Construction method for long shafting of thin-plate naval vessel

Abstract

The invention discloses a thin-plate naval vessel long shafting construction method, belongs to the technical field of naval vessel shafting construction, and solves the technical problem of long construction period of an existing ship body shafting. According to the method, shafting construction can be started after a shafting area of a main hull is folded and formed, follow-up folding of the main hull, superstructure carrying, sealing test of a cabin of the main hull, assembling and welding of a professional base gasket of a turbine and coating of a cabin are carried out according to process requirements while shafting construction is carried out, and shafting construction is finished after the first layer of superstructure carrying is completed. And under the condition that the shafting quality is guaranteed, the construction period of the ship slipway can be greatly shortened, and high-quality conditions are created for advanced construction of subsequent procedures.

Description

Technical Field

[0001] The present invention relates to the technical field of ship shaft system construction, and more specifically, to a method for constructing a thin-plate ship long shaft system. Background Art

[0002] At present, the propulsion systems of ships basically adopt the long shaft system layout. The installation of the long shaft system (especially the ultra-long shaft system) runs through the entire construction stage of the ship. The speed of its construction efficiency will be directly related to the length of the ship construction cycle, and plays an extremely important role in whether the shipbuilding shipyard can complete the project on schedule.

[0003] like Figure 1 As shown, the existing hull shaft system construction can only be carried out after the main hull and superstructure welding and pyrotechnic calibration are completed, the main hull tightness test is completed, and the whole ship is simulated ballasted in place, which makes the ship construction period long, the efficiency low, the shipyard production cost high, and the benefit poor. Summary of the invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art. The purpose of the present invention is to provide a method for constructing a thin-plate ship long axis system that can shorten the ship construction period.

[0005] In order to achieve the above-mentioned purpose one, the present invention provides a method for constructing a long shaft system of a thin-plate ship. The shaft system construction can start after the main hull shaft system area is closed and formed. While the shaft system is being constructed, the subsequent closing of the main hull, installation of the superstructure, main hull cabin tightness testing, welding of the engine room professional base gasket, and engine room painting are carried out in accordance with the process requirements, and the shaft system construction is terminated after the first layer of superstructure is installed.

[0006] As a further improvement, the specific construction procedures are as follows: the main hull shaft area is closed and formed → the berth position is adjusted according to the shaft construction stage, the pier wood is tightened and compacted, the hull in the shaft area is measured and adjusted → the first wire measurement is made to determine the shaft baseline → the shaft tail ground sample line is engraved → the shaft fore and aft reference points are engraved and confirmed, and height monitoring benchmarks are set up on the ground at the fore and aft of the shaft → the main engine seat panel and small base, gear box seat panel, intermediate bearing seat, brake device seat are installed → while the base is installed, the stern shaft frame and stern shaft tube are pre-installed, and the surrounding structure and embedded outer plate thickening plate are installed → the base is measured and Bevel inspection → welding of base, welding of the surrounding structures of stern bracket and stern tube first, including welding of embedded outer plate thickening → welding of base part, welding and post-welding measurement inspection → welding of engine fixing gasket → engine room painting → simulated ballast of the whole ship, measurement and confirmation of hull status → review of fore and aft reference points of shafting, second wire measurement, adjustment of shafting baseline → installation measurement, review and adjustment of stern bracket and stern tube → installation and bevel inspection of bracket arm and stern tube → welding and inspection of bracket arm and stern tube → stress elimination, strengthening removal, flaw detection and tightness of stern bracket after welding → measurement and inspection of post-welding data → delivery to professional engine construction.

[0007] Furthermore, the conditions for shafting construction include:

[0008] In the base part, the main hull in the shafting area is closed and formed, and the main assembly and welding are completed;

[0009] At the tail shaft frame part, the hull is formed, and the main assembly, welding and pyrotechnics are completed; the main hull water-filled compartment tightness test is completed, and the main tightness test of the shafting arrangement area is ended; the first layer of superstructure is installed; ballasting is carried out according to the "Main Equipment Ballast Arrangement Drawing", and the main equipment is put into the cabin or replaced with ballast of similar weight; before the shafting construction, the hull status data is measured, confirmed and recorded.

