Automatic laser welding device and method for corrugated plate of LNG transport ship

Abstract

The invention belongs to the technical field of corrugated plate welding, and particularly relates to an automatic laser welding device and method for a corrugated plate of an LNG transport ship. The device comprises a corrugated plate clamp, a walking track, a welding trolley and a laser welding machine. The corrugated plate clamp achieves clamping of corrugated sections of the corrugated plate through a four-connecting-rod mechanism composed of a pressing rod, a connecting rod, a telescopic rod and a locking fastener. The walking track is fixed to a base of the corrugated plate clamp, and a rack is arranged on the walking track. A gear meshed with the rack is arranged at the bottom of the welding trolley and carries the laser gun head to move along the track. The laser welding machine modulates a single light spot into a plurality of light spots which are linearly distributed in an array mode, a light spot array is perpendicular to a welding seam, the energy of the light spot in the middle is higher than the energy distribution of the light spots on the two sides, and the method for welding the corrugated plate through the device is provided. When the device is used for welding the corrugated plate of the LNG transport ship, the welding speed is high, the forming quality is good, deformation is small, and consistency is high.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of corrugated plate welding, and particularly relates to a LNG transport ship corrugated plate automatic laser welding device and method. BACKGROUND

[0002] The LNG transport ship is an important part of the whole LNG supply chain and plays an important role in the development and utilization of natural gas. The LNG transport ship has a special cargo containment system, represents the top technology of the world cargo ship manufacturing, and has high requirements on construction process and quality control, and is known as the "pearl on the crown" of the world shipbuilding. At present, the LNG transport ships built in the shipbuilding industry adopt the Mark Ⅲ thin film type cargo containment system technology, and the proportion of which is more than 80%. The main screen wall layer is a 1.2mm thick 304L stainless steel corrugated plate, and the industry mainly uses plasma welding to continuously weld the lap joint corrugated plate weld.

[0003] The existing technology corrugated plate automatic welding technology, for the automatic welding operation of the Mark Ⅲ type cargo containment system corrugated plate, in addition to using the plasma welding technology, domestic and foreign shipyards have begun to research and develop the layout of laser welding technology for continuous welding of the lap joint weld of the corrugated plate. The 1.2mm thick 304L stainless steel corrugated plate constituting the main screen wall layer belongs to a thin plate in the plate classification, and laser welding has obvious advantages in the field of thin plate welding compared with plasma welding in terms of welding efficiency and precision. Laser welding is a method of connecting two or more workpieces by locally heating the welding site with a focused laser beam to melt the material and form a weld. The working principle of laser welding is that the high-energy laser beam generated by the laser is focused to a very small spot by the laser head control system, so that the temperature of the spot area rapidly rises to several thousand degrees Celsius. When the laser beam irradiates the workpiece surface, the material is heated to the melting point in a very short time, and the molten pool is formed. With the movement of the laser beam or the movement of the workpiece, the molten pool cools and solidifies to form a firm weld.

[0004] At present, laser welding has not been applied to the construction of Mark Ⅲ cargo containment system of LNG carrier. There are many reasons for not popularizing the application, for example, the Mark Ⅲ cargo containment system adopts corrugated plates to form the main screen wall layer by lap welding, the corrugated plate is a 304L stainless steel corrugated plate with a three-dimensional corrugated shape, and it is difficult for the laser gun head to realize continuous welding along the lap welding direction of the corrugated plate; it is also difficult to keep the laser gun head at a stable height from the lap welding of the corrugated plate during continuous welding of the welding line by laser welding; in addition, the general laser welding equipment on the market cannot guarantee the quality of the lap welding seam of the corrugated plate, and after the general laser welding is used for continuous welding of the lap welding seam of the corrugated plate, uncontrollable and different degrees of spatter and undercutting appear on both sides of the welding seam, and unacceptable quality defects such as pores appear in the welding seam.

[0005] Therefore, the direct application of existing laser welding technology to the welding of corrugated plates of LNG carriers faces many technical challenges: the three-dimensional corrugated structure of the corrugated plate makes it difficult for the laser gun head to maintain a stable motion trajectory and welding height along the lap welding; the general single-spot laser welding mode is prone to cause spatter and undercutting defects on both sides of the welding seam, and pores and other quality problems are prone to occur in the welding seam; there is a lack of special clamping and guiding devices, which cannot guarantee the stability and repeatability of the welding process. At present, although some shipyards have begun to develop laser welding technology for corrugated plates, a mature engineering application scheme has not yet been formed. Therefore, it is urgent to develop a special automatic laser welding device and method for LNG carrier corrugated plate structure to solve the problems of unstable welding quality, low efficiency and other problems in the prior art, and promote the practical application of laser welding technology in the field of LNG ship construction. SUMMARY

