A method for correcting plate deformation of a seagoing vessel

Abstract

The present invention discloses a method for correcting deformation of a plate of a sea-going vessel, comprising the following steps: step S1, preparation before correction; step S2, selecting a correction area; step S3, drawing a heating line; step S4, pyrotechnic heating; step S5, placing a pad; step S6, hammer correction; step S7, cooling; step S8, inspection: inspecting the local flatness and overall flatness of the corrected plate, and completing the deformation correction when the relevant flatness index is met; and repeating steps S2 to S8 when the relevant flatness index is not met. The correction method of this patent changes the traditional repair and correction technology that adopts the principle of proximity and indiscriminately repairs deformations, solves the problem of repeated correction, and has the characteristics of high repair efficiency, time saving and labor saving; this patent formulates specific cooling means according to the carbon equivalent size in high-strength steel, improves cooling efficiency, and ensures the original performance of the plate.

Description

Technical Field

[0001] The present invention relates to a repair and correction technology for a sea-going vessel, and in particular to a method for correcting plate deformation of a sea-going vessel. Background Art

[0002] During the shipbuilding process, strict control of precision can effectively ensure the quality of shipbuilding. The most important factor affecting progress control is hull deformation. Hull deformation is a common phenomenon in the shipbuilding process. Generally, the hull can be corrected to meet the requirements of plate flatness after deformation, but there are still some adverse consequences: the appearance of the ship is affected; the workload of correction is increased, the construction period is extended, the ship cannot be delivered on time, and the company's reputation is affected; correction will affect the line shape, resulting in changes in the ship's draft, affecting the ship's performance; and it will affect the service life and safety of the ship. Therefore, it is of great significance to explore the causes of ship hull deformation and to effectively prevent and correct it.

[0003] In the prior art, there are many reasons for the deformation of the ship hull during the shipbuilding process, including the following:

[0004] 1. Hull deformation caused by raw materials: Product quality is not only influenced by the production process and equipment, but also by raw materials. For shipbuilding companies, steel is the primary raw material, making the selection of steel crucial during shipbuilding. Different steel types result in varying mechanical properties. During the shipbuilding process, steel is subjected to high temperatures, which may alter its mechanical properties, impacting ship deformation. For example, stainless steel deforms much more during welding than carbon steel, and is not suitable for reheating and straightening after deformation. Different types of ships have varying steel requirements, necessitating targeted material selection during ship design. Furthermore, consideration must be given to steel cost and, most importantly, suitability. Poor suitability can easily lead to hull deformation.

[0005] 2. Hull deformation caused by welding: During ship construction, welding processes are required between the main hull and various construction components, sections, and the main body. This welding process can cause steel deformation, primarily due to two factors: first, partial heating of the steel plate during welding, resulting in high temperatures at the weld point and uneven heating at the weld and surrounding areas, which in turn generates incompatible strain. Second, during the actual welding process, due to factors such as management level, welder skill level, and welder quality, some procedures may not be followed, leading to hull deformation. Third, the welding process is affected by the quality of welding in previous steps. Furthermore, insufficient assembly margins can lead to shrinkage and deformation of the welding thread.

[0006] 3. Deformation caused by external forces: During the entire shipbuilding process, external forces can also cause hull deformation. For example, during the lifting of sections, the force generated by the hooks can cause hull deformation; during the welding process, the hull can be deformed by bumps, collisions, falls, and collisions. There are many factors that can cause hull deformation, including the main factors mentioned above, as well as improper structural design, different construction plans and methods, and inadequate corrections.

