welding torch for laser and plasma arc hybrid welding, and a laser and plasma arc hybrid welding method using the present invention.

Background technique

Welding is a manufacturing technology that is critical in various metal manufacturing industries and cannot be completely replaced to date. Welding operations refer to the creation of high energy densities on the workpiece to form a weld pool and move the weld pool. Therefore, if the energy coupling efficiency between the welding tool and the workpiece, that is, the energy density incident on the workpiece, can be improved, significant economic benefits can be obtained, depending on the materials used and the welding technique.

One of them is plasma welding with high energy coupling density. Plasma welding refers to the process of using a compressed plasma arc as an energy source to melt the workpiece for welding. During the welding process, the plasma arc formed by the ionized gas Compressed, the energy is more concentrated, the high-energy plasma arc generates dynamic pressure, and the arc can penetrate the molten pool, so it is also called “small hole” welding. The main advantage of plasma welding is that it can be performed once and relatively quickly. The material is welded and the joint preparation is minimal. In addition, because the plasma arc is concentrated in the "small hole", the stress or deformation in the workpiece is reduced.

Although plasma welding has many important advantages, there are still several serious limitations. The energy density of the plasma arc limits the penetration depth of the "small holes", the thickness of the weldable material, and the welding speed. In addition, "small holes" in plasma welding may collapse under certain operating conditions, thereby causing a reduction in weld quality.

In plasma welding, the energy density incident on the workpiece is the most important parameter for forming "small holes." Plasma welding currents can form "small holes" in the range of 10 to 250 amps, but this also depends on the material of the workpiece and the welding speed. In addition, the energy density of the plasma arc and the energy density in the hot spots on the incoming workpiece depend on the heat transfer mechanism within the plasma arc. When the arc temperature increases, the radiant heat loss of the plasma arc is the main factor, which limits the maximum power density of the plasma welding operation and limits the ability to weld thicker plates or increase the welding speed. In conventional plasma arc welding, radiant heat transfer is the dominant factor for currents of about 200A-250A and plasma power densities of about 3-3.5 KW, so it is virtually impossible to obtain higher plasma welding using existing techniques. Power density, any attempt to increase power density by increasing torch power consumption will reduce welding efficiency; if you try to increase the welding speed, the plasma arc will become unstable and the hot spot on the workpiece will fall behind the torch axis. It is a cause of poor welding quality.

Laser beam welding is another highly efficient and precise machining method that uses a high energy density laser beam as a heat source for welding. Laser beam welding in "small hole" mode provides a relatively large penetration. Laser beam welding has a high energy density (typically 10 ⁴ to 10 ⁶ W/cm ² ) and less heat input than other fusion methods. The residual stress and deformation in the joint area are small, the melting zone and the heat-affected zone are narrow, and the penetration depth is large, the weld microstructure is fine, and the joint performance is good. In addition, laser beam welding does not require vacuum conditions compared to (samely using high energy density soldered) electron beam technology, and the type and pressure range of the shielding gas can be easily selected, and it is difficult to guide the laser beam by means of a deflection prism or an optical fiber. The welding is carried out in close parts, the operation is flexible, and the transparent material can be focused and welded. The laser beam can be flexibly controlled, and the three-dimensional automatic welding of the workpiece can be easily realized.

Laser beam welding also has several major constraints. Since the thickness and penetration depth of the solderable material are subject to the power and heat of the laser beam coupled to the workpiece, the soldering effect can generally only be improved by increasing the laser power. Laser beam welding generally requires large high power gas lasers, solid state lasers or diode lasers to generate and maintain a "small hole" welding mode.

It is well known that the pressure exerted by the metal plasma on the inner walls of the "small holes" is very important to maintain the "small hole" welding pattern during the welding process. However, if the plasma density is too high, the laser beam will be reflected; in fact, the density of the plasma becomes too low or too high, which will result in a reduction in the efficiency of the welding operation. In addition, starting laser beam welding on a material such as metal requires a higher laser beam power to form a "small hole", but the power conversion efficiency of the laser beam is very low.

In general, laser beam welding techniques have the following typical limitations:

(1) A very precise weldment position (within the focus range of the laser beam) is required, and the weldment requires the use of a relatively complex fixture to ensure that the laser beam hot spot is aligned with the final position of the weldment; for thicknesses greater than 19 mm The workpiece is not suitable for laser welding on the production line.

(2) For highly reflective and highly thermally conductive materials such as aluminum, copper and their alloys, the application of laser beam welding is limited. When performing high energy welding, the performance of laser beam welding is affected by the plasma.

(3) The energy conversion efficiency is usually less than 10%; the weld bead solidifies quickly, which may cause pores and embrittlement.

(4) The equipment is expensive.

