Machining method of distorted outer plate for ship

Abstract

The invention discloses a processing method of a distorted marine outer plate and belongs to the technical field of stress release, the processing method of the distorted marine outer plate has the advantages of being flexible in operation, low in processing cost and quick in effect, the beveled rib-shaped defect generated by a conventional line heating plate processing method can be avoided, heat input can be greatly reduced, energy consumption can be saved, and the processing efficiency is improved. The smooth and smooth quality of products is guaranteed, the processing of thick plates is simplified, repeated correction is reduced, and the work efficiency is improved by 35%.

Description

Technical Field

[0001] The invention relates to the technical field of stress release, and in particular to a method for processing a twisted ship outer plate. Background Art

[0002] The hull is made up of numerous steel plates, of which the bow and stern have beautiful and smooth lines, especially the outer plates at the stern shaft and the bulbous bow, which have complex lines. The same segmented outer plates have positive bends, reverse bends, twists, transverse curvatures, S-shaped lines and other lines, and the processing technology is very complicated. Because each outer plate has different linear curvatures, the processing requirements of each outer plate are different, and it is impossible to use a mold to form and press at one time. With the current processing technology, only large plate bending machines and hydraulic presses can be used to process the transverse curvature and a certain amount of twisting. The outer plates after preliminary processing need to enter the next water and fire bending process. Water and fire bending is processed based on the principle of thermal expansion and contraction of steel plates. The processing method is to measure the outer plates after cold processing with a sample box sample, draw heating lines as needed, and use a heating gun for local heating and water cooling to produce contraction to achieve the processing purpose.

[0003] The traditional water-fire bending process uses strip heating, short strip heating, tight triangle, fire ring heating and other methods. During the processing, the heating parameters need to be adjusted according to the thickness of the plate. The processing of large-distortion outer plates generally uses a certain external force, and the water-fire tracking heating method is used to twist the steel plate into shape. However, under a large amount of heat input and water cooling, the steel plate will harden. Repeated heating will greatly reduce the shrinkage rate. Some thick plates with large distortion and complex linear outer plates are difficult to process in place. During the processing, the uneven heating of the parts will produce defects such as tendons, stiff blocks, and corners. Due to the uneven curvature of the outer plate, it becomes very difficult to make mechanical corrections on the hydraulic press, which seriously affects product quality and production and processing progress. Summary of the invention

[0004] The invention discloses a method for processing a twisted ship outer plate to improve the above-mentioned problem.

[0005] The technical solution adopted by the present invention to solve the above technical problems is:

[0006] Based on the above purpose, the present invention discloses a method for processing a twisted marine outer plate, wherein the outer plate includes a first angle, a second angle, a third angle and a fourth angle set in this way, and comprises the following steps:

[0007] Step 1: fix the first angle and the third angle of the outer panel, support the second angle of the outer panel, and apply an upward force to the fourth angle of the outer panel;

[0008] Step 2: heating the outer plate at intervals, the heating shape of each heating position is an ellipse, the long side of the ellipse is arranged along the connecting line direction of the first angle and the third angle, the heating position is cooled down with a delay, the moving speed of the cooling water pipe is equal to the moving speed of the heating structure, and the cooling water pipe lags behind the heating structure, and the force acting on the second angle is kept constant during the heating process;

[0009] Step 3: Cooling the heated outer plate, and continuously increasing the force applied to the second corner during the cooling process;

[0010] Step 4: judging the forming condition of the outer panel, if the outer panel does not meet the forming requirements, providing support to the fourth corner of the outer panel, and applying an upward force to the second corner of the outer panel;

[0011] Step 5: After heating is completed, first remove the force, and then release the fixing structure located at the first corner and the third corner of the outer panel.

[0012] Optionally: in the step 2, each heating position is marked before heating, and the heating positions are set as multiple columns of heating wires, and the multiple columns of heating wires are arranged in sequence along the direction of the connecting line between the second corner and the fourth corner, and the heating positions in adjacent columns of heating wires are staggered.

