NL2026748B1

NL2026748B1 - On-site continuous preheating multi-section welding and installing method for huge marine pile leg field

Info

Publication number: NL2026748B1
Application number: NL2026748A
Authority: NL
Inventors: Qingtian Yang; Hehui Zheng; Hang Gao; Zhengang Wang; Yongkang Zhang; Ming Chou
Original assignee: Univ Guangdong Technology
Priority date: 2020-08-25
Filing date: 2020-10-23
Publication date: 2022-04-29
Also published as: CN112077469B; CN112077469A

Abstract

The present invention discloses an on-site continuous preheating multi-section welding and installing method for a huge marine engineering pile leg. Firstly, a marine platform is moved to a designated position on a sea surface, and then a crane is utilized to hoist a first sectional pile and fix the first sectional pile into an installing hole in the marine platform vertically; and a second sectional pile is hoisted to an upper end part of the first sectional pile, and one section is welded and then moved downwards until a lower end of the pile leg makes contact with seabed. By using a sectional type on-site direct welding and installing mode, an peration cost and a risk factor are greatly reduced, and problems of limited space of the marine platform and excessively high selection requirements for the crane are solved. The present invention builds a welding preheating mathematical model, so that a welding process of welding material selection, welded junction bottoming, filling, capping, groove preparation, back gouging, dehydrogenation treatment and destressing is formed. The solution of the present invention reduces welding stress, improves anti-fatigue performance, and meanwhile, solves a problem of large closure deformation during large-size multi-section welding.

Description

ON-SITE CONTINUOUS PREHEATING MULTI-SECTION WELDING AND INSTALLING METHOD FOR HUGE MARINE PILE LEG FIELD

[0001] The present invention relates to the technical field of marine equipment, in particular to a multi-section welding method for a huge marine pile leg.

BACKGROUND

[0002] Wind energy gets more and more attention from people as an inexhaustible renewable energy source. Not only a wind power plant has been built on land, but an offshore wind plant has started to be built widely. Offshore wind power development has represented the general trend. Installation of an offshore wind power unit has more technical difficulties than that of a land wind power unit, which is one of key technologies of offshore wind plant construction. Aimed at a complex sea condition and a weather situation, it is urgently needed to develop an ultra-large offshore wind power installation platform meeting various functional requirements.

[0003] During existing pile leg installing, after a whole pile leg is completely welded, the whole pile leg is transferred and hoisted to a installing hole in the marine platform on the sea surface, and the whole pile leg is inserted into the installing hole in the marine platform, and then starts to move to underwater slowly until the lower end ofthe pile leg makes contact with the seabed. Due to the large diameter and the hundred- meter length of the pile leg, the weight of the pile leg is at least over one thousand tons, this installing method has high requirements on a crane, and only the ultra-large type crane may complete installing operation, resulting in a high operation cost and a high risk factor.

[0004] The pile leg is an important supporting member of the platform, which bears the weight of a hull during operation and also resists impacts of environmental stress such as sea wind, sea wave and low temperature, and therefore welding of the pile leg is the most difficult work in a wind power installation vessel.

[0005] The pile leg of a wind power installing platform uses ultrahigh-strength steel, which is large in weld joint cold crack sensitivity and large in thickness, the higher a cooling speed is, the more prone a heat affected zone is to generating a quenched structure and generating a crack, a welding requirement is high, and the welding quality 1s difficult to control. In the prior welding art, many factors affect the weld joint quality, including welding material, a groove type, weld preheating and postweld heat treatment, a welding process parameter, back gouging, dehydrogenation treatment or thelike, which directly affect the weld joint quality; and meanwhile, a problem of large closure deformation during large-size multi-section welding further exists.

[0006] The patent for invention CN102699589 disclosed a preheating welding device for a wind power installation vessel circular pile leg and a preheating welding method thereof, and the solution of the patent uses inner and outer ceramic heating sheets to preheat the inner side and the outer side of the pile leg, so that uniform preheating of an ultra-large thick plate is achieved, and the welding efficiency and the welding quality are improved. This solution is used to improve an existing technical solution which uses pile leg single-face preheating for the ultra-large thick plate but cannot achieve uniform heating, only aims at the single factor, namely the weld preheating, and does not consider other influence factors, so that this solution has a few limitations on the improvement of the weld joint quality.

