Aluminum alloy roof and welding deformation control method thereof

Abstract

The present application relates to the technical field of welding manufacturing, in particular to an aluminum alloy top cover and a welding deformation control method thereof, comprising the following steps: step one: single-sided welding after splicing the skeleton side of two sheet skin; step two: placing the spliced sheet skin skeleton side upwards on the welding tool; assembling the thick plate flange and preheating to single-sided weld on the sheet skin; step three: single-sided welding after fixing the profile skeleton on the sheet skin and applying vertical pressure. The present application prepositions the thermal calibration process, increases the rigid fixing point and reserves the reverse deformation to offset the welding deformation caused by the shrinkage of the base metal near the weld due to the welding heat input. The post-weld deformation of the aluminum alloy top cover is reduced, thereby reducing the working strength of the subsequent adjustment, improving the production efficiency, size accuracy and stability of the overall component.

Description

Technical Field

[0001] This invention relates to the field of welding manufacturing technology, specifically to an aluminum alloy top cover and a method for controlling welding deformation thereon. Background Technology

[0002] Aluminum alloys are widely used in rail transit due to their excellent corrosion resistance, lightweight, and high strength. However, aluminum alloys have high thermal conductivity and a large coefficient of linear expansion, leading to significant deformation and residual stress after welding of the aluminum alloy roof cover. The aluminum alloy roof covers of locomotives are mostly welded using segmented welds, with welds 50mm long and spaced 100mm apart, totaling 558 welds and a total weld length of 40m. 95% of these welds are concentrated on the frame side, further exacerbating welding deformation and residual stress in the aluminum alloy. This severely affects the dimensions, flatness, service life, and overall structural stability of the aluminum alloy roof cover.

[0003] Traditional welding processes result in aluminum alloy roof covers with deformations reaching up to 52mm. However, as an exterior component of a locomotive, the aluminum alloy roof cover has extremely stringent requirements regarding its overall structural dimensions, flatness, and stability, with flatness needing to be <2mm / m. Achieving this often requires 4-6 hours of adjustment, accompanied by significant noise, low production efficiency, and serious impacts on the health of workers.

[0004] Therefore, an aluminum alloy top cover and its welding deformation control method are proposed to solve the problems mentioned above. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, this invention provides an aluminum alloy top cover and a method for controlling its welding deformation. This method effectively solves the problem of uncontrollable deformation caused by thermal stress during the welding process of aluminum alloy top covers in existing technologies. It achieves the goals of reducing post-weld deformation of the aluminum alloy top cover, lowering workload, and improving dimensional accuracy and production efficiency.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for controlling welding deformation of an aluminum alloy top cover, comprising assembling a thick plate flange on a thin plate skin after welding, characterized by further comprising the following steps:

[0008] Step 1: Fix the profile frame onto the thin sheet skin and apply vertical pressure before welding on one side;

[0009] Step 2: Flip the thin sheet skin onto the anti-deformation fixture, leave room for anti-deformation, and rigidly fix it with F-type clamps;

[0010] Step 3: After preheating the thick plate flange, weld the non-framed side, and at the same time, perform thermal adjustment on the profile frame;

[0011] Step four: remove the F-shaped clamp after cooling to below 60°C.

[0012] Further, the reverse deformation tool is placed horizontally on the middle of the upper surface of the welding tool, and the reverse deformation amount is adjusted by 8 F-shaped clamps.

[0013] Further, the rigid fixing points of the F-shaped clamps are evenly distributed along the edge of the top cover.

[0014] Further, the preheating temperature of the thick plate flange is 80-120°C, and the hot calibration temperature is 100-120°C.

[0015] The welding uses tungsten argon arc welding, the welding current is 350-400A, and the welding voltage is 15-16V.

[0016] Further, the sequence of welding the non-skeleton side after preheating the thick plate flange is segmented symmetrical welding.

[0017] Further, the sequence of hot calibration of the profile skeleton is starting from the edge, gradually advancing along the spiral convergent path to the geometric center, and finally completing in the center area.

