Construction process of the legs of a self-elevating wind turbine installation platform

Abstract

This invention relates to the field of marine engineering and shipbuilding technology, and in particular to a construction process for the pile legs of a self-elevating wind power installation platform. The unfolded cutting length of the cylindrical steel plate is L1 = DP + δ1 + δ2 - δ4. The allowance on both sides of the steel plate is L2 = L3 + δ1 + δ2 = L3 + 4 based on the width of a single cylindrical section. The cutting must ensure that the straightness error is no greater than 1 / 1000 and ≤5mm, the perpendicularity error in the plate thickness direction is no greater than 1mm, the cutting bevel angle error is ±1°, the cutting depth is no greater than 0.5mm, and the parallelism of the unfolded cutting line is less than 2mm. Thin-layer, narrow-channel, multi-pass welding is used during welding, which can effectively reduce welding deformation and avoid incomplete fusion and slag inclusion defects in full penetration fillet welds. The welding qualification rate is over 98%, which not only has good quality, but also reduces deformation caused by repair welding, reduces costs, and shortens the construction period.

Description

Technical Field

[0001] This invention relates to the field of marine engineering and shipbuilding technology, and in particular to a construction process for the legs of a self-elevating wind power installation platform. Background Technology

[0002] Compared with land-based wind power, offshore wind power has advantages such as less environmental impact, better wind conditions, less wind turbulence, less wind shear, fewer interference restrictions, and no land occupation for offshore wind farms.

[0003] When a wind turbine platform is in use, it needs to be supported by pile legs. In order to ensure the stability of the support provided by the pile legs to the wind turbine platform, welding equipment is required to weld the pile legs to the wind turbine platform. During welding, phenomena such as incomplete fusion of full penetration fillet welds and slag inclusions may occur. At the same time, when repair welding is required, deformation may occur, affecting the construction progress. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a construction process for the legs of a self-elevating wind power installation platform. This addresses the issue that when a wind power platform is in use, it needs to be supported by legs. To ensure the stability of the legs' support for the wind power platform, welding equipment is required to weld the legs to the platform. During welding, issues such as incomplete fusion of full penetration fillet welds and slag inclusions may occur. Furthermore, when repair welding is required, deformation may occur, affecting the construction progress.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A construction process for the legs of a self-elevating wind turbine installation platform includes the following steps:

[0007] a. Material preparation

[0008] All steel plate materials must undergo incoming inspection. The cutting dimensions of the steel are calculated with the center of the steel plate as the reference line. After the steel plate is laid out, the cutting line, track line and inspection line are marked. The unfolded cutting length of the cylindrical steel plate is calculated as L1=DP+δ1+δ2-δ4. The allowance on both sides of the steel plate is calculated as L2=L3+δ1+δ2=L3+4 based on the cutting dimensions of a single section of the cylindrical plate. The cutting must ensure that the straightness error is not greater than 1 / 1000 and ≤5mm, the perpendicularity error in the plate thickness direction is not greater than 1mm, the cutting bevel angle error is ±1°, the cutting depth is not greater than 0.5mm, and the parallelism of the unfolded length cutting line is less than 2mm.

[0009] b. Segment rolling

[0010] The process of rolling the cylinder section is as follows: steel plate pre-bending → rolling → perimeter inspection → allowance cutting → joining → positioning welding → pre-welding inspection → external longitudinal seam grinding treatment → cylinder section rounding and straightening → ovality inspection → NDT testing → cylinder section completion inspection.

[0011] When pre-bending the steel plate, press it once within 150mm of the end of the steel plate, and then press it twice within 300mm to reduce the elasticity of the steel plate. During the rolling process, check the working line to ensure that the steel plate and the rolling roller are always parallel. Gradually increase the force and control the rolling speed throughout the rolling process. Roll it back and forth multiple times to form the shape, and check it with the arc template at any time to ensure the accuracy of the cylinder.

