| 摘要 |
<p>Lengths of polymer-coated tubing are continuously produced from steel strip by roll-forming and welding at a fast rate of speed. The welded tubing is sized, cleaned and heated to raise its temperature to that desired for applying a polymeric coating. After coating, the tubing is heated to a desired baking temperature and then cooled. The tubing is unsupported from a location upstream of the coating station until cooled. Elongated endless belts grip the tubing over a longitudinal distance of at least about two feet and pull the tubing in a controlled manner to maintain the tubing in precise spatial location throughout its heating, coating and baking.</p> |