[0010] Furthermore, at the time of the first shafting wire construction, after the shafting construction conditions are met, the shafting installation and welding work is carried out while the main hull is closed, including the following work:

[0011] Adjust the hull axis baseline according to the previous measurement data of the hull status;

[0012] Construction of the base, installation and positioning of the main engine base and small base, gearbox base, intermediate bearing base, and brake device base;

[0013] Stern frame construction, installation and positioning of stern frame and stern tube;

[0014] Weld the main engine seat and small base, gearbox seat, intermediate bearing seat, brake device seat, and weld the surrounding structures of the stern shaft frame and stern shaft tube, including the welding of the embedded outer plate thickening plate.

[0015] Furthermore, during the second shafting construction, the main hull assembly, welding, pyrotechnics and tightness test were completed, and the adjustment and welding of the shafting stern bracket were carried out while the first layer of superstructure was hoisted, including the following work:

[0016] The whole ship is simulated for ballasting, the hull status is measured, the fore and aft reference points of the shafting are reviewed, the baseline and axis are slightly adjusted, the stern bracket and stern tube installation data are re-measured by secondary pulling, and whether they meet the accuracy requirements are reviewed and adjusted in time;

[0017] The stern shaft bracket arm is reinforced with the surrounding hull structure and the embedded outer plate thickening plate for positioning welding, and then welded in the welding sequence;

[0018] Welding of stern tube;

[0019] Stern tube and stern bracket welding inspection;

[0020] After the welding of the first layer of superstructure is completed and the shaft system data is reviewed to see if it meets the accuracy requirements, it will be handed over to the engine room professional construction.

[0021] Furthermore, the welding sequence requires:

[0022] Before formal welding, welders must perform reinforcement positioning welding inside and outside the cabin;

[0023] The welding procedure is to first symmetrically weld the hull structure connected by the stern shaft bracket arm and the embedded outer plate thickening plate, then carbon planer and grind the weld on the reverse side of the outer cabin of the stern shaft bracket arm and the embedded outer plate thickening plate, and then weld;

[0024] When welding inside the cabin, first weld the structural butt joints, then weld the vertical fillet welds between the bracket arm and the structure, and finally weld the flat fillet welds; before welding the stern shaft bracket arm, use a cutting torch to preheat the welding position and the area within 100mm on both sides, and the preheating temperature is 120-200℃;

[0025] During welding, one welder performs welding symmetrically on the stern shaft bracket arm;

[0026] When welding the angle weld between the embedded outer plate thickening plate and the stern shaft bracket arm, carbon dioxide gas shielded welding is used. Before welding, a cutting torch is used to preheat the welding position and the area within 100mm on both sides thereof. The preheating temperature is 120-200°C.

[0027] Furthermore, the welding of the stern tube includes:

[0028] Welding of fore and aft end base plates of stern tube to transverse bulkhead plating and solid floor reinforcement rings;

[0029] The first and last ends of the stern tube were constructed simultaneously by two welders;

[0030] The welding between the stern tube and the hull structure is mostly circumferential welds. In order to reduce welding deformation, intermittent welding must be used; first perform symmetrical reinforcement welding, and then use full strip bottoming and symmetrical welding;

[0031] Before welding the stern tube, the welding sequence of the stern tube can be adjusted according to the deviation direction of the overall post-welding data of the three stern shaft frames on the same axis.

[0032] Furthermore, after the welding of the stern tube and the stern frame is completed, the stern frame weld is subjected to pyrotechnic stress elimination, and after the weld is cooled, the support reinforcement is removed and the code feet are batch-ground; the welding application for the stern tube and the stern frame is submitted for inspection.

[0033] Furthermore, the E5015 welding rod used in the welding process must be dried at 300-350°C for 1-2 hours before use and stored in a welding rod insulation tube. During the welding process, the insulation tube must be powered on to keep warm and the welding rod can be taken out as needed.

[0034] Furthermore, the monitoring data of the entire shafting construction process was compiled into a book, including the periodic changes in the hull status, the comparison of measurement data before and after welding of the shafting base and stern shaft frame, and the hull completion data, which was used for analysis and summary and as a guide for subsequent ships.

