How to repair defects in mold castings

Traditional electric discharge welding repair machine   

The traditional electric discharge welding repair machine adopts the principle of instantaneous high-frequency discharge of sparks, which instantly applies nickel based welding materials or specialized welding materials in ion state to the surface of the workpiece, so that the welding materials and workpiece are fused into one through metallurgical means. The surface of the workpiece generates minimal heat throughout the entire welding process. The traditional electric discharge welding repair machine welding gun uses a rotating electrode, and the diameter of the welding wire ranges from 1.6-3.0mm. Suitable for repairing casting defects. Moreover, traditional electric discharge welding repair machines can achieve surface coating strengthening in terms of power and discharge frequency settings. Can repair various metals such as steel, copper, aluminum, etc.     

Advantages: Traditional electric discharge welding repair machines are easy to install, simple to operate, and can be operated by general personnel with a little training. The welding repair strength is high, and there is no annealing, cracking, deformation, or internal stress generation in the welding repair area. There will be no hard spots at the welding points, and the repair speed is relatively fast compared to the surface mount machine. The repair accuracy is relatively high, and it can pass X-ray inspection, penetration testing, tensile testing, and other tests. It has been accepted and used by numerous casting manufacturers. In addition, it also has some practical value in mold repair.     

Disadvantages: Traditional electric discharge welding repair machines are slow, and 2mm cast iron takes about 3 minutes. Corresponding to the shortage of welding materials, cast iron parts can only be repaired with nickel based welding materials (around 300/kg), which have high welding costs, and the utilization rate of welding materials can only reach 80%. Compared to argon arc welding, the color difference is relatively large and the bonding strength is low. Due to its principle of high-frequency discharge, which is achieved by particle welding, the bonding strength is relatively low, resulting in poor density of non-ferrous metal pig iron parts. The smoothness is not high, and it cannot meet the requirements for castings with high smoothness. Furthermore, due to the design principle of traditional cold welding machines, the power is generally around 2000W, and the internal electronic components are exposed. In the environment of the casting workshop, the machine often malfunctions, especially the electrode gun (which is easily damaged due to the separation of gas and electricity), which wastes energy and is not suitable for the large-scale repair requirements of foundries.