Narrow-gap multilayer parallel penetration welding rib plate and manufacturing method thereof

Abstract

The narrow-gap multi-layer parallel penetration welding rib plate comprises a bottom plate, a middle rib plate is arranged on one side of the bottom plate, after the middle rib plate and the bottom plate are welded, a first welding seam is formed at the top, and a second welding seam is formed at the bottom; side rib plates are arranged at the top end and the bottom end of the side face, where the middle rib plate is welded, of the bottom plate, the outer sides of the side rib plates and the rib plates are welded to form third welding seams, and ceramic gaskets are arranged at the positions, attached to the bottom plate, of the faces, facing the middle rib plate, of the side rib plates. The middle rib plate adopts the inequilateral double-groove and the welding sequence of'large first and small second ', and mechanical straightening is matched, so that the perpendicularity error is reduced; the two side rib plates are fixed through a special clamp, so that the parallelism error is effectively reduced; and the ceramic gasket realizes single-side welding and double-side forming of the welding seam, the problem of narrow-gap reverse welding is avoided, and the nondestructive testing qualification rate of the welding seam is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of steel structure welding technology, specifically to a narrow-gap multi-layer parallel penetration welded stiffening plate and its manufacturing method. Background Technology

[0002] As modern steel structure engineering develops towards larger scale and higher efficiency, the requirements for steel structure installation period are becoming increasingly stringent. In order to reduce on-site welding workload and improve construction efficiency, pin shaft connection nodes are widely used in steel structure design due to their convenient installation. Such nodes often use multi-layer narrow gap penetration welding to connect the stiffening plate and the base plate.

[0003] The existing multi-layer narrow-gap stiffener welding technology has the following key problems: Deformation of stiffeners leads to insufficient precision: The gap between stiffeners is usually ≤5mm. During welding, the concentration of thermal stress can easily cause the perpendicularity deviation between the middle stiffener and the bottom plate (the deviation can reach 1.0-1.5mm / m using traditional methods). The two side stiffeners will also have parallelism deviation with the middle stiffener, which requires subsequent flame correction. However, flame correction will reduce the yield strength of the stiffener material by 5%-10%, affecting the load-bearing stability of the joint. Moreover, the correction efficiency is low and the cost is high.

[0004] Challenges in reverse welding and poor weld quality: Due to the narrow gap between the stiffening plates, the reverse sides of the two side stiffening plates cannot be directly welded. The traditional method is to use steel strips for reverse protection, but the gap between the steel strips and the bevel is prone to porosity and slag inclusions, resulting in a weld non-destructive testing pass rate of less than 70%, a high rework rate, and further extending the construction period.

[0005] Low process versatility and efficiency: Traditional processes do not optimize bevel parameters for different plate thicknesses, and there are no unified standards for welding parameters. Insufficient penetration or excessive burn-through is prone to occur. Furthermore, the process is highly dependent on the welder's skills, resulting in poor quality stability during mass production.

[0006] Therefore, there is an urgent need for a narrow-gap, multi-layer parallel penetration welding method that can balance stiffener precision, weld quality, and construction efficiency to meet the high-performance requirements of pin connection nodes in steel structure engineering. Summary of the Invention

[0007] The purpose of this invention is to provide a narrow-gap multi-layer parallel penetration welded stiffener and its manufacturing method, aiming to improve the problems of insufficient precision caused by stiffener deformation during welding of existing multi-layer narrow-gap stiffeners, difficulties in reverse welding, poor weld quality, and low process versatility and efficiency.

[0008] This invention is implemented as follows: To achieve the above objectives, according to one aspect of the present invention, a narrow-gap multi-layer parallel penetration welded stiffener plate is provided, comprising a base plate, a central stiffener plate on one side of the base plate, a first weld at the top of the central stiffener plate and a second weld at the bottom after welding; side stiffener plates are provided at the top and bottom of the side of the base plate where the central stiffener plate is welded, a third weld is formed between the outer side of the side stiffener plate and the stiffener plate, and a ceramic backing is provided on the side of the side stiffener plate facing the central stiffener plate at the position in contact with the base plate; the central stiffener plate adopts an unequal-sided double-bevel and a "large to small" welding sequence, combined with mechanical straightening, to reduce verticality error; the two side stiffener plates are fixed by a special clamp to reduce parallelism error.

[0009] Preferably, the top of the end of the central stiffening plate that is attached to the bottom plate has a large bevel and the bottom has a small bevel, which are used to weld the central stiffening plate and the bottom plate together; the side stiffening plate has a side bevel on the side facing outward near the bottom plate, which are used to weld the side stiffening plate and the bottom plate together, and a gap is left between the side stiffening plate and the bottom plate.

[0010] According to a second aspect of the present invention, the present invention provides a method for manufacturing a narrow-gap multilayer parallel penetration welded stiffener plate, the specific steps of which are as follows: S100, Rib Plate Cutting and Beveling: Cut the rib plates according to the design drawings. Process the end of the middle rib plate that is attached to the bottom plate into an unequal double-sided bevel, thus forming a large bevel and a small bevel. Process the two side rib plates into single-sided side bevels. S200, Assembly and welding of intermediate stiffening plates: Mark the installation position of the stiffening plates on the base plate, assemble the intermediate stiffening plates, and weld the intermediate stiffening plates after inspection and approval. S300, Inspection and Straightening of Intermediate Rib Plate: After welding, non-destructive testing is performed on the weld of the intermediate rib plate. At the same time, the perpendicularity of the intermediate rib plate to the base plate is checked. If the perpendicularity error exceeds the limit, straightening is performed until it meets the requirements. S400, Installation and fixing of two side stiffeners: After the intermediate stiffener is inspected and approved, install two side stiffeners on the base plate, control the gap between the two side stiffeners and the base plate to be 4mm, spot weld the two side stiffeners, install a special clamp, adjust the parallelism between the two side stiffeners and the intermediate stiffener to meet the requirements, and tighten the clamping components of the clamp to fix the two side stiffeners. S500, Ceramic gasket installation and welding: Ceramic gaskets are installed on the reverse side of the single-sided large bevel of the two side stiffeners. After cleaning the impurities in the bevel, the two side stiffeners are welded through penetration. S600 Weld Inspection and Fixture Removal: After welding is completed, ultrasonic testing is performed on the welds of the two side stiffener plates. If defects exceeding the standard are found, rework is carried out. After passing the test, the special fixture is removed. S700, Rib Plate Grinding and Inspection: Grind the surface of all rib plates and the weld area. After inspection and approval, mark the components and proceed to the next process.