[0006] To solve the problems of low efficiency, unstable quality, high labor intensity and poor consistency of the prior art LNG carrier corrugated plate automatic laser welding, the present application provides a LNG carrier corrugated plate automatic laser welding device, which comprises: a corrugated plate clamp, the corrugated plate clamp comprises: a pressure rod, a connecting rod, a telescopic rod, a locking fastener, a fixed fastener and a base; a four-bar linkage mechanism composed of the pressure rod, the connecting rod, the telescopic rod and the locking fastener realizes clamping and releasing of the locking fastener and the fixed fastener to the corrugated plate size corrugated intersection position; A walking track is fixed on the base of the corrugated plate clamp by bolts, comprising a concave track and a rack arranged on the bottom surface of the track; A welding trolley is arranged on the concave track of the walking track, the bottom of the welding trolley is provided with a gear wheel engaged with the rack, the inside of the welding trolley is provided with a driving motor, and the outside of the welding trolley is provided with a clamping plate for clamping the laser gun head; The laser welding machine is connected with the laser gun head, and is used for generating a laser beam and modulating a light spot shape; the laser welding machine modulates a single light spot into a plurality of light spots in an array linear distribution, and makes the plurality of light spots perpendicular to the lap weld of the corrugated plate, so as to realize that the energy of the middle light spot is higher than the energy of the two side light spots by adjusting the energy distribution of the plurality of light spots.

[0007] According to the automatic laser welding device for the corrugated plate of the LNG transport ship, the locking fastener of the corrugated plate clamp is hinged between the telescopic rod, the locking fastener can move with the telescopic rod and slide along the sliding groove arranged on both sides of the base; the fixing fastener is fixedly connected between the base; the connecting rod is hinged between the pressure rod and the connecting rod, and the connecting rod is hinged between the telescopic rod.

[0008] According to the automatic laser welding device for the corrugated plate of the LNG transport ship, the rack of the walking track is arranged on the bottom surface of the walking track, the rack and the gear at the bottom of the welding trolley form a gear and rack transmission mechanism, and the accurate movement of the welding trolley on the walking track is realized by controlling the rotating speed and direction of the gear.

[0009] According to the automatic laser welding device for the corrugated plate of the LNG transport ship, the driving motor of the welding trolley is a servo motor, which can accurately control the moving speed and position of the welding trolley; the clamping plate is an adjustable structure, which can install laser gun heads of different models.

[0010] According to the automatic laser welding device for the corrugated plate of the LNG transport ship, the optical properties of the laser welding machine include: cumulative output power 10000W, working mode continuous / modulation, beam quality M2≤1.3, light spot shape one-dimensional light spot, light spot distance 0.25mm±0.005mm, power regulation range: single light spot modulation 1%-100%, light spot power setting range 0-2000W, output power deviation ±1.5%, center wavelength 1070±10nm.

[0011] According to the automatic laser welding device for the corrugated plate of the LNG transport ship, the number of the plurality of light spots is 3, 5 or 7; when the number of the plurality of light spots is 5, the power setting range of the middle light spot is 1000-1200W, the power setting range of the two inner light spots is 750-950W, and the power setting range of the two outer light spots is 500-700W.

[0012] According to the automatic laser welding device for the corrugated plate of the LNG transport ship, the distance between the laser gun head and the lap weld of the corrugated plate is 0.25mm±0.005mm, and the distance is kept stable during the whole welding process.

[0013] According to the automatic laser welding device for the corrugated plate of the LNG transport ship, the base of the corrugated plate clamp is provided with a plurality of screw holes for being connected with the walking track through bolts, so that the walking track can be quickly installed and fixed.

[0014] According to the automatic laser welding device for the corrugated plate of the LNG transport ship, the welding trolley is further provided with a position sensor and a height sensor for detecting and adjusting the position and height of the laser gun head in real time.