[0007] Generally speaking, in order to reduce the deformation of the hull structure, welding deformation is avoided and controlled during the construction of the hull structure by means of good structural design and reasonable selection of construction methods. However, despite these control measures, deformation still exists. This is mainly due to the complexity of the hull structure construction process itself, and the welding process is also very susceptible to various subjective and objective factors. Therefore, this welding deformation can be said to be an inevitable and unavoidable phenomenon. The way to deal with this problem is to further correct the deformation after it occurs, so that its shape is as close to the original state as possible. The correction process is generally used mainly for local deformation of the welding structure, such as bending or wave deformation, but it is generally difficult to play a good corrective role for the overall deformation of the hull. At present, there are two main methods for deformation correction: flame correction and mechanical correction. Among them, flame correction is more commonly used. However, the flame correction method has the following shortcomings in the existing technology: First, repeated correction will occur. For example, when correcting adjacent plates of different materials, during the process of repairing the adjacent second area, the first area that has just been repaired will be deformed again. At this time, the repaired area must be corrected twice, so the efficiency of the repair and correction is low; second, the temperature of pyrotechnic heating is difficult to control. If the temperature is too high, the plate will be burned, and if the temperature is too low, the correction effect will be poor; third, cooling generally uses air cooling, which has a slow cooling speed, while some use water cooling. Improper handling will affect the original performance of the plate. Summary of the Invention

[0008] The object of the present invention is to provide a method for correcting plate deformation of a seagoing vessel, which has high correction efficiency and ensures the original quality of the plate.

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

[0010] A method for correcting plate deformation of a seagoing vessel comprises the following steps:

[0011] Step S1, preparation before correction: fix the oxyacetylene equipment, connect the drying gun to the oxyacetylene equipment, and connect the water spray pipe for water cooling to the water source;

[0012] Step S2, select the correction area: When two adjacent plates of different hardness on a seagoing vessel require pyrotechnic correction, the portion with the higher hardness is corrected first. For plates of the same material on a seagoing vessel, the thicker portion and the portion with the larger area are corrected first. When there are convex and concave deformations on the plate surface of a seagoing vessel, the concave portion is corrected first, followed by the convex portion. When correcting a planar segment with a lightening hole or free edge, the plate frame is selected first, followed by the lightening hole and free edge.

[0013] Step S3, drawing a heating line: first draw the edge of the correction area determined on the seagoing vessel, and then draw a heating line from the center of the correction area;

[0014] Step S4, pyrotechnic heating: the correction personnel start the drying gun, so that the flame ejected from the drying gun is facing the center of the correction area, and starts heating along the heating line. During the pyrotechnic heating process, the heating should be symmetrical with the heating line of the correction area as the center line. When the plate is placed upright, it should be heated from bottom to top; when the plate thickness is 6-12mm, adjust the oxygen-acetylene ratio to 1.10-1.15, the flame core to 0-3mm from the plate surface, the heating speed to 7-20mm / s, and the heating temperature to 750-800℃; when the plate thickness is greater than 12mm and When the thickness is less than 26, adjust the oxygen-acetylene ratio to 1.00-1.09, the flame center to 3-5mm from the plate surface, the heating speed to 4-10mm / s, and the heating temperature to 800-900℃; when the plate thickness is greater than 26mm, adjust the oxygen-acetylene ratio to 1.00-1.09, the heating speed to 4-10mm / s, the heating temperature to 800-900℃, and the flame center to 6-10mm from the plate surface; when the temperature of the plate body approaches the preset temperature, start to evenly swing the nozzle of the drying gun to change the ignition position, and appropriately reduce the oxygen pressure of the oxyacetylene equipment;

[0015] Step S5, placing the pad: When the temperature of the plate reaches the preset temperature and the drying gun is closed, the correction personnel place the pad in the pyrotechnic heating area;

[0016] Step S6, hammer correction: the correction personnel use a hammer to hammer the pad until the corrected area has no unevenness and no obvious hammer marks, close the drying gun, and close the gas valve of the oxyacetylene equipment;

[0017] Step S7, cooling: cooling the correction area;

[0018] Step S8, inspection: inspect the local flatness and overall flatness of the corrected plate. If the plate meets the relevant flatness index, the deformation correction of the plate is completed; if the plate does not meet the relevant flatness index, repeat steps S2 to S8.

[0019] Furthermore, in step S8, the number of times steps S2 to S8 are repeated is ≤ 5 times.

