NT® wire electrodes

Metal-inert-gas (MSG) welding with wire electrodes has become especially well established as a highly economical and appropriate method for automated applications in the future. The method is characterised by a number of process-specific advantages, including high flexibility and suitability for integration of the joining operation in mechanised or even automated production. For this reason, it is now the most widespread welding method in Europe, the United States, and Japan.

As indicated by previous experience with the use of solid wire electrodes, reliable operation is possible at wire-feed rates up to about 23 m/min, which corresponds to a maximal deposition efficiency of 6 to 7 kg/h. With flux-cored wire electrodes, wire-feed rates up to 30 and 45 m/min are attained for rutile or basic versions, respectively; this corresponds to a deposition efficiency up to 20 kg/h.

As a result of progress in the field of equipment technology during recent years, the demand for heavy-duty MAG welding with gas mixtures has increased considerably. The application of heavy-duty MAG welding has been facilitated by developments in process and plant technology such as:

• the development of systems for ensuring continuous wire feed at high feed rates,
• adaptation of the power-supply technology to match the changing conditions in the arc, and
• adaptation of the torch system to handle the high welding current by ensuring appropriate cooling and uniform current shift.

The advantages in comparison with conventional metal-inert-gas welding include the following:

• The attainable deposition efficiency is considerably higher (up to 27 kg/h).
• The notch-impact ductility in the low-temperature range can be improved.
• Higher strength values are attained under dynamic loads.
• Welding can be accomplished without undercutting and with good seam appearance.
• The penetration thus achieved is deep and uniform.