Ron A. Sewell,
Huntingdon Fusion
Techniques Ltd, UK,
discusses the corrosion
problems to be wary of
when welding steel pipes.
M
anufacturers and users of pipelines in the oil and gas sectors have long believed
that so-called ‘stainless steel’, is indeed stainless. The fact is that most of these
materials not only discolour but also can corrode when they come into contact
with some endemic media. The black corrosion spots on cutlery after passing
through a dishwasher cycle are an example, but a more dramatic illustration is salt water
corrosion in pipelines.
One area of production receiving little attention is during pipe and tube fabrication
where welding is widely used. Unless strict welding schedules are adhered to however,
not only will discolouration (heat tint) take place but also corrosion resistance can be
significantly reduced.
I got
PROBLEMS
BUT WELDING
AIN’T ONE
75
