Vol. 3, No. 3 Modern Applied Science 44 Cold Extrusion of Carbon Electrodes Using Dies of CRHS Concept and Performance Analysis Sami Abulnoun Ajeel University of Technology, Bagdad, Iraq E-mail: sami-tech@yahoo.com Ahmed M. Saleem Technical College, Mosul, Iraq E-mail: ah_ms1971@yahoo.com Farhad B. Bahaideen School of Mechanical Engineering Universiti Sains Malaysia 14300 Nibong Tebal, Penang, Malaysia E-mail: farhadbilal62@yahoo.com M. Abdul Mujeebu (Corresponding author) School of Mechanical Engineering Universiti Sains Malaysia 14300 Nibong Tebal, Penang, Malaysia Tel: 60-1-4305-1476 E-mail: mamujeeb5@yahoo.com Hussain J. Mhamed Alalkawi University of Technology, Bagdad, Iraq E-mail: alalkawi2007@yahoo.com Abstract In this article cold extrusion of carbon electrodes using the direct extrusion die that is designed using one of the theoretical concepts, Constancy of the Ratio of the Successive Generalized Homogeneous Strain-increment (CRHS), is presented. On the basis of the above concept we used three types of dies that are categorized as uniform (UCRHS), accelerated (ACRHS), and decelerated (DCRH) according to the deformation rates. All dies were with fixed reduction area of 50%. The mixture used (filler with binder) was extruded in round section carbon electrodes carried out at 60 o C to 80 o C. Ten samples are produced and tested for properties such as electrical resistivity, hardness, density and porosity. The results show that the extrusion die UCRHS is the more efficient die design for the production of carbon electrodes. Keywords: Extrusion die, Carbon electrodes, CRHS, Binder ratio, Porosity 1. Introduction Extrusion is used to produce the large electrodes for electric furnaces, small rods for dry cell batteries, finer grained graphite for molds used by the metallurgical industry, electrolytic anodes, and the bulk material from which certain motor and generator brushes are made. Traditionally, the extrusion processes can be divided into three types: forward extrusion, backward extrusion, and combined forward/backward extrusion. The extrusion processes can also be categorized by the operation temperature into hot, warm, and cold extrusion. Metal extrusion is a near-net-shape manufacturing process that can reduce the machining tasks. This process can be used to produce long and straight extrusion product such as gear spline, bar, wire, and seamless pipe. The die electrode is used to produce the extrusion die cavity [(Kao (2000)]. Regarding the axisymmetric extrusion, the Constancy of the Ratio of the Successive Generalized Homogeneous Strain-increment (CRHS) and the constancy of the Mean Strain Rate (CMSR) had been proposed and used by Vaidyanathan and Blazynski (1973) and Blazynski and Lee (1984) in obtaining the extrusion die profile. Some other