Products : Spiral Pipes

Introduction :

MEIL has been constantly striving to enter into diverse engineering areas to give its customers the best and Megha Spiral Weld Pipes is just another step in this direction. In the early seventies, the sharp rise in energy consumption, particularly that of Natural Gas, has influenced ‘The Development of Transmission of Oil and Gas through Pipelines’ and this development has necessitated the use of Large Diaz Spiral Weld Pipes with High Strength Pipe Materials of Improved Weld ability and Toughness.

Spiral Weld Pipes have been and are being extensively used worldwide. Our pipe production ranges from 400mm dia to 3000 mm of thickness 6mmto 25mm of API-5L grade X70, The quality is indisputable. The quality assurance factors that merit special attention are no different in Spiral Weld Pipes that that of Longitudinal Pipes. Spiral welded Pipes have gained acceptance for excellent applications based on an independent assessment of the manufacturer’s technical capabilities.

Process Flow Diagram for Spiral Pipe Mill Plant :

Production Methodology :

The leading head of the coil shall be opened up and flattened to give a tail of approximate 1.0 meters. to 2.00 meters max in width to enable the coil to be fed into the strip feed in roller system. The coil shall be loaded onto coil lifting frame and loaded onto spiral pipe mill. Incoming coils after physical & visual inspection are stored in Coil Yard. Coil Car receives the coil and lifts it to the right position, (in axis with the de coiler). It also rotates the coil until the end of coil comes in front of the peeler.

Geometric Monitoring

The strip is positioned to the correct helix angle. Smaller pipes require greater angles than larger pipes manufactured from the same width coil.

Welding Procedure and Performance Qualification Tests :

We are having the qualified welders in both SMAW & SAW methods under DNV certifications.

Chemical, Mechanical and Metallurgical Testing

MEIL is a quality Management company where a separate independent quality department to oversee all aspects and operations to ensure that quality is imbibed from the beginning to the end of operation. Quality control, involves inspection of raw materials to pre-shipment inspection and transportation to the customer.

Plates/Coils/Pipes are passed through a series of quality checks. There are various mandatory tests described in the detailed QA/QC procedures in lines with the international technical specifications required.

End Shearing, Butt Welding and side Guide Rollers

Normally when the coils are received from suppliers, its leading and trailing ends are not in a straight line. This is hydraulically operated unit, which cuts both the ends of the coil perpendicularly to its length.

Then the leading edge of the incoming coil and trailing edge of the outgoing coils are joined together by Butt-welding device. Again side guides are used to guide the strip properly.

The Making of Spiral Weld Pipes :

First, a coil of hot rolled wide strip is mounted into the straightening machine. The strip is positioned to the correct helix angle. Smaller pipes require greater angles than larger pipes manufactured from the same width coil. Before passing the strip through, the leading and trailing ends of the incoming and already inserted coil strip respectively are welded together. Shears trim the edges that are then machined simultaneously on both sides by an edge miller. In the forming section, a 3-roller bending device followed by a star shaped inner sizing to old bend the strip helically into a cylindrical pipe System to measure and control gap width, ensures a constant pipe diameter in the context of small variations in the width of the input metal strip. Besides, with Laser control, seam tracking is done automatically with much greater accuracy and consistency that with manual operations. This results in improved weld quality, reduced rework of welds, increased welding speed and overall better product quality

Then the longitudinal edges of the incoming strip are brought into low point contact and the resulting butt joint is continuously welded using the Submerged Arc Welding process, first internally and the externally after a half-turn of the pipe. Finally, it is cut off to the desired length with a plasma torch. System to measure and control gap width, ensures a constant pipe diameter in the context of small variations in the width of the input metal strip. Besides, with Laser control, seam tracking is done automatically with much greater accuracy and consistency that with manual operations. This results in improved weld quality, reduced rework of welds, increased welding speed and overall better product quality.

The level of acceptance for factors such as dimensions and allowable weld-defects do not change. Moreover, the process of fabrication make the Spiral Weld Pipes ensures zero-defects It also make it joviality free during welding. The process of fabrication and forming also ensure pipe straightness.

Ultra-Sonic Testing

The Ultra-sonic testing System can test seam and body of Spiral pipes for detection of longitudinal and transverse defects like cracks, lack of fusion, lack of penetration, porosity, slag & laminar defects. The system is designed for automatic operation with a paint marking facility which will locate and mark the defective area. A test report is also printed after each pipe is tested. Alarms are provided to indicate a decoupling condition and presence of defects above the set threshold level.

The system is designed to meet the requirements of several weld test specifications in general and in particular the API-5L – X70 specification requirements.

X-Ray Test and Fluoroscopy

This is an effective means of testing welds, where one can continuously view the weld seam on video monitor. Real Time Radiography is done essentially on the first pipe from production for setting up the welding and other inspection parameters. It is done every time the pipe size/wall thickness are changed. However, it may be done as per the client’s requirements/specification.

Hydro testing

Each pipe is hydro tested to the required test pressure noted in the specification.

Each pipe section is clamped between two large end plates, one of which is stationary, the other providing thrust by means of hydraulic cylinders. Through an opening in the stationary plate, water is pumped into the pipe section.

Displace air from inside of the pipe is vented by means of a valve and series of gauges are provided to check the proper test pressure. Any leaks visually determined are marked on the exterior wall of the pipe. Such pipe is then sent to a repair station, reworked and subsequently re-tested.

Final Inspection, Visual Checking, Weighing and Measuring

Each pipe is finally inspected after all the required tests / inspections are carried out on the same by works inspectors / third party inspection agency depending on the customer’s requirement for the following within the acceptance norms or not. The inside & outside surface end welds are checked Dimensional checks like outside diameter, wall thickness, length, straightness, joviality, out of square ness etc.

Bevel ends of the pipe for Bevel angle, Bevel root face and workmanship. Finally when the pipe is acceptable, then the pipe is marked, stamped and coated as per the requirement / governing specification.

Each pipe is weighed on a digital weighing scale and measured for the exact meter age also which also helps to compare it with theoretically calculated weight of pipe. Physical measurement helps to find whether it is within the tolerance of clients requirement.

Final Marking

Each pipe is marked and given a specific serial no. which helps to get the complete details or history of the particular pipe such as Raw Material details, date of manufacturing, its U. T., RT reports and other quality checks.

Despatch to Customer / Client: