The expansion ring comprising at least two cylindrical portions with the pharmacological mechanical different, the production of such a ring of expansion and advantages of using the cold expansion in expansion ring

摘要

The present invention relates to a ring of expansion in order to produce a cold expansion which is characterized in that it comprises at least two cylindrical portions (50a - 50d) with different mechanical properties, determined as a function of the desired expansion ratio for the part (32a - 32d) of the stack (30) corresponding. Thus, it is possible to obtain a degree of expansion which varies from one piece with the other of a stack (30). The present invention also relates to a process of expansion in the cold, which uses the said ring of expansion, a method of manufacture of a ring of expansion and a tool for thermally treating a ring of expansion.