Effect of the water jet machining on the surface of 304 stainless steels

E.D. CABANILLAS, J. DESIMONI AND R.C. MERCADER

La Plata

Conferencia; Conferencia Latinoamericana Sobre las Aplicaciones del Efecto Mössbauer; 2008

Water jet machining (WJM), widely used to shape zircalloy (Zry) spacer grids for high power nuclear reactors, consists of a mixture of water and abrasive particles that impinge at high pressure against the metal surface eroding it. Because of the processes involved, modi cations at the surface are prone to occur in systems that exhibit martensitic transformations produced by plastic deformation. To quantify these possible modi cations, we have chosen the well-known 304 AISI stainless steel, which transforms easily by mechanical work. A 304 AISI rod was annealed for 9 hours at 900 oC to ensure a complete conversion of all phases into paramagnetic austenite. Afterwards, a slab was cut by WJM at a pressure of 3000 bar with abrasive particles of 100 m diameter, and characterized by conversion electron Mossbauer spectroscopy (CEMS) and scanning electron microscopy (SEM). Even though SEM micrographs reveal that the method produced deep marks similar to those produced by conventional metal cutting, on the transversal area exposed after the cutting, within the experimental uncertainty, CEMS results indicate that the initial phase of the material was preserved through the WJM procedure contrary to what would have been expected if the 304 had been cut by conventional procedures.oC to ensure a complete conversion of all phases into paramagnetic austenite. Afterwards, a slab was cut by WJM at a pressure of 3000 bar with abrasive particles of 100 m diameter, and characterized by conversion electron Mossbauer spectroscopy (CEMS) and scanning electron microscopy (SEM). Even though SEM micrographs reveal that the method produced deep marks similar to those produced by conventional metal cutting, on the transversal area exposed after the cutting, within the experimental uncertainty, CEMS results indicate that the initial phase of the material was preserved through the WJM procedure contrary to what would have been expected if the 304 had been cut by conventional procedures.100 m diameter, and characterized by conversion electron Mossbauer spectroscopy (CEMS) and scanning electron microscopy (SEM). Even though SEM micrographs reveal that the method produced deep marks similar to those produced by conventional metal cutting, on the transversal area exposed after the cutting, within the experimental uncertainty, CEMS results indicate that the initial phase of the material was preserved through the WJM procedure contrary to what would have been expected if the 304 had been cut by conventional procedures.