In order to eliminate or reduce the defects of laser beam welding, research on the use of other heat sources and laser beam hybrid welding has begun in the 1980s, and now some industrial applications, such as laser beam and arc hybrid welding, have begun. Classified according to the layout, there are mainly laser beam and arc side axis arrangement (typically such as laser and gas metal arc welding GMAW or pulsed laser and gas metal arc welding GMAW-P composite welding), laser beam and arc coaxial arrangement ( Typical such as laser and TIG arc hybrid welding) two categories.

The characteristics of these technologies are that the energy of the laser beam acts directly on the surface of the workpiece and is combined with GMAW or TIG arc. Among them, the high energy density of the laser beam plays a role in the composite effect, especially in increasing the penetration depth and improving the welding efficiency. Decisive role. However, since the diameter of the GMAW or TIG arc is much wider than the laser beam, the quality of the weld surface of the composite welding operation is determined by the GMAW or TIG arc.

In general, laser beam and arc hybrid welding have the following significant advantages:

(1) Under the action of the arc, the composite welding reduces the assembly accuracy of the joint gap, so that the welding can be achieved under a large joint gap.

(2) Increased penetration of the weld. In the "small hole" mode of the laser beam, the arc can reach the depth of the weld. Secondly, the arc increases the absorption rate of the laser beam energy by the metal workpiece, which also helps to increase the weld penetration.

(3) The high-density energy of the laser beam shortens the heating time of the workpiece and reduces the heat-affected zone. At the same time, the arc can slow down the solidification time of the molten pool, so that the phase change of the molten pool can be fully completed.

(4) The "small hole" mode formed by the laser beam attracts the arc, compresses the root of the arc, and increases the density of the arc energy.

(5) Compared with arc welding, a composite heat source of laser beam and arc can increase the welding speed. Of course, in this case, it is possible to use a laser with a lower power, which can reduce the equipment cost.

Although laser beam arc hybrid welding has many important advantages, there are still several serious limitations, which make many laser beam arc hybrid welding technology still in the research stage, and the laser beam arc hybrid welding technology already applied in the industrial field also Limited to a small number.

The laser beam arc hybrid welding torch arranged in the paraxial axis has a simple structure, but generally requires a large arrangement space, and the welding system is relatively complicated. There is an angle between the laser beam and the arc, which makes the working area of the composite heat source on the workpiece asymmetrical. The change of the arc current will easily and easily cause the coupling points of the two heat sources to deviate, which makes the control double The difficulty of coupling the heat source is increased. In the way of the paraxial arrangement, the laser beam passes through the arc to reach the surface of the workpiece. When the arc current is large, the energy of the laser beam is weakened, which also affects the welding efficiency of this method. The only solution that can be used is to use a laser with a higher power. In addition, in practical applications, the laser beam arc hybrid welding technology using the paraxial arrangement still requires relatively precise weld bevel accuracy to ensure high welding quality.

Some research results of the coaxial arrangement of some laser beams and arcs close to the present invention include:

A coaxial symmetric composite heat source method uses a beam splitter to split an incident laser into two symmetrically distributed laser beams, and a gas metal arc welding (MIG welding) electrode is fed by a double beam. Since the double beam is non-closed, the introduction of the MIG electrode can avoid the beam transmission path. The focusing system focuses the dual beams symmetrically from the sides of the electrodes at the same position at the front end of the wire feed direction, and the laser and the arc are coaxial with each other without affecting the beam transmission. The shortcoming of this method is that each laser beam itself has a certain angle with the arc after laser beam splitting, and the symmetry axis of the double laser beam and the arc axis are difficult to overlap, and the feeding of the wire has a great influence on the transmission of the laser beam to the workpiece. Wait.

The research results of several laser beams and arcs in close proximity to the present invention are:

U.S. Patent No. 4,689,466, the disclosure of which is incorporated herein incorporated by reference in its entirety in its entirety in the the the the the the the This patent describes a laser and arc hybrid welding apparatus in which a laser beam is collected by an uncontracted nozzle onto a surface of a workpiece, and an annular non-melting electrode is placed at the end of the nozzle to form an arc discharge between the electrode and the surface of the workpiece, and the auxiliary gas passes through The nozzle and, when ionized by the arc, transforms into a plasma that can absorb a portion of the reflected laser energy and transfer this portion of the energy to the surface of the workpiece. In this case, the energy of some of the laser beams that are usually lost due to the reflection is intercepted by the plasma and applied to the welding process, thereby improving the processing efficiency. That is to say, the coupling efficiency of the system is improved because the plasma recovers a part of the laser reflection energy that is usually lost, and the coupling efficiency is thus improved.

In the above technique, since the laser beam interacts with the uncontracted arc and the plasma temperature is lower than the plasma arc temperature, the absorption capacity of the laser beam to absorb the uncontracted arc is relatively low, if the laser power is reduced, the laser The coupling efficiency between the energy generated by the beam and the workpiece is not significant. In addition, as mentioned above, when the surface of the material to be welded reaches its boiling temperature, a metal vapor plume is generated, which still has an occlusion effect on the laser beam; when a lower power laser is used, the arc dynamic pressure may not be sufficient to start. "Small hole" working mode.

