| 摘要 |
PURPOSE:To prevent a core wire from seizing on a die by using a die consisting of a material softer than a core-wire material as a drawing die for a powder drawing process. CONSTITUTION:A steel wire 1 is provided with a degreasing treatment and a surface grinding and is heated at a temperature of about 400 deg.C under the oxidizing atmosphere of a heating furnace 4, before using it as a core wire. The wire 1 is then introduced to a powder bath 5 and is passed through an Al-powder 2, to reduce the oxidized layer formed on the surface of wire 1 by the Al powder 2 for the purpose of chemically activating the surface of wire 1. Further, when the wire 1 is passed through a die 3 consisting of a material softer than the core wire such as copper, the Al powder 2 is drawn into the die 3 by a frictional adhesive force between it and the wire 1 and a self fluidizing action and is brought into press contact with the outer circumference of wire 1 to cover the wire 1. Thus the seizure between the wire 1 and the die 3 is prevented because of the soft die 3 material, and the manufacturing cost is also reduced because of the inexpensive die 3.
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