Aluminum veneer welding heat-affected zone deformation correction method based on back face progressive correction

Abstract

The application discloses a kind of based on back progressive correction aluminium veneer welding heat affected deformation correction method, it is related to aluminium veneer postwelding correction technical field, the method includes: the planeness detection of aluminium veneer welded with accessory, determine the deformation area formed due to welding heat effect;According to deformation area, determine the area to be corrected on the back of aluminium veneer;First round of cold work correction is carried out to the area to be corrected from the back of aluminium veneer;The deformation area after completing first round of correction is retested;When retest result does not reach preset planeness requirement, subsequent correction amount is determined according to retest result, and next round of progressive correction is carried out to the area to be corrected from the back of aluminium veneer;Repeat retest and progressive correction until reach standard;The application is corrected by back progressive cold work, avoids the secondary influence of heat input on material performance, effectively protects the surface quality of decorative surface while recovering the planeness of aluminium veneer, and the controllability of correction accuracy is improved by the closed-loop control logic that correction amount is ladder decreasing.

Description

Technical Field

[0001] This invention relates to the field of post-weld straightening technology for aluminum single-panel panels, and in particular to a method for correcting the heat-affected deformation of aluminum single-panel panels based on back-side progressive correction. Background Technology

[0002] Aluminum single-layer panels are widely used in curtain wall panels, decorative panels, and related installation components. During the production process, corner brackets, reinforcing ribs, or installation connectors are often welded to the back of the aluminum single-layer panels to meet the requirements for installation connection and structural reinforcement.

[0003] Since welding is a localized heat input process, the weld and the area near the heat-affected zone are prone to deformations such as bulges, depressions, warping, or flatness deviations due to uneven thermal expansion and contraction, which can affect the appearance quality of the board and the accuracy of subsequent assembly.

[0004] In existing technologies, one type of solution controls deformation during welding using molds, fixtures, or clamping tools; another type corrects deformation after welding using flame trimming, shot peening stress adjustment, or general plate leveling methods. For example, patent document CN115121916A discloses an arc welding correction method for post-weld deformation of steel plates, which falls under the category of thermal straightening. It offsets deformation by applying thermal stress generated by the arc weld bead to the deformation zone. Although it mentions "progressive" welding, its essence is the spatial arrangement of weld beads in a single round of correction, and it does not involve multi-round cold working closed-loop correction based on retest results. Another example is patent document CN114619161A, which discloses a method for straightening and leveling thin plate welding deformation. It uses electromagnetic induction heating for leveling and adopts a "retest-re-leveling" process, but it still relies on heat source input.

[0005] The aforementioned solutions either emphasize pre-weld and in-weld control, rely on heat straightening and specialized equipment, or are designed for the flatness restoration of general metal plates. Especially for aluminum panels, heat straightening (such as flame or induction heating) can easily lead to localized softening of the aluminum, coarse grains, or discoloration of the surface coating, making it difficult to meet the comprehensive requirements of aluminum panels after welding accessories in terms of post-weld cold work correction, decorative surface protection, correction springback control, and stable flatness restoration.

[0006] In summary, the existing technology has at least the following technical problems:

[0007] There is a lack of a post-weld correction method that addresses the deformation of aluminum panels caused by heat after welding accessories, avoids heat correction defects, and achieves high-precision flatness restoration through progressive cold working correction on the back side. Summary of the Invention

[0008] The purpose of this invention is to provide a method for correcting heat-affected deformation of aluminum single-panel welding based on back-side progressive correction, in order to solve the problem that in the prior art, aluminum single-panel welding accessories are deformed due to heat, and the existing treatment methods are mostly biased towards in-weld control, heat correction or special stress adjustment processes, which are easy to damage the surface and difficult to accurately control the rebound.

[0009] The preferred technical solutions among the many technical solutions provided by this invention can produce a variety of technical effects, which are described in detail below.