Similarly, it is a technique in which an arc and a laser beam formed by hollow tungsten (non-melting electrodes) are used as a composite welding heat source, so-called laser beam and TIG hybrid welding device. The plasma arc generated between the tip of the hollow tungsten and the workpiece is uncompressed, and the laser beam passes from the center of the tungsten through the annular arc to the surface of the workpiece. The composite principle is as shown in the drawing. In the hybrid welding process, since the laser beam passes through the center of the arc, there is no problem of welding directivity, which is particularly suitable for the welding of three-dimensional parts. Although the adjustment of the coaxial composite welding torch is not as complicated as the side-shaft composite torch, the size of the tungsten pole and the distance between the tungsten tip and the workpiece have a great influence on the welding quality, and the tungsten tip is burned. It will seriously affect the shape of the annular arc, affecting the stability of the welding process and the shape of the weld.

</ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; These technologies combine the characteristics of a laser beam torch with a plasma arc torch, which is a welding technique in which a laser beam is combined with a compressed plasma arc.

For example, U.S. Patent No. 5,705,785 describes a non-melting electrode in the form of a cone, the remainder of which is like a standard plasma arc torch. Wherein, the diameter of the conical electrode is smaller than the diameter of the spot when the laser beam passes through the center, so that the laser beam can be partially irradiated on the conical electrode. When the cone electrode is heated by the laser beam radiation, the shielding gas is ionized and forms a plasma arc. The laser beam is focused on the workpiece after passing through the nozzle and interacts with the plasma arc between the electrode and the workpiece to form a plasma-laser discharge, thereby increasing the energy density at the workpiece solder joint.

Compared with the above-mentioned coaxially arranged laser beam arc hybrid welding technology, the technology uses a compressed plasma arc, part of the laser beam radiantly heats the electrode, and the combined effect of the current and the electrode being heated by the laser beam causes electron emission. The plasma gas is formed, and the plasma gas is compressed and ionized to form a plasma arc. The laser beam interacts with the plasma arc along its axial direction to form a laser plasma composite discharge, thereby improving the coupling efficiency of the laser beam and the plasma arc. However, its significant limitation is that the reliability of the conical electrode is relatively low, the electrode is complicated, the manufacturing cost is high, and the electrode opening may be contaminated by molten metal spatter during the welding process; meanwhile, due to the electrode structure Complex, coaxially arranged laser beam and arc hybrid torches are complex to manufacture and difficult to standardize.

On the basis of the above-mentioned technology, U.S. Patent No. 6,388,227 proposes an improvement in that the integral conical electrode is changed from a round bar tungsten electrode assembly having two spherical heat accumulators at the end, a round bar tungsten electrode. The center line forms a sharp boundary with the center line of the laser beam, and the distance from the center line of the laser beam is smaller than the radius of the laser beam. An improvement of this technical solution is that the integral ring electrode is demarcated into a combined electrode. At the same time, the technical solution proposes a concept of matching pulsed plasma arc and pulsed laser beam through the positive and negative electrodes of the end of the spherical regenerator, in order to reduce the absorption of the laser beam energy by the metal vapor plume.

This technical solution attempts to solve as many defects as possible in the past technical solutions as much as possible, but limited to the state of the art at the time, the improved efficiency is difficult to achieve perfectly, and the composite torch mechanism is still complicated and expensive, and even almost impossible to re-manufacture. The limitation is that the improvement of the solution for the plasma power of alternating polarity is only applicable to some light metal welding; the manufacturing and installation precision of the round bar combination electrode with the spherical regenerator is very high, and the electrode replacement is required. difficult.

Obviously, on the basis of the above-mentioned many laser beam arc composite technical solutions, it is necessary to further overcome the above-mentioned constraints and limitations of the current laser beam plasma arc torch, and at the same time adapt to the welding needs of the current diverse new materials.

In addition, for most users, due to the complexity of the working conditions, in many cases it is necessary to use a different welding method to complete a complete welding construction work, for example, when welding the bottom and upper part of the weld. Normally, the torch can only perform one welding operation, which complicates the welding operation. Users need to purchase multiple torches and spend more time to replace the torch, which affects the welding efficiency.

Summary of the invention

In view of the above problems in the prior art, the present invention provides a welding torch for laser beam and plasma arc hybrid welding and a method of using the same, and by the invention, laser beam plasma hybrid welding can be realized on the same torch , laser beam plasma composite filler wire welding, laser beam plasma MIG hybrid welding and other composite welding operations, laser fill wire welding, laser MIG compound welding, plasma MIG compound welding and other welding operations can also be completed, laser beam welding can also be done separately, Plasma (filled or unfilled) welding, MIG welding.

