Compound forming of outside 3-dimension integral fins on stainless steel tubes

In this paper, a novel plowing/extrusion tool is proposed to develop a new compound forming technique of rolling-plowing/extrusion to machine outside 3-dimension integral fins on stainless steel tubes. The machining process is divided into two stages: to fabricate V-ribs by rolling and to machine 3-dimension integral fins on the V-ribs by plowing/extrusion. Moreover, the morphologies of the ribs and the fins under different processing conditions were experimentally analyzed, and the effect of the plowing/extrusion depth and feed rate on the fin height and pitch were investigated. The results show that the optimal fins are machined at a rolling depth of 1.20 mm, a plowing/extrusion depth of 0.25~0.45 mm and a feed rate of 2.16~3.92 mm/r.