Description
For each welding wire technology, different shaping steps are indispensable and there is at least one wire-drawing operation.
CO2 or submerged arc wires are wires of drawn material:
- in steel, they are drawn with wire-drawing powders, after having been de-scaled (elimination of the machine wire oxides) mechanically or chemically. They are then usually coppered, directly or after a wet wire drawing, before being packaged.
- in aluminium, they are generally drawn in oil
Welding rods are made from drawn wires, straightened and cut then coated with welding flux.
Flux cored wires are made from rolled strips, filled with welding flux and then drawn with powders, and in some cases with liquid lubricants.
Characteristics
The market for CO2 or submerged arc wire in steel is highly competitive. The lubrication procedures used must provide an ever higher level of productivity (speed of drawing, surface quality). A quality welding wire is characterised by good sliding properties and conductivity. This comes from the wire-drawing lubricants, often at the last pass.
Welding rods are drawn in a very economical way. A wire surface must be clean before the step of straightening, cutting and coating with welding flux.
Like CO2 and submerged arc wires, flux cored wires must have excellent surface properties: sliding, conductivity and absence of contaminant for the welding. These wires must undergo a thermal recrystallisation treatment, “baking”.
Applications
CO2 or submerged arc wires in steels can combine a first operation of dry drawing, followed by an operation of wet drawing.
In this case, it is important to take care with the combination of these two technologies, with a view to ensuring a long lifetime for the soluble lubricant, and the cleanliness of the wire before coppering. In fact the wire-drawing powders dragged out in the lubricant by the wire are not necessarily compatible.
For drawing wires intended for welding rods, we recommend the use of CONDABRUSH© spiral brushes following bending, to wipe off the maximum amount of residual scale, ensuring increased die lifetime.
Flux cored wires are generally shaped in a roller assembly. The strip can be pre-lubricated. Certain wires are laminated with liquid lubricants (VICAFIL SL or TFH ranges) then drawn at the last pass with powders that leave minimal residue.
Flux cored wires undergoing baking are often drawn with fine powders containing graphite, which improves the sliding and conductivity properties.
Recommendations regarding these powders, adapted to the equipment and processes used, can be provided by our technical team on simple request.
