Paraaxial laser welding gas protection device and preparation method thereof

Abstract

The invention discloses a paraxial laser welding gas protection device and a preparation method thereof, and belongs to the technical field of laser welding. The preparation method comprises the following steps: welding the main breather pipe and the copper pipe together; the auxiliary breather pipe, the filter screen and the box-shaped gas hood are assembled and welded together; the locking device is machined, the two sets of welding pieces are assembled together through the nut, the bolt and the locking device and installed on the laser welding head, the main breather pipe and the auxiliary breather pipe are connected with the argon pipe through the pipe connector, and in the laser welding process, the welding seam is protected through two paths of argon of the main breather pipe and the auxiliary breather pipe. The continuous use time of the gas protection device in the laser welding process is effectively prolonged, burning loss and deformation of the gas protection pipe in the laser welding process are avoided, meanwhile, the gas protection effect of the surface of a laser welding seam is improved, and the oxidation phenomenon extremely prone to occurring when gas protection of the welding seam is poor is eliminated.

Description

Technical Field

[0001] This invention relates to a gas protection device for off-axis laser welding and its preparation method, which is particularly suitable for processing thick-walled workpieces and belongs to the field of laser welding technology. Background Technology

[0002] Existing high-efficiency laser welding gas protection devices for off-axis applications use a single-tube structure, which has the following problems: 1) Poor removal of photo-induced plasma results in insufficient effective power on the weld surface during laser welding, affecting weld quality stability; 2) For thick-walled workpieces, the laser welding power is high, and the gas protection device is easily burned and deformed during welding, affecting the smooth flow of the shielding gas; 3) After laser welding of thick-walled workpieces, the high-temperature area of ​​the weld is large and the high-temperature residence time is long. The coverage of the gas protection device is insufficient, resulting in severe oxidation of the weld surface and easy occurrence of porosity defects inside the weld. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a side-axis laser welding gas protection device and its preparation method, which solves the problems of short continuous use time, easy deformation, inability to effectively blow away photoinduced plasma during high-power welding, poor protection effect, and severe oxidation of weld seam that exist with the existing laser welding gas protection devices.

[0004] The technical solution of this invention is: a bypass laser welding gas protection device, which includes a main gas pipe, a locking device, a copper pipe, a secondary gas pipe, a filter screen, a gas hood, and a support pipe, wherein: One end of the main vent pipe is the first air inlet, and the other end is welded to a copper pipe. The other end of the copper pipe is machined with a chamfer and a notch. The chamfer is the angle between the axis of the copper pipe and its end face. The notch connects to an internal through-hole in the copper pipe. The laser beam passes through the notch and is aimed at the product from top to bottom, reaching the weld seam. The center of the airflow entering the copper pipe overlaps with the laser beam spot falling on the surface of the product's weld seam. The gas hood is a box-shaped component with its opening facing downwards. The bottom of the gas hood is machined with a curved surface that matches the product's profile. The bottom of the gas hood is flush with the bottom of the copper pipe, and the curved surface faces downwards, covering the surface of the product's weld seam. On the upper part of the gas hood, a bevel with the same angle as the copper tube is machined on one side for bonding and welding to the surface of the copper tube. A through hole is machined on the other side of the gas hood. One end of the auxiliary vent pipe is sealed, and the other end is a second air inlet. The sealed end enters the interior of the gas hood through the through hole, facing and contacting the bevel of the gas hood. Multiple small holes are provided above the auxiliary vent pipe, and a filter screen is spot-welded above the small holes of the auxiliary vent pipe. The filter screen is tightly fitted to the auxiliary vent pipe. A gap is provided between the filter screen and the upper surface of the gas hood, so that the protective gas can reach the surface where the product weld is located from both sides of the gas hood. The upper surface of the air hood is welded to the support pipe, and the locking device connects the main air pipe to the support pipe.

[0005] Preferably, the bevel angle of the copper tube is 30°~35°.

[0006] Preferably, the notch width dimension a of the copper tube is 12 mm - 15 mm, and the notch depth dimension b is 30 mm - 32 mm.

[0007] Preferably, the support pipe is parallel to the main vent pipe.

[0008] Preferably, the locking device consists of two symmetrical pressure blocks, namely a left pressure block and a right pressure block. Both the left and right pressure blocks are machined with two semicircular arcs with a distance L2 between them. After the support tube and the main vent tube are held by the semicircular arc holes of the left and right pressure blocks, they are fixed and locked by screws. The distance L2 is equal to the interval L1 between the support tube and the main vent tube.

[0009] Another technical solution of the present invention is: a method for preparing a gas protection device for off-axis laser welding, the method comprising the following steps: S1. Using copper rods to process copper pipes; S2. Use steel pipes to process the main vent pipe, and weld the main vent pipe and copper pipe together; S3. Use thin steel plates to process the air hood, use steel pipes to process the auxiliary air pipe, cut the filter screen, weld the filter screen, auxiliary air pipe and air hood together, and use steel pipes to process the support pipe; S4. Use steel plate to process the locking device, weld the gas cover and support pipe together, and use the locking device to assemble the main vent pipe and support pipe together to form a laser welding gas protection device.

[0010] Preferably, the copper tube is manufactured from chromium-zirconium copper alloy rod, and the manufacturing process is as follows: An inner hole is machined in the center of the copper rod, and then an angle and a notch are machined at the end of the copper tube. The angle is the angle between the axis of the copper tube and the end face. The notch is connected to the through hole inside the copper tube. The laser beam passes through the notch and is aimed at the product from top to bottom and emitted to the weld. The laser beam spot that falls on the surface of the weld of the product overlaps with the air blowing center of the copper tube.

[0011] Preferably, the main vent pipe and the copper pipe are welded by manual argon arc welding using copper welding wire with a diameter of 3mm and a welding current of 200A-220A to form a fillet weld.

[0012] Preferably, the specific steps of step S3 are as follows: S3.1. A gas cover is assembled and welded from thin steel plates. A curved surface matching the product profile is machined at the bottom of the gas cover. An inclined surface matching the outer profile of the copper tube is machined on one side of the gas cover. A through hole is machined on the other side of the gas cover. The distance between the upper edge of the through hole and the inner top of the gas cover is 2mm-4mm. The welding current for assembling and welding the gas cover from thin steel plates is 100A-120A, without adding welding wire. S3.2. Machining the auxiliary vent pipe, the diameter φd of the small holes on the auxiliary vent pipe is 1 mm - 2 mm, the spacing l of the small holes is 1 mm - 2 mm, and one side of the auxiliary vent pipe is sealed by manual argon arc welding. S3.3. Spot weld the filter screen above the small hole of the auxiliary vent pipe to ensure that the filter screen fits tightly with the auxiliary vent pipe; S3.4 With the curved side of the air hood facing down and the small hole and filter screen on the auxiliary vent pipe facing up, insert the auxiliary vent pipe into the through hole of the air hood, ensuring that the blocked side of the auxiliary vent pipe faces and contacts the inclined side of the air hood. Weld the auxiliary vent pipe and the air hood by manual argon arc welding. S3.5. Machining the support tube: Machining one side of the support tube with the same bevel angle as the copper tube.

[0013] Preferably, the specific steps of step S4 are as follows: S4.1 The locking device is made of aluminum alloy or stainless steel plate; S4.2 Trial assembly of the main vent pipe and copper pipe welding parts, locking device, air hood filter and auxiliary vent pipe welding parts, and support pipe; S4.3 Determine the welding position of the support pipe on the gas cover according to the distance L1 between the support pipe and the main vent pipe. During the trial installation, the inclined surface of the gas cover should be close to the copper pipe. The gas cover and the support pipe should be welded by manual argon arc welding. S4.4 Assemble the main vent pipe and support pipe together using a locking device, adjust the locking position so that the air cover is flush with the bottom of the copper pipe, and tighten the locking position to fix it.

[0014] The advantages of this invention compared to the prior art are: (1) The gas protection device of the present invention has an air blowing center that overlaps with the laser beam spot on the weld surface, which greatly improves the blowing effect of photo-induced plasma, avoids the attenuation of laser power obtained on the workpiece surface, and makes the weld quality more stable. The effect is more obvious, especially for high-power laser welding of 3KW and above.

[0015] (2) The gas protection device of the present invention adopts dual-channel gas protection, which increases the coverage of protective gas. For high-power laser welding of 3KW or above, it can provide good protection for the weld surface, avoid insufficient coverage and weld oxidation, and reduce the probability of defects inside the weld.

[0016] (3) For stainless steel ring workpieces with a thickness of 3mm-8mm, in the range of laser welding power of 3KW-6KW, compared with the original gas protection device, the continuous use time of the gas protection device of the present invention is increased by 6 times, and there is no deformation problem. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the off-axis high-efficiency laser welding gas protection device according to an embodiment of the present invention.

[0018] Figure 2 This is a top view of the copper tube according to an embodiment of the present invention; Figure 3 This is a top view of the left and right pressure blocks according to an embodiment of the present invention; Figure 4 This is a front view of the assembly of the left and right pressure blocks according to an embodiment of the present invention. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] like Figure 1 As shown, the off-axis laser welding gas protection device provided by the present invention consists of a main vent pipe 1, a locking device 2, a copper pipe 3, a secondary vent pipe 4, a filter screen 5, a gas hood 6, and a support pipe 7. The locking device 2 consists of an upper pressure block 8 and a lower pressure block 9.

[0021] A bypass laser welding gas protection device includes a main vent pipe 1, a locking device 2, a copper pipe 3, a secondary vent pipe 4, a filter screen 5, a gas hood 6, and a support pipe 7, wherein: One end of the main vent pipe 1 is the first air inlet, and the other end is welded to the copper pipe 3. The other end of the copper pipe 3 is machined with a chamfer and a notch. The chamfer is the angle between the axis of the copper pipe 3 and the end face. The notch is connected to the internal through hole of the copper pipe. The laser beam passes through the notch and is aimed at the product from top to bottom and emitted to the weld. The center of the air blowing into the copper pipe 3 overlaps with the laser beam spot falling on the surface of the product weld. The gas cover 6 is a box-shaped part with an opening facing downwards. The bottom of the gas cover 6 is machined with an arc-shaped surface that matches the product surface. The bottom of the gas cover 6 is flush with the bottom of the copper pipe 3, and the arc-shaped surface faces downwards, covering the surface of the product weld. One side of the gas hood 6 is machined with a bevel at the same angle as the copper tube 3 for bonding and welding to the surface of the copper tube 3. A through hole is machined on the other side of the gas hood 6. The auxiliary vent pipe 4 is sealed at one end and has a second air inlet at the other end. The sealed end enters the interior of the gas hood 6 through the through hole, facing and contacting the bevel side of the gas hood 6. Multiple small holes are provided above the auxiliary vent pipe 4. A filter screen 5 is spot-welded above the small holes of the auxiliary vent pipe 4. The filter screen 5 is tightly fitted to the auxiliary vent pipe 4. A gap is provided between the filter screen 5 and the upper surface of the gas hood 6, so that the protective gas can reach the surface where the product weld is located from both sides of the gas hood 6. The upper surface of the air hood 6 is welded to the support tube 7, and the locking device 2 connects the main air pipe 1 together.

[0022] During laser welding, the laser is emitted to the point where... Figure 2 The laser beam position shown is from Figure 1 Argon gas is introduced through the first air inlet shown. The argon gas is blown through copper tube 3 to the lower laser beam position to provide high-temperature protection for the weld. Figure 2Argon gas is introduced through the second air inlet shown. It passes through the small hole of the auxiliary air pipe 4, then through the filter screen 5, and is blown to the top inner surface of the gas cover 6. The argon gas then flows to both sides and gradually fills the interior of the gas cover 6 from top to bottom, thereby achieving further protection of the product weld.

[0023] The gas protection device of the present invention adopts a dual-inlet gas protection method, with two argon gases simultaneously protecting the weld. Specifically, the protective gas through the main gas pipe 1 and the copper pipe 3 is mainly used to directly blow protection onto the laser-welded area and remove plasma; the protective gas through the auxiliary gas pipe 4 and the gas hood 6 is mainly used for protection of the weld during the post-weld cooling process from high temperature to room temperature.

[0024] The aforementioned gas protection device's blowing center overlaps with the laser beam spot on the weld surface, significantly improving the blowing effect of photo-induced plasma, avoiding the attenuation of laser power obtained on the workpiece surface, and resulting in more stable weld quality. The effect is even more pronounced for high-power laser welding of 3KW and above.

[0025] In addition, the gas protection device adopts dual-channel gas protection, which increases the coverage of the protective gas. For high-power laser welding of 3KW and above, it can provide good protection for the weld surface, avoid insufficient coverage and weld oxidation, and reduce the probability of defects inside the weld.

[0026] Preferably, the bevel angle of the copper tube 3 is 30°~35°.

[0027] Preferably, the notch width dimension a of the copper tube 3 is 12 mm - 15 mm, and the notch depth dimension b is 30 mm - 32 mm.

[0028] Preferably, the support tube 7 is parallel to the copper tube 3.

[0029] Preferably, the locking device 2 consists of two symmetrical pressure blocks, namely a left pressure block 8 and a right pressure block 9. Both the left pressure block 8 and the right pressure block 9 are machined with two semi-circular arcs with a spacing L2. After the support pipe 7 and the main vent pipe 1 are held by the semi-circular arc holes of the left pressure block 8 and the right pressure block 9, they are fixed and locked by screws. The spacing L2 is equal to the interval L1 between the support pipe 7 and the main vent pipe 1.

[0030] The preparation method of the above-mentioned off-axis laser welding gas protection device includes the following steps: S1. Use copper rods to process copper pipes 3; S2. Use steel pipe to process the main vent pipe 1, and weld the main vent pipe 1 and copper pipe 3 together. S3. Use thin steel plate to process air cover 6, use steel pipe to process secondary air pipe 4, cut filter screen 5, weld filter screen 5, secondary air pipe 4 and air cover 6 together, and use steel pipe to process support pipe 7. S4. Use steel plate to process locking device 2, weld gas cover 6 and support pipe 7 together, and use locking device 2 to assemble main vent pipe 1 and support pipe 7 together to form laser welding gas protection device.

[0031] The copper tube 3 is made from a chromium-zirconium copper alloy rod with an outer diameter of 30mm-35mm. An inner hole with a diameter φD5 of 12mm-15mm is machined in the center of the copper rod. A chamfer and a notch are machined at the end of the copper tube 3. The angle of the chamfer is 30°-35°. Dimension a is the width of the notch, which ranges from 12mm to 15mm. Dimension b is the depth of the notch, which ranges from 30mm to 32mm. The length of the copper tube 3 is 40mm-50mm.

[0032] Dimension b is the notch depth of copper tube 3. If it is too large, too much argon gas will leak from the notch of copper tube 3 during laser welding, and the protection effect will be poor. If it is too small, the distance between the laser beam position and copper tube 3 will be too small, which will easily cause copper tube 3 to be overheated and burn out.

[0033] The main vent pipe 1 is made of 1Cr18Ni9Ti stainless steel pipe with an outer diameter of φD1 and an inner diameter of φD6. φD1 is 16 mm - 19 mm, φD6 is 12 mm - 15 mm, and the length of the main vent pipe 1 is 100 mm - 120 mm.

[0034] The main vent pipe 1 and the copper pipe 3 are welded by manual argon arc welding. The welding wire is made of copper with a diameter of 3mm and the welding current is 200A-220A to form a fillet weld.

