Castings Often Have Defects. How To Minimize The Loss?

In the production process of castings, due to the influence of many factors, defects such as pores, pinholes, slag inclusions, cracks and pits often occur.

At this time, in order to make the casting meet the use standard and reduce the loss and waste, defects are often repaired. The commonly used repair equipment is argon arc welding machine, resistance welding machine, cold welding machine, etc. For casting defects with low quality and appearance requirements, argon arc welding machine and other welding machines with high heat generation and high speed can be used to repair. However, in the field of defect repair of precision castings, due to the great influence of argon welding heat, secondary defects such as casting deformation, hardness reduction, sand hole, local annealing, cracking, pinhole, wear, scratch, undercut, or insufficient bonding force and internal stress damage will be caused during repair. The cold welding machine just overcomes the above disadvantages. Its advantages are mainly shown in the small heat affected area, the casting does not need preheating, and the cold welding repair at normal temperature, so there is no deformation, undercut and residual stress, no local annealing, and no change in the metal structure of the casting.

Therefore, the cold welding machine is suitable for repairing surface defects of precision castings. The scope of cold welding repair is: Φ 1.5- Φ In the process of repeated melting and accumulation of 1.2mm weld repair points, the repair efficiency is the only factor restricting its wide application in the process of large-area defect repair. For large defects, the composite application of traditional welding repair process and casting defect repair machine is recommended. When selecting the cold welding machine, it is also necessary to select the equipment with the advantages of simple operation, high welding repair efficiency, high post welding strength, shot blasting after welding, and no falling off during machining. When such a cold welding machine is selected, no repair trace can be seen after welding, repairing and polishing.