SUMMARY

[0007]

[0008] In order to overcome the above defects, an objective of the present invention is to provide an on-site continuous preheating multi-section welding and installing method for a huge marine pile leg. The method only needs a common crane to complete operation, which is safe and reliable.

[0009] In order to solve the above technical problems, the present invention uses the technical solution:

[0010] the on-site continuous preheating multi-section welding and installing method for the huge marine pile leg includes the following steps:

[0011] S1, welding each sectional pile, wherein each sectional pile is formed by sequentially connecting a plurality of metal cylinders in series through welding, and a continuous preheating welding method 1s used between adjacent metal cylinders; and

[0012] S2, welding and installing a pile leg of a marine platform: A, moving the marine platform to a designated position on a sea surface, then utilizing the crane to hoist a first sectional pile to an installing hole in the marine platform, and fixing the first sectional pile into the installing hole vertically; B, utilizing the crane to hoist a second sectional pile to an upper end part of the first sectional pile in the installing hole S of the marine platform, and aligning the second sectional pile with the first sectional pile; C, utilizing a welding apparatus to weld the second sectional pile and the first sectional pile together; D, moving two welded sectional piles to underwater along the installing hole in the marine platform by a distance of a length of one sectional pile after welding 1s completed; and E, repeating steps B to D until all the sectional piles are welded together, wherein when welding of the pile leg is completed, a lower end of the pile leg makes contact with seabed.

[0013] Furthermore, in S1, the plurality of metal cylinders are conveyed to the marine platform, and welding of the sectional pile is conducted on the marine platform.

[0014] Furthermore, in Sl, the sectional pile is formed by jointing 3 to 4 metal cylinders in a butted mode, and a length of the metal cylinder is 2 to 3 m.

[0015] Furthermore, in S1, the metal cylinder is made of E690 ultrahigh-strength steel, and the metal cylinder has an internal diameter of 5 m and a wall thickness of 50 mm.

[0016] Furthermore, in S1, the continuous preheating welding method includes the following steps:

[0017] S11, developing a special welding software system, and setting up a corresponding welding process parameter database for a welding material, which includes 4 groove type, weld preheating and postweld heat treatment, a welding rod diameter, a welding current, a welding voltage, a welding speed, and heat input;

[0018] S12, building a preheating mathematical model of the huge pile leg in the welding software system according to a material and a size parameter of the metal cylinder on a welding site, calling data in the welding process parameter database to conduct simulation, and optimizing a process parameter,

[0019] S13, issuing an instruction to a controller through the welding software system after optimizing the process parameter to meet a welding requirement,

controlling inner and outer ceramic heating sheets to preheat inner and outer sides of a weld joint position of the metal cylinder, starting a welding program after a preheating temperature meets a requirement, controlling an electric motor to drive a supporting roller to rotate through the controller by the welding software system, driving the metal cylinder to rotate by friction force of the supporting roller, and conducting back gouging and dehydrogenation treatment at the same time; and

[0020] S14, translating the welded metal cylinder axially through a complete welding closing device after welding of a first weld joint is completed, translating the other end of the metal cylinder to a welding station, hoisting the next metal cylinder to the welding station, preparing welding of the next metal cylinder, and executing S13 and S14 circularly until welding of the whole sectional pile is completed.

[0021] Furthermore, in S12, a simulation result comprises result analyses of a welding deformation compensation quantity and a welding shrinkage amount of the sectional pile, which is used for accurately analyzing and accurately positioning a length dimension and a welding position of the metal cylinder. The present invention replaces a traditional building allowance method, thereby reducing a manufacturing cost of the metal cylinder.

[0022] Furthermore, in S13, during starting the welding program, the instruction is issued to the controller through the welding software system, then the controller controls a welding device to achieve output of the process parameter, and the welding speed in the process parameter is achieved by controlling a rotating speed of the electric motor through the controller to control a rotating speed of the metal cylinder.

