CN112743204A - Hollow tungsten electrode coaxial filler wire welding device and regulation and control and welding method - Google Patents
Hollow tungsten electrode coaxial filler wire welding device and regulation and control and welding method Download PDFInfo
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- B23K9/00—Arc welding or cutting
- B23K9/16—Arc welding or cutting making use of shielding gas
- B23K9/167—Arc welding or cutting making use of shielding gas and of a non-consumable electrode
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Abstract
A hollow tungsten electrode coaxial filler wire welding device and a regulation and control and welding method. The welding efficiency of the current hollow tungsten electrode coaxial filler wire welding technology is still low. The invention comprises the following components: the device comprises a hollow tungsten electrode (1), a tungsten electrode clamp (2), a protective gas hood (3), a welding wire (4), an insulating ceramic tube (5) and a plasma buffer filtering gas chamber (12); the hollow tungsten electrode is clamped by symmetrically arranged tungsten electrode clamps, the protective gas hood is positioned outside the tungsten electrode clamps, and a plasma buffering and filtering gas chamber is fixed at the upper end of the hollow tungsten electrode; the hollow tungsten electrode is internally provided with a step, the insulating ceramic tube is inserted into the step in the hollow tungsten electrode, a welding wire is inserted in the insulating ceramic tube, and an ion gas channel (15) is formed in a gap between the welding wire and the hollow tungsten electrode; an ion gas filter screen (14) is fixed in the plasma buffer filtering air chamber, and a closed space formed by the ion gas filter screen and the ion gas buffer air chamber is filled with a porous medium material (13). The invention is used for the control and welding of the core-tungsten electrode coaxial wire filling.
Description
Technical Field
The invention relates to a hollow tungsten electrode coaxial filler wire welding device and a regulation and control method and a welding method.
Background
The traditional argon tungsten-arc paraxial filler wire welding technology is always used as the first choice technology of high-quality welding schemes in some fields due to the unique process stability, and plays an irreplaceable unique role in a plurality of key fields promoting national economic development. However, the traditional argon tungsten-arc welding paraxial wire filling welding technology has the defects of large space size of a welding gun, limited arc heat for effectively melting a welding wire, high dilution rate of a melting layer, directivity in the process implementation process, poor welding protection effect of nonferrous metals and the like, so that the application of the paraxial wire filling welding technology in the fields of welding of special materials and complex structural members or electric arc additive manufacturing and the like has great limitation.
The hollow tungsten electrode coaxial wire-filling welding technology is characterized in that a hole is formed in the center of a conventional tungsten electrode by utilizing a machining method, and a welding wire penetrates through an inner hole of the hollow tungsten electrode, so that the purpose of overlapping the geometric central axis of the tungsten electrode and the geometric central axis of the welding wire is achieved. On one hand, the technology can make up the technical defect that the traditional argon tungsten-arc paraxial filler wire welding has directionality, and the direct feeding of the coaxial welding wires of the tungsten electrode and the welding wire into the high-temperature area at the center of the electric arc can also obviously improve the fuse wire capability of the electric arc and improve the deposition efficiency. The invention patent with the patent number of CN201710512517.2 realizes the insulation between the tungsten electrode and the welding wire by a method of coating an insulating layer on the inner wall of the two half-split tungsten electrodes, then combines the two half-split tungsten electrodes into one tungsten electrode, and finally realizes the purpose of coaxiality of the tungsten electrode and the welding wire, but the method increases the implementation difficulty of the welding process, and the problems of assembly and conduction uniformity between the two tungsten electrodes can not be solved; the patent No. 201610998677.8 provides a hollow tungsten electrode coaxial wire-filling TIG welding device and its welding gun, the patent sends out the welding wire from the inner hole of the hollow tungsten electrode, the inner hole of the tungsten electrode and the protective gas cavity are connected together by the method of punching on the side wall of the tungsten electrode, the effect of gas-wire combined feeding is realized, but the method does not consider the uniformity of gas feeding and the insulation problem between the welding wire and the inner hole of the tungsten electrode, in the process of implementing the process, the phenomenon that the welding wire and the tungsten electrode are simultaneously conductive is very easy to occur, and the stability and the process controllability of the welding process can not be ensured.
Disclosure of Invention
The invention aims to solve the problems that the existing hollow tungsten electrode coaxial filler wire welding method does not consider the uniformity of gas feeding and the insulation between a welding wire and an inner hole of a tungsten electrode, and provides a hollow tungsten electrode coaxial filler wire welding device and a regulation and welding method based on the principle of forming an electric arc for argon tungsten electrode welding, wherein the electric arc form is regulated and controlled by changing the shape characteristic of an electron emission end of the hollow tungsten electrode, the space temperature gradient of an arc column region is regulated and controlled while the requirement of hollow tungsten electrode coaxial filler wire welding is met, the welding wire coaxially and stably fed out from the inner hole of the tungsten electrode is ensured to enter the arc column region in a high-temperature solid form and then enters a molten pool in a liquid bridge transition form, the interference on the flow of the molten pool and the stability of the electric arc during the transition of liquid metal is reduced, and the high-efficiency and stable argon arc filler wire welding.