[0015] A welding method using the automatic laser welding device for the corrugated plate of the LNG transport ship comprises the following steps. S1: tearing off the protective film within the range of about 100 mm from the edge of the front surface of the corrugated plate to be assembled; S2: trimming the edge of the corrugated plate to be assembled using a burr trimming knife or sandpaper; S3: cleaning the range of 60 mm on both sides of the welding bead of the corrugated plate to be assembled using acetone; S4: cleaning the plywood under the corrugated plate to be assembled, the anchor strip and the steel corner area using a dust collector, and checking whether there are foreign matters under the corrugated plate to be assembled; S5: polishing and cleaning the corrugated plate to be welded at the steel corner position of the bulkhead using a stainless steel brush; S6: completing the positioning of the corrugated plate by manual welding, and forming the main screen wall by welding the first corrugated plate of the bulkhead with the steel corner and the anchor strip; S7: performing intermittent manual welding on the anchor strip position of the first corrugated plate and continuous manual welding on the folding edge position; S8: repeating the steps S1-S5 to complete the film tearing, trimming and cleaning work of the second corrugated plate, confirming the welding bead position and the cleanliness of the corrugated plate surface, and assembling the second corrugated plate; S9: performing intermittent manual welding on the anchor strip position of the second corrugated plate, continuous manual welding on the folding edge position and positioning welding on the adjacent corrugated plate; S10: confirming the gap before welding using a feeler gauge, and cleaning the range of ≥60 mm on both sides of the lap welding seam of the corrugated plate using anhydrous ethanol; S11: installing the corrugated plate clamp at the wave knot on the side of the lap welding seam of the two corrugated plates; S12: fastening the walking track to the bottom of the corrugated plate clamp through bolts and nuts, and adjusting the walking track to be kept in a horizontal state; S13: installing the laser gun head on the welding trolley, and placing the welding trolley on the walking track; S14: modulating the spot shape of the one-dimensional spot of the laser welding machine, modulating the single spot of the laser welding machine into a plurality of multi-spots, and confirming that the multi-spots are distributed in an arrayed straight line; S15: Confirm that the multiple light spots in an array are distributed in a straight line and perpendicular to the lap weld of the corrugated plate, and adjust the distance between the laser gun head and the lap weld of the corrugated plate to 0.25mm; S16: Set the power range of each light spot, and the light spots are sequentially labeled from left to right, the power of the light spot labeled as the middle position is set to 1000-1200W, the power of the light spot labeled inside is set to 750-950W, and the power of the light spot labeled outside is set to 500-700W; S17: Complete the pre-welding walking test, check the distance change between the laser gun head and the to-be-welded weld, and ensure that the laser gun head moves along the lap weld path of the corrugated plate at the same height; S18: Start the laser welder to start laser welding, and observe the weld forming shape in real time; S19: During laser welding, monitor the parameter changes of the laser welder and the height, speed and angle changes of the laser gun head at different positions, and adjust in time when deviation occurs; S20: After laser welding is completed, the laser welder is turned off, and the gas source and the main power supply are cut off.

[0016] The beneficial effects of the present application are: 1. Significantly improve the welding quality and reliability. Compared with the existing plasma welding and general laser welding technology, the present application can form a molten pool by the middle light spot (1000-1200W) through the energy difference distribution of multiple light spots, and the two side light spots (500-950W) can undertake the functions of preheating and heat preservation, so that the temperature gradient of the welding area tends to be flat, and the spatter and undercut phenomena are effectively inhibited. At the same time, the slow cooling of the molten pool promotes the escape of internal gas, completely solving the problem of porosity. Combined with the special corrugated plate clamp, the welding trajectory is stable, the weld is uniformly and densely formed, the sealing performance is significantly improved, and the high standard quality requirements of the main screen wall layer of the LNG transport ship are completely met.

[0017] 2. Realize precise control and stability of the welding process. The present application ensures that the laser gun head moves along the lap weld path of the corrugated plate at the same height through the rigid connection of the corrugated plate clamp and the walking track, and the precise transmission of the gear and rack of the welding trolley, and the height fluctuation is controlled within ±0.005mm. Compared with traditional manual or general equipment, the present application overcomes the trajectory deviation problem caused by the three-dimensional shape of the corrugated plate, the light spot centering accuracy is significantly improved, the stable input of laser energy is ensured, and the consistency and repeatability of the welding process are fundamentally improved.

[0018] 3. Greatly improve production efficiency and automation. The present application integrates special fixture, precision track, automatic welding trolley and multi-spot laser system to realize the full-process automation of lap welding of corrugated plate. Compared with traditional plasma welding, the laser welding speed is increased by more than 30%, and there is no need for frequent manual adjustment. The welding trolley automatically walks along the track, and the operator only needs to monitor the parameters, greatly reducing manual intervention and labor consumption, especially suitable for the batch construction demand of LNG transport ship, and the overall construction efficiency is significantly improved.

