Method for welding by magnetically driven arc

• US 4,511,784 A
• Filed: 04/15/1983
• Issued: 04/16/1985
• Est. Priority Date: 04/15/1983
• Status: Expired due to Fees

• Current Assignee: Nippon Kokan Koji Kabushiki Kaisha
• Original Assignee: Nippon Kokan Koji Kabushiki Kaisha
• Inventors: Sato, Shigeru, Takagi, Kenji, Takahashi, Fujio, Ozawa, Mikio, Miyamori, Hideaki
• Primary Examiner(s): Envall, Jr., Roy N.
• Assistant Examiner(s): Sigda, C. M.
• Application Number:
  US06/485,184
• Time in Patent Office: 732 Days
• Field of Search: 219/123, 219/97, 219/100
• US Class Current: 219/123
• 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 welding by a magnetically driven arc, which comprises placing two objects of welding in butt formation with a small gap between the end edges thereof to form a welding line; parallelly connecting a first electric circuit comprising the two objects of welding and a cable arranged on the surface side of the two objects of welding and a second electric circuit comprising the two objects of welding and another cable arranged on the back side of the two objects of welding to a welding power source; flowing a welding current through the first and second electric circuits to produce an arc in the small gap; moving the arc along the welding line under the effect of an electromagnetic force in the direction of the welding line, the electromagnetic force being produced by the magnetic flux of magnetizing coils provided near the end edges of the two objects of welding and welding current flowing through the arc; and changing the amount of welding current flowing through the first and second electric circuits to control the electromagnetic force in the thickness direction of the two objects of welding; thereby continuously moving the arc in the thickness direction of the two objects of welding, thus uniformly heating the end edge of the two objects of welding to a welding temperature by the heat of the moving arc.

Claims

1. In a method for welding together two objects of welding by a magnetically driven arc, each object of welding having a first surface, a reverse surface, a thickness between said first and reverse surfaces, and an end edge comprising the steps of:

placing two objects of welding in butt formation with a small gap between the end edges thereof, said small gap forming a welding line between said two objects of welding;

connecting said two objects of welding to a welding power source by a cable to form an electric circuit comprising said welding power source, said cable and said two objects of welding;

flowing a welding current through said electric circuit to produce an arc in said small gap between said two objects of welding;

providing a magnetizing coil in parallel with said welding line between said two objects of welding, near said end edge of each of said two objects of welding, said magnetizing coils producing a magnetic flux in said small gap in the thickness direction of said two objects of welding;

moving said arc along said welding line under the effect of an electromagnetic force in the direction of said welding line produced by said magnetic flux and said welding current flowing through said arc;

heating said end edges of said two objects of welding to a welding temperature with the heat of said arc along said welding line; and

pushing said heated end edges of said two objects of welding against each other to weld together said two objects of welding along said welding line;

the improvement comprising;

dividing said electric circuit for producing said arc in said small gap between said two objects of welding into a first electric circuit and a second electric circuit, said first electric circuit comprising said two objects of welding and a cable arranged on the first surface side of said two objects of welding, said second electric circuit comprising said two objects of welding and another cable arranged on the reverse surface side of said two objects of welding, and said first electric circuit and said second electric circuit being connected in parallel to said welding power source so that the direction of magnetic flux interlinking with a first region surrounded by said first electric circuit and the direction of magnetic flux interlinking with a second region surrounded by said second electric circuit are opposite to each other;

changing the amount of said welding current flowing through said first electric circuit to control the strength of a first electromagnetic force in the thickness direction of said two objects of welding produced by said welding current flowing through said first electric circuit and said magnetic flux interlinking with said first region surrounded by said first electric circuit; and

simultaneously changing the amount of said welding current flowing through said second electric circuit to control the strength of a second electromagnetic force, having a direction opposite to the direction of said first electromagnetic force, in the thickness direction of said two objects of welding produced by said welding current flowing through said second electric circuit and said magnetic flux interlinking with said second region surrounded by said second electric circuit;

thereby continuously and controllably moving said arc produced in said small gap between said two objects of welding in the thickness direction of said end edges of said two objects of welding by the difference in strength between said first electromagnetic force and said second electromagnetic force, so that said end edges of said two objects of welding are uniformly heated to a welding temperature in said thickness direction with the heat of said arc.

2. The method as claimed in claim 1, further comprising:

increasing and then decreasing the amount of said welding current flowing through said first electric circuit at prescribed time intervals, and simultaneously, decreasing and then increasing the amount of said welding current flowing through said second electric circuit in inverse proportion to said increase and said decrease in the amount of said welding current flowing through said first electric circuit, thereby controlling the strength of said first electromagnetic force in the thickness direction of said two objects of welding in said first electric circuit and the strength of said second electromagnetic force in said thickness direction in said second electric circuit.

3. The method as claimed in claim 1, further comprising:

flowing said welding current through said first electric circuit and said second electric alternately at prescribed time intervals, thereby controlling the strength of said first electromagnetic force in the thickness direction of said two objects of welding in said first electric circuit and the strength of said second electromagnetic force in said thickness direction in said second electric circuit.

4. The method as claimed in claim 1, wherein said two objects of welding are two metal plates.

5. The method as claimed in claim 1, wherein said two objects of welding are two metal pipes.

6. The method as claimed in claim 2, wherein said two objects of welding are two metal plates.

7. The method as claimed in claim 3, wherein said two objects of welding are two metal plates.

8. The method as claimed in claim 2, wherein said two objects of welding are two metal pipes.

9. The method as claimed in claim 3, wherein said two objects of welding are two metal pipes.