[0035] Beneficial Effects

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] The present invention moves the shafting construction process forward so that the shafting construction can be carried out in parallel with other processes. The early construction of the mainline shafting project of the slipway can provide excellent conditions and basis for the early implementation of subsequent processes. Under the premise of ensuring quality, the slipway construction period of the ship can be greatly shortened, especially shortening the slipway construction period by about one month, which will free up valuable slipway space for the company, save various resource costs for the company's main shipbuilding business, and the benefits generated will become increasingly obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a conventional hull shafting construction procedure diagram;

[0039] Figure 2 It is a construction procedure diagram of the hull shaft system of the present invention;

[0040] Figure 3 It is a routine arrangement diagram of the slipway production process;

[0041] Figure 4 It is a diagram of the arrangement of the shipyard production process of the present invention;

[0042] Figure 5 It is a schematic diagram of the stern shaft bracket arm and the embedded outer plate thickening plate;

[0043] Figure 6 A cross-sectional view of the stern shaft bracket arm and the embedded outer plate thickening plate;

[0044] Figure 7 This is a sequence diagram for welding the stern tube to the hull structure. DETAILED DESCRIPTION

[0045] The present invention will be further described below with reference to the specific embodiments in the accompanying drawings.

[0046] See also Figure 1 to Figure 7 A method for constructing a long shaft system of a thin-plate ship. The shaft system construction can begin after the main hull shaft system area is closed and formed. While the shaft system is being constructed, the subsequent closing of the main hull, installation of the superstructure, main hull cabin tightness testing, welding of the engine room professional base gasket, and engine room painting are carried out in accordance with the process requirements. The shaft system construction is completed after the first layer of superstructure is installed.

[0047] The specific construction procedure is: the main hull shaft area is closed and formed → the berth position is adjusted according to the shaft construction stage, the pier wood is tightened and compacted, the hull in the shaft area is measured and adjusted → the first wire measurement is made to determine the shaft baseline → the shaft tail ground sample line is engraved → the shaft fore and aft reference points are engraved and confirmed, and height monitoring benchmarks are set up on the ground at the fore and aft of the shaft → the main engine seat panel and small base, gear box seat panel, intermediate bearing seat, brake device seat are installed → while the base is installed, the stern shaft frame and stern shaft tube are pre-installed, and the surrounding structures and embedded outer plate thickening plates are installed → measurement and groove inspection before base welding → base welding, stern shaft frame and stern shaft tube are pre-installed The structure is welded first, including the welding of the embedded outer plate thickening plate (it should be noted that the welds directly connected to the stern bracket and stern tube are not welded yet) → welding of the base part, welding and post-welding measurement and inspection → welding of the engine fixing gasket → painting of the engine room → simulated ballast of the whole ship, measurement and confirmation of the hull status → review of the fore and aft reference points of the shaft system, second wire measurement, adjustment of the shaft system baseline → installation measurement, review and adjustment of the stern bracket and stern tube → installation and groove inspection of the bracket arm and stern tube → welding and inspection of the bracket arm and stern tube → stress elimination, strengthening and removal, flaw detection and tightness of the stern bracket after welding → measurement and inspection of data after welding → delivery to the engine professional construction.

[0048] The shaft system construction optimization plan is as follows:

[0049] (I) The conditions for shaft system construction include the following two parts:

[0050] 1. In the base part, including the stern frame and stern tube pre-assembly welding stage:

[0051] The main hull in the shafting area is assembled and formed, and the main assembly and welding are completed.

[0052] 2. In the tail shaft frame part, including the final adjustment and welding stage of the stern shaft frame and stern shaft tube:

[0053] (1) Hull forming, mainly completed by assembly, welding and pyrotechnics.

[0054] (2) The main hull water-filled compartment tightness test is completed, and the main tightness test of the shafting arrangement area is completed (except the seabed valve box).

[0055] (3) The loading of the first layer of superstructure is completed.

[0056] (4) Ballasting shall be carried out according to the Ballasting Arrangement Plan for Main Equipment (the Ballasting Arrangement Plan for Main Equipment is formed during the ship design). Main equipment shall be put into the cabin or replaced with ballast of similar weight.