[0013] Optionally, the number of the heating positions contained in the spaced heating lines is equal, and the number of the heating positions in the first heating line is less than the number of the heating positions in the adjacent heating lines.

[0014] Optionally, the distance between each heating position and the edge of the outer panel is greater than or equal to 200 mm.

[0015] Optionally: in the step 2, the heating structure heats the heating position to 700°C to 900°C.

[0016] Optionally: when heating the heating position, for the outer panel with a thickness less than 25 mm, the heating structure heats the heating position to 700°C to 780°C; for the outer panel with a thickness greater than 25 mm, the heating structure heats the heating position to 780°C to 900°C.

[0017] Optionally: the output temperature of the heating structure is 3050°C to 3300°C, the flame core contacts the steel plate to a depth of 1 to 2 mm during heating, and the outer plate is appropriately distanced when it turns red.

[0018] Optionally: in the step 2, when heating the heating position, for the outer panels with a thickness of 14 mm to 20 mm, a straight-line running cooling method and a forward and backward method are adopted, and for the outer panels with a thickness of more than 20 mm, a spiral flame transportation method is adopted.

[0019] Optionally: in step 2, when cooling the outer panel, for the outer panel with a thickness of 14 to 20 mm, the cooling water pipe lags behind the heating structure by a distance of 100 to 120 mm; for the outer panel with a thickness of more than 20 mm, the cooling water pipe lags behind the heating structure by a distance of 120 to 150 mm.

[0020] Optionally: in step 2, the length of the short side of the ellipse is half the length of its long side.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention proposes a method for processing twisted marine outer plates. The method converts the heating shrinkage of the steel plate into twisting to the maximum extent through the steps of heating, lifting, cooling and pressurizing, realizes rapid prototyping of the outer plates, avoids the generation of defects, and ensures the smoothness quality of the outer plates and smooth segmented installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram showing a method for processing a twisted marine outer plate disclosed in an embodiment of the present invention is shown;

[0024] Figure 2 A schematic diagram of a heating gun disclosed in an embodiment of the present invention is shown;

[0025] Figure 3 A schematic diagram of a faucet disclosed in an embodiment of the present invention is shown;

[0026] Figure 4 A schematic diagram of a split hydraulic jack disclosed in an embodiment of the present invention is shown;

[0027] Figure 5 A schematic diagram of a pressure horse disclosed in an embodiment of the present invention is shown;

[0028] Figure 6 A schematic diagram showing a large twisted line shape displayed by combining two processing templates of the bow and stern disclosed in an embodiment of the present invention;

[0029] Figure 7 A schematic diagram of a large twisted linear box disclosed in an embodiment of the present invention is shown;

[0030] Figure 8 A schematic diagram of an outer panel before processing disclosed in an embodiment of the present invention is shown;

[0031] Fig. 9 A schematic diagram of installing an outer panel disclosed in an embodiment of the present invention is shown;

[0032] Fig.10 A schematic diagram of a processed outer panel disclosed in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below through specific implementation examples in conjunction with the accompanying drawings.

[0034] Example:

[0035] See also Figures 1 to 10 The embodiment of the present invention discloses a method for processing a twisted marine outer plate, wherein the outer plate includes a first angle, a second angle, a third angle and a fourth angle set in this way, and comprises the following steps:

[0036] Step 1: Fix the first and third corners of the outer panel, support the second corner of the outer panel, and apply an upward force to the fourth corner of the outer panel;

[0037] Step 2: The outer plate is heated at intervals. The heating shape of each heating position is an ellipse. The long side of the ellipse is set along the connecting line of the first angle and the third angle. The heating position is cooled down with a delay. The moving speed of the cooling water pipe is equal to the moving speed of the heating structure, and the cooling water pipe lags behind the heating structure. During the heating process, the force acting on the second angle is kept constant.

