Magnetic field negating system for weldments

A method for temporarily, during welding operations, negating remnant magnetic fields that exist in the area of the weld joint formed between two workpieces to be welded together without demagnetizing said workpieces, including:

• a. placing an electromagnet on said workpieces in the area of said weld joint, wherein said electromagnet comprises a core and a coil wound on said core, said core including a first foot and a second foot that each form a pole piece of said electromagnet;
• said electromagnet-placing step including the step of placing said first foot on a first workpiece so that substantial surface coupling is made between said first foot and said first workpiece on a first side of said weld joint, and placing said second foot on a second workpiece so that substantial surface coupling is made between said second foot and said second workpiece on a second side of said weld joint;
• b. connecting electrically a source of current to said electromagnet and supplying DC current to said electromagnet to produce a negating magnetic field during welding;
• c. measuring the magnetic field in the area of the weld joint;
• d. adjusting said current source until said measured magnetic field is minimized.

A system for negating remnant magnetic fields that exist in the area of the weld joint formed between two workpieces to be welded together, comprising:

• an electromagnet comprising a core and a coil wound on said core;
• a control means electrically connected to said electromagnet for providing current to said coil to provide a negating magnetic field;
• said electromagnet core including at least a first foot and a second foot that each form a pole piece of said electromagnet;
• said first foot having at least a primary surface for coupling magnetic flux to a first one of said workpieces along a substantial surface area on a first side of said weld joint, and said second foot having at least a primary surface for coupling magnetic flux to a second one of said workpieces along a substantial surface area on a second side of said weld joint, whereby said negating magnetic field is maximized in the area of said weld joint and
• first means for rotatively connecting said first foot to said core, whereby said first foot may be angularly displaced relative to said core to accommodate various workpiece configurations.

A method for temporarily, during welding operations, negating remnant magnetic fields that exist in the area of the weld joint formed between two workpieces to be welded together without demagnetizing said workpieces, including:

• a. placing an electromagnet on said workpieces in the area of said weld joint, wherein said electromagnet comprises a core and a coil wound on said core, said core including a first foot and a second foot that each form a pole piece of said electromagnet;
• said electromagnet-placing step including the step of placing said first foot on a first workpiece so that substantial surface coupling is made between said first foot and said first workpiece on a first side of said weld joint, and placing said second foot on a second workpiece so that substantial surface coupling is made between said second foot and said second workpiece on a second side of said weld joint;
• b. connecting electrically a source of current to said electromagnet and supplying DC current to said electromagnet to produce a negating magnetic field during welding;
• c. observing magnetic field effects in the area of the weld joint;
• d. adjusting said current source until said magnetic field effects are minimized.