CN108145283A - A kind of welding robot - Google Patents

Abstract

The present invention provides a kind of welding robot, including welding gun, rack, linear module, servo motor, wire reel, welding wire, wire feeder, argon tanks, appendix, control cabinet and special fixture, the welding gun is under the driving of servo motor, it is slided with the slide unit level of linear module, the reciprocal welding in the U-shaped groove welding bead of two pieces of airconium alloy plates compositions, and do not stopped in the middle part of each welding bead.The present invention provides welding robot, easy to operate, at low cost, is not limited by ambient enviroment；The degree of automation is higher, and welding efficiency is enhanced about more than once than traditional welding method.

Description

A welding robot

technical field

The invention relates to the field of welding technology, in particular to a welding robot.

Background technique

Zirconium is a corrosion-resistant metal, which is a rare and precious non-ferrous metal material. Zirconium and zirconium alloys have excellent corrosion resistance. It has very good corrosion resistance to most organic acids, inorganic acids, strong alkalis and some molten salts; And it has good heat resistance and processability, and it is used in petroleum, chemical, nuclear energy and other industries. However, zirconium metal has high requirements on welding process and welding conditions during welding, and the weld seam and heat-affected zone are easily polluted by oxygen, hydrogen, nitrogen and other elements in the air, forming hard and brittle compounds and brittle needle-like structures , so that the hardness and strength of the welded joint are increased, but the plasticity is reduced, and the corrosion resistance is also greatly reduced.

The welding of traditional zirconium alloy plates adopts manual argon arc welding as the base and manual arc welding as the cover. Due to the influence of personnel, equipment, materials and the environment, this method is prone to cracks, pores, slag inclusions, incomplete fusion and incomplete welding. Defects such as penetration, excessive heat input, and increased heat-affected zone; moreover, this welding method has low efficiency, high labor intensity for the operator, and the shortcomings of uneven product quality and poor stability.

The use of welding robots can free workers from heavy physical labor and save manpower. The welding parameters of each weld can be set during welding, reducing the influence of human factors on welding quality and reducing the need for workers. Technical requirements have improved welding quality and quality stability. Although welding robots have the above-mentioned advantages in the welding field, there is currently no welding robot specially used for welding zirconium alloy plates.

The invention provides a welding robot, which is easy to operate, low in cost, not limited by the environment, and has a high degree of automation, which protects zirconium materials from pollution during the entire process, and the welded joint has high strength and excellent plasticity and toughness. .

Contents of the invention

In order to solve the above technical problems, the present invention provides a welding robot.

The present invention is realized by following technical scheme:

A welding robot includes a welding gun, a frame, a linear module, a servo motor, a welding wire reel, a welding wire, a wire feeding mechanism, an argon gas tank, a gas pipeline, a control box and a special fixture.

Further, the welding wire is a flux-cored welding wire, and the flux-cored welding wire is composed of a zirconium alloy sheath and a flux core inside.

Further, the flux cored wire includes zircon sand, rutile, metallic chromium, niobium powder, silicon-manganese alloy, ferromolybdenum, ferrovanadium, nickel powder, tungsten powder, cobalt powder, aluminum-magnesium alloy, montmorillonite, aluminum fluoride Potassium Oxide, Antimony Oxide, Palladium Powder, Kaolin, Potassium Feldspar and Iron Powder.

Further, the use process of the welding robot includes the following steps:

Step 1. Machining the two zirconium alloy plates to be welded, and cleaning the surface of the zirconium alloy plates to remove rust, grease and dust;

Step 2, fixing the two zirconium alloy plates on the special fixture, ensuring the relative position and the gap between the two zirconium alloy plates, forming a U-shaped groove, and ensuring the positional relationship between the welding seam and the welding torch;

Step 3. Driven by the servo motor, the welding torch slides horizontally with the sliding table of the linear module, and the welding torch performs "adaptive sine wave" track swing welding in the U-shaped groove welding bead, and at each Reciprocating welding between layers of welds;

The "adaptive sine wave" signal is controlled by the control box and sent to the servo motor and welding torch. The "adaptive sine wave" trajectory is implemented according to the following algorithm:

The expression for a sinusoidal signal is:

Among them: A - the amplitude of the sine wave; -- the initial phase angle of the sine wave; f -- the frequency of the sine wave (Hz); ω -- the circular frequency, equal to 2πf; t -- the time

The feature of the "adaptive sine wave" trajectory S is that the frequency of the sine wave changes gradually with the welding process, and the formula is:

Wherein, A=H/2, the width of described H=U-shaped groove; f ₁ is the initial frequency, calculated according to the groove width H and the alloy plate thickness T, the formula is f ₁ =10*H/3T; f _n =f ₁ -1; t _n =1/f _n , this sine wave The trajectory welding method can ensure full penetration of each weld seam of the alloy plate under the butt joint position under automatic welding, and the thickness of each weld bead is appropriate.