The above purpose is realized by the following technical scheme:
a hollow tungsten electrode coaxial filler wire welding device comprises a hollow tungsten electrode, a tungsten electrode clamp, a protective gas hood, a welding wire, an insulating ceramic tube and a plasma buffering and filtering gas chamber;
the hollow tungsten electrode is clamped by symmetrically arranged tungsten electrode clamps, the protective gas hood is positioned outside the tungsten electrode clamps, and the upper end of the hollow tungsten electrode is fixed with the plasma buffering and filtering gas chamber;
the hollow tungsten electrode is internally provided with a step, the insulating ceramic tube is inserted into the step in the hollow tungsten electrode, the welding wire is inserted in the insulating ceramic tube, and an ion gas channel is formed in a gap between the welding wire and the hollow tungsten electrode;
the ion gas filtering net is fixed in the plasma buffering and filtering air chamber, and a closed space formed by the ion gas filtering net and the ion gas buffering air chamber is filled with a porous medium material.
The hollow tungsten electrode coaxial filler wire welding device is characterized in that the bottom of the hollow tungsten electrode is a horn mouth, the end face of the hollow tungsten electrode is circular, the hollow tungsten electrode is cut along the radial direction and is equally divided into a plurality of electric arc emission points and hollow tungsten electrodes with step petal shapes.
According to the coaxial wire filling welding device for the hollow tungsten electrode, the step for machining the stepped hole in the stepped petal hollow tungsten electrode is located 10-20 mm above the tail end of the hollow tungsten electrode.
The coaxial filler wire welding device for the hollow tungsten electrode is characterized in that the number of petals of the petal-shaped hollow tungsten electrode is generally 2-8.
The hollow tungsten electrode coaxial filler wire welding device is characterized in that the width of the ion gas channel is 0.2-03 mm.
The hollow tungsten electrode coaxial filler wire welding device is characterized in that the porous medium material is a sponge material.
A regulation and control method of a hollow tungsten electrode coaxial filler wire welding device specifically comprises the following steps:
(1) the shape of the hollow tungsten electrode electron emission end is prefabricated, a bell mouth shape is processed on an inner hole of the hollow tungsten electrode electron emission end with the outer diameter of D1 and the inner hole diameter of D4, the inner surface of the bell mouth is called as an inner side wall, and the diameter of the inner side wall is D2; processing an inclined plane on the outer diameter of the electron emission end of the hollow tungsten electrode, wherein a torus formed by the inclined plane is called as an outer side wall; the unprocessed end face of the electron emission end is used for emitting electrons, the end face is called a tungsten electrode electron emission end plane, the end plane is called an end plane for short, and the radial width of the end plane is calculated by the following formula:
(2) regulating and controlling the space temperature gradient of the arc column region;
the diameter D2 of the inner side wall of the bell mouth is used for changing the position of the inner edge of the arc and the distance between the welding wires, the shape of the arc irradiation area is adjusted, and the diameter D3 of the outer side wall of the electron emission end is changed to change the width w of the electron emission end;
(3) effective control of arc stability;
based on the electron tip emission principle, the smaller the w value is, the better the stability of the electric arc is, and the larger the current is, the larger the burning loss degree of the tungsten electrode is;
(4) controlling the positions of the electric arc preheating welding wire and the melting welding wire;
when the welding current is constant, the size of the diameter D2 value of the inner side wall of the horn mouth is changed, so that the accurate control of the distribution characteristics of the space form of the arc column area in the feeding process of the welding wire is realized;
(5) accurately controlling the distribution characteristics of the spatial form of the arc column region;
when the welding current is not changed, the position of the electron emission end is changed by changing the value D2, so that the distance between the welding wire and the arc is regulated and controlled, the larger the value D2 is, the farther the position of the inner edge of the arc is away from the welding wire, the irradiation effect on the welding wire is weakened, the preheating effect of the arc on the welding wire is reduced, and otherwise, the preheating effect of the arc on the welding wire is enhanced;
and adjusting the distance between the electron emission plane of the tungsten electrode and the test plate, namely the distance between the hollow tungsten electrode and the workpiece, and controlling the distance between the position where the welding wire starts to melt and the test plate.
A welding method of a hollow tungsten electrode coaxial filler wire welding device comprises the following steps:
(1) cleaning pollutants at an electron emission end of a tungsten electrode by using a tungsten electrode sample preparation tool, then installing the tungsten electrode sample preparation tool on a welding gun, extending the electron emission end of the tungsten electrode out of a protective gas hood, and controlling the distance between the tail ends of the tungsten electrode sample preparation tool and the protective gas hood to be 8-10 mm;
(2) carrying out decontamination treatment on a welding area on the surface of the workpiece and an area 15mm near the welding area by using a mechanical cleaning or chemical cleaning method;
(3) finely adjusting the posture of a welding gun, ensuring that the central axis of a tungsten electrode is vertical to the surface of a welding sample, and simultaneously adjusting the distance between the welding gun and a workpiece;
(4) and sequentially checking and confirming that the cooling water, the shielding gas, the ion gas, the wire feeding device, the welding travelling mechanism and the welding power supply are in normal working states, and setting the flow of the shielding gas, the wire feeding speed, the welding arc mode, the welding current and the welding speed according to welding parameters.
(5) And pressing a start button to realize the preparation of the hollow tungsten electrode coaxial wire filling welding layer of the workpiece to be welded at a high wire feeding speed.
