There is provided a high-pressure metal pipe which has a connecting head capable of solving the risk of cavitation erosion in the inside of the connecting head by changing the contour shape of a pocket or notch to be formed in the inside of the connecting head during head working into a contour shape having a shallow depth and a gentle cross section. According to various approaches, an inner partition assembly support includes a socket with a tapered upper rim. The antenna is made of wire having a sufficiently large diameter to prevent forming corona discharge point electrode throughout the outer surface of the volume defined by the antenna, thus minimizing corona discharge risk.