In order to achieve the above object, the present invention adopts the following technical solutions:

A welding torch for laser beam and plasma arc hybrid welding, the torch comprising:

a) the torch body, the torch body has an input end, an output end and a hollow inner cavity between the input end and the output end, and the laser beam is incident from the input end and is emitted from the output end;

b) an insulating bushing disposed at the output end of the torch body, the bottom of the insulating bushing is provided with an opening for the laser beam passing through the same central axis as the torch body;

c) a compression nozzle disposed at the output end of the insulating bushing and a protective nozzle surrounding the compression nozzle; the compression nozzle has a through hole and a sectional plane centered on the central axis of the torch body, and the sectional plane of the compression nozzle is perpendicular to the center of the torch body Axis

d) two plasma electrodes disposed on both sides of the insulating bushing, the two plasma electrodes forming a slit above the through hole of the compression nozzle, the center line of the slit is consistent with the welding direction, and the central axis of the torch body passes through the center of the slit. The slit width is smaller than the diameter of the laser beam as it passes through the slit.

Further, the longitudinal axis of each of the plasma electrodes and the central axis of the torch body form an acute angle toward the welding workpiece, the acute angle being between 2 and 89 degrees.

Further, the slit width is 0.1-1.5 mm, and the distance of the slit from the sectional plane of the compression nozzle is 1-5 mm.

A protective gas is input into a region between the compression nozzle and the plasma electrode, and a shielding gas is input between the protection nozzle and the compression nozzle.

Further, the torch further includes a wire feeding tube disposed at a lower portion of the torch body, the wire feeding tube being disposed on an opposite side of the welding direction, the longitudinal axis of the wire feeding tube being at an acute angle with the center line of the torch body And intersecting the solder joint of the workpiece, the acute angle is 20-80 degrees.

Furthermore, the present invention further includes a melting electrode and a nozzle for MIG welding disposed at a lower portion of the torch body and disposed on a side opposite to the welding direction, the molten electrode being located inside the nozzle and having the same axis as the nozzle. The molten electrode is arranged at an acute angle to the central axis of the torch body, the acute angle being 0-45 degrees.

The distance between the longitudinal axis of the molten electrode and the workpiece and the center line of the torch body is D, and D is 3-15 mm.

The method for using the welding torch comprises: separately performing a plasma arc welding operation when the laser beam source is turned off; and adjusting the width of the plasma electrode slit when the plasma source is turned off, separately Perform a laser beam welding operation.

In the case of turning off the laser beam source, the plasma arc welding and the plasma arc wire bonding welding operation can be separately performed; in the case of turning off the plasma source, only the width of the plasma electrode slit needs to be adjusted, and the separation can be performed separately. Laser beam welding, laser beam filling and welding operations.

In the case of turning off the laser beam source and turning off the plasma source, the MIG arc welding operation can be performed separately; in the case of turning off the plasma source and the MIG power source, only the plasma electrode slit needs to be adjusted. The width of the laser beam welding and laser beam filling welding operation can be performed separately; if only the plasma source is turned off, laser beam MIG hybrid welding can be performed; if the laser beam source and the MIG power source are turned off, it can be performed Plasma arc welding, plasma arc filler welding; if only the laser beam source is turned off, plasma MIG hybrid welding can be performed; if only the MIG power supply is turned off, laser beam plasma composite welding and laser beam plasma filling welding can be performed.

The laser beam plasma arc hybrid welding torch is a composite torch that performs welding operation by using the coupling energy of the laser beam and the plasma arc. With the device of the invention, a high-power laser can be used to obtain high composite heat source coupling efficiency on the surface of the workpiece. It eliminates some of the defects of laser beam welding, including the workpiece must have very precise dimensions, fast bead solidification (possibly with porosity and embrittlement), and expensive equipment. With the apparatus of the present invention, some of the defects of plasma welding are also eliminated, including low welding efficiency, inability to weld thicker workpieces, and the like. It eliminates the defects of some existing laser beam plasma hybrid welding devices, including the complicated structure of the torch, the difficulty in manufacturing and installation, and the narrow application range.

The welding torch is a composite welding torch connected to a laser beam based on a conventional plasma welding torch, mainly comprising a laser beam source and a plasma electrode, a nozzle and a gas protection device, wherein the laser beam and the plasma nozzle are arranged coaxially . During the arcing process of the welding, part of the laser beam is incident on the electrode, and a plasma arc is established between the electrode and the nozzle. After the plasma arc is compressed by the nozzle, a working arc is established with the workpiece. Therefore, the present invention is also applicable to the case of using pulsed plasma welding.

