Development Of The Fly Ash Mould Coating For The Cast Iron

Born-on was a frequently defect in sand mould foundry.And the bom-on could not only reduce the surface quality of casting,but also increase the cleaning work and influence on producing efficiency seriously.By contrasting different methods for preventing the born-on of the casting,the casting coating was the most effective method in order to prevent the born-on of the casting.The fly ash coating was prepared which was composed of refractory fillers(fly ash and high aluminous powder),carrier liquids(alcohol),suspension agents,binding agents and other additives.In order to prepare the coating,the preparing process of mixing round and rubbing was used.The main capabilities of fly ash coating which consisted of density,viscosity,suspension property and crack resistance in the high temperature could be examined.By the experiment of single factor including organobentonite,Li-bentonite,CMC and phenolic resin,the effect on capabilities could be researched.By right-angle test to optimize the formulas,the fly ash coating which all of indexes were choiceness could be prepared.In practical production of iron cast,the coating could improve the surface quality of casting and achieve the comprehensive utilization of fly ash.The results of the studies could be stated as follows:(1) The fly ash mould coating for the cast iron had favorable capabilities.(2) Organobentonite and Li-bentonite could improve suspension property of the coating significantly.With the increase of organobentonite and Li-bentonite,suspension property was improved,and viscosity was advanced,but the crack resistance of the coating was reduced.Therefore,bentonite should be confined from 1%to 3%for the coating.(3) With the increase of CMC,suspension property was improved,and viscosity was advanced.And the crack resistance of the coating was betweenâ… andâ…¡.When the addition of CMC was confined from 0.4%to 0.5%,capabilities could satisfy the demand of the coating. (4) The effect of phenolic resin on suspension property was not obvious.With the increase of phenolic resin,the crack resistance of the coating was reduced.The phenolic resin should be confined from 1.5%to 3%for the fly ash mold coating.