[0035] The specific steps of step S3 are as follows: S3.1. A gas cover 6 is assembled and welded from thin steel plates. A curved surface matching the product profile is machined at the bottom of the gas cover 6. An inclined surface matching the outer profile of the copper tube 3 is machined on one side of the gas cover 6. A through hole is machined on the other side of the gas cover 6. The distance between the upper edge of the through hole and the inner top of the gas cover 6 is 2mm-4mm. The welding current of the gas cover 6 assembled from thin steel plates is 100A-120A, without welding wire. S3.2. Machining the auxiliary vent pipe 4, the diameter φd of the small holes on the auxiliary vent pipe 4 is 1 mm - 2 mm, the spacing l of the small holes is 1 mm - 2 mm, and one side of the auxiliary vent pipe 4 is sealed by manual argon arc welding. S3.3. Spot weld the filter screen 5 above the small hole of the auxiliary vent pipe 4 so that the filter screen 5 fits tightly with the auxiliary vent pipe 4. S3.4 With the curved side of the air hood 6 facing down and the small hole and filter screen on the auxiliary vent pipe 4 facing up, insert it into the through hole of the air hood 6, ensuring that the blocked side of the auxiliary vent pipe 4 faces and contacts the inclined side of the air hood 6. Weld the auxiliary vent pipe 4 and the air hood 6 by manual argon arc welding. S3.5. Process the support tube 7, and process one side of the support tube 7 to have the same bevel angle as the copper tube 3.

[0036] The specific steps of step 4 are as follows: S4.1 The locking device 2 is made of aluminum alloy or stainless steel plate; S4.2, Trial assembly of the welded parts of the main vent pipe 1 and copper pipe 3, the locking device 2, the welded parts of the air cover 6 filter screen 5 and the auxiliary vent pipe 4, and the support pipe 7; S4.3 Determine the welding position of the support pipe 7 on the air cover 6 according to the distance L1 between the support pipe 7 and the main vent pipe 1. During the trial installation, the inclined surface of the air cover 6 is close to the copper pipe 3. The air cover 6 and the support pipe 7 are welded by manual argon arc welding. S4.4 Assemble the main vent pipe 1 and the support pipe 7 together using the locking device 2, adjust the locking position so that the air cover 6 is flush with the bottom of the copper pipe 3, and tighten to fix the locking position.

[0037] Specifically, the thin steel plate material can be 1Cr18Ni9Ti stainless steel, with a thickness of 1mm-2mm. The thin steel plates are welded together to form the gas hood 6. The gas hood 6 has a near-rectangular structure, with a width of 30mm-35mm, a length of 80mm-100mm, and a height of 30mm-35mm. A curved surface matching the product profile is machined at the bottom of the gas hood 6. A bevel with the same inclination angle as the copper tube 3 is machined on one side of the gas hood 6. A hole with a diameter of φ16mm-φ19mm is machined on the other side of the gas hood 6. The distance between the upper edge of the hole and the inner top of the gas hood 6 is 2mm-4mm. The welding current for welding the gas hood 6 using thin steel plates is 100A-120A, without welding wire. The secondary vent pipe 4 is machined from a 1Cr18Ni9Ti stainless steel tube with an outer diameter of 16mm-19mm and an inner diameter of 12mm-15mm. The length of the secondary vent pipe 4 is 120mm-150mm, and the diameter φd of the small hole on the secondary vent pipe 4 is 1mm. -2mm, the spacing between the small holes is 1mm-2mm, and one side of the auxiliary vent pipe 4 is sealed by manual argon arc welding. Above the small holes of the auxiliary vent pipe 4, the mesh of the filter screen 5 is rectangular with a size of 0.315mm. 0.014mm, ensuring a tight fit between the filter screen 5 and the auxiliary vent pipe 4; with the curved side of the air hood 6 facing down, and the small holes on the auxiliary vent pipe 4 and the filter screen facing up, insert it into the φ16 mm - φ19 mm hole of the air hood 6, ensuring that the sealing side of the auxiliary vent pipe 4 faces and contacts the inclined side of the air hood 6. Weld the auxiliary vent pipe 4 and the air hood 6 using manual argon arc welding, welding 4 sections, each 5mm-8mm long, welding current: 50A - 70A, welding wire: H0Cr21Ni10, diameter 2mm; the support pipe 7 is made of 1Cr18Ni9Ti stainless steel pipe with an outer diameter φD1 of 16mm-19mm and an inner diameter of 12mm-15mm, with a length of 100mm-150mm. Machine one side of the support pipe 7 with a 30°-35° bevel angle consistent with the copper pipe 3.

[0038] The locking device 2 is manufactured from a 20mm thick aluminum alloy or stainless steel plate, with a thickness of 20mm-25mm, a length of 90mm-100mm, and a width of 30mm-40mm. The locking device 2 consists of two symmetrical pressure blocks: an upper pressure block 8 and a lower pressure block 9. Semicircular arcs with a spacing L2 of 50mm-60mm are machined on the surfaces formed by the length and width of the upper and lower pressure blocks 8 and 9, respectively, with diameters φD2 equal to φD1. Four through holes with a diameter φD3 of 6.5mm-7mm are machined on both the upper and lower pressure blocks 8 and 9, with a spacing L3 of 70mm. -75mm, spacing L4 is 16mm-18mm; trial assembly of the main vent pipe 1 and copper pipe 3 welded parts, locking device 2, air cover 6 filter screen 5 and auxiliary vent pipe 4 welded parts, support pipe 7, L1 and L2 are equal, determine the welding position of support pipe 7 on air cover 6 according to dimension L1. During trial assembly, the inclined surface of air cover 6 needs to be close to copper pipe 3. Weld air cover 6 and support pipe 7 by manual argon arc welding. Welding current: 50A-70A, welding wire: H0Cr21Ni10, diameter 2mm; Assemble the main vent pipe 1 and support pipe 7 together using locking device 2. Adjust the locking position so that air cover 6 is flush with the bottom of copper pipe 3. Use 4 M6×60mm bolts to pass through the holes with diameter φD3 respectively, and use 4 M6 nuts to tighten and fix the M6×60mm bolts.

