Method for the production of welded tubes

• Main Authors: NIEDERHOFF, KURT.., 4030 RATINGEN, DE, REINEKING, KLAUS-JUERGEN., 4330 MUELHEIM, DE, KELLER, MANFRED.., 4150 KREFELD, DE, HOLDER, HEINZ., 4030 RATINGEN, DE, HAGEN VON, INGO.., 4150 KREFELD, DE
• Format: Patent
• Language: English; German
• Published: 01.12.1994
• Edition: 5
• Subjects: AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKINGWITHOUT ESSENTIALLY REMOVING MATERIAL; CHEMISTRY; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; ELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MACHINE TOOLS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES,OTHERWISE THAN BY ROLLING; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PUNCHING METAL; ROLLING OF METAL; SOLDERING OR UNSOLDERING; TRANSPORTING; WELDING; WORKING BY LASER BEAM

The invention relates to a method for the production of welded special-section tubes made of steel, in which, starting from a strip, a slotted tube is first of all produced by cold forming and then a tube by means of high-frequency welding. After inductive heating, this tube is then formed to give the desired final profile dimensions. To provide a method of this kind by means of which it is possible to achieve a good surface finish with low tolerances of the special-section tube and in which it is even possible to use a strip which has been rolled in a controlled manner (TM or TG) without a decisive loss of the TM properties, it is proposed that the welded tube should be heated inductively within a brief period to a temperature in the range between 600 DEG C and a temperature lower than AC1 and that the direct forming to give the desired final profiled dimensions should then be carried out.