| 摘要 |
A collapsible core for casting e.g. tubular well articles, comprising an annular shell (1) which substantially forms a pipe having a longitudinal axis extending between the ends of the pipe, said shell (1) being flexurally flexible about the longitudinal axis of the pipe. According to the invention, the shell (1) has at least two first areas separated by at least one second area (A), said areas extending between the ends of the pipe, said second area (A) having a flexural flexibility about the longitudinal axis of the pipe which is smaller than the corresponding flexural flexibility in the two first areas. This ensures that the collapsible core has a relatively high degree of collapse, while having an extremely stable shape. |