[0018] Further, the hot calibration of the profile skeleton includes:

[0019] Determine the initial welding power based on the welding material;

[0020] Determine the optimal number of region divisions based on the feature parameter set of the welding area;

[0021] Calculate the real-time partition heat power based on the adjusted number of division regions, and calculate the heating rate based on the partition heat power to ensure the uniformity of heat input during welding.

[0022] Further, the determination of the optimal number of region divisions based on the feature parameter set of the welding area includes:

[0023] Calculate the optimal initial division number for dynamically determining the welding heating area based on the feature parameter set, that is:

[0024] ;

[0025] where, is the initial value of the number of divisions; indicates rounding to the nearest integer; is the area scaling coefficient; A is the area level of the welding area; is the reference area; b is the area nonlinear index; is the feature item weight coefficient; is the weight coefficient of the i-th feature parameter; is the i-th feature parameter; F is the feature parameter set;

[0026] According to the initial value of the number of divisions, the generated points are uniformly arranged in the welding area to construct grid cells; the heat flow density of the grid cells in the welding area is collected, and the heat flow density is compared with a preset heat flow threshold value;

[0027] If the heat flow density is greater than the heat flow threshold value, a new generated point is inserted;

[0028] If the heat flow density is less than the heat flow threshold value, the redundant generated point with a higher priority score is deleted.

[0029] An aluminum alloy top cover, the top cover comprising:

[0030] A sheet skin arranged on the top of the top cover;

[0031] A profile skeleton arranged on one side of the sheet skin;

[0032] A thick plate flange horizontally arranged in the sheet skin.

[0033] Further, the sheet skin is 4mm thick 5083-H22 aluminum alloy;

[0034] The profile skeleton is 5mm thick 6005-T6 aluminum alloy;

[0035] The thick plate flange is 32mm thick 6063 aluminum alloy.

[0036] Compared with the prior art, the technical scheme provided by the present application has the following beneficial effects:

[0037] The present scheme pre-positions the thermal calibration process, and simultaneously increases the rigid fixing point and the reserved reverse deformation to offset the welding deformation caused by the shrinkage of the base material near the weld due to the welding heat input. The post-weld deformation amount of the aluminum alloy top cover is reduced, thereby reducing the working strength of subsequent adjustment, improving the production efficiency, the dimensional accuracy and the stability of the overall component. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical schemes in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0039] Figure 1 It is a schematic diagram of the installation position of the sheet skin of the aluminum alloy top cover in the first embodiment of the present application.

[0040] Figure 2 It is a schematic diagram of the installation position of the profile skeleton of the aluminum alloy top cover in the first embodiment of the present application.

[0041] Figure 3 The figure is a schematic diagram of the installation position of the thick plate flange of the aluminum alloy top cover in the first embodiment of the present application.

[0042] Figure 4 The figure is a schematic diagram of the welding deformation control method in the second embodiment of the present application.

[0043] Figure 5 The figure is a schematic diagram of the welding deformation of the aluminum alloy top cover after the welding of the thin plate skin framework and the profile framework in the second embodiment of the present application.

[0044] Figure 6 The figure is a schematic diagram of the reserved reverse deformation of the aluminum alloy top cover in the second embodiment of the present application.

[0045] Figure 7 The figure is a schematic diagram of the distribution of the rigid fixing position of the F-shaped clamp in the second embodiment of the present application.

[0046] Figure 8 The figure is a schematic diagram of the reserved deformation of the aluminum alloy top cover after the rigid fixing in the second embodiment of the present application.

[0047] Figure 9 The figure is a schematic diagram of the structure of the reverse deformation tool in the second embodiment of the present application.

[0048] Figure 10 The figure is a schematic diagram of the welding sequence of the non-framework side of the aluminum alloy top cover in the second embodiment of the present application.

[0049] Figure 11 The figure is a schematic diagram of the heat adjustment position and sequence of the non-framework side of the aluminum alloy top cover in the second embodiment of the present application.

[0050] Figure 12 The figure is a schematic diagram of the post-welding deformation of the aluminum alloy top cover in the second embodiment of the present application.