Further, the argon tank uses argon with a mass purity of 99.99% as a protective gas, and the flow range is 10L/min-15L/min.

Further, the welding wire adopts flux-cored welding wire, and the diameter of the welding wire is 1.2mm-2.0mm, the welding current is 80A-140A, the welding voltage is 15-25V, the welding speed is 10-20cm/min, and there is no preheating before welding , The interlayer temperature of each weld bead is controlled below 100°C.

Further, the U-shaped groove formed by the two zirconium alloy plates has a width range of 5-15mm, and the gap between the two zirconium alloy plates is 1-3mm; Welding bead, the middle part is a filler bead, the top is a capping bead, slag cleaning is required between the weld bead, and the inner diameter of the nozzle of the welding torch is Ф12-24mm.

The beneficial effects of the present invention are:

The special welding robot for the zirconium alloy plate provided by the invention has the advantages of convenient operation, low cost and no limitation of the surrounding environment. The degree of automation is high, and the welding efficiency is more than double that of traditional welding methods. All high-temperature areas in the welding process are given high-purity argon gas protection to protect the zirconium material from pollution during the entire process, and the welded joints have high strength and good plasticity and toughness.

Description of drawings

Fig. 1 is a schematic diagram of a welding robot provided in this embodiment;

Fig. 2 is a side view of the special clamp provided by this embodiment.

Among them: 1-frame, 2-linear module, 3-servo motor, 4-wire reel, 5-welding wire, 6-wire feeding mechanism, 7-welding torch, 81-argon gas tank, 82-gas pipe, 9- Control box, 10-zirconium alloy plate, 11-special fixture, 111-chassis, 112-support column, 113-L-shaped fixture, 114-fastening bolt, 12-welding torch protective cover, 13-left protective cover, 14-right Protective cover, a-bottoming weld bead, b-filling weld bead, c-covering weld bead.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings.

Example 1:

A welding robot, as shown in Figure 1, includes a welding torch 7, a frame 1, a linear module 2, a servo motor 3, a welding wire reel 4, a welding wire 5, a wire feeding mechanism 6, an argon gas tank 81, a gas delivery pipe 82, a control Box 9, special fixture 11 and welding torch protective cover 12;

The servo motor is arranged at the end of the linear module 2 for driving the linear module 2 , and the linear module 2 is installed on the beam of the frame 1 . The argon gas tank 81 and the control box 9 are arranged on the platform of the frame 1 . The argon tank 81 is connected to the welding torch 7 through the gas delivery pipe 82 . The welding torch 7 , welding wire reel 4 , welding wire 5 , and wire feeding mechanism 6 form a whole and are installed on the slide table of the linear module 2 , realizing the "adaptive sine wave" motion track of the welding torch 7 . The special fixture 11 is arranged directly under the welding torch 7, and is used for fastening and positioning the zirconium alloy plate 10 to be welded.

As shown in Figure 2, the special clamp 11 includes a chassis 111, a support column 112, an L-shaped clamp 113, and a fastening bolt 114; the chassis 111 is located on the ground, and the support column 112 is arranged on the upper surface of the chassis 111, For supporting the zirconium alloy plate 10, the L-shaped clamps 113 are arranged on both sides of the chassis 111 and have threaded holes, and the fastening bolts 114 are matched with the threaded holes of the L-shaped clamps 113 to press The upper surface of the zirconium alloy plate 10 is used for fastening the zirconium alloy plate 10 .

As shown in Figure 2, in order to protect the zirconium material from pollution during the entire process, high-purity argon gas protection must be given to all high-temperature areas during the welding process. However, there are always gaps in the protective cover of traditional welding torches, and no gaps are formed. Relatively confined space, if the operation is carried out in an outdoor windy environment, the shielding gas is easily blown away by the wind, and effective supply cannot be guaranteed, which will directly affect the welding quality. For this reason, the present invention is provided with a combined gas shield, wherein the welding torch shield 12 is arranged on the lower end of the welding torch 7, and the welding torch shield 12 has upward bending edges with openings on the left and right sides; Left protective cover 13 and right protective cover 14 are arranged respectively, and described left protective cover 13 and right protective cover 14 are fastened on the special fixture 11 by bolt at front and rear two ends, prevent from moving or falling off in welding process, described left protective cover 13 and the right protective cover 14 all have the bending edge with opening downward; protected.

