| 摘要 |
<p>The production method comprises : a) forming an internal layer (2) in corrosion-resistant metal from an internal metal strip (4), for example, by assembling with a so-called longitudinal weld (5) of at least two so-called internal portions (40) of said internal metal strip (4), with a butting arrangement, forming a so-called longitudinal hollow section (50) between them, b) an external layer (3) made from an external metal strip (6), c) said internal (2) and external (3) layers being connected with a radial assembly means (7) with a radial hollow section (70). The method is characterised in that said longitudinal weld (5) and/or said radial assembly means (7) are produced by the projection of a powder (80) of said corrosion resistant metal into said longitudinal (50) and/or radial (70) hollow section at great speed to form a compact metal mass (51,71) with a density at least 0,8 times the density of said corrosion resistant metal.</p> |
