[ Cover Story ]
[ Cover Story ]
liner and carrier pipe leads to a much better bending behaviour compared to conventional MLPs.” While conventional MLP systems typically achieve mechanical bond strengths in the range of approximately 20 – 30 MPa, EBK’ s target specification exceeds by far 140 MPa- already comparable to values associated with certain metallurgical bonds. In practice, measured average gripping forces for RollClad ® MLP are in the range of 240 – 250 MPa. This represents approximately an order-of-magnitude improvement over standard mechanically lined products. The implications are substantial:
• Enhanced resistance to liner disbondment.
• Improved structural integrity during installation and service.
• Superior bending performance during reel-lay, J- and S-lay operations.
• Improved triple point integrity
Full-scale bending tests conducted during qualification programmes have demonstrated that RollClad ® MLP maintains liner integrity under severe deformation conditions. This is not a theoretical claim; it has been validated through industrial testing witnessed by end users and engineering companies.
Diameter flexibility and large-bore qualification Conventional mechanically lined pipes are generally limited to outer diameters of approximately 26 inches. EBK’ s rolling process imposes no inherent
The technical setup under the press.
The corrosion resistant alloy liner at the beginning of the process to insert it into a carbon steel carrier pipe.
diameter restriction. RollClad ® MLP has been successfully qualified up to 32 inches, opening opportunities in largediameter offshore and subsea pipelines where corrosion-resistant solutions are required but full metallurgical cladding may be cost-prohibitive. The ability to scale to such diameters significantly broadens the application envelope of mechanically lined systems and positions RollClad ® as an alternative to metallurgically clad pipes in selected parts of on- and offshore projects.
Surface finish and flow optimisation A distinguishing feature of RollClad ® MLP is the mirror-like surface finish of the internal liner. The controlled rolling process produces extremely low surface roughness, which is beneficial for hydrocarbon transport, as production fluids may contain solids, scale-forming species, or waxes. A smoother surface:
• Reduces the likelihood of particle adhesion.
• Minimises internal diameter reduction due to deposits.
• Facilitates pigging and cleaning operations.
• Improves hydraulic efficiency.
In offshore oil and gas applications, where multiphase flow and impurity content are common, internal surface quality can have direct operational consequences. The polished-like liner surface, therefore, contributes not only to corrosion resistance but also to long-term flow assurance.
Corrosion-resistant alloy( CRA) liner materials RollClad ® MLP systems are available with a wide range of corrosion-resistant liners in accordance with API 5LD and DNV-ST-F101 specifications. Typical materials include:
• Alloy 825( UNS N08825)
• Alloy 625( UNS N06625)
• AISI 304L
• AISI 316L
• 904L
• 6 % molybdenum austenitic grades
Liner thicknesses typically range from approximately 2.5 mm to 6 mm, depending on service requirements. The system is particularly attractive for sour service, high-CO 2, and chloridecontaining environments where CRA performance is essential but full solid alloy construction would be economically inefficient.
10 Stainless Steel World May 2026 www. stainless-steel-world. net