The plasma electrode refers to a combined electrode having a slit shape, and the center line of the slit of the plasma electrode coincides with the welding direction. During the welding process, a part of the laser beam is incident on the electrode, and the excitation electrode forms a plasma arc of high-density energy, which is coupled with the plasma arc generated by the electrode current to form a plasma arc with a higher energy density; the other part of the laser beam passes through The slit of the electrode passes through the compressed plasma arc with a higher energy density and is associated with and with the plasma arc

The slit electrode is composed of 2 (or 1 or more) electrodes having polygonal or rectangular or rectangular or elliptical ends, and the axes of the two electrodes are arranged sharply with the center line of the laser beam. The end of the electrode forms a narrow slit whose center line coincides with the welding direction, and the width of the slit is smaller than the diameter of the laser beam. In the present invention, since it is only necessary to control the width dimension of the slit, it is relatively easy to realize the mounting of the electrode. At the same time, even if there is a slight movement of the laser beam along the center line of the slit, a part of the laser beam easily passes through the slit and is focused on the surface of the workpiece.

In the welding torch of the laser beam plasma arc hybrid welding technology, the end of the slit electrode is planar in the direction toward the nozzle (the planar shape can be obtained by simply processing the end of the electrode), the shape of the plane It is a polygon or a rectangle or a rectangle or an ellipse. According to the present invention, it is possible to ensure that the electrode has a large area to emit electrons, and at the same time, even if the electrode is partially burned during the soldering process, as long as it does not affect part of the laser beam passing through the slit, the soldering process is not hindered.

In the welding torch of the laser beam plasma arc hybrid welding technology, the slit plasma electrode may also be composed of one end, a tapered polygonal or rectangular or rectangular or elliptical electrode, the axis of the electrode and the laser beam center line. Arranged in a sharp boundary, the ends of the electrodes are planar in the direction towards the nozzle. The distance from the end of the electrode to the centerline of the laser beam is less than the radius of the laser beam.

The invention is equally applicable where welding of aluminum alloys, magnesium alloys, or other applications requiring a variable polarity plasma power source is desired. At the same time, coating the alloys such as yttrium, lanthanum and zirconium at the end of the plasma electrode is beneficial to prolonging the service life of the electrode and also improving the stability of the welding process.

The welding torch of the laser beam plasma arc hybrid welding technology, the wire feeding head (connected with the wire feeder) is arranged on the other side of the welding torch in the welding direction, and the axis of the wire feeding tube is at an acute angle with the center line of the laser beam ( The angle is adjustable), which constitutes a laser beam plasma arc composite wire-filled welding torch. The focus of the present invention is that if a wire feeding head of a gas metal arc welding (ie, MAG/MIG welding method) is used, it becomes a welding torch of a laser beam plasma arc and MIG hybrid welding technology; if the wire feeding mechanism does not introduce a current , it becomes a welding torch for laser beam plasma arc composite wire filling welding technology.

The laser beam plasma MIG multifunctional composite welding torch means that the various welding methods attached to the welding torch of the present invention can be operated 100% separately in the case that other welding methods are closed, and can be realized in combination of two or two. Composite welding operation. For example, when other welding methods are turned off, including the plasma power supply being turned off, the laser beam can be completely passed through the slit and the compression nozzle by focusing the width of the plasma electrode slit, and focused on the workpiece, thereby realizing a separate laser. Beam welding. In addition to the laser beam, both plasma and MIG welding can be operated 100% separately, with other welding methods turned off and without adjustment to the torch. For example, if a laser beam plasma arc composite torch is used, in addition to the laser beam plasma arc hybrid welding, laser beam welding and plasma arc welding may be separately performed in the case where other welding methods are closed; if laser beam plasma is used Arc composite wire-filled welding torch, in addition to the laser beam plasma arc composite filler wire welding, in the case of other welding methods closed, laser beam welding, laser beam filler welding, plasma welding and plasma wire bonding welding can be realized If a laser beam plasma arc MIG composite torch is used, in addition to the laser beam plasma arc MIG hybrid welding, laser beam welding, laser beam filler welding, laser beam plasma composite can be realized under the condition that other welding methods are closed. Welding, laser beam plasma composite wire bonding welding, laser beam MIG compound welding, plasma arc welding, plasma wire bonding welding, plasma MIG compound welding, MIG welding operation, and the like.

The technical effect of the invention:

(1) The present invention provides a method and a welding torch for welding a laser beam with a compressed plasma arc, the most important effects of which include: a higher energy density formed by the dual action of a laser beam and a current. The plasma arc is coupled to the laser beam on the surface of the workpiece, so that a higher composite heat source coupling efficiency can be obtained than conventional laser beam and arc hybrid welding. The method for realizing the above mechanism of the present invention adopts a combined electrode with slits. With the composite welding torch which is relatively simple to manufacture, install and operate, the present invention provides a lower cost and can be similarly higher. Power laser beam welding capability and efficiency, while eliminating some welding methods for laser welding defects, and also provides a more efficient plasma welding method, which not only eliminates the serious limitations of some plasma welding, but also can be close to the laser The quality and efficiency of beam welding.