[0023] Furthermore, in S14, a welding position of the other end of the metal cylinder is translated to the welding station by moving a driver on a super-tonnage hoisting beam to make contact with a self-locking limiting device; firstly, the super- tonnage hoisting beam hoists a welded part of the metal cylinder; then the driver drives the metal cylinder to move in a horizontal direction, when the driver makes contact with the self-locking limiting device, the self-locking limiting device disconnects power of the driver, and at this moment, the welding position of the other end of the metal cylinder reaches a position right above the welding station; and finally, the super-

tonnage hoisting beam places the metal cylinder on a bracket, so that the welding position of the metal cylinder is located at the welding station.

[0024] Furthermore, in S12, the optimized process parameter is as follows:

[0025] for the process parameter of weld bead bottoming: a welding wire diameter 5 1s 4.0 d/mm, the welding current is 555-580 I/A, the welding voltage is 30-33 U/V, the welding speed is 34-35 v/(cmemin-1), and the heat input is 29-31 E/(kJecm-1);

[0026] for the process parameter of weld bead filling: the welding wire diameter is

4.0 d/mm, the welding current is 590-600 I/A, the welding voltage is 30-33 U/V, the welding speed is 35-37 v/(cmemin-1), and the heat input is 29-31 E/(kJecm-1); and

[0027] for the process parameter of weld bead capping: the welding wire diameter is 4.0 d/mm, the welding current is 590-600 I/A, the welding voltage is 30-33 U/V, the welding speed is 34-35 v/(cmemin-1), and the heat input is 29-31 E/(kJecm-1).

[0028] Furthermore, in S11, the preheating temperature of the weld preheating is 115 to 145 °C; and in the postweld heat treatment, a postwelding temperature is controlled to be 245 to 255 °C, which 1s preserved for 1.4 to 1.6 h.

[0029] The beneficial effects of the present invention are as follows:

[0030] by using a sectional type on-site direct welding and installing mode, an operation cost and a risk factor are greatly reduced, a requirement for the crane is lowered, only the common crane needs to be utilized to achieve installation of the pile leg, and problems of limited space of the marine platform and excessively high selection requirements of the crane are solved.

[0031] By building a welding preheating mathematical model in the present patent, an optimal range of the preheating temperature of two sides of a groove is obtained, and by using a movable ceramic circumference uniform automatic heating device, a complete welding process specification of welding material selection, welded junction bottoming, filling, capping, groove preparation, back gouging, dehydrogenation treatment, destressing or the like is formed. The solution of the present invention reduces welding stress, improves anti-fatigue performance, ensures weld joint quality, and meanwhile, solves a problem of large closure deformation during large-size multi- section welding, and the building allowance of the traditional method is replaced with the welding deformation compensation quantity and the welding shrinkage amount of the huge pile leg, thereby saving a manufacturing cost of the metal cylinder.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings are utilized to further explain the present invention, but embodiments in the drawings do not limit the present invention at all, and those of ordinary skill in the art may further obtain other drawings on the basis of the following drawings without making inventive effort:

[0033] Fig. 1 is an installing and welding schematic diagram of the present invention;

[0034] Fig. 2 is a flow diagram of a continuous preheating welding method of the present invention,

[0035] Fig. 3 is a schematic diagram of a welding operation mode of a continuous preheating welding method of the present invention; and

[0036] Fig. 4 is a diagram of hoisting translation of a welded part of a continuous preheating welding method of the present invention.

[0037] In the drawings: 1, welding gun; 2, metal cylinder; 3, outer ceramic heating sheet; 4, inner ceramic heating sheet; 5, supporting roller; 6, bracket; 7, hoisting beam; 8, tie; 9, driver; 10, weld joint; 11, marine platform; 12, sea surface; 13, crane; 14, sectional pile; 15, welding apparatus; 16, pile leg; 17, seabed, and 18, annular sliding rail.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the drawings and particular embodiments, and it has to be noted that on the premise of no contradiction, embodiments in the present invention and features of the embodiments may be combined mutually.

