MAGNETARC WELDING METHOD FOR WORKPIECES WITH OPEN CROSS-SECTIONS

• US 20090294425A1
• Filed: 06/01/2009
• Published: 12/03/2009
• Est. Priority Date: 06/03/2008
• Status: Active Grant

• Current Assignee: Georg Fischer Engineering AG
• Original Assignee: Georg Fischer Engineering AG
• Inventors: Lohken, Thomas
• Granted Patent: US 8,129,649 B2
• Time in Patent Office: Days
• US Class Current: 219/133
• CPC Class Codes: B23K 2101/04 Tubular or hollow articles
• CPC Class Codes: B23K 9/08 Arrangements or circuits for magnetic control of the arc stabilising of the arc position by magnetic means B23K9/0737

Abstract

A method for Magnetarc welding for metallic materials wherein at least one of the workpieces to be welded has an open cross-section. The method comprises bracing the two workpieces and moving them together, wherein the open cross-section of one workpiece is bridged by means of a metallic auxiliary part to form a conducting closed region, and after the activation of a magnetic field of a magnet coil system and of the current required for welding, the workpieces are placed with a defined spacing and an electric arc is ignited, the magnetic field of the magnet coil system sets the electric arc in rotation in order to uniformly heat the end surfaces to be welded, and subsequently, the surfaces, which are to be welded, of the workpieces are pressed against one another.

Claims

1. A method for welding metallic workpieces wherein at least one of the workpieces to be welded has an open cross-section, comprising the steps of:

moving the workpieces together wherein the open cross-section of the one workpiece is bridged by a metallic auxiliary part to form a conducting closed region;

activating a magnetic field of a magnet coil system and obtaining a current required for welding;

placing the workpieces with a defined spacing and igniting an electric arc wherein the magnetic field of the magnet coil system sets the electric arc in rotation, and end surfaces of the workpieces to be welded are uniformly heated; and

thereafter pressing the end surfaces of the workpieces against one another, wherein an open surface region of the metallic auxiliary part is not pressed, or pressed only very lightly, against the opposite surface of the workpiece having an open cross-section.

2. A method according to claim 1, wherein the open cross-section of the workpiece forms an open circle perimeter.

3. A method according to claim 1, wherein the open cross-section of the workpiece is U-shaped.

4. A method according to claim 1, wherein the auxiliary part is designed such that, by means of said auxiliary part, the open circle perimeter of the open cross-section of the workpiece is formed into a closed circle.

5. A method according to claim 3, wherein the auxiliary part is designed such that, by means of said auxiliary part, the U-shape is formed into a closed rectangle.

6. A method according to claim 1, wherein the open cross-section is of arbitrary shape and, together with the auxiliary part, which is likewise of arbitrary shape, forms a closed region.

7. A method according to claim 1, including locating the magnet coil system on at least one of the workpieces.

8. A method according to claim 1, including removing the auxiliary part after welding of the workpiece is completed.