The use flow of described welding robot comprises the following steps:

Step 1. Machining the two zirconium alloy plates 10 to be welded, and cleaning the surface of the zirconium alloy plates 10 to remove rust, grease and dust;

Step 2. Fix the two zirconium alloy plates 10 on the special fixture 11, ensure the relative position and the gap between the two zirconium alloy plates 10, form a U-shaped groove, and ensure the positional relationship between the welding seam and the welding torch 7;

Step 3, the left protective cover 13 and the right protective cover 14 are fastened on the special fixture 11 by bolts at the front and rear ends, and the left protective cover 13 and the right protective cover 14 overlap with the welding torch protective cover 12 respectively;

Step 4. Driven by the servo motor 3, the welding torch 7 slides horizontally with the sliding table of the linear module 2, and the welding torch performs "adaptive sine wave" trajectory swing welding in the U-shaped groove welding bead, and welds on each layer of the bead reciprocating welding;

The "adaptive sine wave" signal is controlled by the control box 9, and the signal is sent to the servo motor and welding torch, and the "adaptive sine wave" track is implemented according to the following algorithm:

The expression for a sinusoidal signal is:

Among them: A - the amplitude of the sine wave; - the initial phase angle of the sine wave; f - the frequency of the sine wave (Hz); ω - the circular frequency, equal to 2πf; t - the time

The feature of the "adaptive sine wave" trajectory S provided by the present invention is that the frequency of the sine wave changes gradually with the welding process, and the formula is:

Among them, A=H/2 (the width of H=U-shaped groove); f ₁ is the initial frequency, calculated according to the groove width H and the alloy plate thickness T, the formula is f ₁ =10*H/3T, it can also be set artificially; f _n =f ₁ -1; t _n =1/f _n .

This sine wave trajectory welding method can ensure full penetration of each weld seam of the alloy plate under the butt joint position under automatic welding, the thickness of each weld bead is appropriate, each layer of weld seam is well formed, and there is very little spatter in the welding process. The appearance of the weld is beautiful, without defects such as cracks and pores, and the non-destructive and mechanical performance tests all meet the relevant requirements.

Further, the argon tank 81 uses argon with a mass purity of 99.99% as the protective gas, and the flow range is 10L/min-15L/min.

Further, the welding wire 5 is a flux-cored welding wire, and the diameter of the welding wire 5 is 1.2mm-2.0mm, the welding current is 80A-140A, the welding voltage is 15-25V, the welding speed is 10-20cm/min, and the welding speed is 10-20cm/min. Preheating, the interlayer temperature of each weld bead is controlled below 100°C.

Further, the width range of the U-shaped groove formed by the two zirconium alloy plates 10 is 5-15mm, and the gap between the two zirconium alloy plates 10 is 1-3mm; when welding, the weld beads are superimposed layer by layer, and the bottom is The bottom pass a, the middle part is the filler bead b, and the top is the capping bead c, and slag cleaning is required between the weld passes.

Further, the nozzle inner diameter range of the welding torch 7 is preferably Φ12-24mm.

Example 2:

A welding robot, the specific working process is:

Step 21, machining the two zirconium alloy plates to be welded, and cleaning the surface of the zirconium alloy plates to remove rust, grease and dust;

Step 22. Fix the two zirconium alloy plates on the special fixture, adjust the relative position and the gap between the two zirconium alloy plates to form a U-shaped groove, the width of the U-shaped groove is 10mm, and the gap between the two zirconium alloy plates 2mm, the welding torch is directly above the weld, and the end of the welding wire is 5mm away from the arc starting point;

Step 23, the left protective cover 13 and the right protective cover 14 are fastened on the special fixture 11 by bolts at the front and rear ends, and the left protective cover 13 and the right protective cover 14 overlap with the welding torch protective cover 12 respectively;

Step 24. Before welding, the argon gas tank uses argon gas with a mass purity of 99.99% as the shielding gas, the flow range is 10L/min, and the inner diameter of the nozzle of the welding torch is Ф20mm; the welding wire uses flux-cored wire with a diameter of 1.2mm;

Step 25. During welding, the welding torch slides horizontally with the slide table of the linear module under the drive of the servo motor, and reciprocates welding in the U-shaped groove welding bead, and the welding bead is superimposed layer by layer, and there is no Do stop; when making the bottom bead, the welding current is 100±5A, the welding voltage is 20±0.5V, and the welding speed is 10cm/min; when filling the bead, the welding current is 110±5A, and the welding voltage is 20±0.5V , The welding speed is 20cm/min; when covering the weld bead, the welding current is 120±5A, the welding voltage is 20±0.5V, and the welding speed is 10cm/min; the interlayer temperature of each weld bead is controlled at 80±5℃; Slag cleaning is required between channels.

