How to reduce the loss of defects in ductile iron castings
During the production process of ductile iron castings, due to various factors, defects such as pores, pinholes, slag inclusions, cracks, and pits often occur.
At this time, in order to make cast iron castings meet the use standards and reduce loss and waste, defects are often repaired. Commonly used repair equipment is argon arc welding machine, resistance welding machine, cold welding machine, etc. Casting defects that do not require high quality and appearance can be repaired by high-heat and fast welding machines such as argon arc welding machines. However, in the field of repairing defects in precision castings, due to the large heat impact of argon welding, casting deformation, hardness reduction, blisters, local annealing, cracking, pinholes, wear, scratches, undercuts, or insufficient bonding force and internal defects will occur during repairing. Secondary defects such as stress damage. The cold welding machine just overcomes the above shortcomings. Its advantages are mainly reflected in the small heat-affected area, the casting does not need to be preheated, and the cold welding repair at room temperature, so there is no deformation, undercut and residual stress, no local annealing, and no change in the metal of the casting. organization status.
Therefore, the cold welding machine is suitable for repairing surface defects of precision castings. The welding repair range of cold welding is the process of repeated melting and accumulation of Φ1.5-Φ1.2mm welding repair points. In the process of repairing large-area defects, the repair efficiency is the only factor restricting its wide application. For large defects, the combined application of traditional welding repair technology and casting defect repairing machine is recommended. When choosing a cold welding machine, it is also necessary to choose equipment with the advantages of simple operation, high welding repair efficiency, high post-weld strength, post-weld shot blasting, and no falling off during machining. Choose such a cold welding machine, after welding, repairing and grinding, no traces of repair can be seen.