Nippon Kokan Kabushiki Kaisha

Naohiro Tamaoki

Yuji Sugitani

Hirokazu Nomura

A method and an apparatus for automatically setting the weaving reversing position in automatic arc welding wherein the welding electrode is subjected to weaving within the extent of the welding groove or bevel. The position of reversing the electrode weaving direction is set by using a mean value of the height levels of the welding electrode subjected to weaving along the groove bottom transversely of the proceeding direction of welding. In this manner, the weaving reversing position is stabilized to promote the formation of the optimum welding bead.

Method and an apparatus for automatically setting the weaving reversing

A control method in which during arc welding a welding torch is moved in its axial direction so as to maintain the arc current or welding current at a predetermined value and thereby maintain the arc length constant and the torch is caused to weave in the width direction with respect to the direction of welding while changing the direction of the weaving each time the axial displacement or position of the torch attains a predetermined value. The weaving speed is decreased when the torch approaches each turning point of the weaving and the gain of the speed control for the torch axial movement is increased when the torch approaches each turning point in the course of its movement from the central area toward the turning point during each weaving cycle.

Automatic groove tracing control method for arc welding

A welding control method in which a deviation of a groove line or variation of a groove width is detected by utilizing the characteristics of a welding arc itself without using a separate sensor and a welding torch is caused to accurately follow the groove line. The oscillation width of the welding torch is detected and the proper welding speed for providing a weld bead of a predetermined height is calculated in accordance with the detected oscillation width thereby automatically controlling the welding speed in accordance with the calculated welding speed value for every cycle of the oscillation or every integral multiple thereof.

Method of automatically controlling height of a weld bead

In the multi-layer welding of a joint of two pieces of metal to be welded by arc welding, the proper number of passes and the desired tracing positions of a welding torch for each layer are automatically established during the welding of the preceding layer. The welding torch is subjected to a Y-axis control so as to maintain constant the arc voltage or current during the welding and simultaneously the torch is caused to weave in the direction of an X-axis within the groove. The tracing of the groove by the torch is accomplished by controlling the weaving turning positions of the torch in accordance with the X-axis and Y-axis direction displacement data of the torch and the torch displacements in the X-axis direction are compared with a predetermined value thereby determining the proper number of passes to be made in the welding of the next layer.

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Tsu, Japan

Naohiro Tamaoki