[0039] In the description of the present invention, it needs to be understood that directions or position relations indicated by terms of “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “upper surface”, “lower surface”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”,

“rotate forward”, “rotate reversely”, “axial”, “radial”, “circumferential” or the like are directions or position relations shown on the basis of the drawings, which are merely used for facilitating description of the present invention and simplifying the description, but do not indicate or imply that the denoted device or component must have a specific direction and be constructed and operated in a specific direction, and therefore cannot be understood as limitations on the present invention.

[0040] An on-site continuous preheating multi-section welding and installing method for a huge marine pile leg includes the following steps:

[0041] S1, each sectional pile is welded, wherein each sectional pile is formed by sequentially connecting a plurality of metal cylinders in series through welding, and a continuous preheating welding method is used between adjacent metal cylinders; the plurality of metal cylinders are conveyed to a marine platform, and welding of the sectional pile is conducted on the marine platform; and the sectional pile is formed by jointing 3 to 4 metal cylinders in a butted mode, and a length of the metal cylinder is 25m.

[0042] S2, a pile leg of the marine platform is welded and installed, wherein as shown in Fig. 1, A, the marine platform 11 is moved to a designated position on a sea surface 12, then a crane 13 is utilized to hoist a first sectional pile 14 to an installing hole in the marine platform 11, and the first sectional pile is fixed into the installing hole vertically, B, the crane is utilized to hoist a second sectional pile to an upper end part of the first sectional pile in the installing hole of the marine platform, and the second sectional pile is aligned with the first sectional pile; C, a welding apparatus 15 is utilized to weld the second sectional pile and the first sectional pile together; D, two welded sectional piles are moved to underwater along the installing hole in the marine platform 11 by a distance of a length of one sectional pile after welding is completed; and E, steps B to D are repeated until all the sectional piles are welded together to form a pile leg 16, when welding of the pile leg 16 is completed, a lower end of the pile leg 16 makes contact with seabed 17, and the pile leg 16 is installed in place. During welding, the sectional pile 14 is fixed, an annular sliding rail 18 is arranged at a position, located at a periphery of the installing hole, on the marine platform 11, the welding apparatus 15 may move along the annular sliding rail 18, and that is to say, the welding apparatus 15 rotates around the sectional pile 14 to weld the sectional pile 14.

[0043] As shown in Fig. 2, in Sl, the continuous preheating welding method includes the following steps:

[0044] S11, a special welding software system is developed, and a corresponding welding process parameter database is set up for a welding material, which includes a groove type, weld preheating and postweld heat treatment, a welding rod diameter, a welding current, a welding voltage, a welding speed, and heat input;

[0045] wherein an initial work amount of this step is large, C/C++ assembly language is needed for writing codes, then the codes are packed into the software system, the welding process parameter database needs a plurality of repeated tests and researches, and great convenience is brought to later corresponding or other welding works along with gradual improvement of the software system and accumulation of the welding process parameter database;

[0046] S12, a preheating mathematical model of the huge pile leg is built in the welding software system according to a material and a size parameter of the metal cylinder on a welding site, data in the welding process parameter database are called to conduct simulation, and a process parameter is optimized,

[0047] and in this step, the metal cylinder is made of E690 ultrahigh-strength steel, the metal cylinder has an internal diameter of 5 m, a wall thickness of 50 mm, and a length of 2.5 m, the preheating mathematical model of the pile leg is built in the welding software system according to a mechanical property of E690 material, then the welding process parameter is called to conduct simulation to obtain the optimized process parameter, and the optimized process parameter is as shown in the following table: Welding Welding | Welding Welding wire current | voltage speed Heat input Weld bead | diameter d/mm V/A UN min E/(kJ-cm™)

[0048] S13, an instruction is issued to a controller through the welding software system after the process parameter is optimized to meet a welding requirement, an inner ceramic heating sheet 4 and an outer ceramic heating sheet 3 are controlled to preheat inner and outer sides of a weld joint position of the metal cylinder 2, a welding program is started after a preheating temperature meets a requirement, an electric motor is controlled to drive a supporting roller 5 to rotate through the controller by the welding software system, the metal cylinder 2 is driven to rotate by friction force, and back gouging and dehydrogenation treatment are conducted at the same time;