[0020] Furthermore, in step S4, when the thickness of the plate is 6-12 mm, the heating width is 1.5-4 times the thickness of the plate; when the thickness of the plate is greater than 12 mm, the heating width is 0.5-3 times the thickness of the plate.

[0021] Furthermore, in step S4, when the thickness of the plate is 6-12 mm, the heating depth is 0.5-0.8 times the thickness of the plate; when the thickness of the plate is greater than 12 mm, the heating depth is greater than 5 mm and less than the thickness of the plate.

[0022] Furthermore, in step S7, when the plate to be corrected is TMCP high-strength steel with a carbon equivalent Ceq>0.38%, the plate to be corrected is first naturally cooled in the air to below 500°C, and then the temperature of the plate to be corrected is cooled to room temperature by water cooling; when the plate to be corrected is TMCP high-strength steel with a carbon equivalent Ceq≤0.38%, the plate to be corrected is naturally cooled in the air to room temperature.

[0023] Furthermore, in step S8, when the plate body is a ship side outer plate or a ship bottom outer plate, the local flatness should be ≤4mm; the overall flatness is ±2L / 1000mm, where L is the value of the detection distance in meters.

[0024] Furthermore, in step S8, when the plate is a ship cabin wall, the local flatness should be ≤6 mm; the overall flatness is ±4L / 1000 mm, where L is the value of the detection distance in meters.

[0025] Furthermore, in step S8, when the plate is a bottom plate of a cabin, the local flatness should be ≤4 mm; the overall flatness is ±3L / 1000 mm, where L is the value of the detection distance in meters.

[0026] Furthermore, in step S8, when the plate body is a deck, the local flatness should be ≤5mm; the overall flatness is ±3L / 1000mm, where L is the value of the detection distance in meters.

[0027] Furthermore, in step S4, the temperature of the plate is detected by manual visual inspection: the correction personnel determine the temperature of the heated plate by observing the color of the heated plate. When the plate is black, the temperature of the plate is below 470°C; when the plate is dark red, the temperature of the plate is 550~600°C; when the plate is red, the temperature of the plate is 700~800°C; when the plate is yellow, the temperature of the plate is 850~950°C; when the plate is light yellow, the temperature of the plate is 1000~1150°C; when the plate is white, the temperature of the plate is 1200~1300°C.

[0028] The beneficial effects of the present invention are:

[0029] This patented correction method adds the ability to select the correction area, changing the traditional restoration and correction technology that uses the principle of proximity and indiscriminately repairs any deformation. It solves the problem of repeated correction and has the characteristics of high restoration efficiency, time saving and labor saving.

[0030] 2. This patent uses a method to infer the temperature of the heated plate by observing the color change of the plate during the heating step. The error of visual observation is generally around ±30°C, which effectively controls the temperature of the pyrotechnic heating, improving the correction efficiency and ensuring the quality of the plate.

[0031] 3. In the cooling step, this patent formulates specific cooling methods according to the carbon equivalent of high-strength steel, which not only improves the cooling efficiency but also ensures the original performance of the plate;

[0032] 4. In particular, this patent summarizes the relevant technical parameters of pyrotechnic heating, providing technical support for more accurate pyrotechnic heating. The use of this patented correction method is conducive to standardizing the operation behavior of pyrotechnic correction, promoting the improvement of product quality, ensuring that all production meets safety and environmental protection requirements, and improving the efficiency of correction work and reducing the error rate;

[0033] 5. In the correction process of this patent, a pad is added to prevent the hammer from directly hitting the surface of the plate, so that the impact force of the hammer is spread from a point to a surface, avoiding damage to the repaired plate, and also reducing and diluting the mark left on the surface of the plate due to the impact as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention is further described with reference to the accompanying drawings. However, the embodiments in the accompanying drawings do not limit the present invention in any way. A person skilled in the art can derive other drawings based on the following drawings without inventive effort.

