Patent ID: 7257874

Claim:
An improved process for manufacturing ring-type metal joints for high pressure ducts or valves and pipelines for high pressure containers, comprising the following steps: a) machining an oval bar, from a round metal bar having cold drawing properties; b) sharpening one end of the round metal bar until the diameter of said end is about half of its original diameter to form a sharpened bar and insuring that the transition zone between the two diameters of the metal bar maintains a cone shape of up to 30°; c) lubricating the resulting sharpened bar; d) subjecting the sharpened bar in a drawing train comprising train jaws wherein the bar is cold drawn through an oval shaped forming die, such that a trimmed end is fastened by the train jaws during pulling of the round bar to form an oval cross section; e) cutting the oval bar into a plurality of oval segments and rolling the oval bar at a required length; f) machining the ends of oval segments through ring bending according to the desired diameter of the joints; g) welding the joints which unite to form a ends to form ring joints through methods selected from the group consisting of butt welding and flash welding; and h) machining the joint to obtain a ring-type joint; and marking the ring type joint.