Influence of Sulphur Diffusion on the Surface of Furan No Bake Casting-A Review

Abstract

Casting process is one of the most used processes in manufacturing industries. Furan no bake casting is a fast developing technology for foundry industries. Furan no bake casting process uses resins and acid catalyst to form a binder system. However this process produces castings with high strength and good surface finish. Hence this method is suitable for producing accurate dimensioned castings. This paper deals with effect of resin binder system on dimensional stability and surface finish. This furan resin mould system sometimes produces product with sulphur diffusion on surface of casting. This paper mainly deals with the issue of sulphur diffusion from the moulding sand to the surface of the furan no bake casting. Main constituents of sulphur in furan no bake sand are furfuryl resins produced on the basis of sulphonic acids or sulphuric acid. This paper also deals with degradation of properties of gray iron castings due to sulphur diffusion and also the assessment of degree of diffusion, influence of hardener and the ways to reduce the diffusion.