Curly stress-tight structure for forming a hollow tube

A stress-tight structure for forming a hollow tube, comprising:

• a thin slice body, having a first side edge and a second side edge opposite to the first side edge;
• a deformation segment formed on the second side edge;
• a tight engagement segment extended outward from the deformation segment by a length;
• a first sharp projection formed on an inside surface of the first side edge;
• and
• a second sharp projection formed on an outside surface of the second side edge and located between the deformation segment and the tight engagement segment;
• wherein the second side edge is curled in a curling direction toward the first side edge to have the outside surface located at the second sharp projection of the second side edge correspond to the inside surface of the first side edge, and the first sharp projection is set in hooking engagement with the second sharp projection, so that an outward-directed stress is induced and accumulated in the thin slice body through the curling to make the outside surface of the tight engagement segment of the second side edge in tight contact with the inside surface of the first side edge, thereby forming the hollow tube.