An electric melting method for forming a cylinder of a pressure vessel of nuclear power station, in which an electric melting head and a base material are connected to the anode and cathode of a power supply respectively. During the forming of a metal component, the raw metal wire is sent to a surface of the base material by a feeder and the electric melting head to create the electric arc between the raw wire and the base material, wherein the electric arc melts certain of deposited auxiliary material and crates a molten slag pool; a current creates the resistance heat and the electroslag heat; the raw wire is molten under the high-energy heat resource composed of the electric arc heat, the resistance heat and the electroslag heat, and creates a molten pool on partial surface of the base material.

Provided is a welding method using a special torch and a flux cored wire, in which the special torch has a suction nozzle between the contact tip and the shield nozzle, and the flux cored wire has a flux filled inside the steel outer casing, and a seam portion where both ends of a metal in a width direction of the steel outer casing are butted or overlapped in a longitudinal direction of the flux cored wire.

Described herein are examples of torch tracking systems that monitor travel directions, speeds, and/or distances of welding torches using retractable cords. In some examples, the torch tracking systems use a sensor to measure a speed at which a reel extends and/or retracts a cord, and/or measure a length of the cord that is extended and/or retracted. The reel or cord can be attached to some portion of the welding torch, such that movement of the torch away from the reel causes the reel to extend more cord, and movement towards the reel allows a spring loaded spool of the reel to automatically retract the cord. While reel based torch tracking systems may provide coarser tracking than the more complex and/or expensive torch tracking solutions, their simplicity and low cost may make them an attractive alternative.

Provided is a welding method using a special torch and a flux cored wire, in which the special torch has a suction nozzle between the contact tip and the shield nozzle, and the flux cored wire has a flux filled inside the steel outer casing, and a seam portion where both ends of a metal in a width direction of the steel outer casing are butted or overlapped in a longitudinal direction of the flux cored wire.