| 摘要 |
PURPOSE:To easily obtain the high size and shape accuracy of an inside surface, straightness, surface smoothness, etc., by easily and inexpensively producing even the cylinder for ram extrusion molding having any inside sectional shape at a high yield. CONSTITUTION:A matrix 1 having an irregular outside sectional shape is formed of an aluminum alloy. The outside surface of this matrix 1 is subjected to electrocasting with nickel, by which a cylindrical body 6 having the same inside sectional shape as the outside sectional shape of the matrix 1 is formed. A reinforcing cylinder 7 is formed on the outside surface of this cylindrical body 6 by executing casting with a zinc alloy. The matrix 1 is eluted into an aq. caustic soda soln., by which the cylindrical body 6 is removed from the matrix 1. |