[0011] Preferably, in step S100, the large bevel depth of the unequal-sided double-sided bevel is 2 / 3-3 / 4 of the thickness of the intermediate stiffener plate, the small bevel depth is 1 / 3-1 / 4 of the thickness of the intermediate stiffener plate, the side bevel depth is 3 / 4-4 / 5 of the thickness of the two side stiffener plates, and the bevel angle is adjusted according to the stiffener plate thickness to meet the requirements of penetration welding.

[0012] Preferably, in step S200, the welding sequence of the central stiffener is as follows: first, weld the large bevel of the unequal double-sided bevel, then perform root cleaning treatment on the small bevel side, and finally weld the small bevel.

[0013] Preferably, in step S200, the assembly area of ​​the intermediate stiffener and the base plate is preheated before welding. The preheating temperature is 80-120℃, and the preheating temperature increases with the thickness of the stiffener. The root cleaning is carried out by mechanical root cleaning, specifically by grinding with an angle grinder. The root cleaning depth is 2-3mm. After root cleaning, the metallic luster of the stiffener substrate is exposed, and there is no oxide scale or slag residue.

[0014] Preferably, in step S300, the non-destructive testing is performed using ultrasonic testing or radiographic testing, and the allowable error for the perpendicularity is ≤0.3mm / m.

[0015] Preferably, the clamp in step S400 includes a clamping frame and a pressing assembly. The clamping frame is engaged with the middle rib plate, and pressing assemblies are installed at both ends of the clamping frame. The pressing assemblies press against the outer side of the side rib plate to fix the position of the side rib plate.

[0016] Preferably, the clamping frame has a central bayonet in the middle, and side bayonets are provided above and below the central bayonet. The clamping frame also has threaded holes at its top and bottom. The clamping assembly includes a clamping screw and a pressure plate. The clamping screw is threadedly connected to the threaded hole, and a rotating handle is provided at the top of the clamping screw. An adapter shaft is provided at the bottom of the clamping screw. An adapter is provided on the upper surface of the pressure plate, and a bearing is provided in the middle of the adapter. The adapter shaft is interference-fitted with the bearing.

[0017] Preferably, in step S500, the ceramic gasket is made of alumina ceramic with a thickness of 3-5mm, the surface roughness Ra of the mating surface is ≤6.3μm, and the fit between the ceramic gasket and the bevels of the two side stiffeners is ≥95%; the bevels are cleaned by degreasing with acetone to remove oil and dust from the bevel surface. In step S600, ultrasonic testing is performed within 24 hours after welding is completed, and the testing range covers the entire length of the weld and the heat-affected zone of 20mm on each side of the weld. When defects exceed the standard, carbon arc gouging is used to clean the root when repairing. The number of repairs is ≤2. After repair, ultrasonic testing is performed again until it is qualified. In step S700, the surface roughness Ra of the rib plate after grinding is ≤12.5μm, and the surface roughness Ra of the weld area after grinding is ≤6.3μm. The appearance inspection requirements are: the weld is free of cracks, porosity, and lack of fusion defects, the undercut depth is ≤0.5mm, and the weld bead height is ≤2mm.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. The precision of this invention is significantly improved: the middle stiffening plate adopts an unequal double-sided bevel and a "large first, small later" welding sequence, and with mechanical straightening, the perpendicularity error is reduced; the two side stiffening plates are fixed by special clamps, and the parallelism error is effectively reduced. 2. The weld quality of this invention is high: the ceramic backing enables single-sided welding and double-sided forming of the weld, avoiding the problem of narrow gap reverse welding, and greatly improving the pass rate of non-destructive testing of the weld. 3. The invention optimizes efficiency and cost: No flame correction is required, reducing rework workload, greatly shortening the production cycle for mass production in factories, and reducing labor and material costs; 4. This invention has strong versatility and safety: the bevel and welding parameters are optimized for different plate thicknesses, making it suitable for various steel structure pin joints; it avoids damage to material properties caused by flame straightening, and the weld has strong low-temperature impact toughness, meeting the requirements for use in low-temperature environments; 5. This invention is easy to operate: the process steps are standardized, the dependence on the welding skills is reduced, the quality stability is high during mass production, and it is easy to promote and apply. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure after the stiffeners of the present invention have been welded; Figure 2 This is a schematic diagram of the structure of the present invention before the stiffeners are welded; Figure 3 yes Figure 2 Enlarged structural diagram at point A; Figure 4 yes Figure 2 Enlarged structural diagram at point B; Figure 5 This is a schematic diagram of the structure of the clamp and stiffening plate of the present invention; Figure 6 This is a schematic diagram of the structure of the clamping frame of the present invention; Figure 7 This is a schematic diagram of the structure of the clamping assembly of the present invention; Figure 8This is a flowchart of the manufacturing method of the present invention.