[0039] In the fabrication process of the protective device of this invention, the main vent pipe and the copper pipe are welded together; the auxiliary vent pipe, the filter screen, and the box-shaped gas hood are assembled and welded together; a locking device is fabricated, and nuts, bolts, and the locking device are used to assemble the two sets of welded parts together and attach them to the laser welding head. Argon gas pipes are connected to the main vent pipe and the auxiliary vent pipe respectively through pipe joints. During laser welding, the weld is protected by argon gas from both the main vent pipe and the auxiliary vent pipe. This invention effectively improves the continuous service time of the gas protection device during laser welding, avoids the burning and deformation of the gas protection pipe during laser welding, improves the gas protection effect on the surface of the laser weld, and eliminates the oxidation phenomenon that easily occurs when the gas protection of the weld is inadequate.

[0040] Example 1 (1) Copper tube 3 processing process: The inner hole is machined in the center of the chromium zirconium copper alloy rod with an outer diameter of 30 mm. Its diameter φD5 is 12 mm; the bevel and notch are machined at the end. The angle A is 30°, the size a is 12 mm, the size b is 30 mm, the size c is 30 mm; the length is 40 mm.

[0041] (2) The main vent pipe 1 is made of 1Cr18Ni9Ti stainless steel pipe with an outer diameter of φD1 and an inner diameter of φD6, where φD1 is 16 mm, φD6 is 12 mm, and the length of the main vent pipe 1 is 100 mm. The main vent pipe 1 and the copper pipe 3 are welded by manual argon arc welding using copper welding wire with a diameter of 3 mm and a welding current of 200 A to form a fillet weld.

[0042] (3) The gas cover 6 is assembled and welded from thin steel plates. The material of the thin steel plate is 1Cr18Ni9Ti stainless steel with a thickness of 1mm. The gas cover 6 is a cuboid structure with a width of 30mm, a length of 80mm, and a height of 30mm. A curved surface matching the product surface is processed at the bottom of the gas cover 6. An inclined surface with the same inclination angle as the copper tube 3 is processed on one side of the gas cover 6. A hole with a diameter of φ16mm is processed on the other side of the gas cover 6. The distance between the upper edge of the hole and the inner side of the top of the gas cover 6 is 2mm. The welding current of the gas cover 6 assembled from thin steel plates is 100A, without adding welding wire. The secondary vent pipe 4 is made of 1Cr18Ni9Ti stainless steel pipe with an outer diameter of 16 mm and an inner diameter of 12 mm. The length of the secondary vent pipe 4 is 120 mm. The diameter of the small holes on the secondary vent pipe 4 is φd, which is 1 mm and the spacing between the small holes is 1 mm. One side of the secondary vent pipe 4 is sealed by manual argon arc welding. A filter screen 5 with a specification of 0.315 / 0.14 is spot welded above the small holes of the secondary vent pipe 4 to ensure that the filter screen 5 fits tightly with the secondary vent pipe 4. With the curved side of the gas hood 6 facing down and the small hole and filter screen on the auxiliary vent pipe 4 facing up, insert it into the φ16 mm hole of the gas hood 6, ensuring that the sealing side of the auxiliary vent pipe 4 faces and contacts the inclined side of the gas hood 6. Weld the auxiliary vent pipe 4 and the gas hood 6 by manual argon arc welding, welding 4 sections, each section 5mm-8mm in length, welding current: 50 A, welding wire: H0Cr21Ni10, diameter 2mm; The support tube 7 is machined from a 1Cr18Ni9Ti stainless steel tube with an outer diameter φD1 of 16mm and an inner diameter of 12mm. The length of the support tube 7 is 100mm. One side of the support tube 7 is machined with a 30° bevel angle, consistent with that of the copper tube 3.

[0043] (4) The locking device 2 is made of aluminum alloy or stainless steel plate with a thickness of 20mm. The thickness is 20mm, the length is 90mm, and the width is 30mm. The locking device 2 consists of two symmetrical pressure blocks, namely upper pressure block 8 and lower pressure block 9. Semicircular arcs with a spacing of 50mm L2 are machined on the surfaces formed by the length and width of upper pressure block 8 and lower pressure block 9, and their diameters φD2 and φD1 are equal. Four through holes with a diameter of 6.5mm φD3 are machined on upper pressure block 8 and lower pressure block 9, with a spacing of 70mm L3 and a spacing of 16mm L4. Trial assembly of the main vent pipe 1 and copper pipe 3 welded parts, locking device 2, air hood 6 filter screen 5 and auxiliary vent pipe 4 welded parts, support pipe 7, L1 and L2 are equal. Determine the welding position of support pipe 7 on air hood 6 according to dimension L1. During trial assembly, the inclined surface of air hood 6 must be close to copper pipe 3. Manual argon arc welding is used to weld air hood 6 and support pipe 7. Welding current: 50A, welding wire: H0Cr21Ni10, diameter 2mm; Assemble the main vent pipe 1 and the support pipe 7 together using the locking device 2. Adjust the locking position so that the air cover 6 is flush with the bottom of the copper pipe 3. Use four M6×60mm bolts to pass through the holes with a diameter of φD3 respectively, and use four M6 nuts to tighten and fix the M6×60mm bolts.

