process for the manufacture of tubes and pipes of stainless steel and application of the process to the manufacture of verbundrohren

摘要

A method and a capsule and a blank for producing tubes, bars or similar profiled elongated dense metal objects, preferably in stainless steel qualities, by single or multi-stage extrusion of capsules which are filled with powder of metals or metal alloys or mixtures thereof or with mixtures of powder of metals and/or metal alloys with ceramic powder and sealed and which are adapted in their form to the desired object or intermediate product, as starting material a powder being used which consists at least predominantly of substantially spherical grains and the capsule filled with said powder and sealed being compressed by means of cold-isostatic pressure acting all round until the density of the powder reaches at least 80% of the theoretical density.