CN109226918B - Pulse coordination control-based arc brazing device and method for plasma shunt consumable electrode of titanium/steel dissimilar metal - Google Patents

Abstract

The invention discloses a device and a method for arc brazing of a titanium/steel dissimilar metal plasma shunt consumable electrode based on pulse coordination control, and the device comprises a main welding power supply 1, a shunt power supply 8, a pulse coordination controller 13, a rear-dragging protective gas hood 2, a plasma shunt consumable electrode welding gun 21, a wire feeding mechanism 6, a current sensor 19 and the like. In the welding process, a pulse coordination control method is adopted, namely when the main circuit current is a basic value, the shunt current is also the basic value, so that the stability of the coupling arc in the welding process can be ensured; when the main current is a peak value, the shunt current is also a peak value, so that lower workpiece heat input during welding can be ensured, and a stable and reliable welding process is realized. In the welding process, a back-dragging protective gas hood is used for protecting the brazing seam, so that the problems of oxidation, nitridation and the like in the high-temperature cooling process of the brazing seam are solved.

Description

Pulse coordination control-based arc brazing device and method for plasma shunt consumable electrode of titanium/steel dissimilar metal

Technical Field

The invention relates to the technical field of dissimilar metal arc welding and brazing, in particular to a device and a method for plasma shunting consumable electrode arc brazing of titanium/steel dissimilar metals based on pulse coordination control.

Background

Titanium has high specific strength and specific rigidity, good heat resistance to bear high temperature and good corrosion resistance, and is widely applied to the fields of naval vessels, aviation, aerospace, petrochemical industry and the like. However, the titanium alloy has high cost and poor processability, which limits the further popularization and application of the titanium alloy in the industrial field. The steel is the most widely used metal material in industrial production, and has the advantages of low cost, high mechanical strength, good toughness, excellent processing performance and the like. In consideration of weight reduction, cost reduction and special use performance, the titanium and the steel are made the best use of things, the advantages are complemented, and the balance between the use performance and the economic benefit of the material is achieved, so that the titanium/steel composite structure has great application potential in the industrial field. However, due to the great difference between the thermophysical properties of titanium and steel, the welding between the titanium and the steel has great difficulty, and further production and application are greatly limited.

Patent No. CN101664852A proposes a method for welding titanium and titanium steel composite plates, wherein a brazing mode of 99.95% silver wires is adopted for welding a titanium material and a steel plate, and an argon arc welding arc is adopted as a heat source. The method can realize the welding of titanium and steel in the atmospheric environment, and the welded welding joint can bear 1MPa of air pressure, but the method still has the following limitations: 99.95% of silver wire solder can cause huge welding cost and is not beneficial to the actual economic requirement of production; the heat affected zone generated by the argon arc welding process is large, and the problem of serious deformation can be generated after welding; only the molten pool protection in the welding process is adopted, and the problems of oxidation and nitridation of the welded titanium and the soldered joint are easy to occur in the cooling process.

Aiming at the limitations of the titanium/steel dissimilar metal welding method, the invention provides a titanium/steel dissimilar metal plasma shunt consumable electrode arc brazing device and method based on pulse coordination control. Meanwhile, silicon bronze is used as the brazing filler metal, and the wettability of the copper-based brazing filler metal on a workpiece can be improved by adding silicon, so that high cost caused by the adoption of the silver-based brazing filler metal is avoided. The plasma shunt consumable electrode arc brazing has the advantages of low heat input of plasma shunt, high energy density of electric arc, high melting efficiency of brazing filler metal, stable welding process and the like, can realize efficient heating of the filled brazing filler metal, and can ensure stable brazing process and good welding seam quality. Meanwhile, the heat input of the workpiece can be further reduced by utilizing a main pulse coordination control method and a bypass pulse coordination control method, namely when the main current is a basic value, the shunt current is also the basic value, and the stability of the coupling arc in the welding process can be ensured; when the main current is the peak value, the shunt current is also the peak value, so that the lower heat input of the workpiece during welding can be ensured, and the stable and reliable titanium/steel dissimilar metal brazing process is realized. The pulse coordination control method is adopted by the main arc and the bypass arc, so that the heat input in the welding process can be well controlled, the molten drop transition mode in the welding process can be effectively controlled, the weld forming can be improved, and a high-quality titanium/steel braze welding joint can be obtained. In addition, the adoption of the mode of a back-dragging protective gas hood can prevent the oxidation and the nitridation of the titanium alloy and the brazing filler metal during the brazing, and further improve the quality of a brazing seam.