[0051] The numbers in the figure respectively represent:

[0052] The aluminum alloy top cover;

[0053] 101, the thin plate skin; 102, the profile framework; 103, the thick plate flange;

[0054] 2, the F-shaped clamp; 3, the welding tool; 4, the reverse deformation tool. DETAILED DESCRIPTION

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0056] The present invention will be further described below with reference to embodiments.

[0057] Example 1:

[0058] like Figures 1-3 As shown, this embodiment proposes an aluminum alloy top cover. The aluminum alloy top cover 1 is composed of three materials welded together: a thin plate skin 101, a profile frame 102, and a thick plate flange 103; its external dimensions are 4000mm×2500mm×54mm.

[0059] like Figure 1 As shown, a thin sheet skin 101 is disposed on the top of the aluminum alloy top cover 1. The thin sheet skin 101 is made of 4mm thick 5083-H22 aluminum alloy. Figure 2 The profile frame 102 shown is located on one side of the thin sheet skin 101, and the profile frame 102 is made of 5mm thick 6005-T6 aluminum alloy. Figure 3 As shown, the thick plate flange 103 is horizontally arranged in the thin plate skin 101, and the thick plate flange 103 is made of 32mm thick 6063 aluminum alloy.

[0060] Example 2:

[0061] Based on Example 1, this example proposes a method for controlling welding deformation of aluminum alloy top covers, such as... Figure 4 As shown, the method includes the following steps:

[0062] Step 1: Welding the side skins of the frame;

[0063] The skeleton sides of the two thin sheet skins 101 are horizontally spliced ​​together and placed on the welding fixture 3. The long side of the splice of the skeleton sides of the two sheet skins 101 is welded on one side.

[0064] Step 2: Welding the side skin of the frame to the flange;

[0065] Place the welded thin plate skin 101 horizontally on the welding fixture 3 with the skeleton side facing upward; assemble and spot weld all the thick plate flanges 103 on the horizontally placed thin plate skin 101, and after preheating the thick plate flanges 103, weld the gap between the skeleton side of the thin plate skin 101 and the thick plate flange 103 on one side.

[0066] Step three: weld the frame side of the skin to the frame;

[0067] Place the frame side of the thin plate skin 101, which has been welded to the thick plate flange 103, horizontally on the welding tool 3;

[0068] Spot weld all the profile frames 102 on the horizontally placed thin plate skin 101, and apply a vertical downward pressure on the upper surface of all the profile frames 102 to deform the aluminum alloy top cover 1 by an amount L. Weld the gap between the frame side of the thin plate skin 101 and the profile frames 102 by single-sided welding. After the welding of the frame side of the thin plate skin 101 and the profile frames 102 is completed, the welding deformation of the aluminum alloy top cover 1 is as shown in Figure 5 .

[0069] Step four: after the welding of the gap between the frame side of the thin plate skin 101 and the profile frames 102 is completed, place the aluminum alloy top cover 1 horizontally on the reverse deformation tool 4 by turning it 180°, as shown in Figure 6 . The reverse deformation tool 4 is as shown in Figure 9 .

[0070] Place the reverse deformation tool 4 horizontally on the welding tool 3 at the middle position of the upper surface, and use the 8 F-shaped clamps 2 to rigidly fix the aluminum alloy top cover 1, leaving a reverse deformation amount.

[0071] The fixing positions of the 8 F-shaped clamps 2 are as shown in Figure 7 , which are used to adjust the distance between the aluminum alloy top cover 1 and the upper surface of the platform of the welding tool 3, leaving a reverse deformation amount, denoted as L. The deformation amount left after the rigid fixation of the aluminum alloy top cover 1 is as shown in Figure 8 .

[0072] Step five: preheat the thick plate flange 103 on the aluminum alloy top cover 1 to a temperature of 80-120℃;

[0073] and weld the non-frame side of the aluminum alloy top cover 1. The welding sequence is as shown in Figure 10 . The welding sequence of the non-frame side is sectional symmetrical welding. The core purpose of sectional symmetrical welding is to achieve spatially balanced distribution of heat input, mutual offset of instantaneous thermal deformation, and self-balancing of residual stress.

