The plasma welding process brings the highest quality standards for industries as diverse as boiler-making using stainless steels, aeronautics using noble metals, chemical engineering, energy production, transformation and transport as well as prefabrication of gas and petrol pipelines.
SAF-FRO can provide various solutions for plasma welding with a wide range of options with NERTAMATIC 450 Plus or HPW Advanced.
Principle of the process
The contribution of energy necessary for welding is ensured by an electric arc in an atmosphere of plasmagene neutral gas. This arc established between an infusible electrode and the parts to be assembled is forced through a nozzle which constricts it mechanically and pneumatically.
The benefits are:
reduction in the preparation times for assemblies, by eliminating bevelling for thicknesses up to 10 mm,
joint quality: complete and regular penetration guaranteed, 100% X- ray quality,
reduction of the heat affected zone thanks to the arc concentration
respect of the base material chemical composition,
reduction or elimination of finishing operations,
excellent visual aspect.
Process and performances
The Plasma process is the ideal extension of TIG for thicknesses greater than 3 mm.
It ensures the same level of quality, higher performances and 100% penetration thanks to Key-Hole technology. The diagram shows the different welding performances according to the materials and thicknesses.
Maximum thickness, which can be welded in a single pass, is reduced for:
vertical down and cornice (2G) welding positions
small diameter and very thick tubes
Plasma + TIG
The Plasma + TIG process is specially designed for assembling panels for the prefabrication of vessels longer than 4 meters and carrying out circular welds for diameters greater than 2 meters.
This process of using 2 torches in tandem gives a productivity gain of 30-50 % over a single-torch plasma installation.
The “plasma” arc penetrates the butt-jointed panels. The “TIG” arc equipped with filler metal, electromagnetic arc oscillation and a gas trailing shield produces a perfect surface finish which can often be left without any further treatment.