Has the advantages that:
1. the invention is based on the electric arc forming principle for argon tungsten-arc welding, regulates and controls the arc shape by changing the shape characteristic of the electron emission end of the hollow tungsten electrode, and regulates and controls the space temperature gradient of the arc column area while meeting the coaxial wire-filling welding requirement of the hollow tungsten electrode, so as to ensure that welding wires coaxially and stably sent out from an inner hole of the tungsten electrode enter the arc column area in a high-temperature solid state form and then enter a molten pool in a liquid bridge transition form, reduce the interference on the flow of the molten pool and the stability of the electric arc during the transition of liquid metal, and meet the basic requirements of the high-efficiency and stable argon arc wire-filling welding technology on the process characteristics. In addition, when the welding wire is contacted with the workpiece, the potential of the welding wire is the same as that of the workpiece, welding arc is burnt between the welding wire and the inner hole of the tungsten electrode, and TIG electric arc plays a role in preheating the welding wire, so that the welding wire is extremely favorable for improving the deposition efficiency of the welding wire, and the heat input to the base metal is further reduced. Meanwhile, the high-temperature welding wire in the hollow tungsten electrode and the liquid molten pool in the welding arc action area are always in a good protection state through the design of the ion gas channel, so that the pollution of oxidizing gas to liquid metal is effectively prevented, and the improvement of welding quality is facilitated.
2. The method eliminates the problem of directionality in the traditional tungsten electrode argon arc paraxial filler wire welding process, and the addition of the porcelain tube well solves the insulation problem between the welding wire and the tungsten electrode, so that the curved surfaces of various complex components can be welded;
3. compared with the method for coating the insulating layer inside the semi-split tungsten electrode, the method adopts the high-temperature-resistant and wear-resistant boron nitride ceramic tube for insulation, obviously reduces the failure problem caused by friction between the welding wire and insulating substances when the welding wire is conveyed for a long time, reduces the manufacturing cost due to the design of the insulating ceramic tube, is convenient to replace and high in reliability, and greatly improves the stability of the hollow tungsten electrode coaxial filler wire welding process in the implementation process.
4. Compared with the conventional annular hollow tungsten electrode, the petaloid characteristic tungsten electrode of a plurality of electric arc emission points adopted by the invention can effectively burn a plurality of points with concentrated current, prevent the high-temperature electric arc and the heat conduction of the electric arc emission end tungsten electrode from damaging a ceramic tube, stabilize the electric arc and improve the welding speed.
5. The inner hole of the hollow tungsten electrode is provided with the step, so that the relative position between the ceramic tube and the tungsten electrode is not dislocated, the step is a reference, the position for mounting the ceramic tube every time is consistent in height, and the consistency of the welding process of the coaxial filler wire of the hollow tungsten electrode is guaranteed.
6. The invention realizes laminar flow of the ion gas before reaching the welding area through the ion gas buffer gas chamber, the porous medium material, the ion gas filter screen and the ion gas channel, which plays a good role in cooperative control on stable combustion of the flexible electric arc, and in addition, the stable flow of the ion gas plays a vital role in protecting the tail end of a high-temperature welding wire and the high-temperature area of a welding pool.
7. According to the invention, through the steady flow design of the ion airflow through the gas path, the protection of the welding wire and the high-temperature area of the molten pool is realized, and meanwhile, the vertical downward flowing mode of the airflow can play a certain promoting role in the transition of molten drops at the tail end of the welding wire, so that the method has an important promoting significance in regulating and controlling the material filling process during welding.
8. The large-diameter hollow tungsten electrode is adopted, so that the surface area of an electron emission region is increased, the current density of an arc column region is obviously reduced, namely the area of an arc column region in a workpiece surface irradiation region is increased, and the capability of an electric arc for melting a base material is also reduced, so that the dilution rate of the base material to deposited metal is reduced, and the performance of the deposited metal of a welding layer is improved;
9. the electron emission area of the hollow tungsten electrode is surface emission, so that the electron density and the arc temperature of an arc column area of the arc can be ensured while the arc irradiation area is increased, the capability of melting a welding wire in unit time of the arc is enhanced on the premise that the heat of a central area is effectively ensured, the wire feeding speed can be further increased, and a foundation is laid for greatly improving the welding efficiency;
10. the shape of the electron emission end of the tungsten electrode is processed into a horn mouth, so that the electron emission area is far away from the central axes of the tungsten electrode and the welding wire, the heat radiation effect of a low-temperature electric arc on the welding wire in the tungsten electrode is reduced, and the problems of tungsten electrode damage or unsmooth wire feeding and the like caused by the melting of the welding wire in the tungsten electrode are prevented. In addition, each micro-area on the electron emission end face is a forming area of a bell-jar type electric arc, and the annular electric arcs surrounded by the infinite micro-areas forming the bell-jar type electric arcs present the characteristics of an annular M-shaped heat source, wherein the heat in the central area of the M-shaped heat source is used for melting the welding wires, and the electric arcs of the M-shaped heat source close to the edge position are used for preheating the welding wires, so that the melting efficiency of the welding wires is improved, and the control of the liquid metal after the welding wires are melted to enter a liquid molten pool in a liquid bridge mode is very beneficial.
11. When the liquid drop at the tail end of the welding wire contacts with the workpiece during welding, the potential of the welding wire is the same as that of the workpiece, the welding arc can be gradually transferred from the workpiece to the inner hole of the tungsten electrode, and the heat of the TIG arc is basically used for preheating the welding wire, so that the welding wire deposition efficiency is greatly improved.
