Using the double element welding machines from ATEC, heating tubes are welded at both ends simultaneously with the corresponding head ends, which are automatically inserted in the mould box for the lower electrodes by a loading handling system. At the same time, the tubes are also inserted fully automatically. Once the process is started with the 2-handed control the parts are first aligned, then clamped and welded together via an adjustable path/time function by means of flash butt-welding.