[0010] To address the aforementioned technical problems, the present invention provides the following technical solution:

[0011] This invention provides a method for correcting the heat-affected deformation of aluminum single-panel welding based on back-side progressive correction, comprising the following steps:

[0012] S1. Perform flatness testing on the decorative surface of aluminum single-panel with welded accessories, obtain flatness deviation distribution data, and identify areas where the flatness deviation exceeds the preset threshold as deformation areas caused by welding heat.

[0013] S2. Based on the location of the deformation area and the distribution of the deviation peak, determine the area to be corrected on the back of the aluminum single panel. The area to be corrected includes a main correction area corresponding to the deviation peak area, and a transition correction area for stress transition set around the main correction area.

[0014] S3. From the back of the aluminum panel, use a cold working correction device to perform a first round of cold working correction on the area to be corrected. The first round of cold working correction is preferentially applied to the main correction area.

[0015] S4. Re-measure the deformed area after the first round of cold working correction to obtain the re-measured flatness data;

[0016] S5. When the retested flatness data does not meet the preset flatness requirement, the correction amount for the next round of progressive correction is determined based on the difference between the retested flatness data and the preset flatness requirement, and the next round of progressive correction is performed on the area to be corrected from the back of the aluminum panel; wherein, the correction amount for the next round of progressive correction is less than the correction amount for the previous round of correction, and when the retest result shows that the main correction area does not meet the standard, the next round of progressive correction continues to be implemented for the main correction area; when the main correction area meets the standard but the transition correction area does not meet the standard, the next round of progressive correction is implemented for the transition correction area.

[0017] S6. Repeat steps S4 and S5 until the flatness of the deformed area reaches the preset flatness requirement.

[0018] Furthermore, the accessory includes at least one of corner brackets, reinforcing ribs, and mounting connectors.

[0019] Furthermore, the flatness detection in step S1 includes one or more of the following methods to detect the aluminum panel: using a straightedge to measure the gap, comparing the platform, laser displacement detection, and contour scanning detection.

[0020] Further, in step S2, the area to be corrected is determined based on the location of the deformed area and the corresponding flatness deviation value, or based on the location of the welded component and its adjacent heat-affected zone.

[0021] Furthermore, the correction methods employed by the cold working correction equipment include roller correction, hammer correction, pressure point correction, or combinations thereof.

[0022] Furthermore, the cold working straightening equipment is selected from one or more of the following: roll forming straightening machine, hammer straightening machine, and pressure point straightening machine.

[0023] Furthermore, the preset flatness requirement is set to a flatness deviation of ≤0.5mm / m².

[0024] Furthermore, the retest in step S4 is used to determine whether there is insufficient correction or rebound after correction in the deformed area, and serves as the basis for whether to perform the next round of progressive correction and to determine the subsequent correction amount.

[0025] This invention achieves precise repair of welding heat-affected deformation by introducing a progressive closed loop of cold working correction and stepwise reduction of correction amount, which not only eliminates dependence on heat source equipment, but also protects the integrity of aluminum single-panel decorative surface.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] Protecting material performance and surface quality: During the calibration process, each round of calibration is performed using cold working from the back of the aluminum panel. Compared to hot calibration methods such as flame straightening or induction heating, this invention uses mechanical force to straighten at room temperature, completely avoiding the problems of aluminum substrate softening, strength reduction, and surface coating carbonization and discoloration caused by heat input. It is particularly suitable for curtain wall decorative aluminum panels with extremely high appearance requirements.

[0028] A precise progressive closed-loop control system is constructed: Through a chain of steps—"flatness detection—first round of back-side cold working correction—retest—determining subsequent correction amounts based on retest results—next round of progressive correction"—the correction process is characterized by progressive advancement, verification, and compensation. In particular, the step-reduction method, where "the correction amount in the next round is less than the correction amount in the previous round," effectively prevents overcorrection and reverse deformation caused by excessive correction force. Compared to empirical, single-stage forceful correction, this significantly improves correction accuracy and process controllability.