Description of the drawings:
FIG. 1 is a schematic structural view of a hollow tungsten electrode coaxial wire filling and wire filling welding device;
in the figure: 1. a hollow tungsten electrode; 2. a tungsten electrode clamp; 3. a protective gas hood; 4. welding wires; 5. an insulating porcelain tube; 6. welding an electric arc; 7. melting the droplets; 8. welding the layers; 9. a sample; 10. a conductive block; 11. an ion gas inlet; 12. a plasma buffer filtering air chamber; 13. a porous dielectric material; 14. an ion gas filter screen; 15. an ion gas channel;
FIG. 2 is a schematic view of a stepped hollow tungsten electrode;
in the figure: 16. A hollow tungsten electrode step; 17. chamfering the inner hole of the hollow tungsten electrode; 18. a hollow tungsten arc emission plane; 19. chamfering the outer side surface of the hollow tungsten electrode;
FIG. 3 is a schematic end view of a conventional annular hollow tungsten electrode;
in the figure: d1 is the inner hole diameter of the hollow tungsten electrode arc emission end; d2 is the diameter of the outer edge of the inner hole chamfer of the core tungsten electrode; d3 is the diameter of the outer edge of the emission plane of the core tungsten electrode arc; d4 is the diameter of the hollow tungsten electrode;
FIG. 4 is a schematic end view of petaloid tungsten electrodes;
FIG. 5 is an arc state diagram of a hollow tungsten electrode and its electron emission end;
in the figure: 20. a hollow tungsten electrode inner hole; 21. an arc irradiation zone; 22. a bell mouth.
The specific implementation mode is as follows:
example 1:
a hollow tungsten electrode coaxial filler wire welding device comprises a hollow tungsten electrode 1, a tungsten electrode clamp 2, a protective gas hood 3, a welding wire 4, an insulating ceramic tube 5 and a plasma buffering and filtering gas chamber 12;
the hollow tungsten electrode is clamped by symmetrically arranged tungsten electrode clamps, the protective gas hood is positioned outside the tungsten electrode clamps, and the upper end of the hollow tungsten electrode is fixed with the plasma buffering and filtering gas chamber;
the hollow tungsten electrode is internally provided with a step, the insulating ceramic tube is inserted into the step of the hollow tungsten electrode, the welding wire is inserted into the insulating ceramic tube, and an ion gas channel 15 is formed in a gap between the welding wire and the hollow tungsten electrode;
the gas passes through the ion gas channel and the porous material in the ion gas buffer chamber to control the uniformity of the gas flow, and then the ion gas passes through the porous ion gas filter and the net to make the gas flow stably enter the ion gas channel in a laminar flow mode;
the ion gas channel is arranged together with the ceramic tube, a gas cabin capable of stabilizing the gas flow state is arranged in the ion gas channel, and the ion gas is introduced into the hollow tungsten electrode through two gas inlet pipelines, so that the effective protection of a welding wire and a high-temperature liquid molten pool is realized, the problems of oxidation and the like of a welding line are prevented, and the reliability of a welding layer in the service process is influenced;
the welding wire 4 is stably fed at a certain wire feeding speed by a wire feeder, the welding wire is fed out through an inner hole of the porcelain tube 5, and the welding wire 4 can be a solid welding wire or a stranded welding wire;
the insulating ceramic tube is made of high-melting-point boron nitride material, when the insulating ceramic tube is arranged inside the hollow tungsten electrode, the step of the arc burning end of the hollow tungsten electrode is utilized for carrying out installation position restraint, the outer diameter size of the ceramic tube is slightly smaller than the inner hole size of the hollow tungsten electrode, the difference between the outer diameter size and the inner hole size is 0.05-0.15 mm, the distance between the tail end of the insulating ceramic tube and the electron emission end of the tungsten electrode is 12-15 mm, the melting point of the material is up to 3000 ℃, and the resistivity can reach 4.5 multiplied by 10 when the temperature is 14943Omega cm, the thermal conductivity is more excellent in ceramics is 41.8W (m.k)-1Maximum working temperature up to 2800 ℃ in an inert atmosphere;
an ion gas filter screen 14 is fixed in the plasma buffering and filtering air chamber, and a closed space formed by the ion gas filter screen and the ion gas buffering air chamber is filled with a porous medium material 13.
Example 2:
according to the hollow tungsten electrode coaxial filler wire welding device in embodiment 1, the bottom of the hollow tungsten electrode is a bell mouth, the end surface of the hollow tungsten electrode is annular, the hollow tungsten electrode is cut along the radial direction, and the hollow tungsten electrode is equally divided into a plurality of arc emission points and is in a stepped petal shape.
The shape of the electron emission end of the hollow tungsten electrode comprises three parts: firstly, a horn mouth shape with a certain angle is processed in an inner hole of a hollow tungsten electrode electron emission end with the outer diameter of D1 and the inner hole diameter of D4, the inner surface of the horn mouth is called as an inner side wall, and the diameter of the inner side wall is D2; processing an inclined plane with a certain chamfer on the outer diameter of the electron emission end of the hollow tungsten electrode, wherein a torus formed by the inclined plane is called as an outer side wall; and thirdly, the unprocessed end surface of the electron emission end is used for emitting electrons, the end surface is called a tungsten electrode electron emission end plane, the tungsten electrode electron emission end plane is called an end plane for short, and the radial width of the tungsten electrode electron emission end plane is calculated by the following formula:
the method for regulating and controlling the space temperature gradient of the arc column region is realized by changing the diameter D2 of the inner side wall of the bell mouth of the electron emission end and the diameter D3 of the outer side wall of the electron emission end, and the purpose of changing the diameter D2 of the inner side wall of the bell mouth is to change the distance between the edge position of the inner side of an arc and a welding wire, namely to regulate the shape of an arc irradiation region, thereby achieving the purpose of accurately regulating and controlling the degree of preheating the welding wire by the arc and the position of melting a fuse by the; the purpose of changing the diameter D3 of the outer side wall of the electron emission end is to change the width w of the electron emission end, so as to effectively control the width of the welding layer and the arc stability in the welding process.
