Strengthening of a welding seam
AssigneeKabel-und Metallwerke
InventorsGerhard Ziemek, Friedrich Schatz
Life of this patent
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Abstract
The longitudinal welding seam of a tube is subjected to flexing to obtain strengthening by up and down bending followed by one or multiple stage rolling which in turn is followed by sizing.
Claims9
Method of strengthening the welding seam of a longitudinally seam welded, thin-walled, nonferrous metal tube comprising the steps of cold rolling the seam and adjacent zones of the tube which did also soften during the welding, by at least one pair of cylindrical rolls acting on the seam from the inside and the outside of the tube respectively on a flattened portion thereof, including the seam and the adjacent zones and acting in lines of engagement with the seam extending transversely to the welding seam, the rolling progressing transversely to the tube in a length direction of propagation of the tube, thereby strengthening the seam and the adjacent zones by at least 10%;
- and sizing the tube immediately following the cold rolling.
Apparatus for strengthening the welding seam of a longitudinally seam welded, thin-walled, nonferrous metal tube comprising at least one pair of cylindrical rolls for cold rolling the seam and adjacent zones of the tube which did also soften during the welding, the rolls of the pair acting from the inside and from the outside of the tube respectively and in lines of engagement with the seam extending transversely to the welding seam and progressing transversely to the tube in a lengthwise direction of propagation of the tube and thereby strengthening the seam and adjacent zone by at least 10%;
- a mandrel in sliding surface to surface contact with at least a portion of the inside surface of the tube and having two parts, a first part thereof carrying the inside roll of the pair, a second part being positioned behind the pair of rolls for sizing the tube following the cold rolling;
- and
- at least one support roll underneath said mandrel to support the mandrel and the tube thereon from below, said outside roll of the pair being above the tube.
Dependencies are inferred from the claim text.