[0029] Adapting to the spatial distribution characteristics of welding deformation: By further dividing the area to be corrected into a main correction zone and a transition correction zone, and dynamically adjusting the focus of the correction based on the retest results during the progressive correction process, this partitioned progressive logic makes the release of correction stress smoother, avoids the generation of new stress abrupt change lines at the boundary of the deformation concentration zone, and solves the technical problem that repeated leveling of a single area can easily produce "hard edges" or "elastic recovery".

[0030] Enhanced springback resistance: Each round of retesting specifically determines whether springback occurs after correction, and this serves as the basis for executing the next round of correction and adjusting the correction amount. This cold-working correction method, combined with multiple rounds of micro-pressure application, helps to eliminate residual stress through reciprocating plastic deformation, resulting in a more stable flatness state of the final aluminum panel correction area. Attached Figure Description

[0031] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the deformation area of ​​the aluminum single-panel after welding accessories in an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the region to be corrected in an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the method flow for back-side progressive correction according to an embodiment of the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0036] This invention provides a method for correcting the heat-affected zone deformation of aluminum panels after welding, based on progressive back-side correction. It is applicable to post-weld correction scenarios where bulging, denting, warping, or flatness deviations occur on the panel surface due to welding heat input and heat-affected zone effects after welding corner brackets, reinforcing ribs, or installing connectors on the back of the aluminum panel. The key point of this invention is to implement multiple rounds of progressive cold-working correction from the back of the aluminum panel for the deformed areas already formed after welding. The results of each round of correction are used as the basis for determining whether to continue with the next round of correction and how to determine the correction amount and key areas for the next round.

[0037] Implementation Method 1

[0038] like Figures 1 to 3First, the flatness of the aluminum panels with welded fittings is inspected to identify the deformation areas caused by welding heat. Flatness inspection can be performed using a straightedge with gap measurement, or by any of the following methods: platform comparison, laser displacement detection, or contour scanning detection. The purpose of this step is to identify areas of flatness deviation on the panel surface and determine the location for subsequent correction.

[0039] Specifically, flatness deviation distribution data of the overall flatness of the aluminum single-panel decorative surface is obtained through flatness testing, forming a deviation cloud map or deviation value matrix. Then, the deviation values ​​are compared with a preset deformation judgment threshold, which is set according to the precision level of the aluminum single-panel product, for example, greater than 0.5mm / m². Areas with continuously distributed deviations exceeding the deformation judgment threshold are marked as deformation areas. For multi-point welding, if the distance between multiple deformation areas is less than a preset spacing (e.g., 50mm), they are merged into a single deformation area. In multi-point welding scenarios, the spatial continuity and expansion characteristics of the welding heat effect need to be considered to ensure accurate determination of deformation areas, enabling more accurate division of correction areas.

[0040] After inspection, the area to be corrected on the back of the aluminum panel is determined based on the deformation area. Specifically, the area to be corrected can be determined based on the location of the deformation area and its corresponding flatness deviation value; it can also be determined by combining the location of the welded fittings and their adjacent heat-affected zones. For aluminum panels with welded corner brackets or reinforcing ribs, when the panel deformation is mainly concentrated in the area corresponding to the welded fitting, the back area corresponding to the welded fitting can be determined as the area to be corrected; when the deformation area extends along the periphery of the welded fitting, the heat-affected zone adjacent to the fitting can also be included in the area to be corrected.

[0041] In this embodiment, the area to be corrected further includes a main correction area corresponding to the deformation area, and a transition correction area surrounding the main correction area. The main correction area is used to correspond to areas where flatness deviations are relatively concentrated, and the transition correction area is used to correspond to the transition range between the outer edge of the main correction area and the normal area of ​​the plate surface. By dividing the area to be corrected into a main correction area and a transition correction area, subsequent progressive correction is no longer a simple repetition of the same area, but rather forms a correction process implemented step by step according to the area hierarchy.