[0038] Step 3: Cool the heated outer plate, and continuously increase the force applied to the second corner during the cooling process;

[0039] Step 4: Determine the forming condition of the outer panel. If the outer panel does not meet the forming requirements, support the fourth corner of the outer panel and apply an upward force to the second corner of the outer panel.

[0040] Step 5: After heating is completed, first remove the force, and then release the fixing structure at the first corner and the third corner of the outer panel.

[0041] The processing method of twisted marine outer plate disclosed in this embodiment has the advantages of flexible operation, low processing cost and quick effect. It can avoid the corner rib defects caused by conventional water and fire bending plate processing methods, greatly reduce heat input, save energy consumption, ensure the smoothness and quality of the product, simplify the processing of thick plates, reduce repeated corrections and improve work efficiency by 35%.

[0042] In one embodiment, in step 2, each heating position is marked before heating, and the heating positions are arranged as multiple columns of heating wires. The multiple columns of heating wires are arranged in sequence along the direction of the connecting line between the second corner and the fourth corner, and the heating positions in adjacent columns of heating wires are staggered.

[0043] In one embodiment, the numbers of the heating positions contained in the spaced heating lines are equal, and the number of the heating positions in the first heating line is smaller than the number of the heating positions in the adjacent heating lines.

[0044] In one embodiment, the distance between each heating position and the edge of the outer panel is greater than or equal to 200 mm.

[0045] In one embodiment, in the step 2, the heating structure heats the heating position to 700° C. to 900° C.

[0046] In one embodiment, when heating the heating position, for the outer panel with a thickness less than 25 mm, the heating structure heats the heating position to 700°C to 780°C, and for the outer panel with a thickness greater than 25 mm, the heating structure heats the heating position to 780°C to 900°C.

[0047] In one embodiment, the output temperature of the heating structure is 3050°C to 3300°C, the flame core contacts the steel plate to a depth of 1 to 2 mm during heating, and the outer plate is appropriately distanced when it turns red.

[0048] In one embodiment, in step 2, when heating the heating position, a straight-line cooling method and a forward and backward method are used for the outer panels with a thickness of 14 mm to 20 mm, and a spiral flame transportation method is used for the outer panels with a thickness of more than 20 mm.

[0049] In one embodiment, in step 2, when cooling the outer panel, for the outer panel with a thickness of 14 mm to 20 mm, the cooling water pipe lags behind the heating structure by a distance of 100 mm to 120 mm; for the outer panel with a thickness of more than 20 mm, the cooling water pipe lags behind the heating structure by a distance of 120 mm to 150 mm.

[0050] In one embodiment, in step 2, the length of the short side of the ellipse is half the length of its long side.

[0051] In a specific embodiment:

[0052] Prepare tools: First, prepare hydraulic jacks and pressure tools for fixing steel plates. The hydraulic jack is a 30T split pipe connection device with a quick lifting and unloading function. The hydraulic jack is a split hydraulic device, and other types of jacks can also be used. According to the thickness of the plate and the distortion line type, 10T, 20T, and 30T matching tonnages are required. The fixed pressure tool is made of high-strength round steel in the shape of a ∧-shaped pressure horse, and the diameter of the round steel corresponds to the circular hole of the platform. At the same time, prepare supporting tools for water and fire bending, including heating guns, oxygen gas, cooling water hoses, special faucets, oxygen and gas.

[0053] The pressure horse that fixes the outer plate downward is made of 40mm-50mm high-strength round steel bent into a 400×300mm long ∧ shape. The diameter of the round steel matches the circular hole of the platform and is fixed by hammering when in use.

[0054] Formulate processing plan: Select the marine outer plate that needs to be processed by water and fire, and formulate a water and fire processing plan. According to the matching of the processed outer plate with the processing sample box or sample, determine the diagonal force direction, and then through heating, lifting, cooling, control of heat input and shrinkage, adjust the lifting ballast and increase the distribution of heating points.

