H P Raju et al Int. Journal of Engineering Research and Applications www.ijera.com ISSN : 2248-9622, Vol. 3, Issue 6, Nov-Dec 2013, pp.1338-1343 www.ijera.com 1338 | Page Extrusion Honed Surface Characteristics of Inconel 600 H P Raju 1 , Devadath V R 2 , N L Murali Krishna 3 1 Professor, Dept. of Mechanical Engineering, P E S C E, Mandya – 571 401, Karnataka, India 2 Research Scholar, Dept. of Mechanical Engineering, P E S C E, Mandya – 571 401, Karnataka, India 3 Research Scholar, Dept. of I & P Engineering, P E S C E, Mandya – 571 401, Karnataka, India. ABSTRACT Precision finishing of internal surfaces and complex geometries is always of concern in industry since it is labour intensive and difficult to control. Due to the development of new difficult-to machine materials like Inconel and also complex geometrical shapes of engineering components, the available traditional finishing processes alone are not capable of producing required surface finish and other characteristics. Extrusion honing (EH) is a relatively new non-traditional micro-machining process to debur, radius, polish and remove recast layer of components in a wide range of applications. Material is removed from the work-piece by flowing abrasive laden medium under pressure through or past the work surface to be finished. Components made up of complex passages having surface/areas inaccessible to traditional methods can be finished to high quality and precision by this process. Inconel alloy 600 is a difficult metal to shape and machine using traditional techniques. In this study, extrude honing of Inconel 600 has been performed in an indigenously built hydraulic operated extrusion honing setup using select grade of polymer as a carrier medium and SiC grit of 36 mesh size as abrasive. The internal surface finish results obtained with the use of extrusion honing process are discussed. Keywords— abrasive, carrier medium, extrusion honing, Inconel, surface finish. I. INTRODUCTION Extrusion honing (EH) also known as abrasive flow machining (AFM) is a process for the production of excellent surface qualities of inner profiles that are difficult to access and outside edges, as well as for deburring and edge rounding. EH process removes small quantity of material by flowing a semisolid abrasive-laden compound called ‘media’ through or across the surface of the workpiece to be finished.Two vertically opposed cylinders extrude media back and forth through passages formed by the workpiece and tooling (Fig.1). Abrasive action occurs wherever the media enters and passes through the most restrictive passages. The media is composed of semisolid carrier and abrasive grains. Most commonly used abrasive grains are silicon carbide, boron carbide, aluminium oxide and diamond. The most commonly used carrier is polyborosiloxane. The unique features of EH such as versatility, efficiency, economy makes the process useful to perform a wide range of precision machining operations in the aerospace and automobile industries, manufacture of dies and medical instruments. Some of the components machined by EH include fuel injector nozzles, turbine blades, combustion liners, dies etc. It can simultaneously process multiple parts or many areas of a single workpiece. Inaccessible areas and complex internal passages can be finished economically and effectively. Inconel 600 is a difficult metal to shape and machine using traditional techniques due to rapid work hardening. Rhoades [3-4] experimentally investigated the basic principles of AFM process and identified its control parameters. He observed that when the medium is suddenly forced through restrictive passage, its viscosity temporarily rises. Significant material removal is observed only when medium is thickened. Jain and Adsul [5] reported that initial surface roughness and hardness of the work-piece affects material removal during AFM process. Material removal and reduction in surface roughness values are reported higher for the case of softer work-piece material as compared to harder materials. Perry [9] reported that abrasion is high where medium velocity is high. An increase in pressure and medium viscosity increases material removal rate while surface finish value (Ra) decreases. Williams and Rajurkar [10] reported that metal removal and surface finish in AFM are significantly affected by the medium viscosity. Jain and Jain [11] also reported that reduction in surface roughness (Ra Value) increases with increase in extrusion pressure and abrasive concentration, but they also observed that reduction in surface roughness (Ra value) is higher with increase in average grain size. RESEARCH ARTICLE OPEN ACCESS