| 摘要 |
A tubular composite element of metal, particularly steel, whereby at least the two opposite ends of the tubular composite element consist of different materials, for example carbon steel and stainless steel, and a process and a pressing for simultaneously producing two or more of such composite elements, at least two powders each consisting of one of the different materials, which have been produced by atomizing melts of the materials in question, are introduced alternately and separately from one another into three or more sections each extending over a predetermined axial length of a metallic hollow cylindrical casing and are condensed by vibration and/or ultrasound to around 60 to 70% of the theoretical density and by cold isostatic pressing of the closed casing under a pressure of at least about 3000 bars to at least 80% of the theoretical density and the pressing thus obtained is heated, subsequently hot-extruded to form a tube and the tube thus formed is divided up into the two or more composite elements mentioned above. |