[0035] Figure 1 Flowchart of the present invention. DETAILED DESCRIPTION

[0036] 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 accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features therein can be combined with each other unless there is a conflict.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper surface", "lower surface", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "forward", "reverse", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0038] like Figure 1 As shown, a method for correcting plate deformation of a seagoing vessel comprises the following steps:

[0039] Step S1: Preparation before correction:

[0040] Correctional personnel should wear appropriate work clothes and use labor protection products correctly; when working at height, they should fasten their safety belts; fix the oxyacetylene equipment, connect the drying gun to the oxyacetylene equipment, and connect the water spray pipe used for water cooling to the water source.

[0041] Step S2: Select the correction area:

[0042] When two adjacent plates of different hardness on a sea-going vessel need to be corrected by pyrotechnics, the part with higher hardness should be corrected first. For plates of the same material on a sea-going vessel, the thicker part and the part with larger area should be corrected first. When there are convex and concave deformations on the plate surface of a sea-going vessel, the concave part should be corrected first, and then the convex part. When correcting a plane segment with lightening holes or free edges, the plate frame should be corrected first, and then the lightening holes and free edges.

[0043] Step S3: Draw the heating line:

[0044] In the correction area determined on the seagoing vessel, first draw the edge of the correction area, and then draw the heating line from the center of the correction area.

[0045] Step S4: pyrotechnic heating:

[0046] The correction personnel start the drying gun so that the flame from the drying gun is facing the center of the correction area and starts heating along the heating line. During the pyrotechnic heating process, the heating should be carried out symmetrically with the heating line of the correction area as the center line. When the plate is placed upright, it should be heated from bottom to top;

[0047] When the plate thickness is 6-12mm, adjust the oxygen-acetylene ratio to 1.10-1.15, the flame center to 0-3mm from the plate surface, the heating rate to 7-20mm / s, and the heating temperature to 750-800℃;

[0048] When the plate thickness is greater than 12mm and less than or equal to 26, adjust the oxygen-acetylene ratio to 1.00-1.09, the flame center to 3-5mm from the plate surface, the heating rate to 4-10mm / s, and the heating temperature to 800-900℃;

[0049] When the plate thickness is greater than 26mm, adjust the oxygen-acetylene ratio to 1.00-1.09, the heating speed to 4-10mm / s, the heating temperature to 800-900℃, and the flame center to 6-10mm from the plate surface;

[0050] When the plate thickness is 6-12mm, the heating width is 1.5-4 times the plate thickness; when the plate thickness is greater than 12mm, the heating width is 0.5-3 times the plate thickness;

[0051] When the plate thickness is 6-12mm, the heating depth is 0.5-0.8 times the plate thickness; when the plate thickness is greater than 12mm, the heating depth is greater than 5mm, less than the plate thickness;

[0052] When the temperature of the plate is close to the preset temperature, start to swing the nozzle of the drying gun evenly to change the ignition position, and appropriately reduce the oxygen pressure of the oxyacetylene equipment;

[0053] The temperature of the plate is detected by manual visual inspection: the correction personnel judge the temperature of the heated plate by observing the color of the heated plate:

[0054] When the plate is black, the temperature of the plate is below 470°C;

[0055] When the plate is dark red, the temperature of the plate is 550~600℃;

[0056] When the plate is red, the temperature of the plate is 700~800℃;

[0057] When the plate is yellow, the temperature of the plate is 850~950℃;

[0058] When the plate color is light yellow, the plate temperature is 1000~1150℃;

[0059] When the plate is white, the temperature of the plate is 1200~1300℃.

[0060] Step S5, placing the pad: When the temperature of the plate reaches the preset temperature and the drying gun is closed, the correction personnel place the pad in the pyrotechnic heating area.

[0061] Step S6, hammer correction: The correction personnel use a hammer to hammer the pad until the corrected area has no bumps and no obvious hammer marks. Then, the drying gun and the gas valve of the oxyacetylene equipment are closed. When performing pyrotechnic correction, the hammer head must not be used to directly hammer the steel plate. A pad must be placed between the hammer and the plate. Do not wear gloves to prevent the hammer from flying out and injuring people.

