Offshore & Subsea Bolting Solutions
Offshore and subsea applications demand fasteners with exceptional corrosion resistance, high strength, and reliability in the harshest marine environments. Our comprehensive range meets all offshore industry standards including NORSOK M-650 and DNV requirements.
Application Areas
Fixed Platforms
Jacket structures, topside modules, helidecks, flare booms
Floating Production
FPSO, SPAR, TLP, Semi-submersibles
Subsea Trees
Wellhead connectors, tree components, control systems
Subsea Manifolds
Jumpers, flowlines, distribution systems
Riser Systems
Flexible risers, rigid risers, riser tensioners
Umbilicals & Flowlines
Connections, terminations, protection structures
NORSOK M-650 Qualified Materials
NORSOK M-650 specifies requirements for qualification of manufacturers of special bolting materials for use in offshore oil and gas installations.
Duplex 2205 (UNS S31803/S32205)
NORSOK M-650 qualified
DNV approved
Up to 250°C
Super Duplex 2507 (UNS S32750)
NORSOK M-650 qualified
Enhanced PREN ≥40
Deep water applications
Zeron 100 (UNS S32760)
Super duplex with tungsten
Maximum chloride resistance
Subsea critical service
Inconel 625 (UNS N06625)
NORSOK M-650 qualified
Severe corrosion environments
High temperature
Inconel 718 (UNS N07718)
Age-hardenable
High strength applications
Deep water high pressure
Incoloy 925 (UNS N09925)
Sour service qualified
High strength
Subsea wells
Corrosion Zones & Material Selection
| Zone | Environment | Recommended Materials |
|---|---|---|
| Atmospheric Zone | Above splash zone, salt spray | 316 SS, Duplex 2205 |
| Splash Zone | Wave impact, highest corrosion | Super Duplex 2507, 6Mo (254 SMO) |
| Tidal Zone | Alternating wet/dry cycles | Super Duplex 2507, Zeron 100 |
| Submerged Zone | Continuous seawater immersion | Duplex 2205, 316 SS |
| Subsea (Deep Water) | High pressure, cold, H2S possible | Super Duplex, Inconel 625/718 |
Testing & Quality Requirements
Material Testing
PMI, chemical analysis, mechanical testing per NORSOK M-650
Corrosion Testing
ASTM G48, critical pitting temperature (CPT)
Impact Testing
Charpy V-notch at service temperature
Traceability
Complete material traceability to mill heat
Documentation
EN 10204 3.2 certificates, DNV certification
Third Party Inspection
DNV, Lloyd's, ABS, Bureau Veritas approved
Subsea Service Conditions
- Water Depth: Up to 3000m+ (10,000+ feet)
- Pressure: Up to 15,000 psi (1034 bar)
- Temperature: 4°C to 150°C seabed to wellhead
- Seawater Composition: Chlorides 19,000 ppm, dissolved oxygen, bacteria
- Sour Gas: H2S in production fluids
- Service Life: 20-30 years design life
Anti-Corrosion Coatings
Electroless Nickel
Uniform coating thickness
Excellent corrosion protection
Zinc-Nickel
12-15% nickel content
Superior to zinc plating
PTFE/Xylan®
Anti-galling properties
Chemical resistance
Geomet®/Dacromet®
Zinc flake technology
No hydrogen embrittlement
Industry Standards & Compliance
NORSOK M-650: Qualification of manufacturers of special bolting materials
NORSOK M-630: Material data sheets for piping
DNV-OS-B101: Metallic materials
ISO 15156/NACE MR0175: Sour service requirements
API 6A/17D: Subsea wellhead and tree equipment
ASME B16.5: Pipe flanges and flanged fittings
Material Comparison for Offshore Service
| Material | PREN Value | Typical Application | Cost Factor |
|---|---|---|---|
| 316L SS | ~24 | Submerged zone, mild conditions | 1.0x |
| Duplex 2205 | ~35 | General offshore, topsides | 1.5x |
| Super Duplex 2507 | ~42 | Splash zone, subsea equipment | 2.5x |
| Zeron 100 | ~45 | Critical subsea, high chloride | 3.5x |
| Inconel 625 | N/A | Severe corrosion, high temp | 5.0x |
PREN (Pitting Resistance Equivalent Number) = %Cr + 3.3(%Mo) + 16(%N)