| 摘要 |
The invention relates to a process and a die for manufacturing big complex hollow pieces, especially vehicle rims. According to the invention, the process consists in a first casting operation by which a hollow cylindrical blank is obtained, said blank being then heated to 700...900°C and afterwards extruded in a die. The resulted piece is cooled and, where appropriate, a bordering operation follows. The die for applying the process comprises a fixed lower part (A) and a detachable upper part (B), the fixed part (A) consisting of a body (7) integral with a central shaft (8), a profiled element (9), a frustoconical body (10), a detachable profiled core (11) and a completing ring (12) being located inside the body (7). The upper part (B) consists of an upper body (14) supported by a profiled element (13) sustaining an outer sleeve (15) and an inner sleeve (16) with a cross-beam (17) passing through both of them and a profiled punch (19) sliding therebetween. The upper part (B) is locked by means of a segmented ring (20) and a sleeve (21).
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