Water-based Coating Material For EPC Steel Casting And Application

Expandable Pattern Casting（EPC） technology is considered to be the mostpossible green casting technology in2l century.Coating is one of the key technologies,its performance determines the success of EPC process.At present,the domesticresearch on EPC coating is relatively backward, commercialization of the coating isless, and the quality varies greatly.To some extent, this hindered the development andapplication of the EPC technology, therefore, the development of EPC coating whichhas excellent performance, convenient storage and transportation, simple andconvenient use is significance to promote the application of EPC technology.Single refractory aggregate of EPC coating sintering and stripping is poor inproduction. According to the theory of sintering and stripping of coating,throughresearch the affect on flexural strength of different types of sintering aids on the quartzcoatings and bauxite coating to select the optimum sintering additive content ascomposite refractory aggregate. Studies have shown that Ca-bentonite andNa-bentonite has promoted the sintering of the quartz aggregate, but the effect ofCa-bentonite is better than Na-bentonite and Ca-bentonite content4%to meet therequirements of water-based coating material for EPC steel casting. SiO₂also canpromote the sintering of the bauxite refractory aggregate, SiO₂content20%to meetthe requirements of water-based coating material for EPC steel casting.The join ofSiO₂to reduce the temperature of liquid phase formation of bauxite coating,so it canformat appropriate amount liquid phase to make the refractory aggregate as a wholeand to prevent the infiltration of liquid steel.Through the single factor experimental research the affect on flexural strength ofdifferent types and content of binder and the affect on suspension of different typesand content of suspending agent to choose the binder and suspending agent which canmeet the requirements of water-based coating material for EPC steel casting Then useorthogonal method to test the coating suspension, painted hanging, thixotropic index,the flexural strength and permeability at room temperature to determine the best ratioof EPC coating additives which is A₂B₃C₂,Ca-bentonite content1.5%,CMC content1.5%,modified starch content1.2%.The application shows that the developed two kinds of water-based coatingmaterial for EPC steel casting preparation process is simple and convenient, the painting, suspension, permeability and so on of the coating is excellent, coatingstrength, crack resistance, peeling resistance are also well and inexpensively.