Patent ID: 6332346
Filing Date: 2001-12-25
Classification: B21D,Y10T

Abstract:
A metal vessel comprising:a cylinder including a shell member and a bottom member, the shell member comprises:a shell part adjacent to the bottom member, the shell part having an external diameter which is larger than the external diameter of the bottom member; anda neck part at an end opposite to the bottom member, the neck part having an external diameter which is smaller than the external diameter of the shell part, the neck part projecting from the shell part and is formed from the same member as the shell part; and the neck part including an opening part;wherein one end of the shell member being made integral to the bottom member by welding, the other end of the shell member providing the opening part wherein the cylinder is formed by a fabrication method comprising the steps of:disposing the cylinder in a die comprising a moving die and a stationary die in a state wherein the moving die and the stationary die are separated, so that the opening part is on the stationary die side and the bottom member is on the moving die side; andfabricating the metal vessel by carrying out hydraulic bulge formation in such a manner that a length of the weld between the shell member and the bottom member is approximately the same before and after the hydraulic bulge formation by moving the moving die towards the stationary die, expanding the shell member of the cylinder, and at the same time injecting a liquid into the cylinder and then applying pressure.