[0012] c. Longitudinal seam welding of the cylinder

[0013] Submerged arc welding is used for longitudinal joint welding of pipe sections. Before preheating and welding, the arc-starting plate is installed, and the straightness, flatness, bevel angle and cleanliness of the bevel are carefully checked. The straightness of a single pipe section is required to be less than 2mm, and the flatness is required to be less than 2mm. For V or X type bevels, the included angle after assembly is required to be greater than 50°. The inner surface of the bevel is smooth, flat and has a metallic luster. After passing the inspection, SAW automatic welding is used. After welding one side, the back side is cleaned. After cleaning, the back side is carefully ground to meet the above requirements before SAW automatic welding is performed.

[0014] As a preferred technical solution of the present invention, in step a, when marking the width cutting line of the cylinder, a cutting seam loss allowance of 1-2mm needs to be added, and a welding shrinkage allowance of 2-3mm needs to be added for each cylinder section for circumferential welding.

[0015] As a preferred embodiment of the present invention, in step b, after the cylindrical section is rolled and formed, the misalignment of the longitudinal seam should not exceed 1mm, and the misalignment of the two end faces should not exceed 1mm.

[0016] As a preferred technical solution of the present invention, in step b, after the cylindrical section is rolled and formed, the ellipticity under natural conditions is ≤3mm at 0°, 90°, 180°, and 270°, and the circumference error is ≤3mm.

[0017] As a preferred technical solution of the present invention, in step c, the groove is preheated within a range of not less than 75mm on both sides by electric heating or flame heating before welding. The preheating temperature is not less than 80℃, and the interpass temperature is controlled not lower than the preheating temperature but not higher than 250℃. After welding, rock wool is used for insulation and slow cooling.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] The construction process of the self-elevating wind power installation platform legs of this invention adopts thin-layer, narrow-channel, multi-pass welding, which can effectively reduce welding deformation and avoid incomplete fusion and slag inclusion defects in full penetration fillet welds. The welding qualification rate is over 98%, which not only has good quality, but also reduces the deformation caused by repair welding, reduces costs, and shortens the construction period. Attached Figure Description

[0020] Figure 1 This is a process flow diagram of the present invention; Detailed Implementation

[0021] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0022] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] Example

[0024] like Figure 1 As shown, a construction process for the legs of a self-elevating wind power installation platform includes the following steps:

[0025] a. Material preparation

[0026] All steel plate materials must undergo incoming inspection. The cutting dimensions of the steel are calculated with the center of the steel plate as the reference line. After the steel plate is laid out, the cutting lines, track lines, and inspection lines are marked. The unfolded cutting length of the cylindrical steel plate is calculated as L1 = DP + δ1 + δ2 - δ4. The allowance on both sides of the steel plate is calculated based on the cutting dimension of the single section of the cylindrical plate as L2 = L3 + δ1 + δ2 (width dimension = drawing dimension + cutting allowance + circumferential shrinkage) = L3 + 4. The cutting must ensure that the straightness error is not greater than 1 / 1000 and ≤5mm, the perpendicularity error in the plate thickness direction is not greater than 1mm, the cutting bevel angle error is ±1°, the cut depth is not greater than 0.5mm, the parallelism of the unfolded length cutting line is less than 2mm, and the diagonal of the cutting dimension is checked according to the cutting inspection line and is less than 2mm.

[0027] Among them, L1 is the length of the steel plate for the cylinder, DP is the middle diameter of the cylinder, L2 is the width of the steel plate for the cylinder, L3 is the width of the cylinder, D is the diameter of the cylinder, δ1 is the gas cutting allowance (1-2mm), δ2 is the longitudinal seam welding shrinkage allowance (2-3mm), and δ4 is the cold rolling elongation (generally 2-5mm).

[0028] In step a, when marking the width cutting line of the cylinder, a cutting seam loss allowance of 1-2mm needs to be added, and a welding shrinkage allowance of 2-3mm needs to be added for each cylinder section for circumferential welding.

[0029] b. Segment rolling

[0030] The process of rolling the cylinder section is as follows: steel plate pre-bending → rolling → perimeter inspection → allowance cutting → joining → positioning welding → pre-welding inspection → external longitudinal seam grinding treatment → cylinder section rounding and straightening → ovality inspection → NDT testing → cylinder section completion inspection.

