The sand mold Dalian casting is completed in two fixed modules. First, place the product model into a module, cover it with sand, and then overlap another wooden frame together. It also needs to be covered with sand and compacted. Then open the overlapping mold frame and take out the model, forming a column mold in the column sand, overlapping the wood ore again, pouring the metal solution into the column mold through the pouring port, and opening the heat dissipation hole in the column mold. The production cost of sand mold casting is relatively low, and large parts can be produced in small batches, but the casting accuracy is low. Products such as engine cylinder blocks and valves can be cast through sand mold casting.
The allowable deviation of the size and net weight of the casting, as well as the remaining processing quantity of the casting, shall be determined according to the specifications of GB6414-86GB/T11351-89GB/T11350-89 and the ordering technical standards. The specific deviation shall be based on the data information of the technical inspection unit. To be frank, casting size manipulation is the manipulation of the dispersion of the average error under the premise that the evaluation of the average value and the casting size meet the premise. These discrete variables are usually caused by arbitrary changes or system errors (such as production process standards and raw material characteristics).
The role of cold iron in Dalian castings:
1. Reduce the size of the riser and improve the production rate of the process.
2. In areas where it is difficult to set a riser in the casting, placing cold iron can prevent shrinkage and porosity.
3. Using cold iron in local areas can control the sequential solidification of castings and increase the feeding distance of the riser.
4. Eliminate local thermal stress and prevent cracks.
Casting light alloys will be more widely used in aviation, aerospace, automotive, mechanical, and other industries due to their low density, high specific strength, and a series of excellent properties, such as corrosion resistance. Especially in the automotive industry, in order to reduce fuel consumption and improve energy efficiency, aluminum has been used as a substitute for steel in nickel alloy castings. Iron castings are a long-term development trend. Among them, the focus is on handling pollution-free, efficient, simple and concise technologies, modification techniques, crystal refinement techniques, and rapid detection techniques in front of the furnace.
For castings that are prone to deformation and fracture, the thin-walled parts of the castings need to be evenly arranged in the internal flow channels, while reducing the mechanical obstacles caused by the flow channels to the castings. Due to the high shrinkage rate of cast steel, it is more prone to defects such as shrinkage cavities, shrinkage porosity, deformation, and cracks. In cases where there is a significant difference in casting thickness and wall thickness, it is necessary to use the directional solidification principle to establish a pouring and riser system during the casting process. Liquid flows into the mold cavity through the riser to enhance the capacity of the feed riser.
