| 摘要 |
PURPOSE:To improve the product quality by closely contacting a coating material around a wire core with a ratio between the sectional area of a wire core and that of the coating material unchanged in a work using the 1st drawing die and reducing the wire by use of the 2nd and succeeding dies. CONSTITUTION:A stock is manufactured by preparatorily coating a wire core with a coating material tape and welding the tape butted part. The tape and core are closely contacted each other and are drawn by a cone die(the 1st drawing die) made of steel, diamond, etc. In that time, a ratio between the sectional area of the wire core and that of the tape is unchanged because a reduction angle theta is set to 8-12 deg. and a bearing length (l) is set to about d/2+ or -10% and the drawing is performed with a draft of 0-15%. Then, the wire is reduced and drawn by the 2nd and succeeding dies of ordinary types. The product accuracy is improved because the drawing stage is divided into the drawing stage not changing the sectional area ratio and the reduction stage.
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