[0020] In the diagram: 1. Base plate; 2. Central stiffening plate; 21. First weld; 22. Second weld; 23. Large bevel; 24. Small bevel; 3. Side stiffening plate; 31. Third weld; 32. Side bevel; 4. Ceramic gasket; 5. Clamping frame; 51. Central bayonet; 52. Side bayonet; 53. Threaded hole; 6. Clamping assembly; 61. Clamping screw; 611. Rotating handle; 612. Adapter shaft; 62. Pressure plate; 621. Adapter; 622. Bearing. Detailed Implementation In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] The following description, in conjunction with the accompanying drawings and specific embodiments, provides further details: Example 1 like Figure 1 As shown, a narrow-gap multi-layer parallel penetration welded stiffener plate includes a base plate 1. A central stiffener plate 2 is provided on one side of the base plate 1. After welding the central stiffener plate 2 to the base plate 1, a first weld 21 is formed at the top and a second weld 22 is formed at the bottom. Side stiffener plates 3 are provided at the top and bottom of the side of the base plate 1 where the central stiffener plate 2 is welded. The outer side of the side stiffener plate 3 is welded to the stiffener plate to form a third weld 31. A ceramic backing 4 is provided on the side of the side stiffener plate 3 facing the central stiffener plate 2 and in contact with the base plate 1. This stiffener plate structure adopts the technical means of opening an unequal double-sided bevel at the joint between the central stiffener plate 2 and the base plate 1, welding the large bevel 23 first, cleaning and grinding the reverse side, and then welding the small bevel 24, and performing welding reverse deformation treatment. This achieves the technical effect of keeping the central stiffener plate 2 perpendicular to the base plate 1 after welding through thermal stress, reducing the workload of flame heat correction, and improving work efficiency. It solves the technical problem that the central stiffener plate 2 is not perpendicular to the base plate 1 due to thermal stress after welding.

[0022] like Figure 2 , Figure 3 and Figure 4As shown, the top of the middle stiffening plate 2, which is attached to the bottom plate 1, is provided with a large bevel 23 and the bottom is provided with a small bevel 24, which are used to weld the middle stiffening plate 2 and the bottom plate 1 together; the side stiffening plate 3, which is close to the bottom plate 1, has a side bevel 32 on the side facing outward, which is used to weld the side stiffening plate 3 to the bottom plate 1, and a gap is left between the side stiffening plate 3 and the bottom plate 1; this structure makes it convenient for workers to effectively weld the entire stiffening plate and ensure the strength of the stiffening plate after welding.

[0023] Example 2 like Figure 8 As shown, a method for manufacturing a narrow-gap multi-layer parallel penetration welded stiffener plate is described, and the specific steps of this method are as follows: S100, Rib Plate Cutting and Beveling S110. According to the design drawings, use a CNC plasma cutting machine to cut the stiffening plates (including the central stiffening plate 2 and the two side stiffening plates 3) and the base plate 1. The cutting accuracy is controlled within ±0.5mm to avoid the subsequent assembly accuracy being affected by the cutting error.

[0024] S120. For the root of the middle stiffener 2, process an unequal double-sided bevel along the length direction: the depth of the large bevel 23 is 2 / 3-3 / 4 of the thickness of the middle stiffener 2, and the depth of the small bevel 24 is 1 / 3-1 / 4 of the thickness of the middle stiffener 2; the bevel angle is adjusted according to the thickness H of the stiffener: when 10mm≤H<20mm, the angle of the large bevel 23 is 60-65° and the angle of the small bevel 24 is 45-50°; when 20mm≤H≤30mm, the angle of the large bevel 23 is 65-75° and the angle of the small bevel 24 is 50-60°.

[0025] S130, Processing a single-sided bevel 32 on the side stiffener 3: The bevel depth is 3 / 4-4 / 5 of the thickness of the side stiffener 3; The bevel angle is adjusted according to the thickness H of the stiffener: when 10mm≤H<20mm, the angle is 65-70°; when 20mm≤H≤30mm, the angle is 70-80°.

[0026] S140. After beveling, the bevel surface is ground with an angle grinder to remove oxide scale and burrs, so that the surface roughness Ra is ≤ 6.3μm.

[0027] S200, Central Rib Plate 2 Assembly and Welding S210. According to the stiffener drawing, mark the installation position line of the middle stiffener 2 on the surface of the base plate 1 with a scribe line, and the marking accuracy is ≤0.3mm.

[0028] S220. Hoist the middle stiffening plate 2 to the marked position on the base plate 1, adjust the fitting gap between the middle stiffening plate 2 and the base plate 1 to ≤0.3mm, and fix it by spot welding (weld length 50-80mm, spacing 150-200mm, weld height 3-5mm).

[0029] S230. Preheating before welding: When the thickness of the stiffener plate H < 20mm, the preheating temperature is 80-100℃; when H ≥ 20mm, the preheating temperature is 100-120℃. The preheating range is 50mm on both sides of the bevel. The preheating temperature is monitored by an infrared thermometer.

[0030] S240, middle stiffener 2 welding: gas shielded welding is adopted, the welding material is low alloy steel welding wire ER50-6 (diameter 1.0-1.2mm), and the shielding gas is 80%Ar+20%CO2 (flow rate 15-20L / min).

[0031] S241. First weld the large bevel with unequal double-sided bevel 23: welding current 190-220A, welding voltage 25-28V, welding speed 15-18cm / min.

[0032] After welding S242 and the large bevel 23, use an angle grinder to mechanically clean the small bevel 24 side to a depth of 2-3mm, ensuring that the metallic luster of the reinforcing plate substrate is exposed and there is no oxide scale or slag residue.

[0033] S243, re-welding the small bevel of the unequal double-sided bevel 24: welding current 180-200A, welding voltage 24-26V, welding speed 18-20cm / min.

[0034] S300, Central Rib Plate 2 Inspection and Straightening S310. After the weld has cooled to room temperature (≥4h after welding), non-destructive testing is performed on the weld of the central stiffener 2: ultrasonic testing (UT) is used, and the testing standard meets the Class I requirements of GB / T11345-2013 "Ultrasonic Testing Technology, Testing Grades and Evaluation of Welds".

[0035] S320. Use a laser rangefinder to detect the perpendicularity between the middle stiffening plate 2 and the bottom plate 1. Set one detection point every 100mm along the length of the stiffening plate. The allowable error of perpendicularity is ≤0.3mm / m.

[0036] S330. If the verticality is out of tolerance, use mechanical straightening (such as a hydraulic jacking straightening machine) to straighten it. Flame straightening is prohibited. After straightening, retest until it meets the requirements.