[0074] At the same time, perform thermal calibration of the profile frames 102 of the aluminum alloy top cover 1 at a temperature of 100-120℃, and the thermal calibration sequence and position are as shown in Figure 11As shown, the thermal calibration is divided into six local regions, and both the local regions and the overall heating are symmetrically heated. During the welding process of the aluminum alloy, heat is conducted from the welding point to the surrounding areas. The central region has the highest temperature, and the temperature gradually decreases towards the edge. This heat conduction characteristic results in the following: the central region has the largest amount of expansion, the edge region is the most constrained, and the central region has the most concentrated shrinkage stress during cooling. Therefore, the stress release path is optimized as follows: the central high-temperature area is processed first to preferentially release the maximum residual stresses a and b; when the periphery c and d is subsequently processed, the center has already formed a stable support structure, which can effectively avoid secondary deformation caused by stress superposition. The E region, as the center point of the structure, has a special position: it is the final convergence point of all welding thermal stresses, the balance fulcrum of the shrinkage force of the surrounding weld, and the epicenter of overall deformation. Therefore, in order to meet the stress buffering requirements, the periphery a, b, c, and d is welded first, allowing 80% of the welding stress to be conducted and released through the profile skeleton 102, and the E region is processed last, which can take advantage of the rigid frame that has already been formed. By welding the periphery first to form a stress container effect, the metal flow in the central E region is constrained when welding the E region last, allowing for precise control of the final 0.5mm level of deformation.

[0075] In this deformed state, preheating, welding, and thermal calibration are performed. Due to the shrinkage of the weld after welding, the aluminum alloy top cover 1 is deformed in the opposite direction of the pre-set deformation direction, thereby achieving Figure 12 a state with a deformation of only 20mm. Compared with the 53mm post-weld deformation of the aluminum alloy top cover welded using the traditional welding process, the post-weld deformation of the aluminum alloy top cover 1 is significantly reduced, improving the efficiency of subsequent fine tuning.

[0076] It is worth mentioning that, during the thermal calibration process, if the heating process is not reasonably controlled, especially the heating speed and cooling speed of the welding heat source, poor thermal calibration can cause cracks, pores, or embrittlement in the metal structure of the welded area, reducing the tensile strength and toughness of the welded joint, and even possibly leading to cracking or fatigue failure during subsequent use. Therefore, by precisely controlling the heating speed and cooling speed during the aluminum alloy welding process to achieve uniform distribution of heat input, the problem of welding deformation and residual stress concentration due to thermal gradients is solved. Specifically, by using a linear heating strategy from the center to the edge and non-linear cooling control, the stress release path is optimized, ensuring effective support in the central region during the welding process, thereby reducing secondary deformation and improving the overall performance and stability of the welded joint. The control method of the heating speed and cooling speed of the welding heat source is as follows:

[0077] The welding area surface level for affecting the thermal calibration region is calculated, which affects the uniformity of heat distribution and the effectiveness of power. If the welding area is larger, higher heat input power is required to ensure that all areas reach a suitable welding temperature to avoid welding defects (such as defective welds, incomplete fusion, etc.) caused by insufficient heating.

[0078] During the welding process, the initial heat power is first determined based on the properties of the welding material (e.g., the thermal conductivity and specific heat capacity of aluminum alloys), that is:

[0079] ;

[0080] In the formula, Initial thermal power, i.e., the energy input required during welding, ensures that the material reaches the target heating temperature rapidly and uniformly; this helps optimize heat transfer efficiency, reduce welding deformation and stress concentration, thereby improving weld quality and structural strength; k is the material's thermal conductivity coefficient (unit: kJ / m²). Thermal conductivity (T) is a physical quantity that measures the thermal conductivity of a material and determines how heat is transferred from the heat source to the interior of the material during the welding process. Different types of aluminum alloys have different thermal conductivity coefficients, which affect the distribution of heat and the effectiveness of the welding process. A higher thermal conductivity coefficient means that heat can spread rapidly in the material, thereby improving the efficiency and quality of welding. A represents the welding area area, which indicates the total area of ​​the metal surface that needs to be heated and welded. The target heating temperature represents the desired temperature value that the welding material is to reach, and it is determined based on the welding process and material requirements. If the target temperature is too low, the welding quality will be poor, while if it is too high, the material properties may deteriorate. The initial temperature of the material represents the initial temperature of the material before welding. It is usually the ambient temperature or the temperature of the material before entering the welding conditions. It is an important reference for adjusting the welding heat power. The heating time required to reach the target temperature is a time parameter for each welding process, reflecting the duration of material heating. A reasonable heating time requires that thermal stress not be concentrated when the target temperature is reached. It is estimated through empirical data or by calculation based on material properties, welding equipment performance, and the heat load of the welding area.

