Lengthening process for medium-thickness steel plate

Abstract

The invention relates to the technical field of manufacturing of offshore wind power pipe piles, in particular to a medium-thickness steel plate lengthening process, which adopts a round rod ceramic gasket and a flux-cored wire arc welding and submerged arc automatic welding process at the root of a groove, reduces the plate turning operation procedure, saves the labor and operation time, reduces the cost, improves the efficiency, and improves the production efficiency. Potential safety hazards caused by plate turning and hoisting are reduced; air gouging and polishing procedures are reduced, noise hazards and dust pollution caused by air gouging and polishing are reduced, the cost is reduced, and the efficiency is improved; and meanwhile, for different wall thickness sizes, different grooves can be selected according to conditions, and the grooves comprise double V shapes or U + V shapes, so that the welding filling amount is reduced, the operation time is shortened, the production cost is reduced, and the operation efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of pipe fitting welding, in particular to a process for lengthening medium-thickness steel plates. Background Art

[0002] Wind turbine piles are important structural parts that support wind turbine heads. Their main manufacturing process is welding. With the increase in offshore wind power, the megawatts are getting bigger and bigger, and the diameter of the piles and the thickness of the steel plates are increasing accordingly. When the diameter increases, the corresponding steel plate expansion size is required to increase. However, due to the limitation of the steel rolling size in the steel mill, the steel plate needs to be extended before the pile barrel is rolled. The number of steel plates that need to be extended has increased from 2 to 3 or even 4. This increases the workload and affects production efficiency and cost.

[0003] At present, the main scheme used is that the weld is an X-shaped groove, also known as a double-sided V-shaped groove, which is mainly suitable for welding work with a plate thickness of 12 to 60 mm. Figure 1 As shown: The groove form is 1 / 3-2 / 3, and the commonly used groove angle is 30 degrees to 45 degrees. When welding, first weld the 2 / 3 large groove side. After welding one side, you need to turn the steel plate over and weld the other side. The operation steps are as follows Figure 2 As shown; then carry out carbon arc air planing root cleaning and grinding work, the operation steps are as follows Figure 3 As shown: Finally, weld the other side. However, the disadvantage of the X-shaped groove is that it requires double-sided welding, which increases the complexity of the operation and requires the quality of the welding on both sides to be consistent, otherwise it may affect the overall welding quality. And as the number of steel plates increases and the thickness of the steel plates increases, the unsafe factors of turning over also increase. At the same time, turning over, gouging, and grinding will also reduce production efficiency and increase a lot of additional work. Summary of the invention

[0004] The purpose of the present invention is to provide a medium-thickness steel plate extension process, which solves the problem of poor welding methods in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A medium thickness steel plate extension process comprises the following steps:

[0007] Step 1: Beveling, using round rod ceramic liner to make the root weld well-formed, without the need for carbon arc gouging and grinding;

[0008] Step 2: The root gap during assembly is 8mm, the tolerance is controlled at ±2mm, and the root welding is well formed without defects;

[0009] Step 3: The groove angle is 45° on the large groove side and 70° on the small groove side. The groove depth can be adjusted according to the thickness of the steel plate.

[0010] Step 4: Weld the small groove side first, in the overhead welding position, using flux-cored arc welding;

[0011] Step 5: Post-weld the large groove side using submerged arc automatic welding technology.

[0012] On the basis of the above technical solution, the present invention also provides the following optional technical solution:

[0013] In one optional solution: Step 4: Weld the small groove side first, in the overhead welding position, using flux-cored arc welding.

[0014] In an optional solution: Step 5: Post-weld the large groove side using a submerged arc automatic welding process.

[0015] In an optional solution, the round rod ceramic liner is an alumina ceramic material.

[0016] In an optional scheme: submerged arc automatic welding process: the diameter of the welding wire is 4.0mm, the flux is dried for 2h, the drying temperature is 300℃-350℃, the welding current is 550A-750A, the voltage is 28V-34V, and the welding speed is 350mm / min-450mm / min.

[0017] In one alternative: flux-cored arc welding: the wire diameter is 1.2 mm, and the shielding gas used is CO with a purity of ≥ 99.8% 2 The welding current is 200A-280A, the welding voltage is 27V-35V, the welding speed is 220mm / min-350mm / min, and the gas flow rate during welding is 15L / min-20L / min.

