Synthesis and characterization of nanostructured Stainless steel 316 L through machining

Abstract

Nanostructured materials exhibit desirable qualitieslike higher strength, hardness, and ductility when compared withthe same material when it is in micro structured. Large strain plastic deformation as well as mechanical alloying aremethods ofmaking nanostructured substances. The present paperemphasizes the production of nanostructured materials bya two-step process, namely, machining and high energy ball milling process. The broad strain-plastic deformation due to the cutting tool while the machining procedure created nanostructured materials by oblique machining. Bar of 50 mm diameter Stainless Steel 316L (SS) was taken for this analysis. For the machining under different cutting conditions, machining criteria such as feed, speed, cut depth, and rake angle were selected. A coated tool for cutting tungsten carbide was taken for analysis. Processed chips were takenas well aswashed ultrasonically. Such chips were then placed, polished and etched for evaluation of the microstructure. Examination of the chips througha scanning electron microscope (SEM) and X-ray diffraction (XRD) presented crystalline sizes within the 40–80 nm range.Such chips were re-assimilate using the high energy ball mill. The SS nanostructured machined chips were milled under two different milling criteria (milling speed, milling time, and ball to powder ratio) in an inactive atmosphere taking hardened steel bowl and balls. They then characterized the milled powders using SEM and X-ray diffraction (XRD). Measuring XRD peak width, crystalline sizes of the milled powders were determined and then calculated using the Scherer formula. Results suggested that the milled powders between 20 and 50 nm.