Example 3:
according to the hollow tungsten electrode coaxial filler wire welding device in the embodiment 1 or 2, the step of the step hole processing in the step-shaped petal hollow tungsten electrode is 10-20 mm above the tail end of the hollow tungsten electrode.
Example 4:
the welding device for the hollow tungsten electrode coaxial filler wire according to embodiment 1, 2 or 3, wherein the petal-shaped hollow tungsten electrode generally has 2 to 8 petals.
Example 5:
according to the hollow tungsten electrode coaxial filler wire welding device in the embodiment 1, 2, 3 or 4, the width of the ion gas channel is 0.2-03 mm.
Example 6:
the hollow tungsten electrode coaxial filler wire welding device according to embodiment 1 or 2 or 3 or 4 or 5, wherein the porous medium material is a sponge material.
The installation method comprises the following steps: fixing an annular or petal-shaped hollow tungsten electrode with a step shape in a TIG welding gun for coaxial wire feeding of the hollow tungsten electrode through a tungsten electrode clamp, setting the distance between the end surface of the tungsten electrode and a workpiece to be 3-10 mm, and slowly placing a porcelain tube into the hollow tungsten electrode through one side of the hollow tungsten electrode without a step hole until the end surface of the porcelain tube is contacted with the step surface of an inner hole of the tungsten electrode. Then, an ion gas buffer air chamber is fixed at the end part of the porcelain tube in an interference fit mode, during welding, ion gas enters the ion gas buffer air chamber through a gas inlet, flows through a porous medium material and then enters an ion gas channel formed by the porcelain tube, a tungsten electrode and a welding wire through an ion gas filter screen, and enters a welding wire and an arc irradiation area to play a good role in protecting a high-temperature area and a liquid molten pool of the welding wire.
The petaloid hollow tungsten electrode with the ladder has the general ladder width of 0.15-0.25 mm, and in order to prevent the damage of the high-temperature electric arc and the heat conduction of the tungsten electrode at the electric arc emission end to the porcelain tube, the distance between the position of the ladder and the end face of the tungsten electrode at the electric arc emission end is 12-15 mm;
the ion gas comprises common argon, helium, hydrogen, oxygen, nitrogen and mixed gas obtained by mixing the different gases according to a certain proportion; the flow of the ionic gas can be set according to actual requirements, and is generally set to be 10-2000 mL;
the ion gas filter screen is made of copper alloy, and the mesh number of the copper screen is 100-200 meshes; the ion gas channel consists of two parts: the front section of the welding wire is composed of a porcelain tube inner wall and a welding wire, the rear end of the welding wire is composed of a tungsten electrode inner wall and a welding wire, and the size of the gap is generally set to be 0.2-0.3 mm in order to guarantee straightness and wire feeding uniformity when the welding wire is fed out.
During actual welding, if the welding current is large, the straightness of the electric arc is good, the ionic gas flow can be properly increased, so that the protection effect is improved, the uniform transition of molten liquid drops at the tail end of the welding wire is promoted, and meanwhile, a large amount of heat can be taken away by the large ionic gas flow, and the effect of a high-temperature tungsten electrode in a cold area is achieved.
When the welding current is larger or a high-frequency pulse arc form is adopted, the straightness of the arc is better, at the moment, in order to prevent the burning loss of the high-temperature arc to the tungsten electrode and cause the phenomenon that a welding seam clamps tungsten, the size w of the arc emission plane 18 can be properly increased, and in order to increase the value of w, the chamfer diameter D2 of the outer side surface of the tungsten electrode can be properly reduced, or the outer edge diameter D3 of the arc emission plane of the hollow tungsten electrode can be properly increased.
Example 7:
a regulation and control method of a hollow tungsten electrode coaxial filler wire welding device specifically comprises the following steps:
(1) the shape of the hollow tungsten electrode electron emission end is prefabricated, a bell mouth shape is processed on an inner hole of the hollow tungsten electrode electron emission end with the outer diameter of D1 and the inner hole diameter of D4, the inner surface of the bell mouth is called as an inner side wall, and the diameter of the inner side wall is D2; processing an inclined plane on the outer diameter of the electron emission end of the hollow tungsten electrode, wherein a torus formed by the inclined plane is called as an outer side wall; the unprocessed end face of the electron emission end is used for emitting electrons, the end face is called a tungsten electrode electron emission end plane, the end plane is called an end plane for short, and the radial width of the end plane is calculated by the following formula:
(2) regulating and controlling the space temperature gradient of the arc column region;
the diameter D2 of the inner side wall of the bell mouth is used for changing the position of the inner edge of the arc and the distance between the welding wires, the shape of the arc irradiation area is adjusted, and the diameter D3 of the outer side wall of the electron emission end is changed to change the width w of the electron emission end;
(3) effective control of arc stability;
based on the electron tip emission principle, the smaller the w value is, the better the stability of the electric arc is, and the larger the current is, the larger the burning loss degree of the tungsten electrode is;
(4) controlling the positions of the electric arc preheating welding wire and the melting welding wire;
when the welding current is constant, the size of the diameter D2 value of the inner side wall of the horn mouth is changed, so that the accurate control of the distribution characteristics of the space form of the arc column area in the feeding process of the welding wire is realized;
(5) accurately controlling the distribution characteristics of the spatial form of the arc column region;
when the welding current is not changed, the position of the electron emission end is changed by changing the value D2, so that the distance between the welding wire and the arc is regulated and controlled, the larger the value D2 is, the farther the position of the inner edge of the arc is away from the welding wire, the irradiation effect on the welding wire is weakened, the preheating effect of the arc on the welding wire is reduced, and otherwise, the preheating effect of the arc on the welding wire is enhanced;
and adjusting the distance between the electron emission plane of the tungsten electrode and the test plate, namely the distance between the hollow tungsten electrode and the workpiece, and controlling the distance between the position where the welding wire starts to melt and the test plate.
