アルミニウム合金溶接管の揺動回転口広げ成形限界 Flaring limit of aluminum alloy welded tube by orbital rotary forming
In order to improve the flaring limit of welded tubes, specimens of 5154 commercial aluminum alloy welded tube were flared to conical shapes with various half-apex angle by orbital rotary forming process, and these deformation phenomena were experimentally investigated. Experimental results showed that flaring limits are determined by the onset of cracking which propagates through the welded line from edge to root in flared tube-end. It is found that the flaring limit in orbital rotary forming is higher than that in press forming with conical dies, and that the formation of the crack can be avoided in the flaring operation by increasing inclined angle of tool and decreasing equivalent tool diameter. Improvements of the flaring limits are also observed in limiting the feed range, <i>f</i>≥<i>f</i><sub>c</sub>, in which the flaring limit increases with decreasing <i>f</i>, and has maxima at <i>f</i><sub>c</sub>; for <i>f</i> below <i>f</i><sub>c</sub>, decrease in the flaring limit is caused by the low-cycle fatigue effect.
軽金属 47(7), 391-395, 1997-07-30
The Japan Institute of Light Metals