[0037] S400, installation and fixing of two side stiffener plates 3 S410. Mark the installation position lines of the two side stiffeners 3 on the surface of the base plate 1 to ensure the design spacing between the two side stiffeners 3 and the central stiffener 2.

[0038] S420. Hoist the two side stiffener plates 3 to the marked positions, adjust the distance between the two side stiffener plates 3 and the bottom plate 1 to 4mm (using a feeler gauge for measurement), and fix them by spot welding (welding parameters are the same as those of the middle stiffener plate 2).

[0039] S430. Install special fixture: The fixture includes a clamping frame 5 and a clamping assembly 6. The middle part of the clamping frame 5 is engaged with the middle stiffening plate 2, and the clamping assembly 6 is installed at both ends of the clamping frame 5. The clamping assembly 6 is pressed against the outer side of the side stiffening plate 3 to fix the position of the side stiffening plate 3, thereby ensuring that the side stiffening plate 3 is welded. The clamping frame 5 has a central bayonet 51 in the middle, and side bayonets 52 are provided above and below the central bayonet 51. The top and bottom of the clamping frame 5 are provided with threaded holes 53. The threaded holes 53 are for easy rotational connection with the clamping assembly 6, which facilitates the up and down adjustment and use of the clamping assembly 6. The clamping assembly 6 includes a clamping screw 61 and a pressure plate 62. The clamping screw 61 is threadedly connected to the threaded hole 53, and the top of the clamping screw 61 is provided with a rotating handle 611. The rotating handle 611 facilitates the rotation of the clamping screw 61, thereby facilitating the clamping screw 61 to drive the pressure plate 62 to be stably pressed onto the side rib plate 3, thus ensuring the stable installation and use of the side rib plate 3. The bottom end of the clamping screw 61 is provided with an adapter shaft 612, the upper surface of the pressure plate 62 is provided with an adapter 621, the middle of the adapter 621 is provided with a bearing 622, the adapter shaft 612 and the bearing 622 are interference-fitted, the adapter shaft 612 and the bearing 622 are in conjunction to facilitate the rotational connection between the clamping screw 61 and the pressure plate 62.

[0040] S440. Adjust parallelism: Use a dial indicator to set one test point every 200mm along the height direction of the stiffener plate, and adjust the parallelism between the two side stiffener plates 3 and the middle stiffener plate 2 to ensure that the allowable error is ≤0.5mm / m.

[0041] S450, Fixing stiffener: Use a torque wrench to tighten the fixing screw, with the torque controlled at 30-40 N·m, to ensure that the stiffener does not shift during the welding process.

[0042] S500, Ceramic Gasket 4 Laying and Welding S510. Ceramic pads 4 are laid on the reverse side of the single-sided bevel 32 of the two side stiffeners 3. The ceramic pads 4 are made of alumina ceramic with a thickness of 3-5mm and a surface roughness Ra≤6.3μm. The ceramic pads 4 are fixed with high-temperature tape to ensure that the pads fit the bevel ≥95% without warping or gaps.

[0043] S520, Bevel Cleaning: Wipe the bevel and ceramic gasket 4 surface with acetone to remove oil, dust and other impurities.

[0044] S530. Preheating before welding: The preheating temperature is the same as that for welding the middle stiffener 2, and is monitored by an infrared thermometer.

[0045] S540, welding of two side stiffener plates 3: The welding parameters are the same as those for welding the large bevel 23 of the central stiffener plate 2. The status of the fixture is monitored in real time during the welding process. If the screw is found to be loose, the welding is stopped immediately and the screw is retightened to the specified torque. Multi-layer and multi-pass welding is used during welding. After each pass, the surface spatter of the weld is cleaned.

[0046] S600, Weld Inspection and Fixture Removal S610. Within 24 hours after welding, ultrasonic testing shall be performed on the welds of the two side stiffener plates 3. The testing range shall cover the entire length of the weld and the heat-affected zone of 20 mm on each side of the weld. The testing standard shall be the same as that in step S300.

[0047] S620. If there are defects exceeding the standard (such as cracks, lack of fusion, porosity, etc.), carbon arc gouging shall be used to clean the root (the root cleaning depth is ≥ the defect depth + 2mm). The number of reworks shall be ≤ 2. After rework, ultrasonic testing shall be carried out again until it passes the test.

[0048] S630. After passing the inspection, use a torque wrench to loosen the fastening screw and remove the special clamp to avoid damaging the stiffening plate by forced disassembly.

[0049] Example 2 like Figure 8 As shown, a method for manufacturing a narrow-gap multi-layer parallel penetration welded stiffener plate is described, and the specific steps of this method are as follows: S100, Rib Plate Cutting and Beveling S110. According to the design drawings, use a CNC plasma cutting machine to cut the stiffening plates (including the central stiffening plate 2 and the two side stiffening plates 3) and the base plate 1. The cutting accuracy is controlled within ±0.5mm to avoid the subsequent assembly accuracy being affected by the cutting error.

[0050] S120. For the root of the middle stiffener 2, process an unequal double-sided bevel along the length direction: the depth of the large bevel 23 is 2 / 3 of the thickness of the middle stiffener 2, and the depth of the small bevel 24 is 1 / 3 of the thickness of the middle stiffener 2; the bevel angle is adjusted according to the stiffener thickness H: when 10mm≤H<20mm, the angle of the large bevel 23 is 60° and the angle of the small bevel 24 is 45°; when 20mm≤H≤30mm, the angle of the large bevel 23 is 65° and the angle of the small bevel 24 is 50°.

[0051] S130, Processing a single-sided bevel 32 on the side stiffener 3: The bevel depth is 3 / 4 of the thickness of the side stiffener 3; The bevel angle is adjusted according to the stiffener thickness H: when 10mm≤H<20mm, the angle is 65°; when 20mm≤H≤30mm, the angle is 70°.

