During the production of castings, defects such as gas porosity, pinholes, slag inclusions, cracks and pits frequently occur due to the influence of various factors. To bring castings up to operational standards and minimize loss and waste, defect repair is typically performed.

Common repair equipment includes argon arc welders, resistance welders, cold welders and so on. For casting defects with low requirements for quality and appearance, welders with high heat output and high efficiency such as argon arc welders can be used for repair. However, in the field of precision casting defect repair, argon arc welding has a large heat-affected zone, which can cause secondary defects in castings, including deformation, hardness reduction, blowholes, local annealing, cracking, pinholes, wear, scratches, undercutting, insufficient bonding strength and internal stress damage. Cold welders precisely overcome these shortcomings. Their main advantages include a small heat-affected zone, no preheating requirement for castings, and repair at room temperature. As a result, there is no deformation, undercutting or residual stress, no local annealing occurs, and the metallic microstructure of the castings remains unchanged.

Therefore, cold welders are suitable for repairing surface defects of precision castings. Cold welding repair involves repeated melting and deposition at welding spots with a diameter range of Φ1.2mm to Φ1.5mm. In the repair of large-area defects, repair efficiency is the only factor restricting its wide popularization and application. For large defects, the combined application of traditional welding processes and casting defect repair machines is recommended.