[0044] Example 2: (1) Copper tube 3 processing process: The inner hole is machined in the center of the chromium zirconium copper alloy rod with an outer diameter of 35mm, and its diameter φD5 is 15mm; the bevel and notch are machined at the end, with angle A being 35°, dimension a being 15mm, dimension b being 32mm, dimension c being 32mm; and the length being 50mm.

[0045] (2) The main vent pipe 1 is made of 1Cr18Ni9Ti stainless steel pipe with an outer diameter of φD1 and an inner diameter of φD6, where φD1 is 19mm, φD6 is 15mm, and the length of the main vent pipe 1 is 120mm. The main vent pipe 1 and the copper pipe 3 are welded by manual argon arc welding using copper welding wire with a diameter of 3mm and a welding current of 220A to form a fillet weld.

[0046] (3) The gas cover 6 is assembled and welded from thin steel plates. The material of the thin steel plate is 1Cr18Ni9Ti stainless steel with a thickness of 2mm. The gas cover 6 is a cuboid structure with a width of 35mm, a length of 100mm, and a height of 35mm. A curved surface matching the product surface is processed at the bottom of the gas cover 6. An inclined surface with the same inclination angle as the copper tube 3 is processed on one side of the gas cover 6. A hole with a diameter of φ19mm is processed on the other side of the gas cover 6. The distance between the upper edge of the hole and the inner side of the top of the gas cover 6 is 4mm. The welding current of the gas cover 6 assembled from thin steel plates is 120A, without adding welding wire. The secondary vent pipe 4 is made of 1Cr18Ni9Ti stainless steel pipe with an outer diameter of 19mm and an inner diameter of 15mm. The length of the secondary vent pipe 4 is 150mm. The diameter of the small holes on the secondary vent pipe 4 is φd, which is 2mm and the spacing between the small holes is 2mm. One side of the secondary vent pipe 4 is sealed by manual argon arc welding. A filter screen 5 with a specification of 0.315 / 0.14 is spot welded above the small holes of the secondary vent pipe 4 to ensure that the filter screen 5 fits tightly with the secondary vent pipe 4. With the curved side of the gas hood 6 facing down and the small hole and filter screen on the auxiliary vent pipe 4 facing up, insert it into the φ19mm hole of the gas hood 6, ensuring that the blocked side of the auxiliary vent pipe 4 faces and contacts the inclined side of the gas hood 6. Weld the auxiliary vent pipe 4 and the gas hood 6 by manual argon arc welding, welding 4 sections, each 8mm long, welding current: 70A, welding wire: H0Cr21Ni10, diameter 2mm; The support tube 7 is machined from a 1Cr18Ni9Ti stainless steel tube with an outer diameter φD1 of 19mm and an inner diameter of 15mm. The length of the support tube 7 is 150mm. One side of the support tube 7 is machined with a 35° bevel angle, consistent with that of the copper tube 3.

[0047] (4) The locking device 2 is made of aluminum alloy or stainless steel plate with a thickness of 20mm, a thickness of 25mm, a length of 100mm, and a width of 40mm. The locking device 2 consists of two symmetrical pressure blocks, namely upper pressure block 8 and lower pressure block 9. Semicircular arcs with a spacing of 60mm between them are machined on the surfaces formed by the length and width of upper pressure block 8 and lower pressure block 9, and their diameters φD2 and φD1 are equal. Four through holes with a diameter of 7mm φD3 are machined on upper pressure block 8 and lower pressure block 9, with a spacing of 75mm between them and a spacing of 18mm between them. Trial assembly of the main vent pipe 1 and copper pipe 3 welded parts, locking device 2, air hood 6 filter screen 5 and auxiliary vent pipe 4 welded parts, support pipe 7, L1 and L2 are equal. Determine the welding position of support pipe 7 on air hood 6 according to dimension L1. During trial assembly, the inclined surface of air hood 6 must be close to copper pipe 3. Weld air hood 6 and support pipe 7 by manual argon arc welding. Welding current: 70A, welding wire: H0Cr21Ni10, diameter 2mm; Assemble the main vent pipe 1 and the support pipe 7 together using the locking device 2. Adjust the locking position so that the air cover 6 is flush with the bottom of the copper pipe 3. Use four M6×60mm bolts to pass through the holes with a diameter of φD3 respectively, and use four M6 nuts to tighten and fix the M6×60mm bolts.

[0048] Example 3 (1) Copper tube 3 processing process: The inner hole is machined in the center of the chromium zirconium copper alloy rod with an outer diameter of 30 mm. Its diameter φD5 is 13 mm; the bevel and notch are machined at the end. The angle A is 32°, the size a is 14 mm, the size b is 31 mm, the size c is 31 mm; the length is 45 mm.

[0049] (2) The main vent pipe 1 is made of 1Cr18Ni9Ti stainless steel pipe with an outer diameter of φD1 and an inner diameter of φD6, where φD1 is 17 mm, φD6 is 14 mm, and the length of the main vent pipe 1 is 110 mm. The main vent pipe 1 and the copper pipe 3 are welded by manual argon arc welding using copper welding wire with a diameter of 3 mm and a welding current of 210 A to form a fillet weld.

