Abstract: This application discloses method and apparatus for solid-phase conversion of particulate metal (or swarf) into continuous metal-jacketed strip by feeding particulate metal, together with any desired reducing or alloying additives, between travelling metal jacket sheet components, the lower channel-shaped and the upper flat strip closely fitting between the channel sides; injecting air-purging reducing or inert gas to create an inside environment of protective gas rather higher than atmospheric air pressure, the gas entering the material and the embrassing jacket sheet components which after filling and closing form a permanent circumferentially and longitudinally complete jacket around the material; compacting the material in the jacket sheet components after closing by repeated compacting actions; feeding this strip forward between successive compacting actions while clear of the compacting die elements; sealing the jacket components closed together over the compacted material to form a circumferentially co