Based on the thermal field analysis of the specific internal energy distribution during casting and solidification, Determine benign heat field, bad heat field and homogenization degree of process heat element, bad heat element and heat field under various process conditions, analyze the main causes of casting defects, and adopt corresponding process measures to eliminate the influence on heat field distribution and obtain sound castings. Through machining bushing the analysis of three casting examples, the practical application of the thermal field analysis method is illustrated. However, the thermal field analysis method of casting process depends on fluid mechanics knowledge and rich casting experience.
At present, only qualitative analysis can be carried out, but quantitative analysis cannot be carried out or computer CAD can be realized. During the period from the time when all the molten metal is poured into the cavity to the time when the molten metal solidifies, the specific internal energy (energy J/kg per particle) distribution of the molten metal (including castings and gating systems) in the cavity with temperature as the surface symptom is the thermal field. In the traditional casting process theory, the material enrichment part in the casting geometric structure, that is, the part with large geometric section, is determined as the hot section, and the hot section is included in the process control focus.
These are all based on the fact that the temperature of the molten metal in the mold cavity is the same at the moment when the molten metal is poured. Then, according to the condition of uniform heat dissipation, the part with the smallest unit specific surface area, that is, the part with the slowest decrease in internal energy, is the final solidification part, that is, the part where the general hot spot is located. However, when the casting process is arranged by using the distribution of casting hot joints, process defects often occur in production practice, that is to say, defects caused by local overheating and overheating of castings do not necessarily appear at geometric hot joints. Therefore, the concept of thermal field is introduced. After pouring the mold,
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