Process and apparatus for production of welded tubes
AssigneeKabel-und Metallwerke Gutehoffnungshuette AG
InventorsWolfram Klebl, Friedrich Schatz, Gerhard Ziemek
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Abstract
An improved process and apparatus for continuous production of welded tubes is disclosed wherein a metal strip material is formed into a tubular form, the longitudinal edges thereof welded, and the welded seam cold worked by the application of a high frequency pulsating force to each area of the seam, while it is supported and widened from within.
Claims4
An improved process for the continuous production of welded tubing from a continuous length of metal strip material comprising:
- continuously feeding the strip material in a longitudinal path;
- forming the strip material into a tubular form so that the longitudinal edges of the strip are positioned opposite to each other;
- welding the edges of the strip to form a continuous length of the tubing having a welded seam;
- and
- cold working the welded seam by:
- (i) supporting an area of the seam from within the formed tube by means of a mandrel positioned in sliding engagement with the inside surface of said tube;
- (ii) applying a force to an area of the outside surface of the seam for urging the cold seam toward said supported area of the seam;
- and
- (iii) supporting the formed tube by
- a lower roller acting against the outside surface of said tubing;
- the improvement comprising:
- said step of applying a force providing a high frequency pulsating force to each area of the seam;
- and
- said step of supporting an area of the seam including a widening of the seam immediately prior to the application of said pulsating force.
An improved apparatus for the continuous production of welded tubing from a continuous length of metal strip material comprising:
- means for continuously feeding the strip material in a longitudinal path;
- forming means for shaping the strip material into a tubular form so that the longitudinal edges of the strip are positioned opposite to each other;
- a welder for uniting the edges of the strip to form a continuous length of tubing having a welded seam;
- and
- means positioned subsequent to the welder for cold working the welded seam, including:
- (i) mandrel support means positioned within the formed tube for supporting the tube;
- (ii) force means for urging the cold seam toward the support means to cold work the seam;
- and
- (iii) a lower roller acting against the outside surface of said tubing;
- the improvement comprising:
- said force means including a sonotrode for applying a high frequency pulsating force into each area of the seam it engages;
- and
- said mandrel support means including a mandrel positioned in sliding engagement with the inside surface of said tubing and having a diameter slightly larger than the inner diameter of said tubing for widening the seam immediately prior to the application of said pulsating force.
Dependencies are inferred from the claim text.