[0050] (3) The gas cover 6 is assembled and welded from thin steel plates. The material of the thin steel plate is 1Cr18Ni9Ti stainless steel with a thickness of 1.5mm. The gas cover 6 is a cuboid structure with a width of 33mm, a length of 90mm, and a height of 33mm. A curved surface matching the product surface is processed at the bottom of the gas cover 6. An inclined surface with the same inclination angle as the copper tube 3 is processed on one side of the gas cover 6. A hole with a diameter of φ17mm is processed on the other side of the gas cover 6. The distance between the upper edge of the hole and the inner side of the top of the gas cover 6 is 3mm. The welding current of the gas cover 6 assembled from thin steel plates is 110A, without adding welding wire. The secondary vent pipe 4 is made of 1Cr18Ni9Ti stainless steel pipe with an outer diameter of 17mm and an inner diameter of 14mm. The length of the secondary vent pipe 4 is 135mm. The diameter φd of the small holes on the secondary vent pipe 4 is 1.5mm, and the spacing between the small holes is 1.5mm. One side of the secondary vent pipe 4 is sealed by manual argon arc welding. The filter screen 5 is spot welded above the small holes of the secondary vent pipe 4 to ensure that the filter screen 5 fits tightly with the secondary vent pipe 4. The filter holes on the filter screen 5 are rectangular with a specification of 0.315 mm / 0.14 mm.

[0051] With the curved side of the gas hood 6 facing down and the small hole and filter screen on the auxiliary vent pipe 4 facing up, insert it into the φ17mm hole of the gas hood 6, ensuring that the blocked side of the auxiliary vent pipe 4 faces and contacts the inclined side of the gas hood 6. Weld the auxiliary vent pipe 4 and the gas hood 6 by manual argon arc welding, welding 4 sections, each 6mm long, welding current: 60A, welding wire: H0Cr21Ni10, diameter 2mm; The support tube 7 is machined from a 1Cr18Ni9Ti stainless steel tube with an outer diameter φD1 of 17mm and an inner diameter of 13mm. The length of the support tube 7 is 130mm. One side of the support tube 7 is machined with a 32° bevel angle, consistent with that of the copper tube 3.

[0052] (4) Use steel plate to process locking device 2, weld gas cover 6 and support pipe 7 together, and use locking device 2 to assemble main vent pipe 1 and support pipe 7 together to form laser welding gas protection device.

[0053] The locking device 2 is made of aluminum alloy or stainless steel plate with a thickness of 20mm, a thickness of 23mm, a length of 95mm, and a width of 35mm. The locking device 2 consists of two symmetrical pressure blocks, namely upper pressure block 8 and lower pressure block 9. Semicircular arcs with a spacing of 55mm between them and the length and width of the upper pressure block 8 and lower pressure block 9 are machined on the surface of the upper pressure block 8 and lower pressure block 9, and their diameters φD2 and φD1 are equal. Four through holes with a diameter of 6.8mm between them and the spacing between them are machined on the upper pressure block 8 and lower pressure block 9, with a spacing of 73mm between them and the spacing between them and the spacing between them. Trial assembly of the main vent pipe 1 and copper pipe 3 welded parts, locking device 2, air cover 6 filter screen 5 and auxiliary vent pipe 4 welded parts, support pipe 7, L1 and L2 are equal. Determine the welding position of support pipe 7 on air cover 6 according to dimension L1. During trial assembly, the inclined surface of air cover 6 must be close to copper pipe 3. Manual argon arc welding is used to weld air cover 6 and support pipe 7. Welding current: 60A, welding wire: H0Cr21Ni10, diameter 2mm; Assemble the main vent pipe 1 and the support pipe 7 together using the locking device 2. Adjust the locking position so that the air cover 6 is flush with the bottom of the copper pipe 3. Use four M6×60mm bolts to pass through the holes with a diameter of φD3 respectively, and use four M6 nuts to tighten and fix the M6×60mm bolts.

[0054] In summary, for stainless steel ring-shaped workpieces with a thickness of 3mm-8mm, within the laser welding power range of 3KW-6KW, the gas protection device of the present invention has a continuous service time that is 6 times longer than the original gas protection device, and there is no deformation problem.

[0055] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A gas protection device for off-axis laser welding, characterized in that... Includes main vent pipe (1), locking device (2), copper pipe (3), auxiliary vent pipe (4), filter screen (5), air hood (6), and support pipe (7), wherein: One end of the main vent pipe (1) is the first air inlet, and the other end is welded to the copper pipe (3). The other end of the copper pipe (3) is machined with a bevel and a notch. The bevel is the angle between the axis of the copper pipe (3) and the end face. The notch is connected to the through hole inside the copper pipe. The laser beam passes through the notch and is aimed at the product from top to bottom and emitted to the weld. The blowing center of the copper pipe (3) overlaps with the laser beam spot falling on the surface of the product weld. The gas cover (6) is a box-shaped part with the opening facing downward. The bottom of the gas cover (6) is machined with an arc-shaped surface that matches the product surface. The bottom of the gas cover (6) is flush with the bottom of the copper pipe (3). The arc-shaped surface faces downward and covers the surface of the product weld. One side of the gas cover (6) is machined with a bevel with the same tilt angle as the copper pipe (3) for use as a bevel. The copper tube (3) is attached to the surface and welded together. A through hole is machined on the other side of the gas cover (6). The auxiliary vent pipe (4) is sealed at one end and the other end is the second air inlet. The sealed end enters the interior of the gas cover (6) through the through hole, facing the inclined side of the gas cover (6) and contacting it. Multiple small holes are provided above the auxiliary vent pipe (4). A filter screen (5) is spot welded above the small holes of the auxiliary vent pipe (4). The filter screen (5) is tightly attached to the auxiliary vent pipe (4). A gap is provided between the filter screen (5) and the upper surface of the gas cover (6) so that the protective gas can reach the surface where the product weld is located from both sides of the gas cover (6). The upper surface of the gas cover (6) is welded together with the support pipe (7). The locking device (2) connects the main vent pipe (1) together.

