Multi-Layer Pipe Coating

	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.

Recent Project Reference List

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.

Checking surface profile

Impact testing

Coating peel adhesion test

Cut back and final inspection of coated pipe