[0057] (5) Before the shafting construction, the hull status data shall be measured, confirmed and recorded. The hull status includes the center, left and right level, keel deflection, and bow and stern tilt. Set up benchmark monitoring points, monitor the hull status at a fixed time every day and keep records, as shown in Table 1 below.

[0058]

[0059] Table 1

[0060] (II) The shaft system construction process optimization plan includes the following three parts:

[0061] 1. At the time of the first shafting wire construction (i.e. the first wire measurement), after the shafting construction conditions are met, the shafting installation and welding work is carried out while the main hull is closed, including the following work:

[0062] (1) Adjust the hull shafting baseline according to the previous measurement data of the hull status. The impact of subsequent hull assembly and welding, superstructure hoisting, and full ship ballasting on the bow and stern warping and keel deflection of the main hull (hull status) should be fully considered. The bow and stern ends and the fore and aft reference points of the shafting can be appropriately applied in the up and down directions, and the first wire drawing inspection of the shafting should be carried out.

[0063] (2) Construction of the base, installation and positioning of the main engine base, small base, gearbox base, intermediate bearing base, and brake device base.

[0064] According to the requirements of the hull shafting line and the hull shafting construction process, cut the upper margin of the main engine seat web, the gearbox seat web, the main engine small base, the intermediate bearing seat, and the lower margin of the brake device seat web. Install and position the main engine seat panel and small base, gearbox seat panel, intermediate bearing seat, and brake device seat. The installation height deviation is ±2mm, the opening half width deviation is ±2mm, and the distance deviation from the tail reference point is required to be in the same direction, and support and strengthen it well.

[0065] Groove form and welding requirements: A single-sided groove without root is opened on the outer side of the upper belly plate of the main engine seat, the upper belly plate of the gearbox seat, and the lower edge of the small base (it should be noted that the internal space of the base is large, which is convenient for subsequent carbon planing and root cleaning work), and the reverse side is carbon planed for root cleaning, and both sides are fully welded.

[0066] (3) Construction of the stern bracket (including the pre-assembly and welding stage of the stern bracket and stern tube), installation and positioning of the stern bracket and stern tube.

[0067] According to the requirements of the hull shaft system cable and the hull shaft system construction process, the hull stern shaft bracket arm and the stern shaft tube bottom outer plate are drilled according to the axis steel wire and the hole pattern, and the positioning stern shaft bracket is installed. The three stern shaft brackets on the same axis are required to be constructed in the same time period to reduce the deformation of the hull caused by the temperature difference and affect the accuracy of the shaft system. When positioning and installing the inner hole of the stern shaft bracket hub, coaxial and directional deviations are required. Due to the large construction volume of the ten stern shaft brackets at the bottom of the stern and their structures, and the embedded outer plate thickening plates, the outer shaft is applied with an anti-deformation shrinkage of 1 to 1.5 mm. Install the hull structure around the stern shaft bracket arm and the embedded outer plate thickening plate, and provide support and reinforcement. According to the deviation direction of the overall installation of the three stern shaft frames on the same axis, the stern shaft tube is positioned and installed. If the top screw is used to adjust the positioning, the deviation direction of the installation is required to be consistent with the stern shaft frame, the front end surface of the stern shaft tube does not release the reverse deformation, and the rear end surface is placed downward with an appropriate amount of reverse deformation. The stern shaft tube reinforcement ring plate at the hull shaft outlet is installed.

[0068] Groove form and welding requirements: The webs, panels, embedded outer plate thickening plates and stern tube reinforcement rings of the structural parts around the stern shaft frame are all grooved on one side without leaving roots. The butt welding parts of the embedded outer plate thickening plates can use ceramic liner grooves, and the reverse side can be cleaned with carbon planing, and both sides are fully welded. The space at the corner weld below the stern tube is narrow, so you can cut out and open a ceramic liner groove to the outside and fix it with a card code, weld with a ceramic liner on the back, and form the weld on both sides and fully weld. It should be noted that the outer plate thickening plate embedded in the stern shaft frame has a groove on the inside of the cabin to facilitate subsequent carbon planing and root cleaning on the outside of the cabin.