Disclosure of Invention

The invention aims to provide a device and a method for arc brazing of a titanium/steel dissimilar metal plasma shunt consumable electrode based on pulse coordination control.

A titanium/steel dissimilar metal plasma shunting consumable electrode arc brazing device based on pulse coordination control is composed of a main circuit power supply 1, a rear dragging shielding gas hood 2, a water-cooling copper bush 3, an insulating porcelain bush 4, a conductive nozzle 5, a wire feeding mechanism 6, a brazing filler metal welding wire 7, a shunting power supply 8, a plasma nozzle 9, a shielding gas hood 10, a titanium plate 11, a steel plate 12, a pulse signal processor 13, a signal controller 14, a pulse coordination control system 15, a current sensor 19 and a plasma shunting consumable electrode welding gun 21; in the welding process, the positive pole of the main circuit power supply 1 is connected with the solder wire 7, and the negative pole is connected with a workpiece; the positive pole of the shunt power supply 8 is connected with the solder welding wire 7, the negative pole is connected with the water-cooling copper sleeve 3, and a shunt loop is formed after the connection with the plasma nozzle 8 through the plasma arc 16; the MIG electric arc 18 and the plasma electric arc 16 are coupled into a composite electric arc 17 in the welding process; the pulse coordination control system 15 comprises a pulse signal processor 13 and a signal controller 14, wherein the pulse signal processor 13 detects a main path current pulse signal of the current sensor 19, and when the main path current is detected to be at a pulse base value, the pulse signal controller 14 is triggered to adjust the bypass current to be the pulse base value, so that the stability of the coupling arc in the welding process can be ensured; when the main current pulse is detected to be at the peak value, the trigger pulse signal controller 14 adjusts the bypass current pulse to be at the peak value, so that lower workpiece heat input during welding can be ensured; in the welding process, the back-dragging protective gas hood 2 is used for protecting the brazing seam 20 and avoiding the oxidation and nitridation phenomena of the brazing seam 20;

a titanium/steel dissimilar metal plasma shunt consumable electrode arc brazing method based on pulse coordination control is characterized by comprising the following steps:

the method comprises the following steps: in order to effectively promote the wettability of the copper brazing filler metal welding wire 7 on the titanium plate 11 and the steel plate 12, a part to be welded of a workpiece is processed into a V-shaped or Y-shaped groove, the surface and two sides of the groove are respectively polished and cleaned by sand paper and acetone, and oil stains and an oxidation film on the surface of the workpiece are removed;

step two: before welding, the titanium plate 11 and the steel plate 12 are placed on a welding workbench, a gap of 0.5-5mm is reserved between the titanium plate 11 and the steel plate 12, a forming groove is installed on the back of a workpiece according to requirements, the position of a plasma shunt consumable electrode welding gun 21 is adjusted, the axis of the welding gun is kept vertical to the workpiece, and the height of a plasma nozzle 9 from the workpiece is 5-15 mm;

step three: during welding, the main/side pulse frequency is set to be consistent, when the main circuit current is at a pulse basic value, the pulse signal controller 14 is triggered to adjust the side current pulse to be a basic value pilot arc, and when the main circuit current is at a pulse peak value, the side current is also at a pulse peak value;

step four: setting welding process parameters according to actual conditions, wherein the main circuit peak current is 100-500A, the main circuit base value current is 10-100A, the bypass base value current is 5-50A, the shunt peak current is 50-300A, the pulse frequency is 2-500Hz, the gap between the titanium plate and the steel plate is 0.5-5mm, the welding speed is 30-300cm/min, the height of a plasma nozzle is 5-15mm, the plasma gas flow is 0.5-2.0L/min, and the protective gas flow is 10-25L/min;

step five: after welding, the protective gas is pulled after the welding is closed at intervals, so that the brazing seam is fully protected in the cooling process, and the welding seam forming with attractive appearance, stability and reliability is obtained.