[0049] as shown in Fig. 3, the outer ceramic heating sheet 3 is closely attached to an outer side weld joint position of the metal cylinder 2, the inner ceramic heating sheet 4 is closely attached to an inner side weld joint position of the metal cylinder 2, wherein in this step, the preheating temperature is 115 to 145 °C, an interlayer temperature is 115 to 190 °C, and a postwelding temperature 1s 245 to 255 °C, which is preserved for

1.4 to 1.6 h; and during welding, a welding gun 1 is fixed in position, the metal cylinder 2 rotates through rotation of the supporting roller 5, a rotating speed of the metal cylinder 2 is the welding speed, and the rotation of the supporting roller 5 is achieved by controlling the electric motor through the controller by the welding software system; and

[0050] S14, the welded metal cylinder 2 is translated axially through a series of complete welding closing devices of a super-tonnage hoisting beam 7, a self-locking limiting device, a bracket 6 or the like after welding of a first weld joint is completed, the other end of the metal cylinder is translated to a welding station, the next metal cylinder is hoisted to the welding station for preparing welding of the next metal cylinder, and S13 and S14 are executed circularly until welding of the whole sectional pile is completed.

[0051] In this step, as shown in Fig. 4, after welding of one weld joint 10 is completed, the super-tonnage hoisting beam 7 utilizes a tie 8 to hoist a welded part of the metal cylinder 2, and then the driver 9 drives the metal cylinder to horizontally and stably move in an axial direction; and Fig. 3 shows leftward horizontal movement, when the driver 9 makes contact with the self-locking limiting device, the self-locking limiting device disconnects power of the driver, and at this moment, a welding position of the other end of the metal cylinder reaches a position right above the welding station, 5S which means that a right side welding position of the metal cylinder 2 reaches a welding operation position, then the super-tonnage hoisting beam 7 places the next metal cylinder 2 on the bracket 6, and S13 and S14 are circulated until welding of the sectional pile is completed.

[0052] This embodiment achieves 10 sectional piles formed by splicing 40 metal 10 cylinders through welding, the 10 sectional piles are welded and installed on site to form the huge pile leg of thousands of tons, and the pile leg has a length of 100 m and a straightness less than 5 mm, which achieves an international first-class level.

[0053] In addition, on the premise of no mutual contradiction, those skilled in the art may combine different embodiments or examples described in the description and characteristics of the different embodiments or examples. Although the embodiments of the present invention are shown and described above, it may be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention, and variations, modifications, substitutions and changes on the above embodiments may be made by those of ordinary skill in the art within the scope of the present invention.

Claims

CONCLUSIONS

1. The on-site continuous preheating of multi-section welding and the installation method for a huge ship pile foot includes the following steps: S1, the welding of each composite pile, each composite pile being formed by sequentially joining a plurality of metal cylinders in series by welding, and a continuous preheating welding method is used between adjacent metal cylinders; and S2, welding and installing a pile foot of a ship platform: A, moving the ship platform to a designated position on a sea surface, then using a crane hoist a first sub-pile to an installation hole in the sea platform and the first fix sub-post vertically in the installation hole; B, using the crane, hoisting a second sub-pile on an upper part of the first sub-pile into the installation hole of the sea platform and aligning the second sub-pile with the first sub-pile; C, welding the second part pile and the first part pile together using a welding machine; D, moving two welded part piles to underwater along the installation hole of the water platform with a distance of one part pile after welding; and E, repeating steps B to D until all subpiles are welded together, when the welding of the pile foot is complete, the underside of the pile foot will come into contact with the seabed.

The continuous on-site preheating of multi-section welding and the installation method for the huge ship pile foot according to claim 1, wherein in S1, the plurality of metal cylinders are conveyed to the sea platform, and the welding of the sectional pile is performed on the sea platform.

The continuous on-site multi-section welding preheating and the installation method for the huge ship pile foot according to claim 1, wherein in S1, the sectional pile is formed by connecting 3 to 4 metal cylinders in a butted mode, and a length of the metal cylinder is 2 to 3m.

