High speed flow finishing of inner wall of stainless steel curved pipe

Abstract

High speed flow finishing method has recently developed, which has an excellent performance for polishing an inner wall of stainless steel capillary. However, its method seems to be unable to finish the inner wall of stainless steel pipe. Present paper focuses on the finishing of the inner wall of stainless steel curved pipe with high speed flow finishing method. It is found that an elastic string-type mandrel inserted into the hole of curved pipe has great performance on finishing, in which a diameter of mandrel is slightly smaller than hole size of the pipe. Experiments indicate that surface roughness of the inner wall of curved pipe decreases with the number of slurry flow pass. It is found that surface roughness of the inner wall of a 90°curved pipe decreases with the number of slurry flow pass, however, it incresases inversely after 80 passes and peculiar roughness curve is generated. On the other hand, a 180°curved pipe indicates that there is different surface roughness curve compared with 90°curved pipe. SEM micrographs describe that the spacing of grain boundary on the inner wall surface of the pipe extends gradually with the number of slurry flow pass, and it may be related to the variation of surface roughness.