[0069] (4) Weld the main engine base and small base, gearbox base, intermediate bearing base, brake device base, and weld the surrounding structures of the stern frame and stern tube, including the welding of the embedded outer plate thickening plate. It should be noted that the welds directly connected to the stern frame and stern tube are not welded for the time being. The welding of the main engine base and small base, gearbox base, intermediate bearing base, brake device base, etc. is reported and inspected, the engine professional measures the base data, and the turbine professional welds the fixing gaskets of each base.

[0070] 2. During the second shafting line construction (i.e. the second line measurement), the main hull assembly, welding, pyrotechnics and tightness test are completed. While the first layer of superstructure is being hoisted, the adjustment and welding of the shafting stern bracket is carried out, including the following work:

[0071] (1) The whole ship is simulated for ballast, the hull status is measured, the fore and aft reference points of the shafting are reviewed, and the baseline and axis are slightly adjusted, that is, the fore and aft reference points of the shafting are determined according to the tolerance standard range of the hull keel deflection tolerance of ±8mm, the upper and lower same-direction deviation of the shafting centerline of ±3mm, and the single-side 5mm boring allowance of the inner hole of the hub. The installation data of the stern shaft frame and stern shaft tube are re-measured by pulling the wire for the second time (confirming the same direction), and whether they meet the accuracy requirements are reviewed and adjusted in time.

[0072] (2) The stern shaft bracket arm is reinforced with the surrounding hull structure and the embedded outer plate thickening plate by positioning welding, and then welded according to the welding sequence. The welding sequence requirements are as follows:

[0073] ① Before formal welding, the welder must perform reinforcement positioning welding inside and outside the cabin.

[0074] ② The welding procedure is to first symmetrically weld the hull structure connected by the stern shaft bracket arm and the embedded outer plate thickening plate, and then carbon planer and grind the weld on the back side of the outer cabin of the stern shaft bracket arm and the embedded outer plate thickening plate, and then weld.

[0075] ③ When welding in the cabin, first weld the structural butt joint, then weld the vertical fillet weld between the bracket arm and the structure, and finally weld the flat fillet weld. Before welding the stern shaft bracket arm, use a cutting torch to preheat the welding part and the area within 100mm on both sides. The preheating temperature is 120~200℃.

[0076] ④During welding, one welder shall perform welding symmetrically on the stern shaft bracket arm.

[0077] ⑤ When welding the angle weld between the embedded outer plate thickening plate and the stern shaft bracket arm, carbon dioxide gas shielded welding is used. Before welding, a cutting torch is used to preheat the welding position and the area within 100mm on both sides thereof. The preheating temperature is 120-200℃.

[0078] According to the welding process requirements, the welding parameters can be adjusted to continuously weld. It is not necessary to wait for the weld to cool down before welding the next weld after each weld. It is also not necessary to pull the wire to monitor the real-time data of the stern shaft frame during the welding process, which leads to inefficient construction. Figure 5 , Figure 6 shown.

[0079] (3) Welding of stern tube, including:

[0080] ① Including welding of front and rear end seat plates of stern tube and transverse bulkhead plating and solid floor reinforcement rings.

[0081] ② The front and rear ends of the stern tube are constructed simultaneously by two welders.

[0082] ③ The welding between the stern tube and the hull structure is mostly circumferential welds. In order to reduce welding deformation, intermittent welding must be used. First, symmetrical reinforcement welding is performed, and then the whole strip is primed and then symmetrically welded. Figure 7 shown.

[0083] ④ Before welding the stern tube, the welding sequence of the stern tube can be adjusted according to the deviation direction of the overall post-welding data of the three stern shaft frames on the same axis.

[0084] (4) Inspection of welding of stern tube and stern bracket:

[0085] After the welding of the stern frame and stern tube is completed, the stern frame weld is subjected to pyrotechnics to eliminate stress, and after the weld is cooled, the support reinforcement is removed and the code feet are ground. The welding of the stern tube and stern frame is reported for inspection.

