Sand casting, as a long-standing metal forming technology, is widely used in mechanical manufacturing, automotive, aerospace, and other heavy industry fields due to its low cost and high adaptability to complex shaped castings. Although this technology has many advantages, it still faces a series of challenges in manufacturing complex structural components, especially how to effectively control casting quality and optimize casting processes. In recent years, sand casting with the rapid development of computer-aided engineering technology, especially the application of casting process simulation software, new development opportunities have been brought to the sand casting process design of complex structural components.
The use of furan resin self hardening sand helps to reduce surface defects in castings and enhance the overall structural density of castings. In the process of casting design, the selection of dimensional tolerances directly affects the functionality of the casting and the complexity of subsequent processing. The commonly used dimensional tolerance level is CT11, sand casting which takes into account the free shrinkage characteristics of the casting during cooling. The quality tolerance level is set to MT10 to ensure consistency in the weight and volume of castings. The tolerance range is usually set to ± 4% of the casting weight to accommodate small changes in production. Considering the physical properties of HT250, the shrinkage rate should be preset at 0.9%, which reflects the reduction in material volume during the transition from liquid to solid state. sand casting Reasonably setting the shrinkage rate is crucial to avoid cracking or deformation of castings during cooling.
In the sand casting process of complex structural components, the selection of pouring position and the determination of parting surface are key factors, which affect the crystallization quality and manufacturing efficiency of the castings. When setting the pouring direction with the dovetail guide sliding surface facing downwards and the large plane facing upwards, this layout is conducive to utilizing gravity to promote the flow of molten metal in the mold, which helps to fill complex and slender geometric shapes, and also effectively avoids bubbles and slag inclusion defects during the filling process, thereby improving the quality of crystallization. In the sand casting process design of complex structural components,sand casting the design of the pouring system is a key link to ensure the quality of the castings and reduce defects, involving the position and form of the internal sprue and the reasonable placement of the sprue and riser. The internal pouring channel is usually designed in a stepped inclined pouring form. This method effectively manages the flow and temperature distribution during the filling process by controlling the entry method and speed of the metal liquid, sand casting which helps to evenly fill and reduce sand mold damage and pore formation caused by liquid flow impact. The stepped design allows the liquid metal to gradually fill various parts of the mold cavity, optimizing the filling sequence from bottom to top and preventing premature solidification and thermal cracking. The setting of the sprue is to capture the slag and gas that may float up during the pouring process, while providing sufficient metal liquid supply to the casting to avoid internal defects caused by cooling shrinkage of the metal liquid. Risers are usually located at the top of castings or above important structures, allowing for continuous supply of hot metal during solidification, sand casting ensuring the integrity and performance of critical areas.
In the design of sand casting process for complex structural components, numerical simulation and optimization are key technical links to improve casting quality and process efficiency, among which preliminary simulation analysis using Anycasting software plays a core role. By simulating the filling process, the software can display in detail the flow path, velocity, and temperature distribution of the molten metal in the mold, thereby identifying possible eddies, bubble generation, and cold zones, which are key factors affecting the quality of castings. sand casting The simulation of the solidification process provides information about the temperature field and solidification of the casting during the cooling stage The important data of transformation rate helps engineers observe and predict the development of thermal stress and shrinkage tendency inside castings, which is crucial for optimizing the structural strength of castings and reducing subsequent processing. Firstly, adjusting the pouring system usually involves redesigning the position and shape of the inner runner to improve the flow of molten metal in the mold and avoid Prevent bubbles and slag inclusions caused by excessive speed, while ensuring that each part of the casting can be evenly filled. Through simulation analysis, engineers can accurately identify which areas perform poorly during filling or solidification processes, and adjust the gating system accordingly to achieve optimal metal flow and reduce casting defects. Secondly, adding a riser is to capture the floating slag and gas during the pouring process, while providing additional metal liquid to compensate for solidification shrinkage. This measure is particularly important for large or thick walled castings, as these areas are more prone to shrinkage and porosity defects. The optimization of the configuration and size of the riser ensures sufficient replenishment of molten metal during solidification of the casting, thereby avoiding the occurrence of internal defects. Thirdly, sand casting the use of cold iron is to control the cooling rate of specific parts of the casting, refine the microstructure through local accelerated cooling, and enhance the mechanical properties of the casting. Placing cold iron in areas of thick castings or complex structures can effectively guide heat distribution, accelerate the solidification process in these areas, and help reduce internal stress and hot cracking caused by uneven cooling. Fourthly, optimizing the solidification sequence of castings is achieved by adjusting the entire casting system, such as pouring temperature, pouring speed, and cooling environment control,sand casting to ensure that key structural parts in the castings solidify first, thereby improving the structural integrity and performance of the entire casting.
By combining modern numerical simulation techniques to optimize traditional casting processes,sand casting the casting quality and process efficiency of complex structural components can be effectively improved, which also has a positive impact on the technological progress and sustainable development of the casting industry.