The invention has the beneficial effects that:

1. by adopting the plasma shunting consumable electrode arc brazing method, the advantages of low heat input of plasma arc shunting, high shrinkage characteristic of plasma arc, high brazing filler metal melting efficiency, stable welding process and the like can be utilized, so that the high-efficiency heating of the filled brazing filler metal can be realized, and the stable brazing process and good welding seam quality can be ensured.

2. The pulse coordination control method is adopted, namely the main current and the side current are pulse basic values or pulse peak values at the same time, so that the stability of the composite electric arc can be ensured, the droplet transition mode in the welding process is effectively controlled, the workpiece is ensured to be in a lower heat input state during welding, the weld forming can be improved, and a high-quality titanium/steel braze welding joint can be obtained.

3. In the welding process, a back-dragging protective gas cover is clamped at the back of a welding gun, so that the oxidation and the nitridation of metal in the cooling process after welding can be avoided, the formation of a welding line is improved, and the mechanical property of a joint is improved.

4. In the welding process, the workpiece is connected with the negative electrode of a power supply, the cathode cleaning function of the electric arc can clean an oxide film on the surface of the titanium alloy, and meanwhile, the coupling characteristic of the plasma arc and the consumable electrode composite electric arc can refine weld grains and further improve the weld quality.

5. The method is simple and convenient to operate, special vacuum environment is not needed, the arc brazing of the titanium/steel dissimilar metal can be realized under the atmospheric condition, and the titanium/steel brazed joint with attractive appearance and high quality can be obtained.

6. The process method has strong adaptability, is not only suitable for the brazing of titanium/steel dissimilar metals, but also suitable for the brazing of titanium/aluminum, steel/aluminum, magnesium/aluminum and other dissimilar metal materials through simple adjustment, and is a low-cost, high-efficiency and high-quality arc brazing method.

Drawings

FIG. 1 is a schematic diagram of a plasma shunt consumable electrode arc brazing device for a titanium/steel butt joint based on pulse coordination control;

FIG. 2 is a schematic diagram of the coordination of the main and bypass pulse currents;

FIG. 3 is a macroscopic view of a titanium/steel butt joint;

FIG. 4 is a titanium/steel lap joint macro topography.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Example 1:

aiming at the problems of easy formation of brittle intermetallic compounds, poor joint performance, high cost, complex equipment, poor stability and the like in titanium/steel welding, the arc brazing device and method for the plasma shunt consumable electrode of the dissimilar metal titanium/steel based on pulse coordination control are provided.

The invention relates to a pulse coordination control-based arc brazing method for a plasma shunt consumable electrode of titanium/steel dissimilar metal, which comprises a main welding power supply, a shunt power supply, a pulse coordination controller, a rear-trailing protective gas hood, a plasma shunt consumable electrode welding gun, a wire feeding mechanism, a current sensor and the like. In the welding process, a pulse coordination control method is adopted, namely when the main circuit current is a basic value, the shunt current is also the basic value, so that the stability of the coupling arc in the welding process can be ensured; when the main current is a peak value, the shunt current is also a peak value, so that lower workpiece heat input during welding can be ensured, and a stable and reliable welding process is realized. In the welding process, a back-dragging protective gas hood is used for protecting the brazing seam, so that the problems of oxidation, nitridation and the like in the high-temperature cooling process of the brazing seam are solved. The welding method implemented by the device comprises the following steps:

step 1: processing the parts to be welded of the titanium plate and the steel plate into a V-shaped or Y-shaped groove, respectively polishing and cleaning the surface and two sides of the workpiece by using sand paper and acetone, and removing oil stains and oxidation films on the surface of the workpiece.

Step 2: before welding, whether the line connection mode is correct or not is checked, the on-off state of the shielding gas and the power supply is checked, the titanium/steel component to be welded is placed on a workbench, the position gap between the titanium and the steel is adjusted, the position of a plasma shunt consumable electrode welding gun is adjusted, and the axis of the welding gun is kept perpendicular to the workpiece.

