| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an extrusion die, configured so that matching surfaces of a core bar and a mandrel ring can be cleaned without disassembling the mandrel in a mandrel provided with the mandrel ring attachable to and detachable from the core bar. <P>SOLUTION: The mandrel ring (35) is formed of a material smaller in thermal expansion coefficient than the core bar (32). The outer periphery of the core bar (32) and the inner periphery of the mandrel ring (35) are set so that a gap (S<SB POS="POST">1</SB>) exists between both at ordinary temperature in a state where the mandrel ring (35) is fitted onto the core bar (32), and so that both contact with each other without the gap (S<SB POS="POST">1</SB>) at least in a part in the axial direction of the mandrel at a die temperature in extrusion. The extrusion die includes fluid passages (40), (46) which allow the outside of the mandrel to communicate with the gap (S<SB POS="POST">1</SB>) between the core bar (32) and the mandrel ring (35) at ordinary temperature to supply a fluid (F) to the gap (S<SB POS="POST">1</SB>) and to discharge the fluid (F) supplied thereto to the outside. <P>COPYRIGHT: (C)2012,JPO&INPIT |
