SCOPE OF INSPECTION OF POLYOLEFIN COATED PIPE COVERS
Checking
of
General
cleanliness of incoming pipes and preheating requirements
to remove moisture if any, prior to shot blasting.
Coating
Raw Material.
Pipe
surface after shot blasting.
Blasted
profile and depth of anchor pattern.
Surface chloride content after
acid wash
Monitoring of temperature of pipe.
Checking and monitoring of temperature
of pipe prior to Fusion Bonded Epoxy application.
Checking and monitoring of Fusion
Bonded Epoxy thickness.
Monitoring of extruder temperature
and pressure.
Thickness of Copolymer Adhesive
and High Density Polyethylene
Holiday detection of 100% pipe
surface area.
Thickness, appearance and uniformity
of coating and coating cut back.
Final marking.
Coating flexibility.
Conducting Peel test
and Impact test.
Coating adhesion properties.
Conducting cathodic
disbondment test
Tensile strength measurement.
Elongation measurement.
Multi-Layer Polyolefin coating is recognized
as a premium coating for buried pipelines
with high mechanical strength as well
as superior adhesion to steel. High quality
is achievable in the mill applied coatings
due to a controlled and cleaner environment.
The spiral pipes produced at CSAPL are
coated with the most advanced coating
system which is reliable, strong, stable
and resistant to aging.
Our coating plant employs the side extrusion
method for Polyolefin coating. The plant
is capable of applying 3-Layer Polyethylene
/ Polypropylene coating, Stand Alone Fusion
Bonded Epoxy and heat shrink tape coating
on steel pipes. The plant has a coating
capacity of 250 sq. Mtr / hour on 3mm
thickness of 3 layer coating, which corresponds
to 600,000 Sq. meter/annum based on single
shift working.
The equipment is arranged
in a sequence within the pipe handling network
starting from incoming pipe racks to the
client's inspection station for coated pipes.
The bare pipes are received at the incoming
racks, pre-heated, shot-blasted to specified
surface profile. There after the shot blasted
pipes are acid washed and chromate treated
before it enters the induction heater where
its temperature is elevated to about 200
degrees C then it enters the Epoxy booth
where Epoxy is sprayed onto the pipes. Then,
adhesive and Polyethylene/ Polypropylene
co-extruded layers are wrapped on to the
pipe surface. The pipes are subsequently
cooled at the Quench station and later subjected
to 100% holiday detection. Thereafter Coating
is removed from pipes ends according to
specified cut back before final inspection.
