The deformation-resistant design of the support plate welding table is a core element in ensuring welding quality and improving structural stability. Key process factors require comprehensive consideration from multiple dimensions, including material properties, structural layout, welding process, thermal management, clamping methods, residual stress control, and dynamic compensation.
Material properties are the foundation of the deformation-resistant design. The coefficients of thermal expansion, yield strength, and thermal conductivity of the support plate and the base material of the support plate welding table directly affect the thermal deformation behavior during welding. If the difference in the coefficients of thermal expansion is too large, uneven heating during welding can easily lead to stress concentration, causing the support plate to bend or the support plate welding table to deform. Therefore, it is necessary to prioritize the selection of material combinations with matching coefficients of thermal expansion, or to adjust the initial stress state of the materials through pre-stretching, pre-compression, or other pretreatment processes. Simultaneously, the yield strength of the material must meet the load-bearing requirements under welding thermal cycles to avoid plastic deformation due to insufficient strength. Furthermore, materials with high thermal conductivity can accelerate heat diffusion, reduce local temperature gradients, and thus lower the risk of thermal deformation.
The rationality of the structural layout is crucial to the deformation-resistant effect. Support plate welding tables should employ a symmetrical or box-type structure, increasing the number and thickness of stiffeners to enhance overall rigidity. For example, reinforcing ribs at the connection between the support plate and the substrate can effectively disperse welding stress and reduce localized deformation. Simultaneously, the design of the support plate welding table should avoid sharp corners or thin-walled structures, as these areas are prone to cracking or deformation due to stress concentration. Furthermore, the layout of the support plates must consider the impact of the welding sequence on deformation; for example, using symmetrical welding or segmented back-welding processes can balance heat input and avoid unidirectional cumulative deformation.
Optimizing welding process parameters is a direct means of controlling thermal deformation. Parameters such as welding current, voltage, speed, and weld size must be precisely matched according to the material thickness and structural characteristics. Excessive welding heat input can lead to excessively high local temperatures, causing expansion differences between the support plate and the support plate welding table, resulting in deformation; while insufficient heat input may lead to defects such as incomplete fusion or porosity, indirectly affecting structural strength. Therefore, it is necessary to determine the optimal parameter range through process experiments and employ pulse welding or multi-layer multi-pass welding processes during welding to reduce heat concentration. Furthermore, the weld shape design must also consider stress distribution. For example, using a U-groove instead of a V-groove can reduce stress concentration at the weld root.
Thermal management measures are a crucial supplement to deformation prevention design. During welding, localized high temperatures can cause uneven expansion between the support plate and the welding table. Therefore, forced cooling or preheating processes are necessary to balance the temperature field. For instance, installing cooling water channels inside the support plate welding table, using circulating water to remove excess heat, can significantly reduce thermal deformation. For thick plate welding, preheating can reduce temperature gradients and prevent excessive shrinkage stress caused by rapid cooling. In addition, temperature control of the welding environment is also important to avoid material shrinkage differences caused by ambient temperature fluctuations.
The clamping method design directly affects stress distribution during welding. The fixture must provide sufficient clamping force to secure the support plate, but excessive clamping force can lead to localized plastic deformation of the material, especially in thin-plate structures. Therefore, the fixture should employ flexible clamping or segmented clamping designs, reducing localized stress concentration by evenly distributing clamping points. Meanwhile, the positioning elements of the fixture must possess high precision and rigidity to prevent welding misalignment due to positioning deviations, which could lead to additional stress.
Controlling residual stress is crucial for long-term deformation prevention design. After welding, tensile or compressive stresses remain within the material. Failure to release these stresses promptly can cause creep or fatigue cracking during use. Therefore, residual stresses must be eliminated through post-weld heat treatment (such as annealing or vibration aging), or by locally adjusting the stress state using mechanical stretching or hammering. Furthermore, the design of the support plate welding table must allow for stress release space to prevent stress from failing to diffuse due to structural constraints.
Dynamic compensation technology is an innovative approach to address complex deformations. For high-precision welding requirements, sensors and actuators can be integrated into the support plate welding table to monitor deformation in real time and automatically adjust clamping force or cooling parameters. For example, using a laser displacement sensor to monitor the real-time displacement of the support plate and dynamically adjusting the fixture position via a servo motor can achieve closed-loop control of deformation. Additionally, numerical simulation technology can be used to predict welding deformation trends, providing data support for deformation prevention design.
