Structure characteristics in industrially centrifugally cast 25Cr20Ni stainless steel tubes solidified under different electromagnetic field intensity

The influences of different electromagnetic field intensities on the solidi fication structures of industrially centrifugally cast 25Cr20Ni stainless s teel tubes have been investigated in detail. The results reveal that the el ectromagnetic field exerted during the centrifugal solidification causes a marked variation in the structures of the cast tubes. With an increase of t he electromagnetic field intensity, the area fraction of the equiaxed struc tures in transverse sections of the cast tubes increases, and the macrostru ctures are gradually refined. The distribution of the eutectic carbides cha nges from the dendrite boundaries to the grain boundaries. However, an exce ssive electromagnetic field intensity gives rise to many intergranular cast defects formed along the inner walls of the centrifugally cast tubes. The effects of fluid flow induced by the electromagnetic field on the solidific ation process of the centrifugally cast tubes are the primary reason for th e previously mentioned structure variations.