Volume 3 Issue 2

Authors: Stanley G. Selig; Darrel A. Doman

Abstract: A review and classification of 42 finite element simulations of the die compaction of powder metals is presented here. The present work aims to provide the powder metallurgy researcher or practitioner a strategy for which a finite element code and a constitutive material model should be chosen for a given powder type. Ferrous powders are the most-investigated material in the literature, with the vast majority of the papers using a granular constitutive material formulation in their work. Works typically concentrating on the simulation of sintered or high density parts generally use porous material models. Of the papers that report which software is being used in the modelling approach, most use either of the commercial codes ABAQUS or LS-DYNA for mainly granular material models. ABAQUS has been noted as being a popular choice for non-ferrous powders.

Keywords: Powder Compaction; Finite Element; Densification; Simulation


Authors: R. K. Tyagi

Abstract: Engineering applications of plasma welding technology hold a marked significance in manufacturing industry. The effect of variation of electric field, magnetic field and other parameters on plasma heat flux, Debye length, temperature of ions etc. has been demonstrated in selected lead range for plasma welding/cutting for metallurgical and non metallurgical use. This review article analyses the experimental and theoretical effect of different plasma factors namely magnetic field , homogenous DC electric field, shear scale length, temperature anisotropy, heterogeneity in DC electric field and density gradient on the heat flux, Debye length, temperature and the number of ions. In this process, effectiveness of heat transfer from plasma to work-piece/electrode depends upon parameters such as temperature of ions, Debye length, number of ions striking the work surface etc. which can be controlled according to specific need by adjusting magnetic, electric field and aforementioned plasma factors without making any dimensional change to the machine. Through plasma welding, defects such as gas porosity, formation of oxide films, tungsten and other inclusions, hot and cold cracks, lack of fusion defects and cavities are reduced. Plasma welding/ cutting process is applicable to a broad range of samples from very small to large sized components by restricting to a set of parameters suited to them.

Keywords: Plasma; Velocity Shear Instability; Plasma Welding; Plasma Metal Cutting; Heat Flux