TUBE EXPANDING DIE FOR STEEL TUBE EXPANDING MACHINE

摘要

PURPOSE: To prevent the development of die mark by forming each die segment constituting a tube expanding die with a crystalline thermoplastic resin to hold the elasticity to each die segment. ;CONSTITUTION: The tube expanding die is selected from any one by forming each die segment 31 with the crystalline thermoplastic resin (A) or the surface side position 311 contacting with the inner surface of the tube stock and the supporting side position 312 contacting with the cone of a steel tube expanding machine with a steel (B) or the surface side position 311 with phenolic resin and the supporting side position 312 with polyamide resin (C). These crystalline thermoplastic resins, i.e., polyamide resin, phenolic resin, etc., have the elasticity and high compressive resistant strength. Therefore, the die mark and polygonal- formation are not developed in the inner surface of the tube stock and the change fo the die for lightening can be executed in a short time.;COPYRIGHT: (C)1996,JPO