[0081] The heating rate is determined by real-time monitoring of the temperature in the heating zone.

[0082] ;

[0083] In the formula, R is the heating rate, which represents the rate of temperature rise of the material during heating. The unit is usually K / s; the heating rate directly determines the time for the material to reach the target temperature and the distribution of thermal stress; L is the total time of the heating process, which refers to the duration from the start of heating to the target temperature, determined by recording experimental data; n is the number of partitions of the heating area, used to divide the welding area into multiple small areas, so as to more accurately measure and balance the heating power of each area; by increasing the degree of detail of data collection through segmentation, the temperature change of each small area can be independently monitored, enabling more accurate thermal control and rapid adjustment of heating strategies; i is the index number; is the heat power value of the ith partition at time t, that is, the partition heat power; the calculation formula is:

[0084] ;

[0085] In the formula, is the heating surface level of the ith partition.

[0086] By dynamically adjusting the heat power output according to the temperature changes of different partitions, it allows dynamic adjustment of the heating rate during the welding process according to the actual heating condition of the material. This flexibility ensures more accurate temperature control during welding, enabling rapid response to temperature changes and reducing the risk of welding deformation.

[0087] It is worth noting that the number of partitions n of the heating area is a key parameter, and a fixed partition strategy cannot dynamically adapt to changes in the thermodynamic properties of the welding area, resulting in insufficient temperature monitoring accuracy and uneven heat input distribution, which is manifested in:

[0088] For complex top cover structures, fixed partitioning will result in uneven heating in some areas; and the thermal conductivity coefficient K of aluminum alloy changes at different temperatures, and fixed partitioning cannot be dynamically adjusted, resulting in uneven heat input in the central and edge regions. Through the adaptive dynamic partitioning strategy, the limitations of the original fixed number of partitions n can be effectively solved, and the welding quality and efficiency are synergistically improved. The implementation of the adaptive dynamic partitioning strategy is:

[0089] Extract the feature parameters of the welding area and construct them into a feature parameter set. Among them, the feature parameters include:

[0090] The planar geometric features (aspect ratio, curvature, etc.) of the thin plate skin, which are used to quantify the shape complexity of the skin, the aspect ratio affects the symmetry of the heat conduction path, and the curvature determines the local heating difficulty;

[0091] The distribution density of the profile skeleton reflects the distribution of structural support strength, and the area with high density has high resistance to thermal deformation, which requires reducing the number of partitions to avoid excessive heat input; the sparse area needs to increase the partition to improve the temperature control accuracy;

[0092] Thick plate flange position and size features, the flange as a rigid component will constrain thermal expansion, its position and size directly affect the degree of local thermal stress concentration, need to adjust the peripheral segmentation strategy;

[0093] Local variation coefficient of area, used to identify the discrete degree of thermal load in the welding area, high variation coefficient indicates the need for non-uniform segmentation (such as increasing the value of high heat flow area n, and merging the low temperature difference area segmentation). The calculation formula of local variation coefficient is:

[0094] ;

[0095] In the formula, CV is the local variation coefficient, which quantifies the thermal-geometric composite non-uniformity of the welding area, and the larger the value indicates that the area needs higher priority segmentation optimization; Y is the number of pre-divided sub-regions; is the area of the i-th pre-divided sub-region; is the average value of the pre-divided sub-region area, which is used to eliminate the influence of absolute size on the variation coefficient, so that the result has cross-scale comparability; is the local heat input, which determines the energy input per unit length of weld, affecting the material melting depth and grain growth, that is:

[0096] ;

[0097] In the formula, is the thermal efficiency coefficient, which is provided by experiment or equipment manual; I is the welding current; U is the welding voltage; v is the welding speed;

[0098] is the average heat input.