Example 8:
a welding method of a hollow tungsten electrode coaxial filler wire welding device takes Q235 carbon steel as a base material, adopts 308L welding wire stainless steel welding wire with the diameter of 1.2 mm, and performs a hollow tungsten electrode coaxial filler wire surface welding experiment on a carbon steel sample with the diameter of 300 multiplied by 200 multiplied by 20mm, and the specific implementation steps are as follows:
step 1: cleaning up pollutants at an electron emission end of a tungsten electrode by using a tungsten electrode sample preparation tool, presetting the electron emission end of a hollow tungsten electrode with the outer diameter D4 of 6mm and the inner hole diameter D1 of 3mm into a specific bell mouth shape, controlling the diameter D2 of the bell mouth to be between 3.5 and 3.6mm and the diameter D3 of the outer side wall to be between 5.0 and 5.1mm, mounting the processed hollow tungsten electrode on a welding gun by using a tungsten electrode clamp, wherein the electron emission end of the tungsten electrode needs to extend out of a protective gas cover, and the vertical distance between the electron emission end of the gap tungsten electrode and the tail end of the protective gas cover is kept between 8 and 10 mm;
step 2: carrying out decontamination treatment on a welding area on the surface of a carbon steel sample with the size of 300 multiplied by 200 multiplied by 20mm and an area 15mm near the welding area by using a mechanical cleaning or chemical cleaning method;
and step 3: finely adjusting the posture of a welding gun, ensuring that the central axis of a tungsten electrode is vertical to the surface of a welding sample, and simultaneously adjusting the distance between the welding gun and a workpiece to set the distance between an electron emission end of the tungsten electrode and the workpiece to be 3-6 mm;
and 4, step 4: the cooling water, the shielding gas, the wire feeding device, the welding travelling mechanism and the welding power supply are checked and confirmed to be in a normal working state in sequence, and the flow of the shielding gas, the wire feeding speed, the welding arc mode (continuous and pulse), the welding current and the welding speed are set according to welding parameters, wherein the welding mode is set to be a continuous welding mode, the welding current is set to be 400-600A, the wire feeding speed is set to be 3-4 m/min, the flow of the shielding gas is set to be 18-20L/min, the flow of the ion gas is set to be 10mL/min, the welding speed is set to be 0.3m/min, the starting welding current is controlled to be 450-650A, the arc starting time is set to be 0.2-0.5 s, the arc stopping current is set to be 250-300A, and.
And 5: and pressing a start button to realize the preparation of the hollow tungsten electrode coaxial wire filling welding layer of the workpiece to be welded at a high wire feeding speed.
The different stages in the welding wire feeding process are divided into three stages according to the different heating modes of the welding wire in the feeding process: firstly, before a welding wire is sent out of a hollow tungsten electrode inner hole, the heat radiation effect of the high-temperature tungsten electrode inner hole can preheat the welding wire to a certain extent; secondly, the welding wire firstly enters the arc irradiation area 15 just before being sent out of the inner hole of the tungsten electrode and enters the arc area, and the heat radiation effect can further play a good preheating role on the welding wire in the area formed by surrounding the edge position of the high-temperature annular arc; and finally, when the tail end of the welding wire preheated to a higher temperature enters the arc column area, the welding wire immediately reaches a melting point and starts to be stably melted to form liquid metal.
Precise control of the spatial morphological distribution characteristics of the arc column region is achieved as follows. When the welding current is not changed, the fact that the position of the electron emission end is changed by changing the D2 value, the distance between the welding wire and the arc is further regulated, the larger the D2 value is, the farther the position of the inner edge of the arc is away from the welding wire, the irradiation effect on the welding wire is weakened, the preheating effect of the arc on the welding wire is reduced, and otherwise, the preheating effect of the arc on the welding wire is enhanced. Meanwhile, the distance between the electron emission plane of the tungsten electrode and the test plate, namely the distance (generally 3-6 mm) between the hollow tungsten electrode and the workpiece, is adjusted, the highest point of the center position of the electric arc is controlled to be 1.0-2.5 mm above the plate surface, namely the position where the welding wire starts to melt is controlled to be 1.0-2.5 mm away from the test plate, and the method is very favorable for the welding wire melting process of liquid bridge transition.
The method is characterized in that the highest point of the center position of the electric arc is controlled to be 1.0-2.5 mm above the plate surface, the liquid metal formed after the welding wire is melted enters the molten pool in a liquid bridge transition mode, the welding wire starts to melt to form liquid drops after the tail end of the welding wire which is preheated to a certain temperature contacts the highest point of the center position of the upper electric arc, the diameter of the liquid drops under the action of surface tension, gravity and the like is about 1.3mm, and the proper position of the highest point position of the center of the electric arc is controlled according to different wire feeding speeds, so that the molten liquid drops at the tail end of the welding wire can accurately enter the molten pool in the liquid bridge transition mode.