[0052] S140. After beveling, the bevel surface is ground with an angle grinder to remove oxide scale and burrs, so that the surface roughness Ra is ≤ 6.3μm.

[0053] S200, Central Rib Plate 2 Assembly and Welding S210. According to the stiffener drawing, mark the installation position line of the middle stiffener 2 on the surface of the base plate 1 with a scribe line, and the marking accuracy is ≤0.3mm.

[0054] S220. Hoist the middle stiffening plate 2 to the marked position on the base plate 1, adjust the fitting gap between the middle stiffening plate 2 and the base plate 1 to ≤0.3mm, and fix it by spot welding (weld length 50mm, spacing 150mm, weld height 3mm).

[0055] S230. Preheating before welding: When the thickness of the stiffener plate H < 20 mm, the preheating temperature is 80℃; when H ≥ 20 mm, the preheating temperature is 100℃. The preheating range is 50 mm on each side of the bevel. The preheating temperature is monitored by an infrared thermometer.

[0056] S240, middle stiffener 2 welding: gas shielded welding is adopted, the welding material is low alloy steel welding wire ER50-6 (diameter 1.0mm), and the shielding gas is 80%Ar+20%CO2 (flow rate 15L / min).

[0057] S241. First weld the large bevel of the unequal double-sided bevel 23: welding current 190A, welding voltage 25V, welding speed 15cm / min.

[0058] After welding S242 and the large bevel 23, use an angle grinder to mechanically clean the small bevel 24 side to a depth of 2mm, ensuring that the metallic luster of the reinforcing plate substrate is exposed and there is no oxide scale or slag residue.

[0059] S243, re-welding the small bevel of the unequal double-sided bevel 24: welding current 180A, welding voltage 24V, welding speed 18cm / min.

[0060] S300, Central Rib Plate 2 Inspection and Straightening S310. After the weld has cooled to room temperature (≥4h after welding), non-destructive testing is performed on the weld of the central stiffener 2: ultrasonic testing (UT) is used, and the testing standard meets the Class I requirements of GB / T11345-2013 "Ultrasonic Testing Technology, Testing Grades and Evaluation of Welds".

[0061] S320. Use a laser rangefinder to detect the perpendicularity between the middle stiffening plate 2 and the bottom plate 1. Set one detection point every 100mm along the length of the stiffening plate. The allowable error of perpendicularity is ≤0.3mm / m.

[0062] S330. If the verticality is out of tolerance, use mechanical straightening (such as a hydraulic jacking straightening machine) to straighten it. Flame straightening is prohibited. After straightening, retest until it meets the requirements.

[0063] S400, installation and fixing of two side stiffener plates 3 S410. Mark the installation position lines of the two side stiffeners 3 on the surface of the base plate 1 to ensure the design spacing between the two side stiffeners 3 and the central stiffener 2.

[0064] S420. Hoist the two side stiffener plates 3 to the marked positions, adjust the distance between the two side stiffener plates 3 and the bottom plate 1 to 4mm (using a feeler gauge for measurement), and fix them by spot welding (welding parameters are the same as those of the middle stiffener plate 2).

[0065] S430. Install special fixture: The fixture includes a clamping frame 5 and a clamping assembly 6. The middle part of the clamping frame 5 is engaged with the middle stiffening plate 2, and the clamping assembly 6 is installed at both ends of the clamping frame 5. The clamping assembly 6 is pressed against the outer side of the side stiffening plate 3 to fix the position of the side stiffening plate 3, thereby ensuring that the side stiffening plate 3 is welded. The clamping frame 5 has a central bayonet 51 in the middle, and side bayonets 52 are provided above and below the central bayonet 51. The top and bottom of the clamping frame 5 are provided with threaded holes 53. The threaded holes 53 are for easy rotational connection with the clamping assembly 6, which facilitates the up and down adjustment and use of the clamping assembly 6. The clamping assembly 6 includes a clamping screw 61 and a pressure plate 62. The clamping screw 61 is threadedly connected to the threaded hole 53, and the top of the clamping screw 61 is provided with a rotating handle 611. The rotating handle 611 facilitates the rotation of the clamping screw 61, thereby facilitating the clamping screw 61 to drive the pressure plate 62 to be stably pressed onto the side rib plate 3, thus ensuring the stable installation and use of the side rib plate 3. The bottom end of the clamping screw 61 is provided with an adapter shaft 612, the upper surface of the pressure plate 62 is provided with an adapter 621, the middle of the adapter 621 is provided with a bearing 622, the adapter shaft 612 and the bearing 622 are interference-fitted, the adapter shaft 612 and the bearing 622 are in conjunction to facilitate the rotational connection between the clamping screw 61 and the pressure plate 62.

[0066] S440. Adjust parallelism: Use a dial indicator to set one test point every 200mm along the height direction of the stiffener plate, and adjust the parallelism between the two side stiffener plates 3 and the middle stiffener plate 2 to ensure that the allowable error is ≤0.5mm / m.

[0067] S450, Fixing stiffener: Use a torque wrench to tighten the fixing screw, and control the torque at 30 N·m to ensure that the stiffener does not shift during the welding process.

[0068] S500, Ceramic Gasket 4 Laying and Welding S510. Ceramic pads 4 are laid on the reverse side of the single-sided bevel 32 of the two side stiffeners 3. The ceramic pads 4 are made of alumina ceramic with a thickness of 3mm and a surface roughness Ra≤6.3μm. The ceramic pads 4 are fixed with high-temperature tape to ensure that the pads fit the bevel ≥95% without warping or gaps.

[0069] S520, Bevel Cleaning: Wipe the bevel and ceramic gasket 4 surface with acetone to remove oil, dust and other impurities.

[0070] S530. Preheating before welding: The preheating temperature is the same as that for welding the middle stiffener 2, and is monitored by an infrared thermometer.

[0071] S540, welding of two side stiffener plates 3: The welding parameters are the same as those for welding the large bevel 23 of the central stiffener plate 2. The status of the fixture is monitored in real time during the welding process. If the screw is found to be loose, the welding is stopped immediately and the screw is retightened to the specified torque. Multi-layer and multi-pass welding is used during welding. After each pass, the surface spatter of the weld is cleaned.