[0019] 4. Effectively reduce energy consumption and material cost. The present application realizes local precise heating through multi-spot energy optimization distribution, reduces the total heat input by about 20% compared with traditional plasma welding, and significantly reduces energy consumption. At the same time, the great reduction of welding defect rate avoids the material loss and energy waste caused by rework. The standardization of cleaning and preparation steps reduces the unnecessary use of consumables such as acetone and sandpaper, conforms to the green manufacturing concept, and effectively controls the overall construction cost.

[0020] 5. Easy to operate and environmentally friendly. The tooling structure of the present application is simple and intuitive, and the clamping and adjustment operation is convenient, which can be completed by non-professional welders. The laser welding process is smokeless and low noise, which reduces the emission of harmful gas and dust compared with plasma arc welding. The integrated degree of the whole system is high, and the site layout is flexible, which is suitable for the complex construction environment of shipyard, significantly improves the working conditions, reduces environmental pollution, and meets the environmental protection development requirements of modern shipbuilding industry. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic diagram of an LNG transport ship corrugated plate automatic laser welding device of the present application.

[0022] Figure 2 is a perspective view of a structural schematic diagram of a corrugated plate fixture of an LNG transport ship corrugated plate automatic laser welding device of the present application.

[0023] Figure 3 is a top view of a structural schematic diagram of a corrugated plate fixture of an LNG transport ship corrugated plate automatic laser welding device of the present application.

[0024] Figure 4 is a top view of a structural schematic diagram of a running track of an LNG transport ship corrugated plate automatic laser welding device of the present application.

[0025] Figure 5 is a top view of the running track of the LNG transport ship corrugated plate automatic laser welding device of the present application installed on the corrugated plate fixture.

[0026] Figure 6 is a structural schematic diagram of the running track and the corrugated plate fixture installing the corrugated plate of the present application.

[0027] Figure 7 Figure 1 is a structure schematic diagram of a laser welding machine and a laser gun head arranged on a welding trolley of an automatic laser welding device for corrugated plates of an LNG transport ship according to the present application.

[0028] Figure 8 Figure 2 is a schematic diagram of a corrugated plate to be welded area of the automatic laser welding device for corrugated plates of the LNG transport ship according to the present application.

[0029] Figure 9 Figure 3 is a comparative schematic diagram of a traditional single-spot a and a multi-spot b used according to the present application for laser welding in a lap joint to-be-welded area.

[0030] In the figure, 1 is a corrugated plate clamp, 10 is a corrugated plate, 11 is a pressing rod, 12 is a connecting rod, 13 is an extension rod, 14 is a locking fastener, 15 is a fixing fastener, 16 is a sliding groove, 17 is a base, 2 is a running track, 21 is a concave track, 22 is a rack, 3 is a welding trolley, 31 is a gear, 4 is a laser welding machine, 5 is a laser gun head, HJX is a welding straight line, and DHQ is a to-be-welded area. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0032] As shown in Figures 1 to 7 Figure 1, the automatic laser welding device for corrugated plates of the LNG transport ship according to the present embodiment comprises a corrugated plate clamp 1, a running track 2, a welding trolley 3, a laser welding machine 4 and its attached laser gun head 5.

[0033] The corrugated plate clamp 1 firmly clamps two pieces of corrugated plates to be welded at the corrugated section position, ensures the stability of the joint during welding, and provides an installation reference for the running track 2.

[0034] The corrugated plate clamp 1 comprises a pressing rod 11, a connecting rod 12, an extension rod 13, a locking fastener 14, a fixing fastener 15, a sliding groove 16 and a base 17.

[0035] The base 17 is the base body of the clamp and is processed from high-strength steel material to ensure the overall rigidity. A plurality of screw holes are arranged on the upper surface of the base 17 for reliable connection with the running track 2 through bolts. A sliding groove 16 is arranged on each side of the base 17, and the sliding groove 16 is a precisely processed straight guide rail for guiding the sliding of the locking fastener 14.

[0036] The fixed fastener 15 is fixedly connected to one end of the base 17. Its lower end is rigidly connected to the base 17, and its upper end is designed with a curved surface or toothed structure matching the shape of the corrugated section of the corrugated plate, so as to increase the friction and prevent damage to the plate or sliding during clamping.

[0037] The locking fastener 14 is arranged opposite to the fixed fastener 15. The lower part of the locking fastener 14 is connected to the end of the telescopic rod 13 through a hinged shaft, and its bottom is provided with a sliding block embedded in the sliding groove 16 of the base 17. This allows the locking fastener 14 to move with the telescopic rod 13 and smoothly slide along the sliding groove 16. The upper end is also provided with a clamping surface matching the corrugated section.

[0038] The telescopic rod 13 can use air pressure, hydraulic pressure or electric push rod to realize its telescopic function. One end of the telescopic rod 13 is hinged to the locking fastener 14, and the other end is hinged to the connecting rod 12.