And step 3: in the welding process, a pulse coordination control method is adopted, namely when the main circuit current is in a pulse base value pilot arc, a pulse signal controller is triggered to enable the shunt current to be in the pulse base value; when the main circuit current is at the pulse peak value, the shunt current is also at the pulse peak value.

And 4, step 4: setting welding process parameters according to actual conditions, wherein the main circuit peak current is 100-500A, the main circuit base value current is 10-100A, the bypass base value current is 5-50A, the bypass peak current is 50-300A, the pulse frequency is 2-500Hz, the welding speed is 30-300cm/min, the height of a plasma nozzle is 5-15mm, the plasma gas flow is 0.5-2.0L/min, and the protective gas flow is 10-25L/min.

Example 2:

referring to fig. 1, the arc brazing method is an implementation mode of plasma shunt consumable electrode arc brazing of a titanium/steel butt joint based on pulse coordination control, and the implementation mode comprises a main circuit power supply 1, a rear-trailing protective gas hood 2, a water-cooling copper bush 3, an insulating porcelain bushing 4, a conductive nozzle 5, a wire feeding mechanism 6, a brazing filler metal welding wire 7, a shunt power supply 8, a plasma nozzle 9, a protective gas hood 10, a titanium plate 11, a steel plate 12, a pulse signal processor 13, a signal controller 14, a pulse coordination control system 15, a current sensor 19, a plasma shunt consumable electrode welding gun 21 and the like. In the welding process, the positive pole of the main circuit power supply 1 is connected with the solder wire 7, and the negative pole is connected with a workpiece; the positive pole of the shunt power supply 8 is connected with the solder welding wire 7, the negative pole is connected with the water-cooling copper sleeve 3, and a shunt loop is formed after the connection with the plasma nozzle 9 through the plasma arc 16; the MIG electric arc 18 and the plasma electric arc 16 are coupled into a composite electric arc 17 in the welding process; the pulse coordination control system 15 is an important part of pulse coordination control, the pulse signal processor 13 detects a main path current pulse signal of the current sensor 19, when the main path current is detected to be at a pulse base value, the pulse signal controller 14 is triggered to adjust the bypass current to be the pulse base value, the stability of the coupled arc in the welding process can be ensured, when the main path current pulse is detected to be at a peak value, the pulse signal controller 14 is triggered to adjust the bypass current pulse to be at the peak value, the low workpiece heat input in the welding process can be ensured, and the stable and reliable titanium/steel dissimilar metal brazing process can be realized; in the welding process, the back-dragging protective gas hood 2 is used for protecting the brazing seam 20 and avoiding the oxidation and nitridation phenomena of the brazing seam 20.

The welding method for welding the titanium/steel butt joint by the pulse coordination control plasma shunt consumable electrode arc brazing based on the embodiment comprises the following steps:

step 1: in order to effectively promote the wettability of the copper brazing filler metal welding wire 7 on the titanium plate 11 and the steel plate 12, a part to be welded of a workpiece is processed into a V-shaped or Y-shaped groove, the surface and two sides of the groove are respectively polished and cleaned by sand paper and acetone, and oil stains and an oxidation film on the surface of the workpiece are removed.

Step 2: before welding, the titanium plate 11 and the steel plate 12 are placed on a welding workbench, a gap of 0.5-5mm is reserved between the titanium plate 11 and the steel plate 12, a forming groove is arranged on the back of a workpiece according to requirements, the position of a plasma shunt consumable electrode welding gun 21 is adjusted, the axis of the welding gun is kept vertical to the workpiece, and the height of a plasma nozzle 9 from the workpiece is 5-15 mm.

And step 3: during welding, the main/side pulse frequencies are set to be consistent, when the main current is at the pulse base value, the pulse signal controller 14 is triggered to adjust the side current pulse to be the base value pilot arc, when the main current is at the pulse peak value, the side current is also at the pulse peak value, and a schematic diagram of a main and side pulse current coordination mode is shown in fig. 3.

