Patent ID: 6674042
Filing Date: 2004-01-06
Classification: B22F,F01N

Abstract:
A process for forming metal components of controlled porosity by welding, comprising the successive steps of:preparing a predetermined amount of metal elements of anistropic geometrical shape, intended for constituting a component; distributing this predetermined amount of metal elements in a mold having at least one movable part; exerting pressure using a movable part of the mold controlled by an external means, in at least one main direction on this predetermined amount of metal elements, said pressure being intended to reinforce and maintain the points of contact between these elements; simultaneously passing an electric current through this predetermined amount of metal elements via a set of two electrodes of opposite polarity in order to join these metal elements together by welding, said two electrodes being placed so that the direction of flow of the current is overall coaxial with said main direction of the pressure exerted on the predetermined amount of metal elements; and removing the component from the mold; characterized in that: the predetermined amount of metal elements is obtained by weighing a mass of metal elements whose value M is defined as a function of the desired degree of porosity &tgr;, the volume of the component Vc and the density of the metal alloy used &rgr;a by the formula: M=VC &rgr;a(1âˆ’&tgr;) the predetermined amount of metal elements is distributed isotropically in the mold; the pressure exerted is progressively increased until the component has the required shape, thus giving the component the desired level of porosity; and the movable part of the mold is then held in position and, simultaneously, the electric current flows through the metal elements and welds them together by local melting at the points of contact due to the Joule effect or by creation of a local arc.