[0031] When pre-bending the steel plate, press it once within 150mm of the end of the steel plate, and then press it twice within 300mm to reduce the elasticity of the steel plate. During the rolling process, check the working line to ensure that the steel plate and the rolling roller are always parallel. Gradually increase the force and control the rolling speed throughout the rolling process. Roll it back and forth multiple times to form the shape, and check it with the arc template at any time to ensure the accuracy of the cylinder.

[0032] When pre-bending the ends of the steel plate, the pre-bending arc should be checked with a template at any time. If there are any protrusions or indentations, steel strips can be used as padding to correct them. In order to control the excessively large corners of the two ends, i.e. the longitudinal seam interface, or the loss of roundness after welding deformation, and to facilitate the straightening after welding, the pre-bending radius of the two ends should be 1-2mm smaller than the actual radius of the pipe section.

[0033] Based on the working lines drawn on the surface of the steel plate, the ends of the steel plate are first pre-bent and inspected using an arc template (outer circular template for pile legs, inner circular template for pile fixing frame);

[0034] Rolling can only begin after the pre-bending inspection of the ends is qualified. During the rolling process, the working line is checked to ensure that the steel plate and the rolling roll are always parallel. The two sides of the steel plate are perpendicular to the center line of the roller. Frequent checks should be performed to prevent deviation and misalignment of the end face. The initial section of the steel plate should be gradually bent and rolled to a suitable radius of curvature, and then continuously rolled into a cylindrical shape. Each time the roller is adjusted, the curvature of the steel plate arc should be checked with a template until it completely conforms to the template.

[0035] After the cylindrical section is rolled into shape, a special longitudinal seam butt joint device is used to align the longitudinal seam joints, align the two ends, and ensure that the gap between the joints meets the requirements of the drawings and process documents. The perimeter error should not exceed 3mm. At the same time, 100mm x 100mm arc-guiding plates of the same material are assembled at both ends.

[0036] In step b, after the cylindrical section is rolled into shape, the misalignment at the longitudinal seam joint should not exceed 1mm, and the misalignment at both ends should not exceed 1mm.

[0037] Among these factors, uneven pressure during the pre-bending and rolling process of the cylinder section, as well as welding deformation, can cause the cylinder to have sharp edges or be out of round. After welding, the cylinder section needs to be corrected and shaped.

[0038] In step b, after the cylindrical section is rolled and formed, the ellipticity under natural conditions is ≤3mm at 0°, 90°, 180°, and 270°, and the circumference error is ≤3mm.

[0039] c. Longitudinal seam welding of the cylinder

[0040] Submerged arc welding is used for longitudinal joint welding of pipe sections. Before preheating and welding, the arc-starting plate is installed, and the straightness, flatness, bevel angle and cleanliness of the bevel are carefully checked. The straightness of a single pipe section is required to be less than 2mm, and the flatness is required to be less than 2mm. For V or X type bevels, the included angle after assembly is required to be greater than 50°. The inner surface of the bevel is smooth, flat and has a metallic luster. After passing the inspection, SAW automatic welding is used. After welding one side, the back side is cleaned. After cleaning, the back side is carefully ground to meet the above requirements before SAW automatic welding is performed.

[0041] In step c, before welding, the groove is preheated within a range of no less than 75mm on both sides by electric heating or flame heating. The preheating temperature is no less than 80℃, and the interpass temperature is controlled to be no lower than the preheating temperature but no higher than 250℃. After welding, rock wool is used for insulation and slow cooling.

[0042] Before preheating for tack welding, the weld bevel and the area within 100mm around the weld should be clean and free of moisture, oil, slag, rust, oxides, or any foreign impurities that may contaminate the weld.

[0043] To control assembly gaps, when using CO2 gas shielded welding with single-sided welding and double-sided forming with ceramic backing, the assembly gap should be 5-7mm. For manual welding, the assembly gap should be 0-3mm. For fillet welds, the assembly gap should be 0-3mm. Otherwise, the fillet weld should be built up before assembly.