[0086] After the elevation weld of the stern bracket arm is completely cooled, the weld and the area within 100mm on both sides are polished and smoothed, and the paint is removed. 24 hours after welding, the surface quality of the fillet weld is inspected by magnetic particle inspection. After the stern bracket and stern tube welds are qualified by flaw detection, the weld density test is carried out. Finally, the post-weld data of the stern bracket and stern tube are measured and reported for inspection.

[0087] (5) After the first layer of superstructure welding is completed, the shaft system data is reviewed and the accuracy requirements are met before it is handed over to the turbine professional for construction. The shaft system data can be reviewed and adjusted within the tolerance standard range according to the hull keel deflection tolerance of ±8mm, the upper and lower same-direction deviation of the shaft system centerline of ±3mm, and the single-side 5mm boring allowance of the inner hole of the hub, and finally the fore and aft reference points of the shaft system are determined.

[0088] (6) The monitoring data of the entire shafting construction process is compiled into a book, including the stage-by-stage changes in the hull status (the fore and aft reference points of the shafting system), the comparison of measurement data before and after welding of the shafting base and stern shaft frame, and the hull completion data, which is used for analysis and summary and as a guide for subsequent ships.

[0089] 3. Hull shafting assembly quality control requirements

[0090] (1) Construction personnel must be familiar with the drawings and construction techniques, and be clear about the construction content and technical requirements.

[0091] (2) The sketches, wire drawing boards and hole pattern provided by the design department must be confirmed by the process engineer before construction can begin.

[0092] (3) Draw the axis line according to the line drawing, install the wire drawing board (rack) and find the bow and stern reference points of the axis line, and report the bow and stern reference points.

[0093] (4) The accuracy of the data of the bow and stern reference points of the main engine and stern axis and the distance from CL and BL. The accuracy of the axis reference point is controlled to be no more than 1mm.

[0094] (5) Ensure the accuracy of the installation height and half-width of the main engine seat, small base, gear seat, intermediate bearing seat, brake device seat, etc. with the axis.

[0095] (6) Control of the installation anti-deformation data of the inner and outer stern brackets and stern tubes.

[0096] (7) Hull shafting structure installation quality control. In order to reduce welding deformation of structural parts and ensure installation quality, the installation gap is controlled to be no more than 2mm.

[0097] (8) All structural parts such as webs and panels must be grooved according to the welding process requirements and drawing requirements.

[0098] (9) After the bracket is installed, three angle steels are used at the front and rear ends for reinforcement. The reinforcement must be supported at the hard stop of the hull, and pads must be added to the connection between the reinforcement and the hull. It is not allowed to be spot welded directly on the outer plate of the hull.

[0099] (10) After the shaft system is installed, the groove is ground, the installation is measured and the test is completed.

[0100] (11) After the assembly is qualified, the data will be provided to the welding process, the process will be explained on site, the welding process will be monitored and the welding deformation will be controlled.

[0101] (III) The welding requirements include the following 4 parts:

[0102] 1. Main welding projects

[0103] Serial number Main welding projects Material quantity Remark 1 Stern shaft bracket ZG230-450H 10 6 outer shafts, 4 inner shafts 2 Stern tube Q345-B 4 roots 2 outer shafts, 2 inner shafts 3 Small base DH36 24 8 outer shafts, 16 inner shafts 4 Main engine seat and gearbox seat panel DH36 10 items 6 pieces for outer shaft, 4 pieces for inner shaft 5 Intermediate bearing seat DH36 6 4 outer shafts, 2 inner shafts 6 Brake seat DH36 4 2 outer shafts, 2 inner shafts

[0104] 2. Welding equipment

[0105] (1) 6 to 8 CO2 gas shielded welding machines are required to ensure symmetrical welding of the shaft system and the welding machines should be debugged before formal welding.

[0106] (2) Wire brush and slag hammer.

[0107] 3. Welding materials

[0108] (1) E5015 welding rod Φ3.2mm. In order to strengthen the control of welding deformation, the welding material selection principles must be strictly implemented. It is prohibited to use Φ4.0mm welding rod for construction.

[0109] (2) E5015 welding rods must be dried at 300-350℃ for 1-2 hours before use and stored in a welding rod insulation tube. During welding, the insulation tube must be powered on to keep the welding rods warm and the welding rods can be taken out as needed.

