There is provided a hole widening method including a preparing process of preparing a forming tool which has a diameter-increasing portion increasing in diameter from a front end side toward a rear end side and a line-shaped projection formed to protrude outward from a surface of the diameter-increasing portion, and a workpiece in which a pilot hole is formed; and a hole widening process of successively widening the pilot hole by pushing the forming tool into the pilot hole such that the line-shaped projection of the forming tool comes into point contact with a part of a circumferential edge portion of the pilot hole in the workpiece two times or more, and forming a stretched flange.

There is provided a hole widening method including a preparing process of preparing a forming tool which has a diameter-increasing portion increasing in diameter from a front end side toward a rear end side and a line-shaped projection formed to protrude outward from a surface of the diameter-increasing portion, and a workpiece in which a pilot hole is formed; and a hole widening process of successively widening the pilot hole by pushing the forming tool into the pilot hole such that the line-shaped projection of the forming tool comes into point contact with a part of a circumferential edge portion of the pilot hole in the workpiece two times or more, and forming a stretched flange.

A quick positioning tube expander includes a clamp mold having a first clamp block and a second clamp block; a pivoting assembly pivotally disposed on the clamp mold for the first and second clamp blocks to open and close with the pivoting assembly as a center of pivoting; and a positioning member. The tube channel is disposed between the first and second clamp blocks for containing a tube body. The first clamp block has a first through hole and a second through hole mutually spaced, and the tube channel is connected with the first and second through holes. The positioning member is connected with the first through hole. The tube body passes through the second through hole to be contained in the tube channel with an end part of the tube body resisting against an end surface of the positioning member to be positioned.

A quick positioning tube expander includes a clamp mold having a first clamp block and a second clamp block; a pivoting assembly pivotally disposed on the clamp mold for the first and second clamp blocks to open and close with the pivoting assembly as a center of pivoting; and a positioning member. The tube channel is disposed between the first and second clamp blocks for containing a tube body. The first clamp block has a first through hole and a second through hole mutually spaced, and the tube channel is connected with the first and second through holes. The positioning member is connected with the first through hole. The tube body passes through the second through hole to be contained in the tube channel with an end part of the tube body resisting against an end surface of the positioning member to be positioned.

A guide and flattening mechanism includes a mounting seat having a support plane and an elastic guide assembly arranged at the mounting seat and having an inclined surface. The inclined surface is arranged around a central axis perpendicular to the support plane and is located on a side of the elastic guide assembly facing away from the support plane. From a side of the inclined surface close to the central axis to a side of the inclined surface away from the central axis, at least a part of the inclined surface is arranged obliquely in a direction away from the support plane. The inclined surface is configured to be elastically deformed in a direction approaching the support plane when being squeezed, so as to guide the bending of the to-be-flattened member and flatten the to-be-flattened member on the circular end surface with the cooperation of the support plane.

A heat pipe and a sealing method thereof; the sealing method for a heat pipe includes the steps of: providing a metal pipe member, the metal pipe member including one end having a sealed end portion formed thereon and another end thereof having a narrowing neck section extended therefrom. The narrowing neck section includes a channel. A compression mold compresses the narrowing neck section and moves away from the metal pipe member in order to compress and elongate the narrowing neck section into a compression elongated column and to seal the channel. Finally, spot welding process is performed on the compression elongated column to form a sealed block thereon. The present invention is of the merits of improved work efficiency for heat pipe bending, compression and testing and increased length of the metal pipe member with enhanced thermal transfer performance of the heat pipe.