[0044] Adding welding shrinkage compensation will reduce the size after welding. The larger the gap, the greater the reduction. Generally, the longitudinal shrinkage is 0.1 / 1000, and the transverse shrinkage is about 1 / 1000. The more joints there are, the greater the shrinkage. The shrinkage of a joint is related to the gap size, and it is generally 2-4mm. The shrinkage of each fillet weld is about 0.2-0.4mm.

[0045] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A construction process for the legs of a self-elevating wind power installation platform, characterized in that: Includes the following steps: a. Material preparation All steel plate materials must undergo incoming inspection. The cutting dimensions of the steel are calculated with the center of the steel plate as the reference line. After the steel plate is laid out, the cutting line, track line and inspection line are marked. The unfolded cutting length of the cylindrical steel plate is calculated as L1=DP+δ1+δ2-δ4. The allowance on both sides of the steel plate is calculated as L2=L3+δ1+δ2=L3+4 based on the cutting dimensions of a single section of the cylindrical plate. The cutting must ensure that the straightness error is not greater than 1 / 1000 and ≤5mm, the perpendicularity error in the plate thickness direction is not greater than 1mm, the cutting bevel angle error is ±1°, the cutting depth is not greater than 0.5mm, and the parallelism of the unfolded length cutting line is less than 2mm. Where L1 is the blanking length of the cylindrical steel plate, DP is the middle diameter of the cylindrical body, L2 is the blanking width of the cylindrical steel plate, L3 is the width of the cylindrical body, δ1 is the gas cutting allowance, δ2 is the longitudinal seam welding shrinkage allowance, and δ4 is the cold rolling elongation. b. Segment rolling The process of rolling the cylinder section is as follows: steel plate pre-bending → rolling → perimeter inspection → allowance cutting → joining → positioning welding → pre-welding inspection → external longitudinal seam grinding treatment → cylinder section rounding and straightening → ovality inspection → NDT testing → cylinder section completion inspection. When pre-bending the steel plate, press it once within 150mm of the end of the steel plate, and then press it twice within 300mm to reduce the elasticity of the steel plate. During the rolling process, check the working line to ensure that the steel plate and the rolling roller are always parallel. Gradually increase the force and control the rolling speed throughout the rolling process. Roll it back and forth multiple times to form the shape, and check it with the arc template at any time to ensure the accuracy of the cylinder. c. Longitudinal seam welding of the cylinder Submerged arc welding is used for longitudinal joint welding of pipe sections. Before preheating and welding, the arc-starting plate is installed, and the straightness, flatness, bevel angle and cleanliness of the bevel are carefully checked. The straightness of a single pipe section is required to be less than 2mm, and the flatness is required to be less than 2mm. For V or X type bevels, the included angle after assembly is required to be greater than 50°. The inner surface of the bevel is smooth, flat and has a metallic luster. After passing the inspection, SAW automatic welding is used. After welding one side, the back side is cleaned. After cleaning, the back side is carefully ground to meet the above requirements before SAW automatic welding is performed.

2. The construction process of the self-elevating wind power installation platform leg according to claim 1, characterized in that: In step a, when marking the width cutting line of the cylinder, a cutting seam loss allowance of 1-2mm needs to be added, and a welding shrinkage allowance of 2-3mm needs to be added for each cylinder section for circumferential welding.

3. The construction process of the self-elevating wind power installation platform legs according to claim 1, characterized in that: In step b, after the cylindrical section is rolled into shape, the misalignment at the longitudinal seam joint should not exceed 1mm, and the misalignment at both ends should not exceed 1mm.

4. The construction process of the self-elevating wind power installation platform leg according to claim 1, characterized in that: In step b, after the cylindrical section is rolled and formed, the ellipticity under natural conditions is ≤3mm under its own weight at 0°, 90°, 180°, and 270°, and the circumference error is ≤3mm.

5. The construction process of the self-elevating wind power installation platform leg according to claim 1, characterized in that: In step c, before welding, the groove is preheated within a range of no less than 75mm on both sides by electric heating or flame heating. The preheating temperature is no less than 80℃, and the interpass temperature is controlled to be no lower than the preheating temperature but no higher than 250℃. After welding, rock wool is used for insulation and slow cooling.

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