Investigation of Roller Burnishing Process on the Mechanical Characteristics, and Micro-hardness of Al-4 wt Cu Under Hot Work Conditions

摘要

Roller Burnishing Process (RBP) considered as one of the main surface plastic deformation of metal used to enhance its surface quality and its dimensional accuracy by implementing some strain hardening. The plastic deformation resulted as the stress generated from the roller exceeds the yield stress of deformable materials, where this stress depend on certain factors namely; U.T.S, surface finish, ductility, and the radius and the geometrical shape of roll. The main reasons to use this process are its low cost, Simple Equipment, and the reduction in the surface roughness. The surface hardness that can this process used is up to 40 HRC [1]. It is essential to prepare the surface before performing this process i.e. the surface should be fine, cleaned and dimensional accurate, however this preparation is also required for operational needs such as; corrosion resistance, fritting wear resistance, fatigue life. Most of material removal processes namely; accurate turning, reaming, milling, and even grinding cannot give the required surface roughness, Therefore, to produce fine surfaces it required to use extra finishing operations like: honing, lapping, super finishing and burnishing [2, 3]. Most of the research work on roller burnishing process that already been published was investigate the effect of this process on the surface characteristics and surface hardness, where it was suggested by many investigators that an improvement in wear resistance can be achieved by burnishing process [4, 5]. As the stress applied by the roller exceeds the yield stress of the workpiece material the crests of the metallic surface will deform to fill the valleys [1]. Metallic parts surface properties are very important issue that it can hinder the wear and fatigue phenomenon failure [6]. Hassan investigated both number of tool passes and burnishing force on the wear resistance so to a certain limits the wear resistance of brass increases [7]. There are many advantages of the burnished surfaces compared to ground surfaces [7-10]. Other authors investigated the effect of other parameters as speed, depth of burnished layer, and burnishing force. It will established that there is an enhancement in the mechanical behavior after burnishing process [1, 11-15]. The main objective of this study is to investigate the effect of hot roller burnishing on the mechanical properties and micro-hardness of pure Al-4 wt% Cu.