[0042] The dynamic linkage between the transition correction zone and the main correction zone during the correction process: When the retest results show that the main correction zone does not meet the preset flatness requirements, the next round of progressive correction not only applies a correction force to the main correction zone, but also applies a matching correction force to the transition correction zone based on the magnitude of the remaining deviation in the main correction zone. The magnitude of the matching correction force is 20% to 40% of the correction force of the main correction zone. Because the plastic flow and stress redistribution that occur in the main correction zone during the correction process will be transmitted to the transition correction zone, if the transition correction zone is not treated at all, a new stress concentration zone is easily formed at the boundary of the main correction zone, leading to "hard edges" or localized springback after correction. By applying an auxiliary correction force to the transition correction zone, the constraint stress at the boundary can be released in advance, creating a smooth stress transition gradient between the main correction zone and the normal plate surface.

[0043] After identifying the area to be corrected, the first round of cold working correction is performed on the back of the aluminum panel. Cold working correction refers to applying mechanical force directly through rolling, localized hammering, or pressing equipment without using a heat source. The first round of cold working correction is prioritized for the main correction area and can be applied simultaneously to the transition correction area depending on the expansion of the deformation area. The purpose of the first round of cold working correction is to initially correct the local deformation caused by heat influence, thereby achieving the first stage of improvement in the flatness deviation of the main correction area.

[0044] After the first round of cold working correction is completed, the deformed area is retested. The retest can continue to be carried out using the aforementioned flatness detection method to determine whether the deformed area has met the preset flatness requirements after the first round of cold working correction (e.g., for high-precision aluminum panels, the flatness deviation should not exceed 1.0 mm / m²). If the retest results show that the aluminum panel has not met the preset flatness requirements, the next round of progressive correction is initiated.

[0045] The criteria for retesting are: (1) Compliance status: the maximum flatness deviation within the deformation area is less than the preset flatness requirement, and the deviation gradient between adjacent measuring points is less than 0.1mm / 100mm, indicating that the correction is sufficient and the stress distribution is uniform;

[0046] (2) Insufficient correction state: The maximum flatness deviation is greater than the preset flatness requirement, and the deviation distribution pattern is basically the same as before correction, indicating that the correction amount in the current round is insufficient, and the correction amount or the holding time needs to be increased in the next round of progressive correction.

[0047] (3) Rebound state: The maximum flatness deviation has rebounded after the previous round of correction, with a rebound range of ≥0.1mm. The rebound area is concentrated at the boundary of the main correction area or at the stress concentration point, indicating that there is elastic aftereffect. In the next round of progressive correction, the rebound area needs to be compensated and corrected, and the holding time should be appropriately increased or a multiple small energy correction strategy should be adopted.

[0048] In this invention, progressive correction refers to: after the previous round of cold working correction is completed and retested, the subsequent correction amount is determined based on the retest results, and subsequent correction is carried out on the area to be corrected from the back of the aluminum panel.

[0049] In progressive correction, the correction amounts differ between adjacent rounds, with each subsequent round of cold working correction involving less than the previous round, resulting in a step-like decrease in correction amount. Specifically: the first round of cold working correction applies pressure to achieve a springback displacement of 70% of the estimated deformation; the second round applies pressure to achieve a displacement of 50% of the remaining deformation, and so on. This process involves progressive advancement, judgment, and compensation, leading to a better final correction effect. Therefore, progressive correction is not simply repeating the same correction actions, but rather a subsequent compensatory correction based on the results of the previous round.

[0050] More precise progressive quantization: A reduction coefficient k (0 < k < 1) is preset, and the correction amount Dn in the nth round is determined by the following formula: Dn = k × D(n-1), where D1 is the correction amount in the first round, determined based on 60% to 80% of the initial deformation peak height H. For example, if k = 0.5, the correction amounts in each round are H × 70%, H × 35%, and H × 17.5% respectively, until the remaining deviation is less than the preset flatness requirement.

[0051] A progressive quantification strategy can ensure the objectivity and repeatability of the correction amount, making the correction amount more accurate and avoiding reliance on the operator's subjective experience.

[0052] Specifically, the progressive correction includes at least a second round of cold working correction. If the preset flatness requirement is still not met after the second round of cold working correction, a third and subsequent rounds of cold working correction can be implemented. Each round of progressive correction is initiated based on the results of the previous round of retesting. That is, after the first round of cold working correction, if the retest results show that there is still a significant flatness deviation in the main correction area, then the second round of progressive correction is performed; after the second round of progressive correction, if the retest results show that a local area still does not meet the standard, then the third round of progressive correction is performed; this process is repeated until the preset flatness requirement is met.

