Forming mechanism of integral serrated high fins by plowing-extruding based on variational feed

Plowing-extruding tool was designed and plowing-extruding process was investigated. Then, a manufacturing method of integral serrated high-finned tube, plowing-extruding based on variational feed was proposed, in which plowing-extruding tool moved forward at two different feeds, f1 and f2, in turn. In this method, overlaps that are usually avoided in practical application were utilized to manufacture high fins and average height of fins was up to 1.58 mm. The critical feed (fc) of overlaps forming and terms of high fins forming were analyzed. The main technical parameters that affect the fins height were discussed. The experimental results show that the fins height increases with extruding inclination angle and plowing-extruding depth, and the fins height increases with f1 increasing when f1 is smaller than fc, and decreases with f1 increasing if f1 is larger than fc.