Research And Development Of Exothermic Insulating Riser Sleeve For Casting

With the development of foundry technique and the continuous enhancement of quality requirements for castings, the traditional sand riser,insulating riser sleeve and exothermic riser sleeve have their own shortcomings such as the inadequacy of heat preservation or give out heat, even act on a single role. They are unable to meet the feeding requirements of castings.Therefore, research and development of both heating and insulation dual role of the exothermic/insulating riser sleeve more and more are attented by foundry workers.In this paper,based on a lot of reading references and analysis the main component of the commercialization of exothermic/insulating riser sleeve developed by Foseco.Aluminum and iron oxide powder were chosen as the main heating materials, carbon materials as the supplement heating materials,sylvite as the oxidant, perlite as insulation materials,water glass as binder, clay and sodium aluminum fluoride included also.The exothermic/insulating riser sleeve has been made.In the testing process, three sorts of commonly used sylvite oxidizers(A,B and C) were selected and the influence of the sylvite oxidizers on properties of exothermic/insulating riser sleeve was investigated. The basic components of exothermic/insulating riser sleeve were determined, and a ratio of the components was optimized,such as:cenosphere 40%,aluminum 17%,8% iron oxide,sylvite A6%,B4% and C1%,Na3AlF64%,graphite 15% and 5% clay. At the same time lab successfully for exothermic/insulating riser sleeve molding tests.A contrast test was researched between self-riser sleeve and Foseco riser sleeve in school casting workshop.The results showed that the same experimental conditions, molten steel temperature in self-made riser sleeve have an average high temperature 30-50℃than that in Foseco riser sleeve at the same time.It indicated that the exothermic/insulating performance of self-made riser sleeve is better than Foseco commercial riser sleeve. Materials which are used to manufacturing exothermic/insulating riser sleeve are very rich and low prices, and produce process is relatively simple, excellent performance, broad application prospects.