[0053] In this embodiment, when the second round of correction is applied to the transition correction zone, an auxiliary rolling pressure of 20 N / cm is simultaneously applied to the boundary of the main correction zone to release the residual stress transmitted from the main correction zone to the transition zone after correction. Retest results show that the flatness gradient at the junction of the main correction zone and the transition correction zone decreased from 0.8 mm / 50 mm before correction to 0.1 mm / 50 mm, significantly improving the smoothness of the transition and eliminating the "hard edge" phenomenon.

[0054] In a preferred embodiment, the correction amounts differ in each round of progressive correction. The first round of cold working correction is used for preliminary correction of the deformed area, while the second and subsequent rounds of progressive correction are used for compensatory correction based on the previous round. In other words, the first round of cold working correction is mainly used to reduce more significant deformation, while subsequent progressive corrections are mainly used to further correct the remaining deviations. The correction amounts in each round can be adjusted based on the results of the previous round of retesting to adapt to the cold working correction requirements under different degrees of welding heat-affected deformation.

[0055] In a preferred embodiment, progressive correction is performed sequentially in the main correction region and the transition correction region. Specifically, this may include the following two methods:

[0056] The first method involves first performing a round of cold working correction on the main correction area, and then performing coordinated cold working correction on the transition correction area, so that the cold working correction process gradually unfolds from the area of ​​concentrated deviation to the outer transition area.

[0057] The second approach involves first completing the cold working correction of the current wheel in the main correction zone and then retesting it. Based on the retest results, it is then determined whether subsequent progressive corrections need to be implemented in the transition correction zone, thereby ensuring that the correction of the transition correction zone is coordinated with the recovery state of the main correction zone.

[0058] In a preferred embodiment, the target of the subsequent progressive correction is not fixed, but is re-determined based on the results of the previous retest. Specifically, when the retest results show that the main correction area has met the preset flatness requirement, but the transition correction area still has local deviations, the next round of progressive correction will prioritize the transition correction area; when the retest results show that the main correction area has not yet met the preset flatness requirement, the next round of progressive correction will continue to target the main correction area, and will coordinate with the transition correction area for correction as needed. This enables the progressive correction to dynamically adjust the focus area based on the test results.

[0059] In a preferred embodiment, the retest is also used to determine whether there is insufficient correction or springback in the deformed area. If the retest result shows insufficient correction, it indicates that the current round of cold working correction has not yet restored the deformed area to the preset flatness requirement; if the retest result shows springback, it indicates that there is still residual elastic stress on the plate surface after the previous round of cold working correction, leading to a tendency for deformation recovery. In both cases, this can serve as the basis for continuing the next round of progressive correction. When performing the next round of progressive correction, the holding time should be appropriately increased or the correction position fine-tuned to eliminate elastic aftereffects.

[0060] Implementation Method 2

[0061] As one optional implementation method, the determination of the area to be corrected needs to correspond to the position of the welded component. Specifically, after completing the flatness inspection, if the inspection finds that the deformation of the plate surface is basically consistent with the area corresponding to a certain welded component, then the back area corresponding to the welded component is determined as the main correction area, and its surrounding area is determined as the transition correction area; if the inspection finds that the deformation area extends along both sides of the welded component, then the range of the transition correction area is expanded accordingly. Subsequently, the main correction area is first cold-worked corrected from the back, and then the transition correction area is cold-worked corrected in conjunction; after retesting, if the main correction area still does not meet the preset flatness requirements, then the next round of progressive cold-worked correction is performed on the main correction area, and a decision is made on whether to simultaneously implement subsequent cold-worked correction on the transition correction area based on the retest results.

