Quality Management at Steel
Quality Control: Raw Material and Suppliers End
Great emphasis is placed on raw material quality specifications and requirements. Raw material specifications are prepared in accordance with API standards and client requirements. Our raw material is purchased from pre-qualified suppliers, for which a rigorous criterion has been set through a vendor evaluation system.
Quality Control: Pipe Plant
We produce spiral weld pipes at our pipe plant, equipped with state of the art technology. Bare pipes are inspected and then tested through the use of sophisticated measuring and testing equipment.
Non Destructive Testing facility
- On-line Automatic Ultrasonic Testing: To ensure that the entire plate as well as the seam is flawless.
- Fluoroscopic Inspection: To analyse the defects identified by Ultrasonic testing.
- Visual Inspection: To determine surface defects.
- Hydrostatic Pressure testing of pipes: To check pipe strength, durability and leakages.
- Residual Magnetism Measurement: To ensure that Residual Magnetism is within the limits of the applicable standard or client’s requirements.
- Final Inspection: To rigorously inspect the different dimensional parameters.
Destructive Testing Facility
- Tensile Testing and Guided Bend Tests: To ensure that the coil received and the pipes manufactured have the required mechanical properties.
- CVN Test: To ensure the fracture toughness of the Pipe Body, Weld and HAZ is in compliance with API standards and client requirements.
- DWT Test: To assess the ductility and toughness of the product.
- Chemical Tests: To ensure the product has met client specified chemical requirements.
- Hardness Testing: To check hardness of the Pipe Body, Weld and HAZ for the sour service pipe.
- Burst Test: To ensure that the pipe exceeds the minimum design pressure requirement.
In order to meet the changes in technical specifications and the emerging requirements of sour gas transmission pipelines CSAPL has installed an Automatic Off-line Ultrasonic Testing unit. The unit checks the expansion caused during Hydrostatic testing which includes tests for Longitudinal Weld defects, Transverse defects and defects in the heat affected zone. During final inspection non destructive testing techniques such as Magnetic Particle Inspection or Dye Pentrant Testing are carried out according to client specifications.
Quality Control at External Coating Plant
Our state of the art coatings plant is equipped with the most sophisticated and advanced technology for coating application. The acid wash facility at our coating plant ensures the removal of chloride traces from pipe surfaces which improves the bond between the coating and pipe surface. Different destructive, non destructive and accelerated tests are carried out to ensure coating quality. Coating inspection and testing is carried out in accordance with international standards. These methods include:
Testing of raw materials
- Determination of gel time of Epoxy Powder.
- Melt flow index of Polypropylene and other tests.
- Inspect pipe prior to shot blasting.
- Pipe surface check after shot blasting.
- An environmental parameters check.
- Inspect depth of anchor pattern and blasted profile.
- Monitor pipe temperature prior to Acid Wash.
- Monitor Chromate application.
During Coating Application
- Check and monitor pipe temperature prior to application of Fusion Bonded Epoxy coating.
- Check and monitor pipe Bonded Epoxy thickness.
- Check and monitor the Copolymer Adhesive and High Density Polyethylene extruder temperature.
- Observe the time lag between the application of Fusion Bonded Epoxy Powder and Copolymer Adhesive Layer.
- Check the thickness of Copolymer Adhesive and High Density Polyethylene/Polypropylene coating.
- Holiday detection of 100% pipe surface.
- Examine foaming, thickness, appearance and uniformity of coatings and coatings cutback.
- Final marking check.
- Conduct Peel and Impact Tests.
- Inspect pipe loading on to customer trailers.
- Conduct Cathodic Disbondment Test.
- Test the percentage of elongation of High Density polyethylene/Polypropylene coatings.
- Hot Water Soak Resistance Test.
- Flexibility Bend Test.
- Indentation Hardness Test.
- Melt Flow Index (MFI/MFR) determination.
- Coating Thermal Analysis using Differential Scanning Calorimeter (DSC).
Quality Control at Internal Coating Plant
A thorough product quality checking system has been set up at the Internal Coatings Plant. A Brief over view of the quality control checks are as follow:
- Pre coating pipe surface inspection to ensure the desired level of cleanliness and surface profile has been achieved.
- During coating application the various parameters such as mixing ratios, temperature and wet film thickness are monitored.
On completion of internal coating, the MEK, Pinhole Detection, Pull- Off Adhesion, Shore-D Hardness, Hold Back Measurement and Thickness Verification tests are carried out to ensure required standards and specifications have been met.