[0062] Step S7, cooling: Cooling the correction area, but different cooling processes are performed for plates of different materials:

[0063] When the plate to be corrected is TMCP high-strength steel with a carbon equivalent Ceq>0.38%, the plate to be corrected is first allowed to cool naturally in air to below 500°C, and then water-cooled to room temperature;

[0064] When the plate to be corrected is TMCP high-strength steel with a carbon equivalent Ceq ≤ 0.38%, the plate to be corrected is allowed to cool naturally to room temperature in the air;

[0065] The above-mentioned TMCP refers to the thermomechanical controlled rolling method.

[0066] Step S8: Inspection: The local and overall flatness of the corrected plate is inspected. If it meets the relevant flatness specifications, the plate deformation correction is complete. If it does not, repeat steps S2 through S8. If correction requires repeated heating, it must be repeated after complete cooling. For standard plates, no more than five times, and for low-alloy steel plates, no more than three times.

[0067] For the flatness index, it is as follows:

[0068] When the plate is the ship's side or bottom outer plate, the local flatness should be ≤4mm; the overall flatness is ±2L / 1000mm, where L is the value of the detection distance in meters;

[0069] When the plate is a ship's cabin wall, the local flatness should be ≤6mm; the overall flatness is ±4L / 1000mm, where L is the value of the detection distance in meters;

[0070] When the plate is the bottom plate of a cabin, the local flatness should be ≤4mm; the overall flatness is ±3L / 1000mm, where L is the value of the detection distance in meters;

[0071] When the plate is a deck, the local flatness should be ≤5mm; the overall flatness is ±3L / 1000mm, where L is the value of the detection distance in meters;

[0072] For the above-mentioned overall flatness, the minimum detection distance L=3m, but for the cabin inner wall and ship side outer plate, the detection distance L=5m.

[0073] This patent is mainly applicable to the treatment of ordinary plates, low-carbon steel and other unhardened steel materials. In addition, this patent is also applicable to the deformation correction of ship structures and profiles.

[0074] The use of this patented correction method is conducive to standardizing the operation behavior of pyrotechnic correction, promoting the improvement of product quality, ensuring that all production processes meet safety and environmental protection requirements, and improving the efficiency of correction work and reducing the error rate.