[0062] Implementation Method 3

[0063] As one optional implementation method, to ensure calibration accuracy and efficiency, the preset flatness requirement in this method is set to a flatness deviation ≤ 0.5 mm / m² (determined according to the size and accuracy level of the aluminum panel). In the cold-working calibration stage, specific methods include roller calibration (pressure output controlled at 50-200 N / cm), hammer calibration (using a rubber or copper hammer, with a single hammering energy not exceeding 5 J), or point calibration (the pressure bar presses the calibration area with a circular or square cross-section). By using a cold-working method performed at room temperature, flame heating or induction coil heating is avoided, thus fundamentally eliminating the risk of yellowing or blistering of the fluorocarbon paint or powder coating on the aluminum panel surface due to high temperatures.

[0064] Implementation Method 4

[0065] As one optional implementation, the determination of the area to be corrected in step S2 can also be based on the deviation distribution of the deformation area. Specifically, after the flatness test, if the test result shows that there is a deviation peak area in the deformation area, the back surface area corresponding to the deviation peak area is determined as the main correction area, and the area outside the deviation peak area that is still within the influence range of the flatness deviation is determined as the transition correction area. This method allows the main correction area to more closely correspond to the location where the deformation is more obvious, while the transition correction area is used to coordinate and correct the transition state of the plate surface outside the main correction area.

[0066] Implementation Method 5

[0067] As one optional implementation, the next round of progressive correction in step S5 does not repeat the correction of all areas to be corrected in the previous round. Instead, it redetermines the key areas for subsequent correction based on the retest results in step S4. When the retest results show that the main correction area has met the preset flatness requirement, but the transition correction area still has local deviations, the subsequent progressive correction will prioritize the transition correction area. When the retest results show that the main correction area has not yet met the preset flatness requirement, the subsequent progressive correction will continue to target the main correction area, and the transition correction area will be coordinated for correction as needed.

[0068] Implementation Method Six

[0069] As one optional implementation method, the correction amounts of adjacent progressive correction rounds are different, with the correction amount of each subsequent round being smaller than that of the previous round, and the overall correction amount showing a step-decreasing trend. Specifically, the first round of cold working correction is used to initially correct the deformed area, and its correction amount (such as compression displacement or applied pressure load) is relatively large to eliminate most of the macroscopic deformation; subsequent progressive corrections are used to compensate for the previous round of correction. For example, the compression amount applied in the first round of cold working correction is about 60%-80% of the peak deformation height, the compression amount in the second round of cold working correction is adjusted to 40%-60% of the remaining deviation value, and so on. By using a step-decreasing correction amount, the reverse bulging of the aluminum plate caused by a single overcorrection can be effectively avoided, while the residual stress is more fully released through multiple micro-plastic deformations, thereby obtaining a more stable flatness restoration effect.

[0070] Implementation Method Seven

[0071] As one optional implementation, the preset flatness requirement is determined based on the flatness quality requirements of the aluminum panel product. In step S6, when the retest result shows that the aluminum panel meets the preset flatness requirement, the progressive correction ends; when the retest result shows that the preset flatness requirement is still not met, subsequent progressive corrections continue. Thus, the present invention forms a closed loop of post-weld progressive correction based on the flatness test result: "detection—correction—retest—recorrection".

[0072] Implementation Method Eight

[0073] In one preferred embodiment, the cold work straightening equipment is selected from one or more of the following: a roll straightening machine that uses a servo motor to control the pressure rollers, a hammer straightening machine that uses hydraulic or compressed air to drive the hammers, and a pressure point straightening machine that uses a servo motor to control the pressure bar. The cold work straightening equipment integrates force sensors and displacement sensors to perform real-time force-displacement monitoring during the straightening process, thereby achieving real-time adaptive straightening.

[0074] Specifically, pressure and displacement sensors are installed on the calibration head of the calibration machine to collect calibration force F(t) and displacement S(t) data in real time. During each calibration cycle, the system plots a force-displacement curve in real time and compares it with a preset reference curve. When the slope of the force-displacement curve changes abruptly or enters a plateau region, it indicates that the aluminum panel has locally entered the plastic yielding stage. At this point, the system automatically determines that the calibration at the current point is sufficient and prompts the operator to move to the next calibration point or stop the current calibration cycle.