[0018] In one alternative: the ceramic liner has a diameter of 10 mm.

[0019] In an optional solution: Step three also includes preheating the groove and blunt edge, and the preheating temperature is 80°C-120°C.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] The present application adopts a round rod ceramic liner at the root of the groove, and a flux-cored arc welding + submerged arc automatic welding process, which reduces the flapping operation process, saves labor and operation time, and reduces the safety hazards caused by flapping and lifting; reduces the gouging and grinding processes, reduces the noise hazards and dust pollution caused by gouging and grinding, and at the same time, for different wall thicknesses, different grooves (double V-type or U+V-type) can be selected according to the situation, reducing the welding filling amount and operation time, reducing production costs, and improving operation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the welding method in the prior art.

[0023] Figure 2 The present invention is a schematic diagram of the turning welding operation structure of the prior art.

[0024] Figure 3 The present invention is a schematic diagram of the root cleaning and grinding work of carbon arc air planing in the prior art.

[0025] Figure 4 It is a schematic diagram of the joint structure of the present invention.

[0026] Figure 5 It is a schematic diagram of the welding structure in the overhead welding position of the present invention.

[0027] Figure 6 It is a schematic diagram of the root weld forming structure of the present invention.

[0028] Figure 7 It is a schematic diagram of the submerged arc welding structure of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] like Figure 4-Figure 7 As shown in the figure, taking a 90mm thick steel plate as an example, it includes beveling, assembly, preheating, tack welding, flux-cored arc welding, liner removal, and submerged arc welding; specifically, it includes:

[0031] a. Beveling: Beveling is done at the welding end of the steel plate. The single-side bevel is 22.5°, and the bevel after assembly is 45°. The blunt edge is 2mm.

[0032] b. Assembly: Assemble the steel plates with grooves on the stand, leaving a gap of 8mm. It is important to keep the gap consistent and do a good job of anti-deformation. After assembly, the groove angle is 45°. After assembly, install the ceramic liner (ceramic liner diameter 10mm);

[0033] c. Preheating: Preheat the groove and blunt edge at a temperature of 80°C-120°C;

[0034] d. Positioning welding: flux-cored arc welding is used for positioning welding at the butt weld of steel plates. The diameter of the flux-cored arc welding wire is 1.2 mm, and the shielding gas used is CO with a purity of ≥99.8%.2 , welding is done in the overhead welding position, the welding current is 180A-260A, the voltage is 27V-34V, the welding speed is 240mm / min-360mm / min, and the gas flow rate is 15L / min-25L / min;

[0035] e. Flux-cored arc welding: flux-cored arc welding is used to fill the groove where positioning welding has been completed. The welding wire is flux-cored wire with a diameter of 1.2mm. The shielding gas used is ≥99.8% CO2. The welding current is 200A-280A, the welding voltage is 27V-35V, the welding speed is 220mm / min-350mm / min, and the gas flow rate is 15L / min-20L / min. Use flux-cored arc welding, in the overhead welding position, finish welding the small groove side, and then weld the large groove side;

[0036] f. Removal of liner: After the weld has cooled, remove the round rod ceramic liner; (Removal of the liner is very simple, just tap it and it will fall off) The root weld is well formed; no gouging or grinding is required;

[0037] g. Submerged arc welding: Use submerged arc automatic welding for full welding in the flat welding position. The diameter of the welding wire is 4.0mm. The flux is dried for 2h at a drying temperature of 300℃-350℃. The welding current is 550A-750A, the voltage is 28V-34V, and the welding speed is 350mm / mim-450mm / min.

[0038] Welding is completed;

[0039] 1. Comparison of efficiency improvement data

[0040] Savings in flipping operation:

[0041] The traditional process requires four turns (base welding → filling welding → cover welding → root cleaning), and this solution achieves single-sided welding and double-sided forming:

[0042] Time required for a single panel flip: 15-20 minutes (including hoisting / positioning / testing)

[0043] Total time saved: 4 times × 18 minutes / time = 72 minutes / weld

[0044] Calculated based on a 10-meter-long weld: The traditional process takes 6 hours, while this solution only takes 4.2 hours (efficiency increased by 30%)

[0045] Simplified process, eliminating gouging and grinding processes:

