Development Of Wear And Corrosion Resistant Scroll Cover For New Type Pulping Machine

Firstly, the wear and corrosion mechanisms of scroll covers are analyzed by scanning electronic microscope (SEM) method in this article. The results show that corrosive abrasion of transporting scroll cover is heavier than that of pulping scroll cover, but high stress grinding abrasion of pulping scroll cover is heavier than that of transporting scroll cover. The main failure form of transporting scroll cover is corrosive abrasion accompanying grinding abrasion. The main failure form of pulping scroll cover is high stress grinding abrasion accompanying corrosive abrasion. By ICP and SEM methods, the microstructure, composition and property of imported scroll cover material are analyzed. The results show that scroll cover material is Co-matrix superalloy, the matrix is Co-austenite, network structure enclosing matrix is Cr-carbide and there is a little W-carbide among the network structure. The HRC hardness range is from 48.5 to 51.Secondly, according to the drawing of scroll cover, the external permanent-mold is designed to be used to centrifugal casting. Through adding metal internal liner or resin sand internal liner, we can fabricate scroll cover in external permanent-mold. In addition, the wood model and core-box of scroll cover are designed to be used to sand casting, metal internal liner of scroll cover and the flask and wood model used to resin sand model molding are designed to be used to centrifugal casting. Through restructuring the existing centrifugal casting machine, infinitive stage transmission is achieved and the rotational speed can be regulated in the production process.Lastly, by contrast experiment methods, the effect of different fabricating technologies on surface quality, macrofracture and microstructure of scroll cover is studied. The results show that there are pits on the casting surface and there are shrinkage cavities and shrinkage porosities in the castings of gravity force sand...