| 摘要 |
PURPOSE:To perform a relay welding without crack in short time and to improve the efficiency in pipe making by limiting a groove angle, root gap width and the height of the cut wire packed inside a groove in executing the relay welding of a coil terminal and the starting end of the following coil. CONSTITUTION:The groove angle theta of the groove 2 between a coil terminal 1 and the starting end 1 of the following coil is taken at 5-20 deg., a root gap width (a) is set more than equal to the diameter of a welding wire used in relay welding, a cut wire 5 is sprayed at the height of 30-50% of the plate thickness (t) of coils 1, 1' and packed inside the groove 2 to execute the one pass one side welding of a flux 3 and Cu backing metal 4. And the reason for limiting the groove angle root gap is that a high temp. crack is easy to cause when the groove angle theta is less than 5 deg.. When the groove angle exceeds 20 deg., the bead external appearance is deteriorated. Also in the case of the root gap (a) being smaller than the used wire diameter a good back bead cannot be secured. In the case of the root gap being larger than the used wire diameter the bead external appearance is deteriorated. And if the height of the cut wire 5 is out of the limitation range the melting of a backing metal and the back bead cannot be secured.
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