| 摘要 |
<p>Flexible spirally grooved metal tubing is mfd. from pregrooved metal foil or sheet strip. This is done by winding the strip over a mandrel in either one or several layers each turn overlapping the previous turn. A finishing consolidation operation is carried out. It consists of applying an outer profile roll and an inner smooth roll pressing the tube wall together reducing its section by a third. The resultant tubes are considerably stronger than conventionally produced tubing of this kind and cannot be pulled apart.</p> |