[0075] Real-time monitoring avoids material damage or reverse deformation caused by excessive pressure on the same calibration point, while significantly shortening the offline waiting time for calibration and retesting, thus improving calibration efficiency. It is especially suitable for mass production scenarios involving post-weld straightening of aluminum panels.

[0076] Implementation Method Nine

[0077] The present invention will be further illustrated by a set of specific embodiments below.

[0078] Example 1

[0079] A 3003 aluminum alloy panel measuring 1200mm × 800mm × 2.5mm was used, and four corner brackets (made of the same material as the aluminum panel and welded using argon arc welding) were welded to its back. After welding, a laser flatness tester was used to scan and inspect the front of the aluminum panel. The results showed that the deformation area was concentrated in the area corresponding to the welding position of the corner brackets, with a maximum flatness deviation of 3.2mm (bulging deformation).

[0080] Based on the location of the deformation area, the area on the back of the corner code is determined as the main correction area (approximately 150mm × 100mm), and the area extending 30mm outward from the main correction area is determined as the transition correction area.

[0081] First round of correction: The main correction area is cold-worked by rolling from the back. The rolling pressure is 120 N / cm, and the pressing displacement is set to 65% of the peak deformation height (about 2.1 mm). At the same time, the transition correction area is corrected with a linear pressure of 60 N / cm.

[0082] Retest: After the first round of calibration, laser flatness testing was performed again. The maximum flatness deviation was reduced to 1.0 mm, and the deviation of the center position of the deformation area was significantly improved. However, there was still a local deviation of 0.4 mm at the boundary of the transition calibration area.

[0083] Second round of progressive correction: Based on the retest results, the main correction area has met the flatness requirement (≤1.0mm), while the transition correction area still has local deviations. The correction amount in the second round is adjusted to 50% of the correction amount in the first round. Local pressure point correction is performed on the transition correction area, with a pressure of 40N and a holding time of 3 seconds.

[0084] Retest: After the second round of calibration, the maximum flatness deviation was measured to be reduced to 0.3mm, which meets the preset flatness requirement (≤0.5mm / m²), and the progressive calibration was completed.

[0085] Tests showed that the aluminum panel had no scratches or indentations on the front decorative surface, and the coating was intact.

[0086] Example 2

[0087] A 5052 aluminum alloy single panel with dimensions of 1500mm×1000mm×3.0mm was taken, and two reinforcing ribs (material same as the aluminum single panel, welding method: argon arc welding) were welded to its back. After welding, the flatness was checked by measuring the gap with a straightedge. It was found that there was continuous concave deformation along the welding direction of the reinforcing ribs, with a maximum concave depth of 2.5mm.

[0088] Based on the location of the deformation area, the area on the back side of the reinforcing rib welding line, 40mm on each side, is defined as the main correction area, and the area extending 25mm outward from the main correction area is defined as the transition correction area.

[0089] First round of correction: Hammering and cold working correction is performed on the main correction area from the back. A copper hammer is used, and the energy of a single hammering is controlled within 3J. Correction is performed point by point along the direction of the reinforcing rib, and the amount of pressure is about 60% of the deformation depth (about 1.5mm).

[0090] Retest: After the first round of calibration, the maximum flatness deviation was reduced to 0.9mm, but there was a rebound of 0.3mm in some areas.

[0091] The second round of progressive correction: compensation correction is performed on the rebound area, with the correction amount adjusted to 40% of the first round, and the holding time is appropriately extended to 5 seconds.

[0092] Retest: After the second round of calibration, the maximum flatness deviation was reduced to 0.2mm, which meets the preset flatness requirement (≤0.5mm / m²), and the progressive calibration was completed.

[0093] Testing revealed that the front decorative surface of the aluminum panel was undamaged and the coating was intact.

