Methods for repairing casting defects

Find ways to solve the defects during casting. Many repair methods have been adopted.
1、 Foundry adhesive: A simple and rough casting that generally does not require subsequent processing for repair and does not have special strength and hardness requirements. This type of casting has relatively low added value.
2、 Welding repair: More than 90% of casting manufacturers choose welding repair to solve casting defects encountered in production. Due to the use of metal fillers, the performance of welding repair can basically meet the standards of the base material, and the operation is simple with high welding efficiency, which has been recognized and trusted by many manufacturers. At present, there are many types of welding machines in the market, which are generally used for defect repair, including the following:
Welding machine: a traditional method commonly used for welding and repairing cast iron and steel parts. 
Advantages: Repairing major defects with high efficiency. 
Disadvantages: After welding, the hardness of the solder joint is too high, there is internal stress, and it is easy to produce cracks. Generally, annealing heat treatment is also required to meet the processing requirements. And due to welding conditions limitations, secondary defects such as porosity and slag inclusion are prone to occur inside
Argon arc welding: Precision castings and aluminum alloy die castings are often repaired using argon arc welding machines. Some mold manufacturing and repair manufacturers also use this welding machine to repair mold defects.
1. Advantages: High welding repair efficiency and higher precision compared to electric welding machines. There are many types of welding wires, with stainless steel and aluminum alloy products being the most widely used. Can be used for welding, with high strength.
2. Disadvantage: Used for defect repair. When repairing small defects, there may be traces on the edge of the melt pool due to excessive impact. The welded steel parts have hard spots. Due to thermal effects, thermal deformation is prone to occur when welding colored castings or thin-walled parts. The operational technical requirements are relatively high.
3、 Cold welding machine: It is a newly emerged repair technology in the early 21st century. Due to the minimal heat generated by the workpiece during the welding process, it is known as a cold welding machine. After several years of development, the application direction and technology of welding machines have made great progress and have already occupied a large share in the repair market. According to the classification of repair products, there are surface mount machines and electric discharge welding repair machines. 
SMT machine: It uses the principle of instantaneous high-frequency discharge to paste the solder pad onto the surface of the workpiece. The maximum thickness of each paste is equivalent to the thickness of the solder pad, and the welding quality depends on whether the discharge is uniform. Suitable for repairing workpiece wear and processing deviations, it has a certain influence in the mold market. This machine can also fill welding powder into the defect area and repair it after discharge. The repaired workpiece has a small color difference. The disadvantage is that the repair speed is slow. The common disadvantage of cold welding machines is that their welding repair efficiency is not as high as that of electric welding machines and argon arc welding machines. However, when repairing millimeter level defects and machined surface defects, their outstanding advantages make people more inclined to choose cold welding