[0055] Fix the steel plate: Use pressure horse tools to fix the diagonal corner of the steel plate that needs to be twisted downward on the steel platform. The number of pressure horses should be consistent with the thickness of the steel plate, the degree of twisting, and the size of the jacking pressure. Use a wedge to pad one corner of the upward twisted diagonal corner, and put a hydraulic jack in the other corner.

[0056] Mark out the heating points: Mark out the heating points on the outer plate, the length of the heating point line is controlled at 80mm, and the heating points are distributed and staggered. The distribution density of the heating points is proportional to the amount of twisting, and the distance between the heating points and the edge of the plate is controlled to be ≥200mm.

[0057] Heating steel plate: Use a heating gun to perform spiral heating at the heating point of the outer plate to form an elliptical heating zone. The heating gun uses a mixture of oxygen and fuel gas (propane, natural gas, acetylene gas) to form a 3050-3300℃ light blue high-temperature fixed flame as a heating source. The heating temperature is controlled at 750℃ until all heating is completed.

[0058] Lifting, pressurizing and cooling: After the heated outer plate is lifted by hydraulic jack, water is used to cool the outer plate evenly. During the cooling process, check the limit of the press jack's lifting height, keep the pressurizing and lifting continuous during the cooling process, and observe and control the pressurizing and lifting height and the distortion of the outer plate.

[0059] Inspection and correction: Remove the pressure horse after unloading, and use the sample plate or sample box to check the overall twisting and forming accuracy and surface finish quality. For the parts with deviations, use the water-fire bending method to heat the strips and follow the water to cool them to produce angular deformation for accuracy correction.

[0060] The first step is to prepare the supporting tools for water and fire bending, which include a heating gun for local heating of the outer plate, gas and oxygen and supporting hoses, faucet cooling water, pressurized lifting hydraulic jack, and pressure horse for fixing the outer plate. The oxygen and gas are respectively input into the heating gun through pipelines ( Figure 2 ), after the oxygen and gas valves of the heating gun are adjusted, they are mixed into a certain proportion in the gun chamber and then ejected from the gun nozzle to burn to form a light blue flame with a temperature of 3050℃-3300℃. The structure of the faucet includes a faucet body, a water flow control valve, a water inlet and a water outlet pipe ( Figure 3 ), where the faucet outlet pipe is long and the top is bent downward, which is convenient for the water and fire bending plate to track the heat source and cool it in time. The hydraulic jack ( Figure 4 ) is a split structure including a manual pressure pump body, a hydraulic connection high-pressure oil pipe, and a hydraulic jack. The split hydraulic jack is convenient for placement at any angle and is easy and safe to operate. Figure 5 ) is cut into 800mm length by 50mm diameter high-strength round steel (the diameter of the round steel needs to match the size of the platform hole and can be smoothly inserted into the platform hole). The upper insertion end is 450mm long and the lower insertion end is 350mm as the tangent point and bent into an angle of about 75°. When in use, clamp the upper end to the outer panel, insert the lower end into the platform hole, hit the upper end of the bend with a hammer, and use the tension of the angle to clamp and fix the outer panel.

[0061] The second step is to select the outer panels and processing sample boxes that need water and fire processing, such as Figures 6 to 8 As shown, place the sample or sample box correctly according to the bow and stern, up and down directions marked on the outer plate, visually observe the distortion and linear distribution, estimate the workload of water and fire processing, determine the distribution position of the heating points to ensure the force direction, and formulate a water and fire processing plan. The plan is to arrange the heating points in the middle plate of the outer plate in a short line, and the short lines of the rows are staggered, draw a line 200mm inward from the top of the edge, arrange them left and right, and stagger them front and back.

