China direct manufacture 6061 7005 7075 T6 Aluminum pipe / 7075 T6 Aluminum tube

Structural and seamless tube are both extruded. That means a billet of material is forced through a hole in a die shaped to form the two dimensional cross-section you need. (We’ve called it the “toothpaste process” in the past and compared it to decorating a cake.)

Sometimes you want that extruded material to have a hole down the center. The simplest example is circular tube or pipe. for an explanation of the difference. Porthole and seamless are different ways of forming that hollow internal section.