[0039] The pressing rod 11 is hinged to the connecting rod 12, the other end of the connecting rod 12 is hinged to the telescopic rod 13, and the middle or end of the pressing rod 11 is hinged to the base 17 through a fixed shaft to form a hinged fulcrum. Thus, the pressing rod 11, the connecting rod 12, the telescopic rod 13 and the base 17 together form a four-bar linkage mechanism.

[0040] When the free end of the pressing rod 11 is pressed downward, the telescopic rod 13 is driven to extend through the transmission of the four-bar linkage mechanism, and then pushes the locking fastener 14 to slide along the sliding groove 16 towards the fixed fastener 15, thereby realizing the clamping of the corrugated section of the corrugated plate placed between them. When the pressing rod 11 is lifted, the mechanism moves in reverse, the locking fastener 14 retreats, and the corrugated plate is released. This lever clamping method provides sufficient and stable clamping force, and is convenient to operate.

[0041] The walking track 2 is the movement guide and driving basis of the welding trolley 3, which must have high straightness, flatness and rigidity.

[0042] The walking track 2 is fixed to the base 17 of the corrugated plate clamp 1 by high-strength bolts. It includes a concave track 21 and a rack 22.

[0043] The concave track 21 has a cross-section in the shape of a "concave" character, which provides an accurate guide and support surface for the walking wheels of the welding trolley 3, preventing the trolley from derailing.

[0044] The rack 22 is fixedly installed on the bottom surface of the walking track 2, i.e. the inner bottom surface of the concave track. The accuracy of the rack 22 directly affects the positioning accuracy of the welding trolley 3.

[0045] The welding trolley 3 is a mobile platform for performing welding operations, carrying the laser gun head 5 and driving it to move accurately along the weld.

[0046] The welding trolley 3 is arranged on the concave track 21 of the walking track 2. Inside it is integrated with a driving module, a control module and a sensing module.

[0047] The gear 31 is installed at the bottom of the welding trolley 3 and precisely engages with the rack 22 on the walking track 2, constituting a gear-rack transmission mechanism.

[0048] The driving motor is preferably a high-precision servo motor. It drives the gear 31 to rotate, and by controlling the rotation speed and direction of the servo motor, stepless speed regulation, precise displacement and forward and reverse movement of the welding trolley 3 on the walking track 2 can be achieved.

[0049] The clamping plate is arranged outside the welding trolley 3 and is used to clamp the laser gun head 5. The clamping plate is of an adjustable structure, for example, the clamping aperture or position is adjusted by a knob, which can be compatible with the installation of laser gun heads 5 of different models and sizes, enhancing the versatility of the device.

[0050] Sensor system: The welding trolley 3 is also integrated with a position sensor and a height sensor. The position sensor, such as a rotary encoder, cooperates with the driving motor to feedback the position of the trolley in real time, constituting a closed-loop control.

[0051] The height sensor, such as a laser displacement sensor or a contact probe, is used to detect the distance change between the laser gun head 5 and the surface of the corrugated plate in real time and feedback the signal to the control system. The control module can drive the fine adjustment mechanism inside the clamping plate, such as a piezoelectric ceramic or a servo motor, to dynamically adjust the height of the laser gun head 5 during welding, so that it maintains a constant distance from the weld.

[0052] The laser welding machine 4 is the welding energy source, and its performance parameters and beam control ability are crucial. The brand of the laser welding machine 4 in this embodiment is Zide Zone 5.0; the model is MZCZ5.0 2000 / 10000 (W), and its specific optical properties include: Cumulative output power: ≥10000W, to ensure sufficient penetration capacity.

[0053] Working mode: continuous / modulation optional, suitable for different process requirements.

[0054] Beam quality: M² ≤ 1.3, to ensure that the beam can be focused into a very small spot, with concentrated energy.

[0055] The laser welding machine 4 is integrated with a special optical system inside, such as a beam splitter and a shaper, which can modulate the traditional single-point Gaussian spot into multiple spots in an array-type straight-line distribution.

[0056] Spot distance: the center-to-center distance between adjacent spots is 0.25mm ± 0.005mm.

[0057] Power regulation: precise power control can be performed independently for each spot. Single-spot amplitude modulation range 1% ~ 100%, spot power setting range 0-2000W, output power deviation controlled within ±1.5%.

[0058] Center wavelength: 1070nm ±10nm.

