Method and press for producing cold-formed tubular fittings - uses tubular blank subjected to mechanical axial stress and hydraulic internal pressure

摘要

The equipment has a split forming die (6) which is opened and the blank (8) is placed into it. The die is closed and held firmly together by devices (13,14). Subsequently the mechanical devices (9,10) are actuated, and hydraulically operated pistons (15,16) with sealing rings (23) are pushed against front surfaces (11,12). The dias. of the pistons (15) correspond with the ID of the opening in the die (6) so when pressurised medium is supplied to the cylinders (9,10) the pistons (15,16) subject the blank (8) to axial compressoin. At the same time pressurised medium is supplied via a connection (20) into the blank. The combined axial stress and internal fluid pressure causes the material of the blank (8) to bulge out into the recess part (7) of the die. USE/ADVANTAGE - The method has shorter production times in comparison with presses working with hot-forming methods mainly because times necessary for heating up the blanks are eliminated.