| 摘要 |
A mill system which receives a flat strip, embosses the outside surface to form flutes and transversely bends the strip to form a curved shape without substantially flattening the flutes. The curved fluted strip is then bent to a circle, welded, given final cylindrical and dimensional forming treatment coated and tensioned wall suface surrounding the vertical bore. By the use of a stationary sleeve which holds solidified pieces during the pouring process, quality of the casting is improved. The invention prevents a shell from intruding into the cavity and minimises the sizes of solidified metal pieces. The metal pouring device facilitates sepn. of the die casting from the cavity.
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