| 摘要 |
PURPOSE:To prevent the decrease in the strength of a joint part by a decrease in the wall thickness thereof in the stage of joining metals to each other by a resistance heating and press-welding method by interposing a specific low melting metal between both joining members. CONSTITUTION:An annular insert material 7 consisting of a low melting metal such as Sn or Zn is interposed between a flange part 5 of a Cu pipe 4 having the flange part 5 and a steel plate 6 having a hole 6a in the joint part in the stage of press- welding and energizing the Cu pipe and the steel plate 6 by the flange part 5 of the Cu pipe 4 and welding and joining the same by the resistance heat thereof. A projecting part 9a of a lower electrode 9 is at the same time inserted into a hollow hole 8a of a cylindrical upper electrode 8 and the flange 5 of the Cu pipe 4 and the plate 6 are pressurized by both electrodes 8, 9. A set value equal to the wall thickness (t) of the steel pipe 4 is set in a controller 20. Electricity is conducted to both electrodes 8, 9 from a power source. The displacement of the electrode 8 is detected by a detector 18 if such displacement arises. The heating and pressurizing by the conduction of electricity are stopped at the point of the time when the wall thickness 2t of the flange part 5 of the Cu pipe 4 is equal to the set value (t). The resistance heating and press-welding with the high joint strength are made possible.
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