| 摘要 |
Method for producing a pin/tie-bolt (110;210) extending in the longitudinal direction (X-X), comprising the steps of:
a) providing a solid workpiece (10a) made of suitable material and having a suitable length in the longitudinal direction and width/diameter in the transverse direction;
wherein the length in the longitudinal direction of the initial workpiece is less than the lenght in the longitudinal direction of the finished pin/tie-bolt;
c) compressing the solid workpiece (10b) inside a second mould (20c) associated with a second punch (30c) with formation of a workpiece (10c) having a length in the longitudinal direction elongated to the final desired size and with an internal longitudinal cavity (11c) having a suitable final depth;
e) compressing in the transverse direction the workpiece (10d) inside a fourth mould (20e) with a longitudinally directed stretching and partial closing of the longitudinal internal cavity with formation of a workpiece (10e) which has a cylindrical top part (10f 1 ) closed to the final desired diameter, a hollow conical connecting collar (13e) with the final size and a hollow cylindrical middle part (10f 2 ) of larger diameter than the cylindrical top part (10f 1 ) and with the final size.
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