The liquid metal formed after the welding wire is melted enters the molten pool in a liquid bridge transition mode, that is, the liquid metal formed after the high-temperature welding wire enters the high-temperature arc column area and is melted can be contacted with the surface of the liquid molten pool before dropping into the molten pool in a drop shape, and under the action of the surface tension of the liquid metal, the liquid metal stably transits into the molten pool to finish the material filling process
The width of a welding layer prepared by the method is 14-20 mm, the melting depth of a matrix is only 0.8-1.0 mm, the dilution rate of the matrix to deposited metal is extremely low, the wire feeding speed in the method is 2-4 times that in the conventional tungsten electrode argon arc filler wire welding, and the welding speed is 1.5-2 times that in the conventional similar welding method.
Example 9:
the method is characterized in that TC4 titanium alloy is used as a base material, a TC4 welding wire with the same material diameter of 1..2mm is used for carrying out a hollow tungsten electrode coaxial filler wire welding experiment on a titanium alloy sample with the diameter of 200 x 150 x 3mm, and the specific implementation steps are as follows:
step 1: cleaning up pollutants at an electron emission end of a tungsten electrode by using a tungsten electrode sample preparation tool, presetting the electron emission end of a hollow tungsten electrode with the outer diameter D4 of 6mm and the inner hole diameter D1 of 3mm into a specific bell mouth shape, controlling the diameter D2 of the bell mouth to be between 3.6 and 3.7mm and the diameter D3 of the outer side wall to be between 5.2 and 5.3mm, mounting the processed hollow tungsten electrode on a welding gun by using a tungsten electrode clamp, wherein the electron emission end of the tungsten electrode needs to extend out of a protective gas cover, and the vertical distance between the electron emission end of the gap tungsten electrode and the tail end of the protective gas cover is kept between 8 and 10 mm;
step 2: carrying out decontamination treatment on the end face of a region to be welded of a titanium alloy sample of 200 multiplied by 150 multiplied by 3mm and a region 15mm near the end face by using a mechanical cleaning or chemical cleaning method, wiping the titanium alloy sample by using alcohol, and airing the titanium alloy sample for later use;
and step 3: finely adjusting the posture of a welding gun, ensuring that the central axis of a tungsten electrode is vertical to the surface of a welding sample, and simultaneously adjusting the distance between the welding gun and a workpiece to set the distance between an electron emission end of the tungsten electrode and the workpiece to be 4-5 mm;
and 4, step 4: the cooling water, the shielding gas, the wire feeding device, the welding travelling mechanism and the welding power supply are checked and confirmed to be in a normal working state in sequence, and the flow rate of the shielding gas, the wire feeding speed, the welding arc mode (continuous and pulse), the welding current and the welding speed are set according to welding parameters, wherein the welding mode is set to be the continuous welding mode, the welding current is set to be 450A, the wire feeding speed is set to be 4.5m/min, the flow rate of the shielding gas is set to be 18-20L/min, the flow rate of the ion gas is set to be 5mL/min, the welding speed is set to be 0.5m/min, the starting current is controlled to be 500A, the arcing time is set to be 0.5s, the arcing current is set to be 180A, the arcing time is set.
And 5: and the single-side welding and double-side forming of the coaxial wire filling of the titanium alloy hollow tungsten electrode with the thickness of 3mm are realized by pressing a start button. The titanium alloy welded by the method has uniform and consistent surface formation, compared with the conventional solid argon tungsten-arc welding, the method has the advantages that the welding efficiency is improved by 1.3-2 times, the surfaces of welding seams are silvery white and have no yellow or blue oxidation colors, and the mechanical property of welding joints also reaches 96% of that of a base metal.
Claims (8)
1. The utility model provides a coaxial filler wire welding set of hollow tungsten utmost point which characterized by: the hollow tungsten electrode coaxial filler wire welding device comprises a hollow tungsten electrode, a tungsten electrode clamp, a protective gas hood, a welding wire, an insulating ceramic tube and a plasma buffer filtering gas chamber;
the hollow tungsten electrode is clamped by symmetrically arranged tungsten electrode clamps, the protective gas hood is positioned outside the tungsten electrode clamps, and the upper end of the hollow tungsten electrode is fixed with the plasma buffering and filtering gas chamber;
the hollow tungsten electrode is internally provided with a step, the insulating ceramic tube is inserted into the step in the hollow tungsten electrode, the welding wire is inserted in the insulating ceramic tube, and an ion gas channel is formed in a gap between the welding wire and the hollow tungsten electrode;
the ion gas filtering net is fixed in the plasma buffering and filtering air chamber, and a closed space formed by the ion gas filtering net and the ion gas buffering air chamber is filled with a porous medium material.
2. The hollow tungsten electrode coaxial filler wire welding device according to claim 1, characterized in that: the bottom of the hollow tungsten electrode is a horn mouth, the end surface of the hollow tungsten electrode is circular, the hollow tungsten electrode is cut along the radial direction and is equally divided into a plurality of electric arc emission points and is provided with a stepped petal-shaped hollow tungsten electrode.
3. The hollow tungsten electrode coaxial filler wire welding device according to claim 2, characterized in that: the step for processing the stepped hole in the hollow tungsten electrode with the stepped petals is located 10-20 mm above the tail end of the hollow tungsten electrode.
4. The hollow tungsten electrode coaxial filler wire welding device according to claim 3, wherein: the petal-shaped hollow tungsten electrode generally has 2-8 petals.
5. The hollow tungsten electrode coaxial filler wire welding device according to claim 4, which is characterized in that: the width of the ion gas channel is 0.2-03 mm.