And 4, step 4: setting welding process parameters according to actual conditions, wherein the main circuit peak current is 100-500A, the main circuit base value current is 10-100A, the bypass base value current is 5-50A, the shunt peak current is 50-300A, the pulse frequency is 2-500Hz, the gap between the titanium plate and the steel plate is 0.5-5mm, the welding speed is 30-300cm/min, the height of a plasma nozzle is 5-15mm, the plasma gas flow is 0.5-2.0L/min, and the protective gas flow is 10-25L/min.

And 5: after welding, the protective gas is pulled after the welding is closed at intervals, so that the brazing seam is fully protected in the cooling process, and the welding seam forming with attractive appearance, stability and reliability is obtained.

Example 3:

referring to fig. 2, the embodiment is an embodiment of arc brazing of a titanium/steel lap joint plasma shunt consumable electrode based on pulse coordination control, and the embodiment comprises a main circuit power supply 1, a rear-trailing shield gas hood 2, a water-cooled copper bush 3, an insulating porcelain bushing 4, a conductive nozzle 5, a wire feeding mechanism 6, a brazing filler metal wire 7, a shunt power supply 8, a plasma nozzle 9, a shield gas hood 10, a titanium plate 11, a steel plate 12, a pulse signal processor 13, a signal controller 14, a pulse coordination control system 15, a current sensor 19, a plasma shunt consumable electrode welding gun 21 and the like. In the welding process, the positive pole of the main circuit power supply 1 is connected with the solder wire 7, and the negative pole is connected with a workpiece; the positive pole of the shunt power supply 8 is connected with the solder welding wire 7, the negative pole is connected with the water-cooling copper sleeve 3, and a shunt loop is formed after the connection with the plasma nozzle 8 through the plasma arc 16; the main electric arc 18 and the plasma electric arc 16 are coupled into a composite electric arc 17 in the welding process; the pulse coordination control system 15 is an important part of pulse coordination control, the pulse signal processor 13 detects a main path current pulse signal of the current sensor 19, when the main path current is detected to be at a pulse base value, the pulse signal controller 14 is triggered to adjust the bypass current to be the pulse base value, the stability of the coupled arc in the welding process can be ensured, when the main path current pulse is detected to be at a peak value, the pulse signal controller 14 is triggered to adjust the bypass current pulse to be at the peak value, the low workpiece heat input in the welding process can be ensured, and the stable and reliable titanium/steel dissimilar metal brazing process can be realized; in the welding process, the back-dragging protective gas hood 2 is used for protecting the brazing seam 20 and avoiding the oxidation and nitridation phenomena of the brazing seam 20.

The welding method for welding the titanium/steel lap joint by the pulse coordination control plasma shunt consumable electrode arc brazing based on the embodiment comprises the following steps:

step 1: in order to effectively promote the wettability of the copper brazing filler metal wire 7 on the titanium plate 11 and the steel plate 12, the portions to be welded of the workpiece are polished and cleaned with sandpaper and acetone to remove oil stains and oxidation films on the surface of the workpiece.

Step 2: before welding, the titanium plate 11 and the steel plate 12 are placed on a welding workbench, the titanium plate 11 is arranged on the upper portion, the steel plate 12 is arranged on the lower portion, a proper lap joint width is selected according to requirements, the position of a plasma shunt consumable electrode welding gun 21 is adjusted, the axis of the welding gun is kept perpendicular to a workpiece, and the height of a plasma nozzle 9 from the workpiece is 5-15 mm.

And step 3: during welding, the main/side pulse frequencies are set to be consistent, when the main current is at the pulse base value, the pulse signal controller 14 is triggered to adjust the side current pulse to be the base value pilot arc, when the main current is at the pulse peak value, the side current is also at the pulse peak value, and a schematic diagram of a main and side pulse current coordination mode is shown in fig. 3.

And 4, step 4: setting welding process parameters according to actual conditions, wherein the main circuit peak current is 100-500A, the main circuit base value current is 10-100A, the bypass base value current is 5-50A, the shunt peak current is 50-300A, the pulse frequency is 2-500Hz, the titanium plate is below the upper steel plate, the welding speed is 30-300cm/min, the height of the plasma nozzle is 5-15mm, the plasma gas flow is 0.5-2.0L/min, and the protective gas flow is 10-25L/min.