[0075] In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are mutually inconsistent. Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for correcting plate deformation of a seagoing vessel, characterized in that: The following steps are involved: Step S1, preparation before correction: fix the oxyacetylene equipment, connect the drying gun to the oxyacetylene equipment, and connect the water spray pipe for water cooling to the water source; Step S2, select the correction area: When two adjacent plates of different hardness on a seagoing vessel require pyrotechnic correction, the portion with the higher hardness is corrected first. For plates of the same material on a seagoing vessel, the thicker portion and the portion with the larger area are corrected first. When there are convex and concave deformations on the plate surface of a seagoing vessel, the concave portion is corrected first, followed by the convex portion. When correcting a planar segment with a lightening hole or free edge, the plate frame is selected first, followed by the lightening hole and free edge. Step S3, drawing a heating line: first draw the edge of the correction area determined on the seagoing vessel, and then draw a heating line from the center of the correction area; Step S4, pyrotechnic heating: the correction personnel start the drying gun so that the flame ejected from the drying gun is facing the center of the correction area and starts heating along the heating line. During the pyrotechnic heating process, the heating should be symmetrical with the heating line of the correction area as the midline. When the plate is placed upright, it should be heated from bottom to top; when the plate thickness is 6-12mm, adjust the oxygen-acetylene ratio to 1.10-1.15, the flame core to 0-3mm from the plate surface, the heating rate to 7-20mm / s, and the heating temperature to 750-800℃; when the plate thickness is >12mm and ≤26, adjust the oxygen-acetylene ratio to 1.00-1.09, the flame core to 3-5mm from the plate surface, the heating rate to 4-10mm / s, and the heating temperature to 800-900℃; when the plate thickness is >26mm, adjust the oxygen-acetylene ratio to 1.00-1.09, the heating rate to 4-10mm / s, and the heating temperature to 800-900℃. s, the heating temperature is 800-900℃, and the flame core is 6-10mm away from the plate surface; when the temperature of the plate is close to the preset temperature, start to swing the nozzle of the drying gun evenly to change the pyrotechnic position, and appropriately adjust the oxygen pressure of the oxyacetylene equipment; the temperature detection of the plate body is carried out by manual visual inspection: the correction personnel judge the temperature of the heated plate body by observing the color of the heated plate body. When the plate body color is black, the plate body temperature is below 470℃; when the plate body color is dark red, the plate body temperature is 550~600℃; when the plate body color is red, the plate body temperature is 700~800℃; when the plate body color is yellow, the plate body temperature is 850~950℃; when the plate body color is light yellow, the plate body temperature is 1000~1150℃; when the plate body color is white, the plate body temperature is 1200~1300℃; Step S5, placing the pad: When the temperature of the plate reaches the preset temperature and the drying gun is closed, the correction personnel place the pad in the pyrotechnic heating area; Step S6, hammer correction: the correction personnel use a hammer to hammer the pad until the corrected area has no unevenness and no obvious hammer marks, close the drying gun, and close the gas valve of the oxyacetylene equipment; Step S7, cooling: Cooling the corrected area: When the corrected plate is made of TMCP high-strength steel with a carbon equivalent Ceq greater than 0.38%, first allow the corrected plate to cool naturally in air to below 500°C, and then use water cooling to cool the corrected plate to room temperature; when the corrected plate is made of TMCP high-strength steel with a carbon equivalent Ceq ≤ 0.38%, allow the corrected plate to cool naturally in air to room temperature; Step S8, inspection: inspect the local flatness and overall flatness of the corrected plate. If the plate meets the relevant flatness index, the deformation correction of the plate is completed; if the plate does not meet the relevant flatness index, repeat steps S2 to S8.

2. The method for correcting plate deformation of a seagoing vessel according to claim 1, characterized in that: In step S8, the number of times steps S2 to S8 are repeated is ≤ 5 times.

3. The method for correcting plate deformation of a seagoing vessel according to claim 1, characterized in that: In step S4, when the thickness of the plate is 6-12 mm, the heating width is 1.5-4 times the thickness of the plate; when the thickness of the plate is greater than 12 mm, the heating width is 0.5-3 times the thickness of the plate.

4. The method for correcting plate deformation of a seagoing vessel according to claim 3, characterized in that: In step S4, when the thickness of the plate is 6-12 mm, the heating depth is 0.5-0.8 times the thickness of the plate; when the thickness of the plate is greater than 12 mm, the heating depth is greater than 5 mm and less than the thickness of the plate.

5. The method for correcting plate deformation of a seagoing vessel according to claim 1, characterized in that: In step S8, when the plate body is a ship side outer plate or a ship bottom outer plate, the local flatness should be ≤4mm; the overall flatness is ±2L / 1000mm, where L is the value of the detection distance in meters.

6. The method for correcting plate deformation of a seagoing vessel according to claim 5, characterized in that: In step S8, when the plate is a ship cabin wall, the local flatness should be ≤6 mm; the overall flatness is ±4L / 1000 mm, where L is the value of the detection distance in meters.

7. The method for correcting plate deformation of a seagoing vessel according to claim 6, characterized in that: In step S8, when the plate is a bottom plate in a cabin, the local flatness should be ≤4 mm; the overall flatness should be ±3L / 1000 mm, where L is the value of the detection distance in meters.

8. The method for correcting plate deformation of a seagoing vessel according to claim 7, characterized in that: In step S8, when the plate body is a deck, the local flatness should be ≤5mm; the overall flatness is ±3L / 1000mm, where L is the value of the detection distance in meters.

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