(2) With the present invention, it is possible to weld a laser beam plasma arc composite wire. This laser beam plasma arc composite wire filling welding method greatly expands the application range of plasma welding, can obtain the ability and efficiency close to laser beam welding, and is beneficial to improve the performance of welds and joints, and is suitable for welding various steels. With non-ferrous metals, the thickness range of the welded workpiece is also expanded.

(3) The present invention also provides a laser beam plasma arc composite MIG welding method. Compared with the prior art, the present invention eliminates some defects of the prior art, and can perform high-efficiency welding operations with a laser of a lower power. It is beneficial to reduce the equipment cost of the laser beam arc hybrid welding system. At the same time, because of its higher heat source coupling efficiency than conventional plasma arcs, this laser beam plasma arc composite MIG welding method is very suitable for the welding of medium and heavy plate high strength steel, and the welding quality is superior to the prior art.

(4) Another important effect of the present invention is to simplify the composite torch electrode structure for ease of manufacture, installation, and operation, including replacement of electrodes. The invention is suitable for adopting the latest laser technology and plasma power supply technology, and the torch may be further reduced in size, which is more convenient for welding construction and helps to reduce the cost of the composite torch.

(5) Another important effect of the present invention is that the welding torch has a plurality of welding functions, and the operation of a certain welding method can be separately operated, or the operation of a certain composite welding method can be separately operated, which can It greatly simplifies the welding operation of a specific workpiece. Different welding methods can be used to complete complicated welding work without adjusting the welding torch or requiring only a few adjustments. This makes sense for automated welding lines.

DRAWINGS

The present invention is further described below in conjunction with the accompanying drawings:

1 is a laser beam and plasma arc composite torch according to Embodiment 1 of the present invention.

2 is a laser beam and plasma arc composite filler wire welding torch according to Embodiment 2 of the present invention.

3 is a laser beam plasma arc and MIG composite torch according to Embodiment 3 of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Example 1

The welding torch 100 of the present invention includes a torch body 110 having a central axis 111 and a cavity 113. At one end of the torch body 110 is an optical system that includes a lens 112. The lens 112 is used to focus the incident laser beam 114 such that the beam 114 is collinear with the central axis 111 of the torch body 110 and is focused on a focus FP located outside of the torch 100.

In FIG. 1, the torch body 110 includes two (or one, or four, and two oppositely disposed)

electrodes

130 and 230, a compression nozzle 120, and a conical outer portion of the compression nozzle that is concentric with the compression nozzle 120. The protective nozzle is disposed, and the shielding gas is introduced into the inside and outside of the compression nozzle 120 (between the compression nozzle 120 and the protection nozzle). The laser beam 114 has a certain radius r1 at the slit composed of two electrodes, and has a certain radius r2 at the opening of the compression nozzle 120.

An insulating bushing 160 made of an electrically insulating material is disposed at the output end of the torch body 110. The insulating bushing 160 has an opening through which the laser beam 114 is passed and a cavity for receiving the

electrodes

130, 230.

Two (or one, or four two-two opposite arrangement)

electrodes

130 and 230 form a slit in the upper portion of the opening of the compression nozzle 120, the width of the slit being d, two (or one, or four two) The two opposite arrangements of the lower end faces of the

electrodes

130 and 230 are at a distance h from the upper surface of the opening of the compression nozzle 120.

The lower section plane at the distal end of the compression nozzle 120 is perpendicular to the central axis 111, and the through hole has a radius R that is greater than the radius r2 at which the laser beam is located at the opening of the compression nozzle 120. The radius R preferably ranges from 0.5 mm to 5 mm and should not block the laser beam 114 from passing through the compression nozzle.

According to the experimental test by the inventors, the slit width d formed by the

electrodes

130 and 230 in the upper portion of the opening of the compression nozzle 120 may range from 0.1 mm to 1.5 mm; the distance from the upper surface of the opening of the compression nozzle 120 may be in the range of h. Between 1 mm and 5 mm; the radius r1 of the laser beam 114 at the slit composed of 2 electrodes may range from 0.1 mm to 1.5 mm, and the value of the radius r1 should be larger than half the width d of the electrode slit, so that part The laser beam is incident on the edge of the electrode slit. The best effect is to ensure that the heat of the laser beam incident on the electrode in this section is sufficient to ignite the plasma arc between the electrode and the compression nozzle while facilitating electrode mounting. At least one of the electrodes is reciprocable along its longitudinal axis, which facilitates adjustment of the slit width of the ends of the two electrodes.

The

longitudinal axes

131, 231 of the two

electrodes

130, 230 intersect the central axis 111 near the plane of the plane of the compression nozzle 120. The longitudinal axes 132, 232 of the

electrodes

130, 230 form an acute angle A with the central axis 111 that faces the body 110. The range of acute angle A is most preferably between 2° and 89°. The best effect is to ensure that part of the laser beam is incident on the end of the electrode and is sufficient for the plasma arc between the ignition electrode and the compression nozzle, while facilitating electrode mounting, Will make the torch size too bulky.