[0059] The laser gun head 5 is connected with the laser welding machine 4 through an optical fiber, and usually contains a collimating mirror, a focusing mirror and a protective gas nozzle inside. It is firmly clamped on the clamping plate of the welding trolley 3. During the welding process, the distance between the laser gun head 5 and the lap weld of the corrugated plate is kept stable at 0.25mm ± 0.005mm through sensing and control system.

[0060] For lap welding of corrugated plate, a single spot is modulated into multiple, for example, 3, 5 or 7, linearly arranged spots, and the straight line is perpendicular to the direction of the lap weld of the corrugated plate. More importantly, by adjusting the optical system, the energy of the middle spot is higher than that of the two side spots.

[0061] As shown in Figure 8 and Figure 9 Take the 5 multi-spot configuration of the present embodiment as an example: The middle spot, marked as 3#: power setting is 1000 ~ 1200W. As the main energy input, it is mainly responsible for penetration and forming the main body of the weld.

[0062] The two inner spots, marked as 2# and 4#: power setting is 750 ~ 950W. They play the role of auxiliary heating, stabilizing the molten pool and improving the weld forming.

[0063] The two outer spots, marked as 1# and 5#: power setting is 500 ~ 700W. They mainly perform preheating and slow cooling, reduce welding stress and inhibit crack generation.

[0064] This energy distribution pattern forms a wide and gentle heat source, significantly improves the tolerance to weld gap and misalignment, effectively prevents weld deviation and undercut, and is particularly suitable for welding of three-dimensional curved welds.

[0065] The method for automatic laser welding of corrugated plate of LNG carrier using the above device includes the following steps: Preparation of the plate before welding: tear off the protective film of the corrugated plate to be assembled within a range of about 100 mm from the edge of the front surface, exposing the clean metal surface. Use a burr trimming knife or fine sandpaper to carefully trim the edge of the corrugated plate to be assembled, remove burrs and oxides, and ensure the assembly gap. Use acetone or a special metal cleaner to thoroughly wipe and clean at least 60 mm of the corrugated plate to be assembled on both sides of the welding bead, removing oil, moisture and impurities. Use a vacuum cleaner to thoroughly clean the plywood base, anchor strip and steel corner area below the corrugated plate to be assembled, and carefully check to confirm that there are no foreign objects. At the steel corner position of the bulkhead, use a stainless steel brush to polish and clean the corrugated plate welding area until the metal luster is exposed.

[0066] Positioning and manual welding of the first corrugated plate: use manual welding to complete the preliminary positioning and welding of the first corrugated plate with the steel corner and anchor strip, forming the basis of the main screen wall. Perform intermittent manual welding on the connection position of the first corrugated plate and the anchor strip; perform continuous manual welding on the folded edge position.

[0067] Assembly and positioning of subsequent corrugated plates: repeat the film tearing, trimming and cleaning steps for the second corrugated plate. Assemble the second corrugated plate to the predetermined position, carefully check its lap relationship with the first corrugated plate, welding bead position and surface cleanliness. Perform intermittent manual welding on the anchor strip position of the second corrugated plate, and perform continuous manual welding on the folded edge position, and perform several spot welds at intervals on the adjacent lap weld between the first and second corrugated plates to preliminarily connect the two plates.

[0068] Final confirmation before laser welding and installation of the device: use a feeler gauge to confirm the gap before welding of the entire length of the corrugated plate lap weld, ensuring that the gap is within the allowable range of the laser welding process, with a requirement of ≤0.1 mm. Use anhydrous ethanol to perform final cleaning before welding within a range of ≥60 mm on both sides of the corrugated plate lap weld. Install a plurality of corrugated plate clamps 1 at the wave joints on both sides of the corrugated plate lap weld at intervals, for example, 0.5-1 meters. Press down the pressing rod 11 of each clamp, so that the locking buckle 14 and the fixed buckle 15 firmly clamp the corrugated plate. Fasten the walking track 2 to the base 17 of the corrugated plate clamp 1 already installed below by means of bolts and nuts. Use a level to adjust the walking track 2 to ensure that it remains horizontal throughout the length of the weld, or is consistent with the macroscopic undulations of the corrugated plate. Reliably install the laser gun head 5 on the clamping plate of the welding trolley 3 and ensure that it is clamped. Then place the welding trolley 3 at the starting welding position of the walking track 2.

[0069] Laser welder parameter setting and calibration: start the laser welder 4, and modulate the spot shape through its control interface. Select the multi-spot mode, and set the number to 5. Confirm that the 5 spots are in a uniform array linear distribution through internal monitoring or external instruments. Manually fine-tune the angle of the welding trolley 3 or the laser gun head 5 to confirm that the array linear distribution of the multi-spots is perpendicular to the path of the lap weld of the corrugated sheet. Adjust the height of the laser gun head 5 to keep the distance to the lap weld of the corrugated sheet stable at 0.25 mm.

