Formation mechanism of external finned tubes by extrusion-plough method
(1.广东省广州市华南理工大学机械工程学院2.College of Mechanical Engineering, South China University of Technology, Guangzhou 510640, China)
Abstract: The formation mechanism of bulge on the work’s surface during the extrusion process was analyzed. The bulge’s size and the reasons for abscission were studied. The results show that the abscission of bulge from works is resulted from the integrated actions of pressure and friction between the plough tool and works. During the extrusion-plough process, it is noticed that four kinds of fins are appeared, which are gestation fin, multi-dimensional fin, tumor and overlap fin, when using different machining parameters. And multi-dimensional fin which has high heat transmission efficiency is a kind of complicated fin with cockscomb-like 3D substructure fin on the tip of 3D macrostructure fin. Based on the studies of those four kinds of fins, the conditions of their formation are concluded, as well as the formation mechanism is obtained.
Key words: multi-dimensional fin tube; surface functional structure; formation mechanism; extrusion-plough