Projection resistance welding method
AssigneeInland Steel Company
InventorWarren A. Peterson
Life of this patent
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Abstract
Two pieces of steel strip are welded together by a method employing projection resistance welding. A portion of one strip is formed with a series of aligned projections and arranged in superimposed relation with a portion of the other strip. The superimposed portions are moved through a welding zone located between upper and lower electrodes, typically a pair of rotatable welding wheels, through which a continuous electrical current flows. As the projections move into and through the welding zone, they are heated, flattened, melted and welded to the other of the two superimposed portions. The projections may be in the form of a continuous, elongated ridge (when the steel strips are uncoated) or in the form of spaced apart dimples (when the steel strips are coated or uncoated).
Claims24
A method for projection resistance welding at least two unconnected pieces of steel each derived from a steel strip, said method comprising:
- forming a series of aligned projections on a portion of one of said pieces of steel;
- arranging another of said pieces of steel so that a portion thereof is in superimposed relation with said series of projections on said one piece of steel;
- sandwiching said superimposed portions between a pair of electrodes comprising at least one rotatable welding wheel, at a welding zone;
- moving either (a) said two pieces of steel or (b) each welding wheel to advance said welding zone;
- rotating each welding wheel as said welding zone advances;
- applying pressure to said sandwiched portions, through said electrodes as each welding wheel rotates, to flatten said projections;
- applying a continuous welding current to said superimposed portions, through said electrodes, to concentrate the current at said projections and form weldments where the projections are flattened;
- employing a speed of advancement at said welding zone greater than 250 inches per minutes (635 cm per minute);
- and maintaining a welding current range greater than 3,000 amperes by employing at least one of the following expedients:
- (a) controlling said pressure applied through said electrodes, (b) controlling said speed of advancement, and (c) selecting an appropriate configuration and dimensions for said series of aligned projections;
- said method being characterized by a welding current range greater than 3,000 amperes at all speeds of advancement in the range 350-700 inches per minute (889-1778 cm per minute).
Dependencies are inferred from the claim text.