[0062] The third step is to determine the water and fire workload, draw the heating line and the force direction, and then use wooden pillows to pad to the appropriate position according to the jack height and distortion. Use pressure horses to fix the downward diagonal corner, use wooden pillows to stabilize the upward diagonal corner, and put a jack under the outer plate of the other upward corner and lift it to 5 tons of pressure. Fig. 9As shown. During operation, oxygen and fuel gas are mixed in a certain proportion through the heating gun, and then burned by jet through the heating nozzle of the heating gun to form a 3050-3300℃ light blue fixed flame, which heats the marked heating point to form an elliptical heating belt with a length of 80mm and a width of 40mm. Before processing, the operator needs to adjust the heating gun to ensure that the flame size matches the thickness of the steel plate. When heating, the flame core contacts the steel plate with a depth of about 1mm-2mm, and the steel plate is properly pulled away when it turns red. When processing thicker steel plates, the spiral swing heat source method should be used to allow heat to penetrate into the steel. Pay attention to prevent the surface from being oxidized due to excessive surface temperature. The heating temperature is maintained at about 750℃, and the plate thicker than 25mm is appropriately increased to about 800℃. The limit cannot exceed 900℃. Jump heating is used during the heating process. After a certain period of air cooling, the empty point line is heated to avoid excessive heat input and thermal expansion. During heating, the pressure relief of the jack is constantly checked, and it is necessary to continuously lift and maintain a certain pressure. After all the heating wires have been heated, they are evenly cooled with water. During the cooling process, the jack is continuously lifted and pressurized to continuously release the shrinkage stress and convert it into distortion.

[0063] Step 4: After completing the above operations, use a sample or sample box to check the forming condition. When the outer panel with a large twist cannot be put in place at one time, the outer panel needs to be turned over and placed, and the second and third steps need to be repeated. It should be noted that the arrangement of the heating point lines must be staggered from the first heating point to avoid overlapping heating. Attention should be paid to the twisting forming condition and not excessive processing.

[0064] The fifth step is to remove the lifting pressure first, then remove the pressure horse that fixes the outer plate, and use the sample box to check the forming situation. When the basic forming is completed, if there is still a small amount of error, according to the change of each rib position of the sample or sample box, use a long strip heating line to arrange heating to make it produce angular deformation for correction. During operation, the operator holds the heating gun in one hand and the faucet in the other hand to achieve timely connection between heating and cooling. Adjust the flame of the heating gun during operation, and move forward when heated to a dark red color visible to the naked eye. The flame transportation method is adjusted appropriately according to the plate thickness. 14mm-20mm uses straight running and forward and backward method, and 20mm or more uses spiral flame transportation method. Water cooling adopts tracking heat source cooling, and the water-fire distance of 14mm-20mm is maintained at 100mm-120mm, and the water-fire distance of 20mm or more is maintained at 120-150mm. The heating temperature should be adjusted according to the amount of deformation or the number of heating lines. Strip heating can correct the lateral curvature at the same time. During operation, attention should be paid to the simultaneous combination of distortion correction and lateral curvature correction, and the heat input should be controlled to the optimal level to achieve the maximum effect with the minimum workload.

[0065] Step 6: After completing the above preset heating line processing, Fig.10As shown, check again the conformity of the outer plate with the sample box linear structure, check the outer plate surface is smooth and clean until it meets the inspection standards, and after processing, draw the surrounding alignment lines and rib structure lines, and mark the code and direction.

[0066] In summary, the method for processing a twisted marine outer plate disclosed in this embodiment has at least the following beneficial effects:

[0067] 1. The steel plate is heated evenly, so that the plate body is heated as a whole. The fiber distribution structure of the steel plate can be changed during the orderly lifting of the hydraulic jack. The shrinkage stress of the steel plate can be released during the uniform cooling of water and the lifting of the jack, and the difference in the fiber length ratio between the middle and the edge of the plate can be maximized, so that the steel plate can be twisted and formed.

[0068] 2. Effectively avoid the large amount of heating shrinkage stress inside the steel plate that has nowhere to be released, causing corner defects and rib-like stiff block defects at the edge, ensuring the smoothness quality of the outer plate, ensuring the consistency with the line shape of the sample box sample, reducing repeated corrections, and improving work efficiency by more than 35%.