2. The gas protection device for off-axis laser welding according to claim 1, characterized in that, The angle of the copper tube (3) is 30°~35°.

3. The off-axis laser welding gas protection device according to claim 1, characterized in that, The notch width dimension a of the copper tube (3) is 12 mm - 15 mm, and the notch depth dimension b is 30 mm - 32 mm.

4. The gas protection device for off-axis laser welding according to claim 1, characterized in that, The support tube (7) is parallel to the copper tube (3).

5. A gas protection device for off-axis laser welding according to claim 4, characterized in that, The locking device (2) consists of two symmetrical pressure blocks, namely the left pressure block (8) and the right pressure block (9). Both the left pressure block (8) and the right pressure block (9) are machined with two semi-circular arcs with a spacing L2. After the support tube (7) and the main vent tube (1) are held by the semi-circular arc holes of the left pressure block (8) and the right pressure block (9), they are fixed and locked by screws. The spacing L2 is equal to the interval L1 between the support tube (7) and the main vent tube (1).

6. The method for preparing the off-axis laser welding gas protection device according to any one of claims 1 to 5, characterized in that... Includes the following steps: S1. Use copper rods to process copper pipes (3); S2. Use steel pipe to process the main vent pipe (1), and weld the main vent pipe (1) and copper pipe (3) together; S3. Use thin steel plate to process air cover (6), use steel pipe to process auxiliary air pipe (4), cut filter screen (5), weld filter screen (5), auxiliary air pipe (4) and air cover (6) together, and use steel pipe to process support pipe (7). S4. Use steel plate to process locking device (2), weld gas cover (6) and support pipe (7) together, and use locking device (2) to assemble main vent pipe (1) and support pipe (7) together to form laser welding gas protection device.

7. The method for preparing the off-axis laser welding gas protection device according to claim 6, characterized in that, The copper tube (3) is made from chromium-zirconium copper alloy rods, and the processing steps are as follows: An inner hole is machined in the center of the copper rod, and then an angle and a notch are machined at the end of the copper tube (3). The angle is the angle between the axis of the copper tube (3) and the end face. The notch is connected to the through hole inside the copper tube. The laser beam passes through the notch and is aimed at the product from top to bottom and emitted to the weld. The laser beam spot that falls on the surface of the weld of the product overlaps with the air blowing center of the copper tube (3).

8. The method for preparing the off-axis laser welding gas protection device according to claim 6, characterized in that, The main vent pipe (1) and the copper pipe (3) are welded by manual argon arc welding. The welding uses copper welding wire with a diameter of 3mm and a welding current of 200A-220A to form a fillet weld.

9. The method for preparing the off-axis laser welding gas protection device according to claim 6, characterized in that, The specific steps of step S3 are as follows: S3.

1. A gas cover (6) is assembled and welded from thin steel plates. A curved surface matching the product profile is machined at the bottom of the gas cover (6). An inclined surface matching the outer profile of the copper tube (3) is machined on one side of the gas cover (6). A through hole is machined on the other side of the gas cover (6). The distance between the upper edge of the through hole and the inner side of the top of the gas cover (6) is 2mm-4mm. The welding current of the gas cover (6) assembled from thin steel plates is 100A-120A, without adding welding wire. S3.2, process the auxiliary vent pipe (4), the diameter φd of the small hole on the auxiliary vent pipe (4) is 1 mm - 2 mm, the spacing of the small hole is 1 mm - 2 mm, and the side of the auxiliary vent pipe (4) is sealed by manual argon arc welding; S3.

3. Spot weld the filter screen (5) above the small hole of the auxiliary vent pipe (4) so ​​that the filter screen (5) fits tightly with the auxiliary vent pipe (4); S3.

4. With the arc-shaped side of the air hood (6) facing down and the small hole and filter screen on the auxiliary air pipe (4) facing up, insert it into the through hole of the air hood (6) to ensure that the blocked side of the auxiliary air pipe (4) faces the inclined side of the air hood (6) and is in contact with it. Weld the auxiliary air pipe (4) and the air hood (6) by manual argon arc welding. S3.

5. Process the support tube (7) and process one side of the support tube (7) to have the same bevel angle as the copper tube (3).

10. The method for preparing the off-axis laser welding gas protection device according to claim 6, characterized in that, The specific steps of step S4 are as follows: S4.1 The locking device is made of aluminum alloy or stainless steel plate (2). S4.2, trial assembly of the welding parts of the main vent pipe (1) and copper pipe (3), the locking device (2), the welding parts of the air cover (6) filter screen (5) and the auxiliary vent pipe (4), and the support pipe (7). S4.

3. Determine the welding position of the support pipe (7) on the gas cover (6) according to the distance L1 between the support pipe (7) and the main vent pipe (1). During the trial installation, the inclined surface of the gas cover (6) is close to the copper pipe (3). The gas cover (6) and the support pipe (7) are welded by manual argon arc welding. S4.4 Assemble the main vent pipe (1) and support pipe (7) together using locking device (2), adjust the locking position so that the air cover (6) is flush with the bottom of the copper pipe (3), and tighten to fix the locking position.

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