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Chapter 8: Welding methods
Brushed tubes
On the marketplace brushed tubes are available. The brushing is made on the external surface only,
to avoid the chemical treatment of pickling.
These products, however, have a lower corrosion resistance than pickled tubes if submitted to the
same environmental attack. This is due both to the deposits on the metal surface contaminated during
the production process and to the greater surface roughness which can easily retain oxides and
traces of ferrous contamination. The abrasive belts in itself can leave material that could originate
corrosion.
Brushed tubes, because of their finishing, need a more frequent periodical maintenance compared
to pickled tubes.
It must be underlined that brushing is exclusively external and therefore cannot remove any contamination
existing on the inside surface and at the ends cut by shears made of steel based materials.
Eddy Current test
Welded tubes produced by Ilta Inox, after being calibrated, are submitted to an Eddy Current test
with circumferential coils with differential windings.
Such non-destructive control is carried out by creating a Magnetic Field around the tube and detecting
any interruption caused by leaks or holes.
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