[0099] Based on the feature parameter set, the optimal initial segmentation number for dynamically determining the welding heating area is calculated, that is:

[0100] ;

[0101] In the formula, is the initial value of the segmentation number; indicates rounding off; is the area scaling coefficient, which controls the dominant degree of the area item to the segmentation number; b is the area nonlinear index, which reflects the nonlinear relationship between area and segmentation number (sublinear growth, avoiding excessive segmentation of small areas); is the reference area, which provides a normalized reference to eliminate the influence of absolute size, so that different size workpieces are comparable; is the feature item weight coefficient, which balances the weight of geometric features and area influence; is the weight coefficient of the i-th feature parameter, which quantifies the importance of different geometric features to the segmentation strategy (e.g. curvature weight > aspect ratio); is the i-th feature parameter (e.g. aspect ratio, curvature, skeleton density, etc.); F is the set of feature parameters.

[0102] According to the initial value of the number of partitions, generate points are uniformly arranged in the welding area to construct an initial Voronoi grid, and each grid cell represents an independent temperature control sub-area. The initial uniform distribution ensures basic coverage.

[0103] Real-time temperature data of the welding area are collected by an infrared thermal imager or a thermocouple array, and heat flux density is derived through the Fourier heat conduction law, which is used to quantify the thermal load intensity of each region and identify high heat flux areas (such as welds) and low temperature areas. Compare the heat flux density with the preset heat flux threshold:

[0104] If the heat flux density is greater than the heat flux threshold, insert a new generating point in the area, i.e.

[0105] ;

[0106] wherein, is the number of generating points that need to be added, i.e. the number of partitioned regions, which directly determines the degree of partition refinement in high heat flux areas and improves temperature control accuracy; is the heat flux density at position (x, y), which quantifies the local thermal load intensity and identifies areas that need to be controlled (such as the center of the weld); is the heat flux threshold; g is the number of generating points corresponding to a unit heat flux increment, which is calibrated through process experiments.

[0107] If the heat flux density is less than the heat flux threshold, delete the redundant generating points, i.e.

[0108] ;

[0109] wherein, is the number of generating points that need to be deleted; is the total area of the low temperature area; is the average cell area of the current grid cell.

[0110] Calculate the quantified heat flux abnormality degree of the area corresponding to the generating point to guide the deletion decision, i.e.

[0111] ;

[0112] wherein, S is the priority score of the generating point; is the average heat flux density of the entire field; is the area of the i-th grid cell. Arrange all generating points in descending order of priority score, and delete the generating point with the highest priority score first.

[0113] Step six: after the aluminum alloy top cover 1 whole component maximum temperature cooling to 60℃ below, remove F type clamp 2.

[0114] It should be noted that the above welding method adopts tungsten argon arc welding TIG, the welding current is 350-400A, and the welding voltage is 15-16V.

[0115] In the traditional process: after the welding of the skeleton side of the sheet skin 101 of the aluminum alloy top cover 1 and the weld of the profile skeleton 102 is completed, the aluminum alloy top cover 1 is turned over 180° and placed horizontally on the welding tool 3, the thick plate flange 103 is directly preheated, and then welded.

[0116] The difference between the present scheme and the traditional process is that:

[0117] After the welding of the skeleton side of the sheet skin 101 of the aluminum alloy top cover 1 and the weld of the profile skeleton 102 is completed, the reverse deformation tool 4 is placed on the surface of the welding tool 3, then the aluminum alloy top cover 1 is turned over 180° with the skeleton side facing down and placed horizontally on the reverse deformation tool 4, rigidly fixed by 8 F type clamps 2 and preformed reverse deformation, the thick plate flange 103 is preheated, and then welded, and the skeleton profile 102 is simultaneously heat adjusted. After welding and heat adjustment, the F type clamps 2 are removed after the whole component is cooled to a maximum temperature below 60℃.