In order to operate the torch 100 of the present invention, a current is typically established between the electrode 230 and the workpiece 180. A laser beam 114 provided by an external laser source (not shown) propagates through the lens 112 collinearly along a central axis 111 of the body 110. The compression nozzle 120 directs the plasma flow, which is collinear with the central axis 111 and the laser beam 114, thus forming a high energy density spot on the surface of the workpiece 180, i.e. having a high degree of concentration from the torch 100 in a very small range of regions. energy. The laser beam 114 propagates along a central axis 111 of the torch body 110, and the

electrodes

130, 230 are heated by a portion of the laser beam 114 and form a plasma arc in the cavity between the compression nozzles, which in turn establishes between the compression nozzle 120 and the workpiece 180. The compressed plasma arc; the laser beam 114 is focused to a focus FP outside the torch body 110, a compressed plasma arc formed in a region between the welding body 110 and the workpiece 180, and a compressed plasma nozzle 120 The laser beam 114 interacts and produces a more highly contracted plasma arc that has a high energy density and is delivered to the workpiece 180.

The width d of the electrode slit composed of the

electrodes

130, 230 is smaller than the diameter (2xr1) of the laser beam 114. With such a geometric configuration, a portion of the laser beam 114 is absorbed by the slit edge regions of the

electrodes

130, 230, which causes the ends of the

electrodes

130, 230 to heat up, thereby enhancing electron emission, and at the electrodes 130 and 230 A plasma arc is established in the chamber between the compression nozzles 120, thereby completing the laser arcing.

After the plasma arc formed between the electrode and the compression nozzle 120 is compressed by the nozzle 120, it interacts with the laser beam 114 to form a laser plasma composite discharge, and a high energy plasma arc is established with the workpiece 180 and directly acts on the workpiece 180. Compared to a separate laser beam or plasma arc, the torch of the present invention increases the energy density of the surface of the workpiece 180, thereby increasing the coupling efficiency.

When the laser beam 114 is incident on the workpiece 180, the surface of the workpiece 180 is vaporized to form a surface plasma jet. Since the ionization potential of the surface jet is lower than that of the general nozzle and the shielding gas, the plasma conductivity above the laser spot is enhanced, and the plasma arc is further shrunk, thereby increasing the energy density and coupling efficiency at the workpiece 180.

The hybrid laser and plasma arc interactions also have the added benefit of contracting and stabilizing the plasma arc. In the case of additional heating by a partial laser beam, a larger volume near the tip of the electrode is at a higher temperature than a conventional plasma arc, thereby increasing the current density in the plasma. In addition, as the laser beam 114 interacts with and is absorbed by the plasma, the plasma temperature and current density along the axis of the laser beam are also increased.

The primary physical effects that occur in the enhanced interaction between the laser beam 114 and the plasma arc include a 1 plasma arc contraction resulting in a higher energy density; 2 reducing the heat affected zone or hot spot on the workpiece 180; 3 increasing the plasma temperature; 4 improve plasma arc stability; 5 reduce energy consumption. The overall net effect is to create a higher energy density spot on the workpiece 180 that is more efficiently coupled to the arc 180 and transmitted to the workpiece 180.

It is well known that a through hole is formed by a plasma arc or a plasma jet as a black surface radiator of the laser beam 114, thereby enhancing the absorption of the energy of the laser beam 114 by the workpiece 180.

In addition, the present invention also adopts some mature technical solutions, such as coating a metal oxide such as ruthenium, osmium and zirconium on the surface of a cathode made of tungsten metal, which can improve the service life of the tungsten electrode. According to the present invention, since the electrode is heated by the laser beam, the electrode spot size is increased, which reduces the peak temperature of the electrode spot, and thus the electrode life is remarkably extended.

Example 2

As shown in FIG. 2, on the basis of Embodiment 1, the welding torch 100 further includes a wire feeding tube 330 for laser beam plasma filling welding, and the wire feeding tube 330 is at an acute angle with the central axis 111 of the torch body 100. Arranged and disposed on the opposite side of the welding torch 100 in the welding direction, the acute angle between the wire feeding tube 330 and the central axis 111 of the torch body 100 is most preferably between 20° and 80°, and the effect is preferably It is ensured that the welding wire and the plasma arc intersect on the upper surface of the workpiece 180 without making the torch size too bulky. The longitudinal axis 332 of the wire feed tube 330 intersects the centerline 111 of the torch body at the upper surface of the workpiece 180.