[0072] S600, Weld Inspection and Fixture Removal S610. Within 24 hours after welding, ultrasonic testing shall be performed on the welds of the two side stiffener plates 3. The testing range shall cover the entire length of the weld and the heat-affected zone of 20 mm on each side of the weld. The testing standard shall be the same as that in step S300.

[0073] S620. If there are defects exceeding the standard (such as cracks, lack of fusion, porosity, etc.), carbon arc gouging shall be used to clean the root (the root cleaning depth is ≥ the defect depth + 2mm). The number of reworks shall be ≤ 2. After rework, ultrasonic testing shall be carried out again until it passes the test.

[0074] S630. After passing the inspection, use a torque wrench to loosen the fastening screw and remove the special clamp to avoid damaging the stiffening plate by forced disassembly.

[0075] Example 3 like Figure 8 As shown, a method for manufacturing a narrow-gap multi-layer parallel penetration welded stiffener plate is described, and the specific steps of this method are as follows: S100, Rib Plate Cutting and Beveling S110. According to the design drawings, use a CNC plasma cutting machine to cut the stiffening plates (including the central stiffening plate 2 and the two side stiffening plates 3) and the base plate 1. The cutting accuracy is controlled within ±0.5mm to avoid the subsequent assembly accuracy being affected by the cutting error.

[0076] S120. For the root of the middle stiffener 2, process an unequal double-sided bevel along the length direction: the depth of the large bevel 23 is 3 / 4 of the thickness of the middle stiffener 2, and the depth of the small bevel 24 is 1 / 4 of the thickness of the middle stiffener 2; the bevel angle is adjusted according to the thickness H of the stiffener: when 10mm≤H<20mm, the angle of the large bevel 23 is 65° and the angle of the small bevel 24 is 50°; when 20mm≤H≤30mm, the angle of the large bevel 23 is 75° and the angle of the small bevel 24 is 60°.

[0077] S130, Processing a single-sided bevel 32 on the side stiffener 3: The bevel depth is 4 / 5 of the thickness of the side stiffener 3; The bevel angle is adjusted according to the stiffener thickness H: when 10mm≤H<20mm, the angle is 70°; when 20mm≤H≤30mm, the angle is 80°.

[0078] S140. After beveling, the bevel surface is ground with an angle grinder to remove oxide scale and burrs, so that the surface roughness Ra is ≤ 6.3μm.

[0079] S200, Central Rib Plate 2 Assembly and Welding S210. According to the stiffener drawing, mark the installation position line of the middle stiffener 2 on the surface of the base plate 1 with a scribe line, and the marking accuracy is ≤0.3mm.

[0080] S220. Hoist the middle stiffening plate 2 to the marked position on the base plate 1, adjust the fitting gap between the middle stiffening plate 2 and the base plate 1 to ≤0.3mm, and fix it by spot welding (weld length 80mm, spacing 200mm, weld height 5mm).

[0081] S230. Preheating before welding: When the thickness of the stiffener plate H < 20 mm, the preheating temperature is 100℃; when H ≥ 20 mm, the preheating temperature is 120℃. The preheating range is 50 mm on each side of the bevel. The preheating temperature is monitored by an infrared thermometer.

[0082] S240, middle stiffener 2 welding: gas shielded welding is adopted, the welding material is low alloy steel welding wire ER50-6 (diameter 1.2mm), and the shielding gas is 80%Ar+20%CO2 (flow rate 20L / min). S241. First weld the large bevel of the unequal double-sided bevel 23: welding current 220A, welding voltage 28V, welding speed 18cm / min.

[0083] After welding S242 and the large bevel 23, use an angle grinder to mechanically clean the small bevel 24 side to a depth of 3mm, ensuring that the metallic luster of the reinforcing plate substrate is exposed and there is no oxide scale or slag residue.

[0084] S243, re-welding the small bevel of the unequal double-sided bevel 24: welding current 200A, welding voltage 26V, welding speed 20cm / min.

[0085] S300, Central Rib Plate 2 Inspection and Straightening S310. After the weld has cooled to room temperature (≥4h after welding), non-destructive testing is performed on the weld of the central stiffener 2: ultrasonic testing (UT) is used, and the testing standard meets the Class I requirements of GB / T11345-2013 "Ultrasonic Testing Technology, Testing Grades and Evaluation of Welds".

[0086] S320. Use a laser rangefinder to detect the perpendicularity between the middle stiffening plate 2 and the bottom plate 1. Set one detection point every 100mm along the length of the stiffening plate. The allowable error of perpendicularity is ≤0.3mm / m.

[0087] S330. If the verticality is out of tolerance, use mechanical straightening (such as a hydraulic jacking straightening machine) to straighten it. Flame straightening is prohibited. After straightening, retest until it meets the requirements.

[0088] S400, installation and fixing of two side stiffener plates 3 S410. Mark the installation position lines of the two side stiffeners 3 on the surface of the base plate 1 to ensure the design spacing between the two side stiffeners 3 and the central stiffener 2.

[0089] S420. Hoist the two side stiffener plates 3 to the marked positions, adjust the distance between the two side stiffener plates 3 and the bottom plate 1 to 4mm (using a feeler gauge for measurement), and fix them by spot welding (welding parameters are the same as those of the middle stiffener plate 2).

