| 摘要 |
PURPOSE:To improve the quality characteristics of a wire by sealing hermetically the joint of a metallic pipe then coating a metal on the surface and drawing the metallic pipe. CONSTITUTION:A long-sized metallic belt 11 is successively bent in the transverse direction to form the metallic pipe 12. Powder 13 consisting of flux powder and metallic powder is packed into the pipe 12 during the formation and a closing material 15 such as an adhesive agent is filled in the joint part 14 thereof, then the joint part is hermetically closed. The pipe 12 is subjected to copper electroplating to form a metallic film 16 thereon. The pipe 12 is thereafter drawn and the powder-cored welding wire 17 having a prescribed outside diameter is obtd. The intrusion of moisture and air into the wire 17 is obviated by the above-mentioned method, by which an excellent shelf life is obtd. and the long-term preservation is made possible. Since the wire has the metallic coating 16, the quality characteristics such as electricity conductability and rust resistance are improved.
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