[0110] (3) CO2 gas shielded welding uses flux-cored wire Supercored-71, Φ1.2mm.

[0111] 4. Welding process parameters

[0112] (1) Manual arc welding

[0113] Welding rod diameter (mm) Flat welding current (A) Vertical welding current (A) Horizontal welding current (A) Overhead welding current (A) Φ3.2 110～150 100～130 100～140 90～130

[0114] (2) CO2 gas shielded welding

[0115]

[0116] Innovative breakthroughs have been made in process upgrade optimization, process parallelization, process connection, and inspection procedure optimization. The original hull shaft system construction can only be carried out after the main hull and superstructure are welded, pyrotechnic calibration is completed, the main hull test is completed, and the simulated ballast of the entire ship is in place. The new shaft system construction process research plan is that construction can be carried out after the main hull shaft system area is closed and formed, and the subsequent closing of the main hull, superstructure loading, main hull cabin test, and professional engine base gasket welding and engine room painting work are carried out at the same time. It ends after the first layer of superstructure is loaded, which can shorten the slipway construction period by about one month.

[0117] By formulating a hull status monitoring sheet and tracking and recording it on a daily basis, and based on control measures such as the tightness of the slipway pier timbers, the main hull closing accuracy and the amount of anti-deformation after closing, and temporary pressure iron ballast at the bow and stern of the main hull, and then adjusting and controlling within the range of hull construction tolerances and shafting component margins, we try our best to control all variables affecting the shafting within the accuracy range.

[0118] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A method for constructing a thin-plate ship long axis system, characterized in that: The shafting construction can begin after the main hull shafting area is closed and formed. During the shafting construction, the subsequent closing of the main hull, installation of the superstructure, main hull cabin tightness testing, welding of the engine room professional base gaskets, and engine room painting are carried out in accordance with the process requirements. The shafting construction is completed after the first layer of superstructure is installed.

2. A method for constructing a thin plate ship long axis system according to claim 1, characterized in that: The specific construction procedures are as follows: the main hull shaft area is closed and formed → the berth position is adjusted according to the shaft construction stage, the pier wood is tightened and compacted, the hull in the shaft area is measured and adjusted → the first wire measurement is made to determine the shaft baseline → the shaft tail ground sample line is engraved → the shaft fore and aft reference points are engraved and confirmed, and height monitoring benchmarks are set up on the ground at the fore and aft of the shaft → the main engine seat panel and small base, gearbox seat panel, intermediate bearing seat, brake device seat are installed → while the base is installed, the stern shaft frame and stern shaft tube are pre-installed, and the surrounding structure and embedded outer plate thickening plate are installed → measurement and groove inspection before base welding → Welding of base, welding of the surrounding structures of stern bracket and stern tube first, including welding of embedded outer plate thickening plate → Welding of base part, welding and post-welding measurement and inspection → Installation and welding of engine fixing gasket → Painting of engine room → Simulated ballast of the whole ship, measurement and confirmation of hull status → Review of fore and aft reference points of shafting, second wire measurement, adjustment of shafting baseline → Installation measurement, review and adjustment of stern bracket and stern tube → Installation and groove inspection of bracket arm and stern tube → Welding and inspection of bracket arm and stern tube → Stress elimination, strengthening removal, flaw detection and tightness of stern bracket after welding → Post-welding data measurement and inspection → Delivery for professional engine construction.

3. A method for constructing a thin plate ship long axis system according to claim 2, characterized in that: The conditions for shafting construction include: In the base part, the main hull in the shafting area is closed and formed, and the main assembly and welding are completed; At the tail shaft frame part, the hull is formed, and the main assembly, welding and pyrotechnics are completed; the main hull water-filled compartment tightness test is completed, and the main tightness test of the shafting arrangement area is ended; the first layer of superstructure is installed; ballasting is carried out according to the "Main Equipment Ballast Arrangement Drawing", and the main equipment is put into the cabin or replaced with ballast of similar weight; before the shafting construction, the hull status data is measured, confirmed and recorded.