Example 3:

The invention also provides a new type of seamed flux-cored welding wire, which is composed of a zirconium alloy sheath and a flux core. The powder ratio of the powder, set up a comparative test to test the influence of different raw material component contents on the performance of the flux-cored welding wire, the raw material component contents of different test groups are shown in Table 1 (the content is wt.%):

Table 1 Raw material component content ratio of different test groups

Flux-cored welding wires were produced according to the above proportions by steel strip forming method, and 8 types (No. 1, No. 2, No. 3, No. 4, No. 5, No. 6, No. 7 and No. 8) with a diameter of 1.2 mm and a diameter of 1.6 mm were obtained. , each flux-cored wire includes two specifications (diameter 1.2mm and diameter 1.6mm), and the production process adopts the existing technology. The transition of trace elements and rare earth elements into the weld metal will produce strengthening effects such as fine grain strengthening, solid solution strengthening and precipitation strengthening; while refining the grains, the strength and toughness of the weld metal will be improved, and the activation of zirconium metal at high temperature will be improved. It is fragile under certain conditions, but the optimal ratio of adding trace elements and rare earth elements to the drug core needs a lot of research and experiments to obtain.

Example 4:

The welding robot provided in Example 1 was used to detect the above-mentioned 8 kinds of flux cored wires: the welding test plate was selected as a 600Mpa grade zirconium alloy plate, and the size of the welding test plate was 50mm×200mm×20mm. The welding process refers to the GB/T 17493-2008 standard. The main welding parameters are: when making the bottom weld bead, the welding current is 100±5A, the welding voltage is 20±0.5V, and the welding speed is 10cm/min; when filling the weld bead, the welding The current is 110±5A, the welding voltage is 20±0.5V, and the welding speed is 20cm/min; when covering the weld bead, the welding current is 120±5A, the welding voltage is 20±0.5V, and the welding speed is 10cm/min; The interlayer temperature of the weld bead is controlled at 80±5°C; the slag removal process is required between the weld passes. After each welding is completed, the slag is removed, and the next weld is welded after the slag removal is completed.

1. Mechanical performance test

The mechanical performance test of the weld metal is carried out in accordance with the requirements of GB/T 17493-2008. The impact and tensile samples are taken from the weld metal part. The Vickers hardness test of the weld metal is carried out on the HVS-1000 digital microhardness tester. The results As shown in table 2:

Table 2 mechanical properties test results

test group 1 2 3 4 5 6 7 8 Yield strength MPa 269 272 307 281 292 335 281 289 Tensile strengthMpa 531.2 556.0 617.1 552.5 569.7 618.9 573.4 542.3

2. Microstructure observation

After the tensile and impact tests are completed, the samples are wire-cut to prepare metallographic and SEM samples. After hot-mounting, the samples need to be polished step by step with 240 ^# , 400 ^# , 800 ^# , 1200 ^# , and 1600 ^# water-grinding sandpaper until There are no obvious scratches under a low-magnification metallographic microscope, and backscatter imaging is performed with a scanning electron microscope. Cracks and pores are graded as none, less, moderate, more, and more, and are scored for No. 1-8 flux-cored welding wires. The scoring results are shown in Table 3:

Table 3 Microstructure Observation Results

test group 1 2 3 4 5 6 7 8 crack Moderate many none less none none Moderate many Stomata more less none many many none none Moderate

Combined with the appearance of the weld seam and the above test results, the No. 6 flux-cored wire with a diameter of 1.6mm has the best performance, showing a uniform, continuous, and well-formed weld appearance during the welding process; the spatter is small, and the spatter particles are mainly small particles; The tensile strength is 617.1Mpa, the yield strength is 307Mpa, which is significantly higher than similar products, and the fracture is from the base metal during the fracture test, and the crack is far away from the heat-affected zone of the weld; on any direction of the weld and the heat-affected zone on the tensile surface There is no opening defect; the flux-cored wire will not generate a lot of smoke and harmful gas during the welding process; Good viscosity and solidification properties, can be welded in all positions, especially suitable for vertical down welding.

