INVESTIGATION OF SHRINKAGE RELATED LEAKAGE IN CI SAND CASTING - STUDY AND CONTROL USING SIMULATION AND EXPERIMENTAL VALIDATION

摘要

The purpose of this study is to investigate various parameters causing shrinkage and leakage in heavy castings like engine cylinder heads. Due to intricate shape and extreme functional requirements, engine cylinder heads and blocks are made through casting and need to be free from shrinkage and leakage defects to avoid seizures. However, green sand casting is prone to defects, namely, shrinkage porosity, cold shuts, and sand inclusion. Therefore, balancing needs to be done in related casting parameters like gating and feeding system, chemical composition, part geometry, pouring temperatures, etc. In the current research, an optimization of gating and feeding parameters was made to control the shrinkage and leakage in the casting. Consequently, further the effect of input parameters on defects was also studied. On the basis of Pareto analysis of existing defects, experiments were planned for parameters like size and location of feeders, casting modulus, and venting area. A total of 7 experiments were done and the results were simulated through MAGMAS software to modify the casting and feeder modulus, venting area and localized chill application. The experimental validation was done over a batch of 1100 castings in a foundry. It was observed from the experimental results that the leakage cases are reduced from 5.5% to 0.7%, with a savings of 20,000 USD over a span of 4 months. Implication of this study involves identification and optimization of critical parameters like feeder modulus, venting area, and casting geometry for different models of cylinder heads.