Example 3

As shown in FIG. 3, on the basis of Embodiment 1, the welding torch 100 further includes a molten electrode tip 430 for the laser beam plasma MIG welding, a wire feeding tube 431 and a protective gas jacket 432, and the contact nozzle 430 is located. The inside of the gas sleeve 432 is protected and concentric with 432; the contact tip 430 is disposed at an acute angle to the central axis 111 of the torch body 100, the acute angle being in the range of 0 to 60 degrees, and disposed on the opposite side of the welding torch 100 in the welding direction On the side, the longitudinal axis 432 intersects the centerline 111 of the torch body 110 below the upper surface of the workpiece 180 and the distance from the intersection of the torch centerline 111 at the upper surface of the workpiece 180 is D; D is defined as the melting arc The distance between the arc impact point on the surface of the workpiece 180 and the plasma arc impact point of the non-melting electrode (130, 230), the distance D ranges from 3 to 15 mm, and the distance D can be adjusted according to different welding parameters.

The inventive concept can be implemented in various ways as the technology advances, as will be appreciated by those skilled in the art. The embodiments of the invention are not limited to the embodiments described above, but may be varied within the scope of the claims. It should be understood that the phraseology and terminology used herein is for the purpose of description Accordingly, the components, operation, and implementation of the laser and plasma arc composite torch in accordance with the present invention are better understood with reference to the drawings and the accompanying description. It should be noted that the present invention shown herein is for illustrative purposes only and is not intended to be limiting.

Claims

A welding torch for laser beam and plasma arc hybrid welding, characterized in that the welding torch comprises:

a) the torch body, the torch body has an input end, an output end and a hollow inner cavity between the input end and the output end, and the laser beam is incident from the input end and is emitted from the output end;

b) an insulating bushing disposed at the output end of the torch body, the bottom of the insulating bushing is provided with an opening for the laser beam passing through the same central axis as the torch body;

c) a compression nozzle disposed at the output end of the insulating bushing and a protective nozzle surrounding the compression nozzle; the compression nozzle has a through hole and a sectional plane centered on the central axis of the torch body, and the sectional plane of the compression nozzle is perpendicular to the center of the torch body Axis

d) two plasma electrodes disposed on both sides of the insulating bushing, the two plasma electrodes forming a slit above the through hole of the compression nozzle, the center line of the slit is consistent with the welding direction, and the central axis of the torch body passes through the center of the slit. The slit width is smaller than the diameter of the laser beam as it passes through the slit.
A welding torch for laser beam and plasma arc hybrid welding according to claim 1, wherein a longitudinal axis of each of the plasma electrodes and a central axis of the torch body form an acute angle toward the welding workpiece, The acute angle is between 2 and 89 degrees.
A welding torch for laser beam and plasma arc hybrid welding according to claim 2, wherein said slit has a width of 0.1 to 1.5 mm, said slit being spaced from a sectional plane of said compression nozzle The distance is 1-5mm.
A welding torch for laser beam and plasma arc hybrid welding according to claim 1, wherein a protective gas is input into a region between the compression nozzle and the plasma electrode, and an input between the protection nozzle and the compression nozzle is provided. There is a protective gas.
A welding torch for laser beam and plasma arc hybrid welding according to claim 1, further comprising a wire feeding tube disposed at a lower portion of the torch body, the wire feeding tube being disposed opposite to the welding direction On the side, the longitudinal axis of the wire feeding tube is at an acute angle to the center line of the torch body and intersects the welding point of the workpiece, the acute angle being 20-80 degrees.
A welding torch for laser beam and plasma arc hybrid welding according to claim 1, further comprising a molten electrode for MIG welding disposed at a lower portion of the torch body and disposed on a side opposite to the welding direction And a nozzle, the molten electrode being located inside the nozzle and having the same axis as the nozzle, the molten electrode being disposed at an acute angle to a central axis of the torch body, the acute angle being 0-45 degrees.
A welding torch for laser beam and plasma arc hybrid welding according to claim 6, wherein the distance between the longitudinal axis of the molten electrode and the workpiece and the center line of the torch body is D, D is 3 -15mm.
A method of using a welding torch according to claim 1, wherein the plasma arc welding operation can be performed separately when the laser beam source is turned off; and the plasma electrode is narrowed in the case of turning off the plasma source With the width of the slit, the laser beam welding operation can be performed separately.
A method of using a welding torch according to claim 5, wherein the plasma arc welding and the plasma arc filling welding operation can be separately performed in the case of turning off the laser beam source; in the case of turning off the plasma source, It is only necessary to adjust the width of the slit of the plasma electrode to perform laser beam welding and laser beam filling welding operations separately.
A method of using a welding torch according to claim 6, wherein in the case of turning off the laser beam source and turning off the plasma source, the MIG arc welding operation can be performed separately; when the plasma source is turned off, In the case of the MIG power supply, the laser beam welding and the laser beam filling welding operation can be separately performed only by adjusting the width of the plasma electrode slit; if only the plasma source is turned off, the laser beam MIG can be performed. Composite welding; if the laser beam source and the MIG power source are turned off, plasma arc welding and plasma arc filler welding can be performed; if only the laser beam source is turned off, plasma MIG hybrid welding can be performed; if only the MIG power supply is turned off, Laser beam plasma composite welding, laser beam plasma filling welding.