And 5: after welding, the protective gas is pulled after the welding is closed at intervals, so that the brazing seam is fully protected in the cooling process, and the welding seam forming with attractive appearance, stability and reliability is obtained.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (2)

1. A titanium/steel dissimilar metal plasma shunt consumable electrode arc brazing device based on pulse coordination control is composed of a main circuit power supply (1), a rear-dragging protective gas hood (2), a water-cooling copper sleeve (3), an insulating ceramic sleeve (4), a conductive nozzle (5), a wire feeding mechanism (6), a brazing filler metal welding wire (7), a shunt power supply (8), a plasma nozzle (9), a protective gas hood (10), a titanium plate (11), a steel plate (12), a pulse coordination control system (15), a current sensor (19) and a plasma shunt consumable electrode welding gun (21); in the welding process, the positive electrode of the main circuit power supply (1) is connected with a solder welding wire (7), and the negative electrode is connected with a workpiece; the anode of the shunting power supply (8) is connected with the brazing filler metal welding wire (7), the cathode is connected with the water-cooling copper sleeve (3), and a shunting loop is formed after the shunting power supply is connected with the plasma nozzle (9) through a plasma arc (16); the MIG electric arc (18) and the plasma electric arc (16) are coupled into a composite electric arc (17) in the welding process; the pulse coordination control system (15) comprises a pulse signal processor (13) and a signal controller (14), wherein the pulse signal processor (13) detects a main path current pulse signal of the current sensor (19), and when the main path current is detected to be at a pulse base value, the trigger signal controller (14) adjusts the bypass current to be the pulse base value, so that the stability of the coupling arc in the welding process is ensured; when the main circuit current pulse is detected to be at the peak value, the trigger signal controller (14) adjusts the bypass current pulse to be at the peak value, and low workpiece heat input during welding is ensured; in the welding process, the back-dragging protective gas hood (2) is used for protecting the brazing seam (20) and avoiding the oxidation and nitridation phenomena of the brazing seam (20).

2. A titanium/steel dissimilar metal plasma shunt consumable electrode arc brazing method based on pulse coordination control is characterized by comprising the following steps:

the method comprises the following steps: in order to effectively promote the wettability of the copper brazing filler metal welding wire (7) on a titanium plate (11) and a steel plate (12), a part to be welded of a workpiece is processed into a V-shaped or Y-shaped groove, the surface and two sides of the groove are respectively polished and cleaned by sand paper and acetone, and oil stains and an oxidation film on the surface of the workpiece are removed;

step two: before welding, a titanium plate (11) and a steel plate (12) are placed on a welding workbench, a gap of 0.5-5mm is reserved between the titanium plate (11) and the steel plate (12), a forming groove is installed on the back of a workpiece according to requirements, the position of a plasma shunt consumable electrode welding gun (21) is adjusted, the axis of the welding gun is kept vertical to the workpiece, and the height of a plasma nozzle (9) from the workpiece is 5-15 mm;

step three: during welding, the main/side pulse frequency is set to be consistent, when the main circuit current is at a pulse basic value, the trigger signal controller (14) adjusts the side current pulse to be a basic value pilot arc, and when the main circuit current is at a pulse peak value, the side current is also at the pulse peak value;

step four: setting welding process parameters according to actual conditions, wherein the main circuit peak current is 100-500A, the main circuit base value current is 10-100A, the bypass base value current is 5-50A, the shunt peak current is 50-300A, the pulse frequency is 2-500Hz, the gap between the titanium plate and the steel plate is 0.5-5mm, the welding speed is 30-300cm/min, the height of a plasma nozzle is 5-15mm, the plasma gas flow is 0.5-2.0L/min, and the protective gas flow is 10-25L/min;

step five: after welding, the protective gas is pulled after the welding is closed at intervals, so that the brazing seam is fully protected in the cooling process, and the welding seam forming with attractive appearance, stability and reliability is obtained.

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