Increase Characteristics of Local Wall Thickness of a Pipe during Die Forming

Abstract

In recent years global warming has become a worldwide problem. Reduction of carbon dioxide emissions is one of the most important issues also in the automobile industry. This weight reduction technology is important even if applied to electric vehicles rather than gasoline vehicles, as reduction of energy consumption is an important issue. Plastic processing of hollow pipes is an important technology for realizing weight reduction of automobile components. As an example of research into pipe forming there is the research by Ohashi et al. [1-2], who have carried out processing to enlarge pipe diameters using a lost core, which achieved suppressing reduction in wall thickness and greater pipe expansion than hydroforming. In this research, a method of increasing the wall thickness of pipe by press forming was investigated. The establishment of technology for controlling the wall thickness of pipe without buckling the pipe is an important technology for weight reduction of products. Using the finite element analysis method it was predicted that it is possible to increase the wall thickness of aluminum pipe with 2mm wall thickness by approximately 20% by hollow pipe press forming. Also, it was predicted that it is possible to increase the wall thickness by approximately 30% in places by eccentric pipe wall thickness increase. Also, the effect of the metal die which has a large effect on processing a pipe from a circular cylindrical shape to a rectangular tube shape was investigated.

Characteristics of Wall Thickness Increase in Pipe Reduction Process Using Planetary Rolls

“…2. Because of this load in t axial direction, if the pipe diameter becomes too small, buckling of the pipe will occur similar to the method of increasing wall thickness by shortening the pipe length It was reported that compression up to a diameter of 26mm is possible in a pipe with a diameter of 30mm, a wall thickness of 2mm and a length of 100mm [6]. According to similar analysis, with a pipe with the same diameter of 30mm but with a length of 200mm and a thickness of 3mm, if the bottom edge of the pipe is fixed in the die, buckling occurs at compression to a diameter of 28mm, as shown in Fig.…”

Manufacturing Method of Increasing Hollow Steel Shaft Thickness Using Uniaxial Pressing

“…They suppressed reduction in wall thickness and achieved greater pipe expansion than by hydroforming. Kotani et al [3][4][5][6][7][8] used finite-element analysis to predict the wall thickness increase of aluminum pipe with 2mm wall thickness when its diameter was reduced. Kamei [9][10][11][12] This research investigated a method of increasing the wall thickness of steel pipe by pressing.…”

Thickness Increasing Characteristics of Steel Pipe during Die Forming

“…They suppressed reduction in wall thickness and achieved greater pipe expansion than by hydroforming. Kotani et al [3] used finite-element analysis to predict the wall thickness increase of aluminum pipe with 2mm wall thickness when its diameter was reduced. This research investigated a method of increasing the wall thickness of steel pipe by pressing.…”