[0094] Example 3 (Comparison of Decreasing Correction Amounts)

[0095] To verify the effectiveness of the stepwise reduction technique, a control group was set up as follows:

[0096] Aluminum panels of the same specifications as in Example 1 were used, and the same welding process was employed, resulting in a peak deformation height of 3.0 mm. The control group underwent equal-amount correction, with a first-round correction reduction of 1.5 mm and a second-round correction reduction of 1.5 mm. The results showed that after the second round of correction, localized areas exhibited reverse bulging (over-correction), with a final flatness deviation of 0.7 mm.

[0097] By using the step-decreasing correction method of the present invention (the first round of correction is 1.9 mm, and the second round of correction is 0.8 mm), the final flatness deviation is 0.2 mm, with no over-correction phenomenon.

[0098] The above embodiments demonstrate that the present invention, through a method of progressive correction on the back side combined with a step-decreasing correction amount, can effectively restore the flatness of aluminum panels, while protecting the surface quality of the decorative surface and avoiding reverse deformation caused by a single over-correction.

[0099] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described.

Claims

1. A method for correcting heat-affected deformation during welding of aluminum single-layer panels based on back-side progressive correction, characterized in that, Includes the following steps: S1. Perform flatness testing on the decorative surface of aluminum single-panel with welded accessories, obtain flatness deviation distribution data, and identify areas where the flatness deviation exceeds the preset threshold as deformation areas caused by welding heat. S2. Based on the location of the deformation area and the distribution of the deviation peak, determine the area to be corrected on the back of the aluminum single panel. The area to be corrected includes a main correction area corresponding to the deviation peak area, and a transition correction area for stress transition set around the main correction area. S3. From the back of the aluminum panel, use a cold working correction device to perform a first round of cold working correction on the area to be corrected. The first round of cold working correction is preferentially applied to the main correction area. S4. Re-measure the deformed area after the first round of cold working correction to obtain the re-measured flatness data; S5. When the retested flatness data does not meet the preset flatness requirement, the correction amount for the next round of progressive correction is determined based on the difference between the retested flatness data and the preset flatness requirement, and the next round of progressive correction is performed on the area to be corrected from the back of the aluminum panel. Wherein, the correction amount of the next round of progressive correction is less than the correction amount of the previous round of correction, and when the retest result shows that the main correction area does not meet the standard, the next round of progressive correction continues to be implemented for the main correction area; when the main correction area meets the standard but the transition correction area does not meet the standard, the next round of progressive correction is implemented for the transition correction area. S6. Repeat steps S4 and S5 until the flatness of the deformed area reaches the preset flatness requirement.

2. The method for correcting heat-affected deformation during aluminum single-panel welding according to claim 1, characterized in that, The accessories include at least one of corner brackets, reinforcing ribs, and mounting connectors.

3. The method for correcting heat-affected deformation during aluminum panel welding according to claim 1, characterized in that, The flatness detection in step S1 includes one or more methods, such as measuring the gap with a straightedge, comparing with a platform, laser displacement detection, and contour scanning detection, to detect the aluminum panel.

4. The method for correcting heat-affected deformation during aluminum single-panel welding according to claim 1, characterized in that, In step S2, the area to be corrected is determined based on the location of the deformed area and the corresponding flatness deviation value, or based on the location of the welded component and its adjacent heat-affected zone.

5. The method for correcting heat-affected deformation during aluminum panel welding according to claim 1, characterized in that, The correction methods used by the cold working correction equipment include roller correction, hammer correction, pressure point correction, or a combination thereof.

6. The method for correcting heat-affected deformation during aluminum single-panel welding according to claim 5, characterized in that, The cold working straightening equipment is selected from one or more of the following: roller straightening machine, hammer straightening machine, and pressure point straightening machine.

7. The method for correcting heat-affected deformation during aluminum panel welding according to claim 1, characterized in that, The preset flatness requirement is set to a flatness deviation of ≤0.5mm / m².

8. The method for correcting heat-affected deformation during aluminum panel welding according to claim 1, characterized in that, The retest in step S4 is used to determine whether there is insufficient correction or rebound after correction in the deformation area, and serves as the basis for whether to perform the next round of progressive correction and to determine the subsequent correction amount.

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