Offshore Steel for Marine Projects

Marine and offshore structures are exposed to seawater, wave loading, wind, fatigue, low temperatures and highly corrosive atmospheres. For this reason, material selection must consider strength, toughness, weldability, fatigue performance and long-term corrosion protection.

FERTIACO can support the supply of steel materials and fabricated components in accordance with project specifications, applicable international standards and third-party inspection requirements.

For primary offshore structures, jackets, topsides, modules, pipe racks, access platforms, offshore wind structures and marine terminals, commonly specified grades include:

• EN 10225 offshore structural steels
  S355G2+N, S355G7+N, S355G8+N, S420G2+M and other project-specified offshore grades.
• Structural sections and plates
  S355J2+N, S355K2+N, S420 and higher-strength grades, subject to project design and toughness requirements.
• Offshore tubular sections and piles
  Circular hollow sections, tubular piles and heavy-wall pipes manufactured to relevant EN, ASTM, API or project standards.
• Line pipe and tubular materials
  API 5L grades such as X52, X60 and X65 may be specified for pipeline, tubular and project applications, subject to service conditions and engineering approval.

Steel grades are selected according to the required yield strength, Charpy impact toughness, through-thickness properties, plate thickness, welding procedure and design temperature.

For areas exposed to seawater, splash zones, marine atmosphere or aggressive process fluids, corrosion-resistant materials may be required.

Available material solutions include:

• Carbon steel with offshore protective coating systems
• Stainless steel 316 / 316L for suitable marine applications
• Duplex stainless steel 2205
• Super duplex stainless steel 2507
• Project-specified corrosion-resistant alloys, cladding or lined materials

The final material selection depends on the corrosion category, immersion condition, operating temperature, chloride exposure and expected design life.

Depending on the project, materials and fabrication may be supplied in accordance with relevant standards including:

• EN 10225 — Weldable structural steels for fixed offshore structures
• EN 10210 / EN 10219 — Structural hollow sections
• EN 10025 — Hot-rolled structural steel products
• API 5L — Line pipe for pipeline transportation systems
• ASTM standards — Where required by project specification
• EN 10204 3.1 / 3.2 — Material inspection certificates and traceability
• ISO 3834 — Quality requirements for fusion welding of metallic materials
• ISO 9606 — Qualification testing of welders
• ISO 15614 — Welding procedure qualification
• ISO 12944-9 — Protective paint systems for offshore and related structures
• NORSOK M-501 — Surface preparation and protective coating requirements, where specified
• DNV offshore rules and standards — Where required by the client, certifying authority or project class requirements

FERTIACO can coordinate fabrication and supply with project-specific requirements for:

• Material certificates and heat-number traceability
• Cutting, forming, drilling and fit-up
• Qualified welding procedures and welder qualifications
• Visual inspection, dimensional inspection and NDT
• Surface preparation, shot blasting and offshore paint systems
• Third-party inspection, when required
• Packing, marking and export delivery for marine projects

Every offshore project has unique requirements. Steel grade, coating system, welding consumables, testing scope and certification level must be confirmed against the approved technical specification before procurement or fabrication begins.

Send FERTIACO your drawings, material take-off, data sheets or technical specification for review and a project-specific proposal.