[0046] Traditional gouging time: 30-45 minutes / meter (including gouging + cleaning)

[0047] Grinding dust generation: 2.8kg / m weld in traditional process → 0kg in this solution

[0048] 2. Cost Reduction Data

[0049] Comparison of welding material consumption:

[0050] Optimize groove design to reduce filling volume:

[0051] Groove type | Filling amount (10mm plate thickness) | This solution (45° V-shaped + ceramic liner)

[0052] - Traditional 60° V-groove, 8.2kg / m weld, 5.6kg / m weld (reduced by 31.7%)

[0053] Traditional U-shaped groove, 6.8kg / m weld, 5.6kg / m weld (reduced by 17.6%)

[0054] Labor cost savings:

[0055] Cost of gouging: 200 yuan / hour x 0.75 hours / meter = 150 yuan / meter Cost of grinding: 80 yuan / hour x 0.5 hours / meter = 40 yuan / meter

[0056] This solution saves 190 yuan per meter of weld (1900 yuan for 10 meters of weld)

[0057] First pass rate of weld:

[0058] Ceramic liner ensures root penetration: Traditional process root non-penetration rate: 8-12%

[0059] The root incomplete penetration rate of this solution: <0.5% (ultrasonic test data)

[0060] Deformation Control:

[0061] Anti-deformation + Ceramic liner rigid fixation:

[0062] Parameters | Traditional technology | This solution |

[0063] Angular deformation, 3.2-4.5mm / m, 1.5-2.1mm / m

[0064] Transverse shrinkage, 2.8-3.6mm / m, 1.2-1.8mm / m

[0065] 4. Safety and Environmental Data

[0066] Reduced safety risks:

[0067] Cancellation of flap lifting operation:

[0068] Accident probability of traditional hoisting technology: 0.18 times / thousand tons of steel structure → 0 times in this solution

[0069] Reduction of working time at height: from 6.5 hours / weld → 2.2 hours / weld

[0070] Pollution emission comparison:

[0071] Pollutant type | Emissions from traditional processes | Emissions from this solution

[0072] Welding fume, 12.5g / m2 weld, 8.2g / m2 weld (reduced by 34%)

[0073] Noise peak: 110dB (gouging), 85dB (no gouging)

[0074] V. Typical Case Data

[0075] Application comparison of deck sections in a shipyard (plate thickness 90mm, total weld length 380m):

[0076] index Traditional crafts This program Decline Total construction period 28 days 19 days 32.1％ Comprehensive cost 860,000 yuan 630,000 yuan 26.7％ Number of repairs 11 times 2 times 81.8％ .

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for extending medium-thickness steel plates, characterized in that: The following steps are involved: Step 1: Bevel the groove and use round rod ceramic liner; Step 2: The root gap during assembly is 8mm, and the tolerance is controlled within ±2mm; Step 3: Bevel angle size, 45° on the large bevel side and 70° on the small bevel side; Step 4: First weld the small groove side; Step 5: Next, weld the large groove side; When welding the large groove side, the submerged arc automatic welding process is adopted; Submerged arc automatic welding process: the diameter of the welding wire is 4.0mm, the flux is dried for 2h, the drying temperature is 300℃-350℃, the welding current is 550A-750A, the voltage is 28V-34V, and the welding speed is 350mm / min-450mm / min; Step 6: Welding is complete.

2. The process for extending medium-thickness steel plates according to claim 1, characterized in that: Step 4: Weld the small groove side first, in the overhead welding position, using flux-cored arc welding.

3. The process for extending medium-thickness steel plates according to claim 1, characterized in that: The round rod ceramic liner is made of alumina ceramic material.

4. The process for extending medium-thickness steel plates according to claim 1, characterized in that: Flux-cored arc welding: The diameter of the welding wire is 1.2mm, the shielding gas used is CO2 with a purity of ≥99.8%, the welding current is 200A-280A, the welding voltage is 27V-35V, the welding speed is 220mm / min-350mm / min, and the gas flow rate during welding is 15L / min-20L / min.

5. The process for extending medium-thickness steel plates according to claim 1, characterized in that: Ceramic liner diameter 10mm.

6. The process for extending medium-thickness steel plates according to claim 1, characterized in that: Step three also includes preheating the groove and blunt edge, and the preheating temperature is 80°C-120°C.

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