The continuous on-site preheating of multi-section welding and the installation method for the huge ship pile foot according to claim 3, wherein in S1, the metal cylinder is made of E690 ultra-high strength steel, and the metal cylinder has an internal diameter of Sm and a wall thickness of 50 mm.

The continuous on-site preheating of multi-section welding and the installation method for the huge ship pile foot according to any one of claims 1 to 4, wherein in S1, the continuous preheating welding method comprises the following steps: S11, developing a special weld software system and setting up a corresponding welding process parameter database for a welding material, which consists of a groove type, weld preheating and aftertreatment, a welding bar diameter, a welding current, a welding voltage, a welding speed and a heat input; S12, building a preheating mathematical model of the huge pile foot in the welding software system using a material and size parameter of the metal cylinder at a welding site, querying data in the welding process parameter database to perform a simulation , and optimizing a process parameter; S13, issuing an instruction to a driver by the welding software system after optimizing the process parameter to meet a welding requirement, checking the inner and outer ceramic heating plates to seal the inner and outer sides of a weld joint position of the metal cylinder for to heat, starting a welding program after a preheating temperature meets a requirement, controlling an electric motor to rotate a supporting roller by the welding software system, driving the metal cylinder to rotate by the frictional force of the supporting roller, and simultaneously performing the gouging and dehydrogenation treatment; and S14, axially translating the welded metal cylinder by a full welder after welding a first weld joint, translating the other end of the metal cylinder to a welding station, and performing S13 and S14 circularly to weld the whole composite pile is completed.

The continuous on-site multi-section welding preheating and the installation method for the huge ship pile foot according to claim 5, wherein in S12 a simulation result includes result analyzes of a weld deformation compensation amount and a weld shrinkage of the section pile to obtain a length measure and a welding position of accurately analyze and accurately position the metal cylinder.

The continuous on-site preheating of multi-section welding and the installation method for the huge ship pile foot according to claim 5, wherein in S13, when starting the welding program, the instruction is given to the controller through the welding software system, then the controller sends a welding machine to achieve the output of the process parameter, and the welding speed in the process parameter is achieved by controlling a rotational speed of the electric motor through the controller to control a rotational speed of the metal cylinder.

The continuous on-site multi-section welding preheating and the installation method for the huge ship pile foot according to claim 5, wherein in S14, a welding position of the other end of the metal cylinder is translated to the welding station by a float on a supertonage moving lifting beam to contact with a self-locking limiter, first, a welded part of the metal cylinder is lifted by the supertonage lifting beam; then the metal cylinder is driven in horizontal direction, when the float makes contact with the self-locking limiter, the self-locking limiter turns off the power of the float, and at that time the welding position of the other end of the metal cylinder reaches a position just above the welding station; and finally, the super tonnage lifting beam puts the metal cylinder on a bracket, so that the welding position of the metal cylinder is in the welding station.

The continuous on-site multi-section welding preheating and the installation method for the huge ship pile foot according to claim 5, wherein in S12, the optimized process parameter is as follows: for the welding bead bottom process parameter: a welding wire diameter is 4.0d/ mm, the welding current is 555-5801/A, the welding voltage is 30-33 U/V, the welding speed is 34-35v/(cm-

min-1), and the heat input is 29-3 1E/(kJ-cm-1); for the process parameter of filling the welding bead: the welding wire diameter is 4.0 d/mm, the welding current is 590-6001/A, the welding voltage is 30-33U/V, the welding speed is 35-37v/(em-min -1}, and the heat input is 29-31E{kJ-cm-1}; and for the welding bead termination process parameter: the welding wire diameter is 4.0 d/mm, the welding current is 590-6001/A, the welding voltage is 30-33U/V, welding speed is 34-35v/(cm-min-1), and heat input is 29-3 1E/(kJ-cm-1).

The continuous on-site multi-section weld preheating and the installation method for the huge ship pile foot according to claim 5, wherein in S11, the preheating temperature of the weld preheat is 115 to 145°C; and in the post-welding heat treatment, a post-welding temperature is controlled to be 245 to 255 °C, which is kept for 1.4 to 1.6 hours.