[0069] 3. It is particularly suitable for processing thick plates of 20mm or more on the hull of large civilian ships, especially the ultra-thick outer plates of 30mm-40mm, which have obvious processing advantages and almost no possibility of defects.

[0070] 4. It is an improvement on the traditional water and fire bending method, without increasing the processing cost, and has been successfully applied to the outer plate processing of various different ship types.

[0071] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for processing a twisted marine outer plate, the outer plate comprising a first angle, a second angle, a third angle and a fourth angle arranged in this way, characterized in that: The steps include: Step 1: fix the first angle and the third angle of the outer panel, support the second angle of the outer panel, and apply an upward force to the fourth angle of the outer panel; Step 2: heating the outer plate at intervals, the heating shape of each heating position is an ellipse, the long side of the ellipse is arranged along the connecting line direction of the first angle and the third angle, the heating position is cooled down with a delay, the moving speed of the cooling water pipe is equal to the moving speed of the heating structure, and the cooling water pipe lags behind the heating structure, and the force acting on the second angle is kept constant during the heating process; Step 3: Cooling the heated outer plate, and continuously increasing the force applied to the second corner during the cooling process; Step 4: judging the forming condition of the outer panel, if the outer panel does not meet the forming requirements, providing support to the fourth corner of the outer panel, and applying an upward force to the second corner of the outer panel; Step 5: After heating is completed, first remove the force, and then release the fixing structure located at the first corner and the third corner of the outer panel.

2. The method for processing a twisted marine outer plate according to claim 1, characterized in that: In step 2, each heating position is marked before heating, and the heating positions are arranged as multiple columns of heating wires. The multiple columns of heating wires are arranged in sequence along the connecting line direction of the second corner and the fourth corner, and the heating positions in adjacent columns of heating wires are staggered.

3. The method for processing a twisted marine outer plate according to claim 2, characterized in that: The numbers of the heating positions contained in the spaced heating lines are equal, and the number of the heating positions in the first heating line is less than the number of the heating positions in the adjacent heating lines.

4. The method for processing a twisted marine outer plate according to claim 2, characterized in that: The distance between each heating position and the edge of the outer plate is greater than or equal to 200 mm.

5. The method for processing a twisted marine outer plate according to claim 1, characterized in that: In the step 2, the heating structure heats the heating position to 700° C. to 900° C.

6. The method for processing a twisted marine outer plate according to claim 5, characterized in that: When heating the heating position, for the outer panel with a thickness less than 25 mm, the heating structure heats the heating position to 700° C. to 780° C., and for the outer panel with a thickness greater than 25 mm, the heating structure heats the heating position to 780° C. to 900° C.

7. The method for processing a twisted marine outer plate according to claim 5, characterized in that: The output temperature of the heating structure is 3050°C to 3300°C. During heating, the flame core contacts the steel plate to a depth of 1 to 2 mm. When the outer plate turns red, the outer plate is appropriately distanced.

8. The method for processing a twisted marine outer plate according to claim 1, characterized in that: In the step 2, when heating the heating position, the straight running cooling method and the forward and backward method are adopted for the outer panels with a thickness of 14 mm to 20 mm, and the spiral flame transportation method is adopted for the outer panels with a thickness of more than 20 mm.

9. The method for processing a twisted marine outer plate according to claim 1, characterized in that: In step 2, when cooling the outer panel, for the outer panel with a thickness of 14 mm to 20 mm, the cooling water pipe lags behind the heating structure by a distance of 100 mm to 120 mm; for the outer panel with a thickness of more than 20 mm, the cooling water pipe lags behind the heating structure by a distance of 120 mm to 150 mm.

10. The method for processing a twisted marine outer plate according to claim 1, characterized in that: In the step 2, the length of the short side of the ellipse is half the length of its long side.

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