If the engine cracks, the fundamental solution to the problem still has to be welding. Using caster glue or similar soft soldering applications to repair cracks in the engine block is an indicator but does not cure the root cause and cannot solve the fundamental problem. of. If welding is used for crack repair, manual electric welding is an ideal welding method. However, if the heat effect of argon arc welding on cast iron is too concentrated, the heat effect will be greater and the tendency of cracks will be greater.
In terms of welding technology, there are two conventional welding processes: hot welding and cold welding. For hot welding, it is generally difficult to have hot welding conditions on site. Therefore, cold welding is often used at emergency repair sites. Cold welding is the most common welding process. The crack resistance of cast iron electrodes and the control of the welding process are particularly important. Extended information
Causes for leakage:
1. Due to the looseness, adhesion and floating sand in the sand core/sand mold, the paint ball has not been cleaned, and the sand core flash has not been cleaned, etc. The reason is that during the pouring process, due to the baking and erosion of high-temperature molten iron, the sand particles fall off, move with the molten iron, and eventually gather in a certain part of the casting, forming sand inclusions that penetrate the inner and outer walls, causing leakage.
2. During the sand core assembly process, sand particles fall into the mold cavity or the assembled sand mold is contaminated twice before pouring, eventually causing sand inclusions and leakage.
The reasons for leakage caused by slag inclusion defects: the molten iron was poured without sufficient slag removal, the molten iron was impure, and the ladle, sprue cup, and pouring system had poor slag-avoiding effects, which ultimately resulted in molten slag. The molten iron enters the mold cavity and adheres to the surface of the mold cavity, forming penetrating slag holes, eventually leading to leakage.
Leakage caused by shrinkage porosity: The occurrence of shrinkage porosity is closely related to the shrinkage of castings. Shrinkage porosity defects generally occur in thick and large hot spots of castings, with irregular regional distribution in shape. The tissue in the pine area is coarse and has dendritic crystal structure characteristics. In the shrinkage area, scattered hole structures can be clearly seen under an electron microscope, and serious holes are visible to the naked eye. Since there is a dendritic structure in the shrinkage area, it can be used as a criterion for defect determination.