Corresponding penetration testing and radiographic testing of the welds did not find excessive defects, which met the assessment requirements of CB3958/-2004/II and CB/T3558-2011B II respectively; the tensile strength of welded joints was greater than 600MPa; after the corrosion test, the magnification was 800 times No visible cracks, lack of fusion and other defects were found on the joint welds and heat-affected zone surfaces of the macro-corrosion samples. The welds have a beautiful appearance, excellent weld performance, high strength, good plasticity and toughness.

The new flux-cored welding wire provided by the invention can realize high-efficiency mechanized automatic welding, it is easy to control the welding state and can directly observe the arc; the deposition speed is high, especially in the process of all-position welding, it can still use high current operation, and the welding efficiency is greatly improved. The welding heat input is small, the welding deformation is small, and the pores are small; the zirconium-containing flux-cored welding wire provided by the invention overcomes the disadvantage that zirconium metal can only be welded with titanium, niobium, silver, and vanadium, and can be directly welded with various alloys and metals; The flux-cored welding wire provided by the invention ensures the heat-resistant and corrosion-resistant properties of the zirconium alloy; the arc is soft and almost spatter-free during the welding operation; and the appearance of the weld bead is beautiful.

The above disclosures are only preferred embodiments of the present invention, and certainly cannot limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.

Claims (7)

1. a kind of welding robot, it is characterised in that：The welding robot includes welding gun, rack, linear module, servo electricity Machine, wire reel, welding wire, wire feeder, argon tanks, appendix, control cabinet and special fixture.

2. welding robot according to claim 1, it is characterised in that：The welding wire is flux-cored wire, the medicine core weldering Silk is made of medicine core of wrapping up in intradermal outside zircaloy.

3. welding robot according to claim 2, it is characterised in that：The flux-cored wire include zircon sand, rutile, Crome metal, niobium powder, silicomangan, molybdenum-iron, vanadium iron, nickel powder, tungsten powder, cobalt powder, almag, montmorillonite, potassium fluoroaluminate, oxidation Antimony, palladium powder, kaolin, potassium feldspar and iron powder.

4. according to any welding robots of claim 1-3, it is characterised in that：The process for using of the welding robot Include the following steps：

Step 1 needs the airconium alloy plates welded to be machined, and clear up airconium alloy plates discharge surface to two pieces, goes Removing rust, grease and dust；

Two pieces of airconium alloy plates are fixed on special fixture by step 2, it is ensured that the relative position of two pieces of airconium alloy plates and its gap, U-shaped groove is formed, while ensures the position relationship of weld seam and the welding gun；

Step 3, the welding gun slide, welding gun is in U under the driving of the servo motor with the slide unit level of the linear module " adaptive sine wave " track swing welding, and the reciprocal welding between each layer welding bead are carried out in type groove welding bead；

" adaptive sine wave " signal is controlled by control cabinet, is sent to servo motor and the welding gun, " adaptive sine Implement by following algorithm wave " track：

The expression formula of sinusoidal signal is：

Wherein：The amplitude of A-- sine waves；-- the starting phase angle of sine wave；The frequency (Hz) of f-- sine waves；ω-circle frequency Rate, equal to 2 π f；The t-- times

The characteristics of " adaptive sine wave " track S be sine wave freuqency as welding process gradually changes, formula is：

Wherein, A=H/2, the width of the H=U shapes groove；f₁For original frequency, according to groove width H and alloy plate thickness Degree T is calculated, formula f₁=10*H/3T；f_n=f₁-1；t_n=1/f_n, the welding method of this sine wave track can ensure that Each weld seam of alloy sheets under docking location full penetration, thickness of each welding bead under Full-automatic welding is suitable.

5. welding robot according to claim 4, it is characterised in that：The argon tanks use quality purity for 99.99% argon gas is as protection gas, range of flow 10L/min-15L/min.

6. welding robot according to claim 5, it is characterised in that：The welding wire uses flux-cored wire, and the weldering Silk a diameter of 1.2mm-2.0mm, welding current 80A-140A, weldingvoltage 15-25V, 10~20cm/min of speed of welding, It is not preheated before weldering, each welding bead interlayer temperature control is below 100 DEG C.

7. welding robot according to claim 6, it is characterised in that：The U-shaped groove that two pieces of airconium alloy plates are formed Width range for 5-15mm, the gap size of two pieces of airconium alloy plates is 1-3mm；During welding, welding bead is successively superimposed, and bottom is beats Back welding road, middle part are filler pass, and top is final pass, need to carry out scarfing cinder processing between welding bead, in the nozzle of the welding gun Diameter ranging from Ф 12-24mm.