[0090] S430. Install special fixture: The fixture includes a clamping frame 5 and a clamping assembly 6. The middle part of the clamping frame 5 is engaged with the middle stiffening plate 2, and the clamping assembly 6 is installed at both ends of the clamping frame 5. The clamping assembly 6 is pressed against the outer side of the side stiffening plate 3 to fix the position of the side stiffening plate 3, thereby ensuring that the side stiffening plate 3 is welded. The clamping frame 5 has a central bayonet 51 in the middle, and side bayonets 52 are provided above and below the central bayonet 51. The top and bottom of the clamping frame 5 are provided with threaded holes 53. The threaded holes 53 are for easy rotational connection with the clamping assembly 6, which facilitates the up and down adjustment and use of the clamping assembly 6. The clamping assembly 6 includes a clamping screw 61 and a pressure plate 62. The clamping screw 61 is threadedly connected to the threaded hole 53, and the top of the clamping screw 61 is provided with a rotating handle 611. The rotating handle 611 facilitates the rotation of the clamping screw 61, thereby facilitating the clamping screw 61 to drive the pressure plate 62 to be stably pressed onto the side rib plate 3, thus ensuring the stable installation and use of the side rib plate 3. The bottom end of the clamping screw 61 is provided with an adapter shaft 612, the upper surface of the pressure plate 62 is provided with an adapter 621, the middle of the adapter 621 is provided with a bearing 622, the adapter shaft 612 and the bearing 622 are interference-fitted, the adapter shaft 612 and the bearing 622 are in conjunction to facilitate the rotational connection between the clamping screw 61 and the pressure plate 62.

[0091] S440. Adjust parallelism: Use a dial indicator to set one test point every 200mm along the height direction of the stiffener plate, and adjust the parallelism between the two side stiffener plates 3 and the middle stiffener plate 2 to ensure that the allowable error is ≤0.5mm / m.

[0092] S450, Fixed stiffener: Use a torque wrench to tighten the fixing screw, and control the torque at 40 N·m to ensure that the stiffener does not shift during the welding process.

[0093] S500, Ceramic Gasket 4 Laying and Welding S510. Ceramic pads 4 are laid on the reverse side of the single-sided bevel 32 of the two side stiffeners 3. The ceramic pads 4 are made of alumina ceramic with a thickness of 5mm and a surface roughness Ra≤6.3μm. The ceramic pads 4 are fixed with high-temperature tape to ensure that the pads fit the bevel ≥95% without warping or gaps.

[0094] S520, Bevel Cleaning: Wipe the bevel and ceramic gasket 4 surface with acetone to remove oil, dust and other impurities.

[0095] S530. Preheating before welding: The preheating temperature is the same as that for welding the middle stiffener 2, and is monitored by an infrared thermometer.

[0096] S540, welding of two side stiffener plates 3: The welding parameters are the same as those for welding the large bevel 23 of the central stiffener plate 2. The status of the fixture is monitored in real time during the welding process. If the screw is found to be loose, the welding is stopped immediately and the screw is retightened to the specified torque. Multi-layer and multi-pass welding is used during welding. After each pass, the surface spatter of the weld is cleaned.

[0097] S600, Weld Inspection and Fixture Removal S610. Within 24 hours after welding, ultrasonic testing shall be performed on the welds of the two side stiffener plates 3. The testing range shall cover the entire length of the weld and the heat-affected zone of 20 mm on each side of the weld. The testing standard shall be the same as that in step S300.

[0098] S620. If there are defects exceeding the standard (such as cracks, lack of fusion, porosity, etc.), carbon arc gouging shall be used to clean the root (the root cleaning depth is ≥ the defect depth + 2mm). The number of reworks shall be ≤ 2. After rework, ultrasonic testing shall be carried out again until it passes the test.

[0099] S630. After passing the inspection, use a torque wrench to loosen the fastening screw and remove the special clamp to avoid damaging the stiffening plate by forced disassembly.

[0100] S700, Rib Plate Grinding and Inspection S710. Use an angle grinder to grind the surface of all stiffeners and the weld area: the surface roughness Ra after grinding is ≤12.5μm; the surface roughness Ra after grinding the weld area is ≤6.3μm, and the weld reinforcement is controlled within 0-3mm.

[0101] S720. Visual inspection: The weld is free from defects such as cracks, porosity, lack of fusion, and incomplete penetration. The undercut depth is ≤0.5mm and the weld bead height is ≤2mm.

[0102] S730, Dimensional Verification: Re-inspect the verticality of the central stiffener 2 and the parallelism of the two side stiffeners 3 to ensure they meet the requirements.

[0103] S740, Component Numbering: Use a laser marking machine to mark the component number (such as "JX-Year-Serial Number") in the non-stressed area of ​​the base plate 1. The marking is clear and not easily worn.

[0104] S750. After passing the inspection, the component will be transferred to the next process (such as painting or storage).

[0105] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A narrow-gap multi-layer parallel penetration welded stiffener plate, comprising a base plate (1), characterized in that, The base plate (1) has a central stiffener (2) on one side. After the central stiffener (2) is welded to the base plate (1), a first weld (21) is formed at the top and a second weld (22) is formed at the bottom. The base plate (1) has side stiffeners (3) at the top and bottom of the side of the central stiffener (2). The side stiffeners (3) are welded to the stiffeners on the outside and form a third weld (31). The side stiffeners (3) facing the central stiffener (2) are fitted with ceramic pads (4) at the position of the base plate (1). The central stiffener (2) adopts an unequal double-sided bevel and a "large first, small later" welding sequence, and is straightened by mechanical adjustment to reduce verticality error. The two side stiffeners (3) are fixed by special clamps to reduce parallelism error.

2. The narrow-gap multi-layer parallel penetration welded stiffener plate according to claim 1, characterized in that, The middle stiffener (2) has a large bevel (23) at the top and a small bevel (24) at the bottom of the end that is in contact with the bottom plate (1), which is used to weld the middle stiffener (2) and the bottom plate (1) together; the side stiffener (3) has a side bevel (32) on the side facing outward at the end near the bottom plate (1), which is used to weld the side stiffener (3) and the bottom plate (1) together, and there is a gap between the side stiffener (3) and the bottom plate (1).