[0070] Set the power of each spot. According to the aforementioned strategy, set the power of the middle 3rd spot to 1100 W, the power of the inner 2nd and 4th spots to 850 W, and the power of the outer 1st and 5th spots to 600 W. Without emitting laser, start the welding trolley 3 to run along the walking track 2 for one round. Check whether the distance between the laser gun head 5 and the weld to be welded is within the allowable fluctuation range, ±0.005 mm, through the feedback data of the height sensor or visual observation. Ensure that the moving track of the laser gun head 5 can accurately follow the three-dimensional path of the lap weld of the corrugated sheet for equal height or preset track movement.

[0071] Perform welding and process monitoring: after confirming that all parameters are correct, start the output of the laser welder 4 and the drive of the welding trolley 3 to start automatic laser welding. At the same time, turn on the shielding gas. Observe the forming shape of the initial segment of the weld in real time, and confirm that the weld width, excess height, and color are normal, without defects such as spatter and undercut. During the entire laser welding process, monitor whether the parameters such as the power and voltage of the laser welder 4 are stable. At the same time, closely observe the automatic adjustment of the height, moving speed, and attitude angle of the laser gun head 5 at different positions such as the wave crest and wave trough displayed by the control system. If it is found that the parameters are out of the preset range or the weld forming is abnormal, timely suspend and intervene to adjust through the control system.

[0072] Post-welding treatment: when the welding trolley 3 runs to the end of the track, the laser welding cycle is completed. Turn off the laser output of the laser welder 4 in sequence, then turn off the power of the welding trolley 3, and finally cut off the total power of the shielding gas source and device. After the weld is cooled, perform necessary non-destructive testing such as PT penetration testing and appearance inspection.

[0073] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacement or change within the technical range disclosed by the present application according to the technical solution and inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. An automatic laser welding device for LNG carrier corrugated panel, characterized in that, The utility model relates to a corrugated plate welding device, comprising: A corrugated plate clamp (1) comprises a pressing rod (11), a connecting rod (12), an extension rod (13), a locking fastener (14), a fixed fastener (15) and a base (17); the four-bar linkage mechanism formed by the pressing rod (11), the connecting rod (12), the extension rod (13) and the locking fastener (14) realizes the clamping and releasing of the locking fastener (14) and the fixed fastener (15) on the position of the corrugated section of the corrugated plate; A walking track (2) is fixed on the base (17) of the corrugated plate clamp (1) by bolts, comprising a concave track (21) and a rack (22) arranged on the bottom surface of the track (21); A welding trolley (3) is arranged on the concave track (21) of the walking track (2), and the bottom thereof is provided with a gear (31) engaged with the rack (22), the inside thereof is provided with a driving motor, and the outside thereof is provided with a clamping plate for clamping a laser gun head (5); A laser welding machine (4) is connected with the laser gun head (5) and is used for generating a laser beam and modulating the spot shape; the laser welding machine (4) modulates a single spot into a plurality of spots in an array type linear distribution, and makes the plurality of spots perpendicular to the lap weld of the corrugated plate, so that the energy of the middle spot is higher than that of the two side spots by adjusting the energy distribution of the plurality of spots.

2. The automatic laser welding device for corrugated plates of an LNG carrier according to claim 1, wherein The locking fastener (14) and the extension rod (13) of the corrugated plate clamp (1) are hinged, the locking fastener (14) can move with the extension rod (13), and slides along the sliding groove (16) arranged on both sides of the base (17); the fixed fastener (15) is fixedly connected with the base (17); the pressing rod (11) and the connecting rod (12) are hinged, and the connecting rod (12) and the extension rod (13) are hinged.

3. The automatic laser welding device for corrugated panels of an LNG carrier according to claim 2, characterized in that, The rack (22) of the walking track (2) is arranged on the bottom surface of the walking track (2), the rack (22) and the gear (31) on the bottom of the welding trolley (3) form a gear and rack transmission mechanism, and the accurate movement of the welding trolley (3) on the walking track (2) is realized by controlling the rotating speed and direction of the gear (31).

4. The automatic laser welding device for corrugated panels of an LNG carrier according to claim 3, characterized in that, The driving motor of the welding trolley (3) is a servo motor, which can accurately control the moving speed and position of the welding trolley; the clamping plate is an adjustable structure, which can install different models of laser gun heads (5).

