Study on the Coating Technology for the Evaporative Pattern Casting Process

摘要

The Evaporative Pattern Casting(EPC) process is a special casting process, The use of coating has a significant impact on the casting quality. So, mastering the coating composition and properties to obtain high quality castings is a question worth to explore. Various self-designed coatings are employed to investigate the effect of different coating composition on coating property including permeability, adhesive property, room temperature, high temperature crack properly, etc. Then, optimum parameters combination among different properties will be figured out to establish better coating manufacturing technology for the EPC process. The experimental results indicate that Type II coating has excellent room temperature permeability but worst adhesive property and crack property. The room temperature permeability of Type I coating is better than Type III but worse than Type II, but have excellent adhesive property and crack property. In order to balance among the previous three properties, the basic Type II coating composition (refractory A) is used as the standard, then the refractory B was added and regard as the various type coatings. The effect of various type coating composition on the coating properties were investigated. The results of different composition of coating indicated that increasing the quantity of refractory A will cause the permeability declined slightly. The adhesive property will be increased and the crack resistance decreased gradually. Based on this research, the various Type VI coating is the most suitable one for the EPC process. The permeability of Type VI is as high as 2.6(expected value >0.5). In the adhesive property and crack resistance, Type VI are the runner-up in all tested coatings.