Half-Shell Aluminum Bracelet Anode - Product Specification Page
Half-Shell Aluminum Bracelet Anodes consist of two semi-circular aluminum alloy casting shells bolted together around subsea pipelines, risers, or vertical structural piles. They provide galvanic cathodic protection by sacrificing the aluminum alloy to prevent corrosion of underlying carbon steel in marine environments. Each half-shell is fitted with steel backing straps and welded/cast-in electrical contact inserts to ensure low-resistance current output and mechanical stability under subsea currents.
Key Features
Dual Half-Shell Design: Symmetrical two-piece construction enables direct clamping onto operational or pre-commissioned subsea pipelines.
Secure Mechanical Fastening: Assembled using heavy-duty stainless steel or high-tensile galvanized bolts, recessed to prevent snagging by fishing gear or trenching tools.
Low Electrical Resistance: Integral steel cores welded to internal contact pads ensure continuous metallic bonding between the anode and the carrier pipe.
Optimized Current Output: Controlled alloy electrochemistry delivers steady current capacity throughout the design life of subsea assets.
Technical Specifications
|
Parameter |
Specification |
|
Anode Material |
Aluminum-Zinc-Indium (Al-Zn-In) Alloy |
|
Standard Electrochemical Capacity |
>= 2,500 Ah/kg |
|
Closed Circuit Potential (vs. Ag/AgCl/seawater) |
-1,050 mV to -1,100 mV |
|
Inner Diameter (ID Range) |
Customizable to match pipeline outer diameter (4" to 48" + insulation thickness) |
|
Design Life |
15 to 30 years (dependent on pipeline surface area and current demand) |
|
Manufacturing Standard |
Manufactured in accordance with DNV-RP-B401 and ASTM B418 specs |
Materials & Available Options
Alloy Composition (Al-Zn-In Series)
|
Aluminum (Al) |
Balance |
|
Zinc (Zn) |
4.0% - 5.5% |
|
Indium (In) |
0.018% - 0.040% |
|
Iron (Fe) |
<= 0.09% (Strictly controlled to prevent intermetallic phase passivation) |
|
Copper (Cu) |
<= 0.005% |
|
Silicon (Si) |
<= 0.12% |
Configuration Options
- Insulation Spacers: Neoprene or polyurethane lining pads integrated inside the half-shells to protect pipeline anti-corrosion coatings (FBE, 3LPE).
- Fastener Material: Stainless Steel 316 / A4 or Cadmium-plated high-tensile steel bolts.
Applications
Subsea Pipelines: Offshore oil, gas, and water injection flowlines.
Offshore Structures: Jacket legs, tripod foundations, and conductor pipes.
Marine Infrastructure: Piles for jetties, ports, and deep-water terminals.
Riser Protection: Splash zone and subsea riser pipe protection.
Customization & Engineering Support Options
Dimension-to-Spec Matching: Custom inner diameters engineered to exact pipe ODs, accounting for field joint coatings and thermal insulation thicknesses (3LPP/3LPE).
Weight Optimization: Tailored net-to-gross metal ratios and custom sizing per client cathodic protection (CP) design calculations.
Design Verification Support: Capability to cross-check client anode sizing, current demand, and spacing layouts against DNV-RP-B401 guidelines prior to casting.
Hardware & Marking: Specific bolt torque requirements, custom core insert configurations, and stamped project identification markings (heat numbers, client tags).
Manufacturing Facility & Quality Control
Production Capacity: Supported by in-house induction melting furnaces, automated pouring lines, and dedicated pattern-making shops capable of executing bulk EPC project orders with stable lead times.
Melting & Spectrometry: Direct-reading spectrometer analysis conducted prior to every pour to verify strict trace-element limits.
Dimensional Inspection: CMM and laser profile verification for half-shell inner radius, bolt-hole alignment, and core positioning.
Electrochemical Testing: Batch sample testing in accordance with DNV-RP-B401 test procedures to verify actual closed-circuit potential and current capacity.
Traceability & Certification: Each anode is stamped with a unique heat number corresponding to a traceable Mill Test Certificate (MTC EN 10204 3.1). Third-party factory acceptance testing (FAT) via DNV, BV, ABS, or SGS is fully supported.
Packaging & Shipping
Stacked on heavy-duty ISPM 15 heat-treated wooden pallets, secured with steel strapping and corrosion-inhibiting wrapping.
Half-shells separated with wooden dunnage or protective interleaving to prevent coating or surface damage during transit.
Supplied with complete documentation packages including packing lists, MTCs, and TPI reports.
Shipped via 20ft/40ft container loads or breakbulk vessels from major manufacturing ports.
Frequently Asked Questions
Q: How do you prevent damage to the pipeline's 3LPE/FBE coating during installation?
A: Internal surfaces of the bracelet anodes can be lined with neoprene or polyurethane spacer pads. These pads distribute clamping forces evenly and eliminate direct metal-to-polymer contact.
Q: What is the maximum allowable iron content in your aluminum anodes?
A: Iron content is strictly maintained below 0.09%. Exceeding this threshold forms Fe-Al intermetallic particles that cause self-corrosion and reduce electrochemical current efficiency.
Q: Can these anodes be installed on operational pipelines using ROVs?
A: Yes. The two-piece half-shell design allows remote intervention tooling (ROV) or divers to position the shells around the pipe and tighten the heavy-duty bolts using torque-verified hydraulic tools.
Q: What standards do your chemical compositions comply with?
A: Production strictly adheres to DNV-RP-B401 and ASTM B418 specifications. Full chemical and electrochemical test reports are provided with every delivery.
Q: How is electrical continuity established between the anode and the pipe?
A: Internal steel core inserts are welded or mechanically bonded directly to the aluminum casting. When the bolts are torqued, the steel inserts press firmly against the bare steel contact strips on the pipeline (or connect via pre-installed cadwelds).
Q: What is the typical lead time for bulk project orders?
A: Standard production runs take 3 to 5 weeks, depending on mold availability, total tonnage, and third-party inspection schedules. Stocking options are available for fast-track projects.
Request a Quote (RFQ)
To receive a detailed technical proposal and commercial quotation for your project, please include the following parameters in your inquiry:
1.Pipeline Outer Diameter (OD) and wall thickness.
2.Coating type (e.g., 3LPE, FBE) and thickness.
3.Required individual anode net weight / total project tonnage.
4.Design life and operating temperature.
5.Applicable standards (e.g., DNV-RP-B401) and required TPI agency.
Send specifications directly to our engineering sales team for a formal response within 24 hours.
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