In the practical application ofat home and abroad, ferroalloy is the most widely used metal material with the largest production. Compared with Zhaozhao (magnesium) alloy lost foam casting, the technology and materials are relatively mature, but compared with ordinary (cavity) technology, the grain structure of ferroalloy parts made by lost foam casting is relatively large and the performance is low Straight did not get a good solution. With the development of mechanical manufacturing technology, higher requirements are put forward for the properties of lost foam casting cast iron alloy parts. The problems of coarse grain structure and low properties of lost foam casting cast iron alloy parts are solved, and further improving the quality and properties of EPC become one of the hot spots of lost foam casting technology research. At present, the main problems of EPC cast iron alloy are as follows:
1) In lost foam, dry sand is used for molding, the cooling rate of dry sand is slow, and the cooling rate of cast iron alloy is low, which results in the coarse structure and low mechanical properties of the final cast iron alloy. Refining the structure and improving the mechanical properties of lost foam cast iron alloy is one of the key problems to be solved.
2) The quality of cast iron alloy lost foam casting is affected by many factors. For example, the composition of the alloy, the technology of inoculation and modification, the temperature of molten iron treatment and other technological factors will have an important impact on the quality of the parts. How to optimize the EPC process and improve the quality of iron alloy EPC parts is another key problem to be solved.
3) in the process of lost foam casting, the non bonded dry sand is used for vibration modeling. In the process of casting, negative pressure is used to mould the mold, and the stability of the prayer type is maintained by the pressure difference method. In the process of molten iron passing into the prayer type, the high temperature liquid metal heat is injected to make the foam plastic vaporized and form a cavity in the model. At this time, if the speed of round injection, the rising speed of liquid metal, the exhaust speed, and the matching of the air pressure in the model can not meet the requirements of finalization during the round injection process, there will be some problems, such as missing type, tank collapse and so on.
Based on the above, there are some problems in lost foam casting cast iron alloy, such as coarse structure, low mechanical properties, etc.