4. A method for constructing a thin plate ship long axis system according to claim 3, characterized in that: At the time of the first shafting wire construction, after the shafting construction conditions are met, the shafting installation and welding work is carried out while the main hull is closed, including the following work: Adjust the hull axis baseline according to the previous measurement data of the hull status; Construction of the base, installation and positioning of the main engine base and small base, gearbox base, intermediate bearing base, and brake device base; Stern frame construction, installation and positioning of stern frame and stern tube; Weld the main engine seat and small base, gearbox seat, intermediate bearing seat, brake device seat, and weld the surrounding structures of the stern shaft frame and stern shaft tube, including the welding of the embedded outer plate thickening plate.

5. A method for constructing a thin plate ship long axis system according to claim 3, characterized in that: During the second shafting construction, the main hull assembly, welding, pyrotechnics and tightness test were completed. While the first superstructure was being hoisted, the adjustment and welding of the shafting stern bracket was carried out, including the following work: The whole ship is simulated for ballasting, the hull status is measured, the fore and aft reference points of the shafting are reviewed, the baseline and axis are slightly adjusted, the stern bracket and stern tube installation data are re-measured by secondary pulling, and whether they meet the accuracy requirements are reviewed and adjusted in time; The stern shaft bracket arm is reinforced with the surrounding hull structure and the embedded outer plate thickening plate for positioning welding, and then welded in the welding sequence; Welding of stern tube; Stern tube and stern bracket welding inspection; After the welding of the first layer of superstructure is completed and the shaft system data is reviewed to see if it meets the accuracy requirements, it will be handed over to the engine room professional construction.

6. A method for constructing a thin plate ship long axis system according to claim 5, characterized in that: Welding sequence requirements: Before formal welding, welders must perform reinforcement positioning welding inside and outside the cabin; The welding procedure is to first symmetrically weld the hull structure connected by the stern shaft bracket arm and the embedded outer plate thickening plate, then carbon planer and grind the weld on the reverse side of the outer cabin of the stern shaft bracket arm and the embedded outer plate thickening plate, and then weld; When welding inside the cabin, first weld the structural butt joints, then weld the vertical fillet welds between the bracket arm and the structure, and finally weld the flat fillet welds; before welding the stern shaft bracket arm, use a cutting torch to preheat the welding position and the area within 100mm on both sides, and the preheating temperature is 120-200℃; During welding, one welder performs welding symmetrically on the stern shaft bracket arm; When welding the angle weld between the embedded outer plate thickening plate and the stern shaft bracket arm, carbon dioxide gas shielded welding is used. Before welding, a cutting torch is used to preheat the welding position and the area within 100mm on both sides thereof. The preheating temperature is 120-200°C.

7. A method for constructing a thin plate ship long axis system according to claim 5, characterized in that: Stern tube welding includes: Welding of fore and aft end base plates of stern tube to transverse bulkhead plating and solid floor reinforcement rings; The first and last ends of the stern tube were constructed simultaneously by two welders; The welding between the stern tube and the hull structure is mostly circumferential welds. In order to reduce welding deformation, intermittent welding must be used; first perform symmetrical reinforcement welding, and then use full strip bottoming and symmetrical welding; Before welding the stern tube, the welding sequence of the stern tube can be adjusted according to the deviation direction of the overall post-welding data of the three stern shaft frames on the same axis.

8. A method for constructing a thin plate ship long axis system according to claim 5, characterized in that: After the welding of the stern tube and stern frame is completed, the stern frame weld is subjected to pyrotechnic stress relief. After the weld is cooled, the support reinforcement is removed and the code feet are ground; the welding of the stern tube and stern frame is reported for inspection.

9. A method for constructing a thin plate ship long axis system according to claim 2, characterized in that: The E5015 welding rod used in the welding process must be dried at 300-350℃ for 1-2 hours before use and stored in a welding rod insulation tube. During the welding process, the insulation tube must be powered on to keep warm and the welding rod can be taken out as needed.

10. A method for constructing a thin plate ship long axis system according to claim 2, characterized in that: The monitoring data of the entire shafting construction process is compiled into a book, including the periodic changes in the hull status, the comparison of measurement data before and after welding of the shafting base and stern shaft frame, and the hull completion data, which is used for analysis and summary and as a guide for subsequent ships.

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