6. The hollow tungsten electrode coaxial filler wire welding device according to claim 5, which is characterized in that: the porous medium material is a sponge material.
7. A method for regulating the hollow tungsten electrode coaxial filler wire welding device of any one of claims 1 to 6, which is characterized in that: the method specifically comprises the following steps:
(1) the shape of the hollow tungsten electrode electron emission end is prefabricated, a bell mouth shape is processed on an inner hole of the hollow tungsten electrode electron emission end with the outer diameter of D1 and the inner hole diameter of D4, the inner surface of the bell mouth is called as an inner side wall, and the diameter of the inner side wall is D2; processing an inclined plane on the outer diameter of the electron emission end of the hollow tungsten electrode, wherein a torus formed by the inclined plane is called as an outer side wall; the unprocessed end face of the electron emission end is used for emitting electrons, the end face is called a tungsten electrode electron emission end plane, the end plane is called an end plane for short, and the radial width of the end plane is calculated by the following formula:
(2) regulating and controlling the space temperature gradient of the arc column region;
the diameter D2 of the inner side wall of the bell mouth is used for changing the position of the inner edge of the arc and the distance between the welding wires, the shape of the arc irradiation area is adjusted, and the diameter D3 of the outer side wall of the electron emission end is changed to change the width w of the electron emission end;
(3) effective control of arc stability;
based on the electron tip emission principle, the smaller the w value is, the better the stability of the electric arc is, and the larger the current is, the larger the burning loss degree of the tungsten electrode is;
(4) controlling the positions of the electric arc preheating welding wire and the melting welding wire;
when the welding current is constant, the size of the diameter D2 value of the inner side wall of the horn mouth is changed, so that the accurate control of the distribution characteristics of the space form of the arc column area in the feeding process of the welding wire is realized;
(5) accurately controlling the distribution characteristics of the spatial form of the arc column region;
when the welding current is not changed, the position of the electron emission end is changed by changing the value D2, so that the distance between the welding wire and the arc is regulated and controlled, the larger the value D2 is, the farther the position of the inner edge of the arc is away from the welding wire, the irradiation effect on the welding wire is weakened, the preheating effect of the arc on the welding wire is reduced, and otherwise, the preheating effect of the arc on the welding wire is enhanced;
and adjusting the distance between the electron emission plane of the tungsten electrode and the test plate, namely the distance between the hollow tungsten electrode and the workpiece, and controlling the distance between the position where the welding wire starts to melt and the test plate.
8. A welding method of the hollow tungsten electrode coaxial filler wire welding device of one of the claims 1 to 6, which is characterized in that: the method comprises the following steps:
(1) cleaning pollutants at an electron emission end of a tungsten electrode by using a tungsten electrode sample preparation tool, then installing the tungsten electrode sample preparation tool on a welding gun, extending the electron emission end of the tungsten electrode out of a protective gas hood, and controlling the distance between the tail ends of the tungsten electrode sample preparation tool and the protective gas hood to be 8-10 mm;
(2) carrying out decontamination treatment on a welding area on the surface of the workpiece and an area 15mm near the welding area by using a mechanical cleaning or chemical cleaning method;
(3) finely adjusting the posture of a welding gun, ensuring that the central axis of a tungsten electrode is vertical to the surface of a welding sample, and simultaneously adjusting the distance between the welding gun and a workpiece;
(4) checking and confirming that the cooling water, the shielding gas, the ion gas, the wire feeding device, the welding travelling mechanism and the welding power supply are in normal working states in sequence, and setting the flow of the shielding gas, the wire feeding speed, the welding arc mode, the welding current and the welding speed according to welding parameters;
(5) and pressing a start button to realize the preparation of the hollow tungsten electrode coaxial wire filling welding layer of the workpiece to be welded at a high wire feeding speed.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113210837A (en) * | 2021-06-10 | 2021-08-06 | 四川航天长征装备制造有限公司 | Double-speed double-shaft-shoulder internal material supplementing type friction stir welding device |
| CN113319404A (en) * | 2021-06-18 | 2021-08-31 | 哈尔滨焊接研究院有限公司 | Hollow tungsten argon arc welding method for nickel-saving austenitic stainless steel |
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| CN115815759A (en) * | 2023-02-06 | 2023-03-21 | 苏州友得利金属制品有限公司 | Hollow tungsten electrode coaxial wire feeding argon arc welding device and welding gun and welding method thereof |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113210837A (en) * | 2021-06-10 | 2021-08-06 | 四川航天长征装备制造有限公司 | Double-speed double-shaft-shoulder internal material supplementing type friction stir welding device |
| CN113319404A (en) * | 2021-06-18 | 2021-08-31 | 哈尔滨焊接研究院有限公司 | Hollow tungsten argon arc welding method for nickel-saving austenitic stainless steel |
| CN113560720A (en) * | 2021-06-18 | 2021-10-29 | 上海宝钢阿赛洛激光拼焊有限公司 | Split welding method of vehicle aluminum-silicon plated steel plate based on split high-order laser beam |
| CN113560720B (en) * | 2021-06-18 | 2023-02-10 | 上海宝钢阿赛洛激光拼焊有限公司 | Split welding method of vehicle aluminum-silicon plated steel plate based on split high-order laser beam |
| CN115815759A (en) * | 2023-02-06 | 2023-03-21 | 苏州友得利金属制品有限公司 | Hollow tungsten electrode coaxial wire feeding argon arc welding device and welding gun and welding method thereof |
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