The welding forming process is a systematic process that transforms dispersed metal components into a reliable connected body with overall mechanical properties through the action of heat, pressure, or a combination of both.Its essence lies in altering the material state through external fields, promoting stable interatomic bonding, and then solidifying and shaping it during subsequent cooling or pressurization. The quality of this process directly determines the strength, density, and service life of the welded component; therefore, the design and manufacturing must adhere to material properties and metallurgical principles, implementing precise control throughout the entire process.
The first step in the forming process is determining the joint type and bevel design. Based on the component thickness, stress state, and weldability, butt joints, corner joints, T-joints, and lap joints are commonly selected, matched with V-grooves, U-grooves, double V-grooves, or single-sided bevels to ensure penetration and uniform stress distribution. Thick plate structures often employ multi-layer, multi-pass welding, which allows for balanced heat input during layer-by-layer accumulation, reducing the risk of deformation and cracking caused by uneven shrinkage.
The selection of welding energy and parameter settings are the core of forming quality. Arc welding, with its stable and controllable heat source, is widely used in steel structures. Manual arc welding offers high flexibility and is suitable for on-site maintenance. Submerged arc welding (SAW) provides concentrated heat and deep penetration, facilitating the automated and efficient production of thick-walled components. Gas-shielded welding (such as MIG/MAG and TIG) significantly reduces oxide inclusions and improves weld purity, and is commonly used for atmosphere-sensitive materials such as aluminum and stainless steel. For lightweight or dissimilar metals, resistance welding and friction welding can achieve rapid connection in the solid state, avoiding microstructural changes caused by melting. Brazing utilizes low-melting-point filler metal to fill gaps, wetting the base material through capillary action to achieve reliable sealing of precision parts or complex cavities.
The thermal cycle and sequence arrangement during the forming process are crucial. A reasonable welding sequence should be adopted, such as symmetrical welding or segmented back-welding, to counteract deformation caused by uneven thermal expansion and contraction. For frame components with insufficient rigidity, pre-set anti-deformation or additional clamping constraints can be used. Multi-layer welding requires control of interpass temperature to prevent overheating that could lead to grain coarsening or increased cold cracking tendency. Thick plates or high-strength steel components often undergo stress-relieving annealing or localized heat treatment after welding to improve joint toughness and dimensional stability.
After forming, weld slag and spatter must be removed, and dimensions must be adjusted. If necessary, machining or straightening may be used to restore accuracy. Quality inspection is ongoing throughout the process, including pre-weld material verification, in-weld parameter monitoring, and post-weld non-destructive testing to ensure that internal defects and forming deviations are effectively controlled.
The forming process of welded components is an organic integration of thermal energy, materials, and craftsmanship. Only by striving for excellence in joint design, energy selection, process control, and post-processing can high-quality components with consistent performance, reliability, and durability be obtained, providing a solid connection foundation for modern industrial equipment.