Study On The Sintering Mechanism Of Refractory Aggregate Of The Coating Of Evaporated Pattern Casting (EPC) In Cast Steel

Coating as one of the key technologies of the evaporated pattern casting (EPC)，plays a vital role in the success of EPC. Quartz powder as the single refractoryaggregate for EPC coating in steel casting has a high melting point, a wide source andcheap advantage, but the sintering of the coating is not good, casting sticky powderdefects are often happened, poor stripping, low quality of the casting surface, sandremoving is difficult. By joining the sintering additives or other refractory aggregate toimprove the sintering of quartz powder as a single refractory aggregate, and to studythe mechanism of sintering to theoretical guidance for the configuration of the EPCcast steel coating.In this paper, to join the bauxite and quartz powder to form a composite refractoryaggregate, anorthite and dust as sintering additives to improve the sintering of quartzpowder.First of all, according to the ratio of the test required for the preparation of therefractory aggregate, sintered at different temperatures, research the influence ofdifferent content of bauxite, anorthite and dust to quartz powder sintering, andultimately determine the most reasonable ratio.Secondly, the most reasonable proportion of the aggregate was sintered constantlyat the1400℃and1500℃, to study the sintering mechanism, And the sintered samplesby a scanning electron microscope (SEM) analysis, the conclusions are as follows：1. Quartz powder content of40%, bauxite content of60%, the sintering ofcomposite refractory aggregate was well, meet the requirement of refractoriness, meetthe requirements of the refractory aggregate of the coating of EPC in cast steel;2. Anorthite as sintering additives, the content of30%, the sintering of refractoryaggregate was best, meet the requirements of the refractory aggregate of the coating ofEPC in cast steel;3. Dust as sintering additives, the content of4%, good sintering of refractoryaggregate, meet the requirements of the refractory aggregate of the coating of EPC incast steel;4. Other refractory aggregate and sintering additives added, to promote liquidsintering of quartz powder, but had no effect on the solid sintering;5. For solid sintering, extending the sintering time can not achieve the sinteringeffect; for liquid sintering, the extension of sintering time can be further deepened the sintering;6. During the sintering process, liquid sintering contributed to the entire sinteringprocess was much larger than the solid sintering.Lastly, the most reasonable ratio of aggregate and then add the other suspendingagent, binder and additives, and the on-site pouring test was done in one aluminumfactory, the coating easily stripped from the casting surface, meet the requirements ofthe refractory aggregate of the coating of EPC in cast steel.