Seawater Piping for Marine and Offshore Projects

Case Overview

A shipyard and offshore fabrication supplier was replacing mild-steel seawater pipes after premature pitting failures in ballast and main-engine cooling lines on a vessel project. The customer needed CuNi seawater tubes with verified chemistry and documented pressure-test readiness, delivered to an inflexible construction schedule.

DZX qualified with CuNi10Fe and CuNi30Mn tubes with verified chemistry, dimensional reports and pressure-test documentation, delivered to the shipyard’s block-construction schedule with zero material delays.

This case summarizes the application requirements, materials supplied by DZX and delivery value. For case-specific technical data, please contact our engineering team.

Item Details
Client Profile Shipyard and offshore fabrication supplier
Project Scale Vessel seawater piping systems, block construction
Application Ballast, main-engine cooling, fire-main and sanitary seawater piping
Materials Supplied CuNi10Fe and CuNi30Mn tubes and fittings
Supply Forms Tube, fittings and plate
Lead Time Standard sizes: 2-3 weeks; mill batches: 5-6 weeks
Project Country South Korea
Project Year2024

Our Solution

The project required three supply assurances:

  • Seawater service life: ballast and cooling lines needed CuNi grades with verified chemistry for erosion-corrosion resistance at typical service flow velocities.
  • Fabrication readiness: tubes had to be straight, round and uniform enough for bending and welding without rework, with dimensions verified for every coil.
  • Schedule discipline: block-construction windows were fixed; deliveries needed confirmed dates aligned with the shipyard schedule.
CuNi alloy tubes for shipboard seawater piping systems

DZX matched supply to the shipyard’s fabrication process:

CuNi10Fe tubes were supplied at 25 mm × 2.5 mm, with chemistry verified to ASTM B151 and dimensional reports for bending and welding. CuNi30Mn covered high-flow and impingement-prone sections, while plate served headers and flanges. Every batch included chemistry, dimensional and pressure-test documentation, with deliveries scheduled to block-construction windows.

Material Representative Grades Key Properties Available Forms
CuNi alloysCuNi10Fe Seawater piping, general service Tube and plate
CuNi alloysCuNi30Mn High-flow, impingement-resistant service Tube and plate
Copper alloys To drawing Fittings and flanges Plate and bar

View CuNi Alloys →  |  View Copper and Copper Alloys →

CuNi 90/10 copper-nickel tubes—seawater piping
CuNi 90/10 Copper-Nickel Tubes
Seawater piping
CuNi 70/30 copper-nickel tubes—high-flow seawater service
CuNi 70/30 Copper-Nickel Tubes
High-flow seawater service
CuNi fittings and flanges—matching piping components
CuNi Fittings and Flanges
Matching piping components

Technical Specifications

Key technical parameters agreed before production. Contact us for grade-specific datasheets and tolerance-verification reports.

Parameter Agreed Specification Verification Method
Tube dimensions (typical) 25 mm OD × 2.5 mm wall Micrometer + thickness measurement
Chemical composition CuNi10Fe / CuNi30Mn to ASTM B151 Batch chemical analysis
Straightness To fabrication requirements Coil-by-coil straightness inspection
Pressure-test readiness To classification-society rules/specification Hydrostatic test records within the agreed scope
Delivery schedule Aligned with block-construction windows Dates confirmed per order

Each supplied batch includes a quality inspection certificate with chemical analysis, meeting the applicable standard for each grade.

Material Applicable Standards
CuNi alloysASTM B151、B171
Copper alloysASTM B152、B187
Quality System Quality certificate including chemical analysis and mechanical properties

Delivery and Quality Support

  • Fast delivery: Sample and production lead times follow the project schedule; standard grades and sizes can be dispatched promptly from stock.
  • Quality traceability: Every batch includes material certificates and inspection reports, with full heat and batch traceability.
  • Technical support: Responsive support covers pre-sale material selection, drawing review and post-sale processing advice.
  • Ongoing service: Regular follow-up after delivery tracks performance and addresses feedback promptly.

Customer Feedback

  • Seawater service life restored: verified CuNi chemistry replaced pitting-prone carbon steel in ballast and cooling lines
  • Zero fabrication rework: straight, uniform tubes bent and welded without material-related rework
  • Schedule achieved: deliveries matched shipyard block-construction windows
  • Pressure-test readiness: documented hydrostatic-test readiness within the agreed scope
  • Auditable batches: chemistry, dimensional and test reports for every coil
  • One-stop piping package: tubes, plate and fittings coordinated by one manufacturer

Our Capabilities

Jiangsu DZX Technology Co., Ltd. (Changzhou DLX Alloy) was founded in 2016. Its core team has worked in the field since 2002, with 24 years of precision-alloy R&D and production experience, operating a self-owned 12,000-square-meter modern factory with an ISO9001 system covering three inspection stages. Annual alloy output exceeds 1,200 tonnes, serving 1500+ business customers worldwide. The company operates integrated melting, drawing, annealing and precision-machining workshops, supporting volume customization of strip, wire, tube and bar. Every batch includes a chemical analysis report (MTC) for full delivery-quality traceability.

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Frequently Asked Questions

Do you supply CuNi seawater tubes to ASTM B151?

Yes. CuNi10Fe and CuNi30Mn tubes are supplied to ASTM B151 with verified chemistry and dimensional reports for fabrication.

Can you provide pressure-test documentation?

Within the agreed scope, tubes include hydrostatic test records to classification-society rules or your specification.

Can deliveries match shipyard block-construction windows?

Yes. Deliveries are scheduled to your block-construction windows with dates confirmed per purchase order.

What sizes are available for seawater piping?

CuNi tubes are supplied to drawing, typically 15 mm to 300 mm OD, with plate also available for headers and flanges.

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