5. The automatic laser welding device for corrugated panels of an LNG carrier according to claim 4, characterized in that, The optical properties of the laser welding machine (4) include: cumulative output power 10000W, working mode continuous / modulation, beam quality M2≤1.3, spot shape one-dimensional spot, spot distance 0.25mm±0.005mm, power adjustment range: single spot amplitude 1%-100%, spot power setting range 0-2000W, output power deviation ±1.5%, center wavelength 1070±10nm.

6. The automatic laser welding device for corrugated panels of an LNG carrier according to claim 5, characterized in that, The number of the plurality of spots is 3, 5 or 7; when the number of the plurality of spots is 5, the power setting range of the middle spot is 1000-1200W, the power setting range of the two inner spots is 750-950W, and the power setting range of the two outer spots is 500-700W.

7. The automatic laser welding device for corrugated panels of an LNG carrier according to claim 6, characterized in that, The distance between the laser gun head (5) and the lap weld of the corrugated plate is 0.25mm±0.005mm, and the distance is kept stable during the whole welding process.

8. The automatic laser welding device for corrugated panels of an LNG carrier according to claim 7, characterized in that, The base of the corrugated plate clamp (1) is provided with a plurality of screw holes for connecting with the walking track (2) through bolts to realize quick installation and fixation of the walking track (2).

9. The automatic laser welding device for corrugated panels of an LNG carrier according to claim 8, characterized in that, The welding trolley (3) is also provided with a position sensor and a height sensor for real-time detection and adjustment of the position and height of the laser gun head (5).

10. A welding method using the automatic laser welding device for corrugated plates of an LNG carrier according to any one of claims 1 to 9, characterized by, It comprises the following steps: S1: tear off the protective film within the range of about 100mm from the edge of the front surface of the corrugated plate to be assembled; S2: use a burr trimming knife or sandpaper to trim the edge of the corrugated plate to be assembled; S3: use acetone to clean the range of 60mm on both sides of the weld of the corrugated plate to be assembled; S4: use a vacuum cleaner to clean the plywood under the corrugated plate to be assembled, the anchor strip and the steel corner area, and at the same time check whether there are foreign matters under the corrugated plate to be assembled; S5: use a stainless steel brush to polish and clean the area to be welded of the corrugated plate at the steel corner position of the bulkhead; S6: use manual welding to complete the positioning of the corrugated plate, and make the first corrugated plate of the bulkhead form the main screen wall by welding with the steel corner and the anchor strip; S7: perform intermittent manual welding on the anchor strip position of the first corrugated plate and continuous manual welding on the folded edge position; S8: repeat steps S1-S5 to complete the film tearing, trimming and cleaning of the second corrugated plate, confirm the weld position and the cleanliness of the surface of the corrugated plate, and assemble the second corrugated plate; S9: perform intermittent manual welding on the anchor strip position of the second corrugated plate, continuous manual welding on the folded edge position, and positioning welding on the adjacent corrugated plate; S10: use a feeler gauge to confirm the gap before welding, and use anhydrous ethanol to clean the range of ≥60mm on both sides of the lap weld of the corrugated plate; S11: install the corrugated plate clamp at the wave knot on both sides of the lap weld of the corrugated plate; S12: fasten the walking track (2) to the bottom of the corrugated plate clamp (1) through bolts and nuts, and adjust the walking track (2) to keep it in a horizontal state; S13: install the laser gun head (5) on the welding trolley (3), and place the welding trolley (3) on the walking track (2); S14: modulate the spot shape of the one-dimensional spot of the laser welder (4), modulate the single spot of the laser welder (4) into several multi-spots, and confirm that the multi-spots are arrayed in a straight line; S15: confirm that the arrayed multi-spots in a straight line are perpendicular to the lap weld of the corrugated plate, and adjust the distance between the laser gun head (5) and the lap weld of the corrugated plate to 0.25mm; S16: set the power range of each spot, mark the spots from left to right, and set the power range of the spot marked as the middle position to 1000-1200W, the power range of the spot marked inside to 750-950W, and the power range of the spot marked outside to 500-700W; S17: complete the pre-welding walking test, check the distance change between the laser gun head (5) and the weld to be welded, and ensure that the moving track of the laser gun head (5) moves along the path of the lap weld of the corrugated plate at the same height. S18: start the laser welder (4) to begin laser welding, and observe the weld formation shape in real time; S19: during laser welding, monitor the laser welder (4) parameter changes and the laser gun head (5) height, speed, angle changes in different positions, and adjust in time when deviation occurs; S20: laser welding is completed, the laser welder (4) is turned off, and the gas source and the main power supply are cut off.

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