[0118] Compared with the traditional welding process, the post-weld deformation of the aluminum alloy top cover 1 is 53mm. After the welding deformation control method of the present scheme is adopted, the post-weld deformation of the aluminum alloy top cover is only 20mm; and the adjustment time is shortened from the original 4-6 hours to 3.5 hours or less. The present scheme prepositions the heat adjustment process, simultaneously increases the rigid fixing point and preforms the reverse deformation, to offset the welding deformation caused by the shrinkage of the base material near the weld due to welding heat input. The post-weld deformation of the aluminum alloy top cover 1 is reduced, thereby reducing the working intensity of subsequent adjustment, improving the production efficiency, size accuracy and stability of the whole component.

[0119] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements will not make the essence of the corresponding technical solutions deviate from the protection scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for controlling welding distortion of an aluminum alloy top cover, comprising assembling a thick plate flange (103) on a thin plate skin (101) after the completion of the tailor welding, characterized in that, Further comprising the following steps: Step one: single-sided welding after fixing the profile skeleton (102) on the sheet skin (101) and applying vertical pressure; Step two: turn over the sheet skin (101) to the reverse deformation tooling (4), reserve the reverse deformation amount and rigidly fix it through the F-shaped clamp (2); Step three: weld the non-skeleton side after preheating the thick plate flange (103), and at the same time, heat adjust the profile skeleton (102), the order of heat adjusting the profile skeleton (102) is from the edge, along the spiral converging path, and gradually advancing to the geometric center, and finally completed in the center area; The preheating temperature of the thick plate flange (103) is 80-120℃, and the heat adjusting temperature is 100-120℃; The welding adopts tungsten argon arc welding, the welding current is 350-400A, and the welding voltage is 15-16V; The heat adjusting of the profile skeleton (102) comprises: Determine the initial welding power based on the welding material; Determine the optimal region segmentation number based on the feature parameter set of the welding area; Calculate the real-time partition heat power based on the adjusted segmentation region number, and calculate the heating rate based on the partition heat power to ensure the uniformity of heat input during welding; Step four: remove the F-shaped clamp (2) after cooling to below 60℃.

2. The welding distortion control method according to claim 1, characterized by, The reverse deformation tooling (4) is horizontally placed in the middle position of the upper surface of the welding tooling (3), and the reverse deformation amount is adjusted through the eight F-shaped clamps (2).

3. The welding distortion control method according to claim 2, characterized by, The rigid fixing points of the F-shaped clamp (2) are uniformly distributed along the edge of the top cover.

4. The welding distortion control method according to claim 1, characterized by, The order of welding the non-skeleton side after preheating the thick plate flange (103) is sectional symmetrical welding.

5. The welding distortion control method according to claim 1, characterized by, The determination of the optimal region segmentation number based on the feature parameter set of the welding area comprises: Calculate the optimal initial segmentation number for dynamically determining the welding heating area based on the feature parameter set, that is: ； In the formula, is the initial value of the number of divisions; represents rounding off; is the area scaling coefficient; A is the area level of the welding region; is the reference area; b is the area nonlinear index; is the characteristic term weight coefficient; is the weight coefficient of the i th characteristic parameter; is the i th characteristic parameter; F is the characteristic parameter set; According to the initial value of the segmentation number, generate points uniformly in the welding area to construct grid cells; compare the heat flux density of the welding area grid cells collected with the preset heat flux threshold value; If the heat flux density is greater than the heat flux threshold value, insert a new generated point; If the heat flux density is less than the heat flux threshold value, delete the redundant generated point with higher priority score.

6. An aluminum alloy top cover prepared by the welding deformation control method according to any one of claims 1 to 5, characterized by The top cover comprises: A sheet skin (101) arranged at the top of the top cover; A profile skeleton (102) arranged on one side of the sheet skin (101); A thick plate flange (103) horizontally arranged in the sheet skin (101).

7. The aluminum alloy top cover of claim 6, wherein, The sheet skin (101) is 4mm thick 5083-H22 aluminum alloy; The profile skeleton (102) is 5mm thick 6005-T6 aluminum alloy; The thick plate flange (103) is 32mm thick 6063 aluminum alloy.

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