3. A method for manufacturing a narrow-gap multi-layer parallel penetration welded stiffener, used to manufacture the narrow-gap multi-layer parallel penetration welded stiffener as described in claim 2, characterized in that, The specific steps of this production method are as follows: S100, Rib plate cutting and beveling: According to the design drawings, the rib plate is cut, and the end of the middle rib plate (2) that is attached to the bottom plate (1) is processed into an unequal double-sided bevel, thereby forming a large bevel (23) and a small bevel (24). The two side rib plates (3) are processed into single-sided side bevels (32). S200, Assembly and welding of intermediate stiffening plates: Mark the installation position of the stiffening plates on the base plate (1), assemble the intermediate stiffening plates (2), and weld the intermediate stiffening plates after inspection and approval; S300, Inspection and Straightening of Intermediate Rib Plate: After welding, non-destructive testing is performed on the weld of the intermediate rib plate. At the same time, the perpendicularity between the intermediate rib plate and the base plate (1) is checked. If the perpendicularity error exceeds the limit, straightening is performed until the requirements are met. S400, Installation and fixing of two side stiffeners (3): After the intermediate stiffener is inspected and qualified, two side stiffeners (3) are installed on the base plate (1). The gap between the two side stiffeners (3) and the base plate (1) is controlled to be 4mm. After spot welding the two side stiffeners (3), a special clamp is installed. The parallelism between the two side stiffeners (3) and the intermediate stiffener is adjusted to meet the requirements. The clamping assembly (6) of the clamp is tightened to fix the two side stiffeners (3). S500, Ceramic gasket (4) laying and welding: Ceramic gasket (4) is laid on the reverse side of the single-sided large bevel (23) of the two side stiffeners (3), and after cleaning the impurities in the bevel, the two side stiffeners (3) are welded through. S600, Weld inspection and fixture removal: After welding is completed, ultrasonic testing is performed on the welds of the two side stiffener plates (3). If there are defects exceeding the standard, rework is carried out. After the test is qualified, the special fixture is removed. S700, Rib Plate Grinding and Inspection: Grind the surface of all rib plates and the weld area. After inspection and approval, mark the components and proceed to the next process.

4. The method for manufacturing a narrow-gap multi-layer parallel penetration welded stiffener plate according to claim 3, characterized in that, In step S100, the depth of the large bevel (23) of the unequal-sided double bevel is 2 / 3-3 / 4 of the thickness of the intermediate stiffener plate, the depth of the small bevel (24) is 1 / 3-1 / 4 of the thickness of the intermediate stiffener plate, and the depth of the side bevel (32) is 3 / 4-4 / 5 of the thickness of the two side stiffener plates (3). The bevel angle is adjusted according to the thickness of the stiffener plate to meet the requirements of penetration welding.

5. The method for manufacturing a narrow-gap multi-layer parallel penetration welded stiffener plate according to claim 3, characterized in that, In step S200, the welding sequence of the middle stiffener (2) is as follows: first weld the large bevel (23) of the unequal double-sided bevel, then perform root cleaning treatment on the small bevel (24) side, and finally weld the small bevel (24).

6. The method for manufacturing a narrow-gap multi-layer parallel penetration welded stiffener plate according to claim 5, characterized in that, In step S200, the assembly area of ​​the intermediate stiffening plate and the base plate (1) is preheated before welding. The preheating temperature is 80-120℃, and the preheating temperature increases with the increase of the stiffening plate thickness. The root cleaning is carried out by mechanical root cleaning, specifically by grinding with an angle grinder. The root cleaning depth is 2-3mm. After root cleaning, the metallic luster of the stiffening plate substrate is exposed, and there is no oxide scale or slag residue.

7. The method for manufacturing a narrow-gap multi-layer parallel penetration welded stiffener plate according to claim 3, characterized in that, In step S300, the non-destructive testing is performed using ultrasonic testing or radiographic testing, and the allowable error for the perpendicularity is ≤0.3mm / m.

8. The method for manufacturing a narrow-gap multi-layer parallel penetration welded stiffener plate according to claim 3, characterized in that, The fixture in step S400 includes a clamping frame (5) and a pressing assembly (6). The clamping frame (5) is engaged in the middle of the middle stiffening plate (2), and the clamping assembly (6) is installed at both ends of the clamping frame (5). The pressing assembly (6) presses against the outer side of the side stiffening plate (3) to fix the position of the side stiffening plate (3).

9. The method for manufacturing a narrow-gap multi-layer parallel penetration welded stiffener plate according to claim 8, characterized in that, The clamping frame (5) has a central bayonet (51) in the middle, and the clamping frame (5) has side bayonet (52) above and below the central bayonet (51). The clamping frame (5) has threaded holes (53) at the top and bottom. The clamping assembly (6) includes a clamping screw (61) and a pressure plate (62). The clamping screw (61) is threaded to the threaded hole (53). The top of the clamping screw (61) has a rotating handle (611). The bottom of the clamping screw (61) has an adapter shaft (612). The upper surface of the pressure plate (62) has an adapter (621). The adapter (621) has a bearing (622) in the middle. The adapter shaft (612) is interference-fitted with the bearing (622).

10. The method for manufacturing a narrow-gap multi-layer parallel penetration welded stiffener plate according to claim 3, characterized in that, In step S500, the ceramic pad (4) is made of alumina ceramic with a thickness of 3-5mm, the surface roughness Ra of the mating surface is ≤6.3μm, and the fit between the ceramic pad (4) and the bevel of the two side stiffeners (3) is ≥95%. The bevel is cleaned by degreasing with acetone to remove oil and dust from the bevel surface. In step S600, ultrasonic testing is performed within 24 hours after welding is completed, and the testing range covers the entire length of the weld and the heat-affected zone of 20mm on each side of the weld. When defects exceed the standard, carbon arc gouging is used to clean the root when repairing. The number of repairs is ≤2. After repair, ultrasonic testing is performed again until it is qualified. In step S700, the surface roughness Ra of the rib plate after grinding is ≤12.5μm, and the surface roughness Ra of the weld area after grinding is ≤6.3μm. The appearance inspection requirements are: the weld is free of cracks, porosity, and lack of fusion defects, the undercut depth is ≤0.5mm, and the weld bead height is ≤2mm.

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