Hastelloy C-276 Corrosion-Resistant Tubes for Marine Seawater Cooling Systems
In marine and offshore industries, where constant exposure to saltwater, acids, and chlorides puts materials to the ultimate test, DLX Alloy’s Hastelloy C-276 corrosion-resistant tubes provide the reliability and performance that engineers depend on. Designed to handle aggressive seawater environments and high-temperature applications, these tubes are the backbone of marine cooling systems, heat exchangers, and chemical processing equipment.
Built from a nickel-molybdenum-chromium alloy with tungsten enhancement, Hastelloy C-276 is one of the most versatile corrosion-resistant materials available. DLX Alloy manufactures these precision tubes with exceptional purity, tight dimensional control, and flawless internal finishes, ensuring performance even under extreme pressure and continuous seawater exposure.
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Hastelloy C-276 (UNS N10276 / W.Nr. 2.4819) is a nickel-based superalloy known for its outstanding resistance to both oxidizing and reducing environments. It resists pitting, crevice corrosion, and stress cracking in seawater, chlorine, and other harsh chemical environments. The alloy maintains strength and stability at high temperatures, making it suitable for long-term use in marine heat exchangers, condensers, and cooling circuits.
At DLX Alloy, our C-276 tubes are precision cold-drawn, annealed, and surface-treated to achieve mirror-like inner surfaces, allowing smooth fluid flow and reducing fouling in seawater systems. Each tube is produced under strict standards such as ASTM B622, ASME SB622, and ISO 9001, ensuring compliance with marine and offshore project requirements.
item | HC-276 | C-22 | C-4 | B2 | B3 | N |
C | ≤0.01 | ≤0.015 | ≤0.015 | ≤0.02 | ≤0.01 | 0.04-0.08 |
Mn | ≤1 | ≤0.5 | ≤1 | ≤1 | ≤3 | ≤1 |
Fe | 4-7 | 2-6 | ≤3 | ≤2 | ≤1.5 | ≤5 |
P | ≤0.04 | ≤0.02 | ≤0.04 | ≤0.04 | -- | ≤0.015 |
S | ≤0.03 | ≤0.02 | ≤0.03 | ≤0.03 | -- | ≤0.02 |
Si | ≤0.08 | ≤0.08 | ≤0.08 | ≤0.1 | ≤0.1 | ≤1 |
Ni | rest | rest | rest | rest | ≤65 | rest |
Co | ≤2.5 | ≤2.5 | ≤2 | ≤1 | ≤3 | ≤0.2 |
Ti+Cu | -- | -- | ≤0.7 | -- | ≤0.4 | ≤0.35 |
Al+Ti | -- | -- | -- | -- | ≤0.5 | ≤0.5 |
Cr | 14.5-16.5 | 20-22.5 | 14-18 | ≤1 | ≤1.5 | 6-8 |
Mo | 15-17 | 12.5-14.5 | 14-17 | 26-30 | ≤28.5 | 15-18 |
B | -- | -- | -- | -- | -- | ≤0.01 |
W | 3-4.5 | 2.5-3.5 | -- | -- | ≤3 | ≤0.5 |
V | ≤0.35 | ≤0.35 | -- | 0.2-0.4 | -- | ≤0.5 |
Shape | Size (mm) |
Wire | 0.5-7.5 |
Rod/Bar | 8.0-200 |
Strip | (0.5-2.5)*(5-180) |
Tube/Pipe | Custom made |
Sheet/Plate | Custom made |
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Seawater cooling and desalination systems
Offshore platforms and marine heat exchangers
Power plant condensers and pipelines
Chemical reactors and evaporators
Pulp & paper bleaching systems
Acid handling and exhaust gas scrubbers
In seawater environments, corrosion from chlorides and biofouling can quickly degrade traditional materials. Hastelloy C-276’s high nickel and molybdenum content make it immune to such failures, ensuring extended service life and lower maintenance costs.
Industry Analysis
The marine and offshore energy industries are undergoing rapid transformation, driven by global energy transition and sustainability demands. Modern vessels, LNG carriers, and offshore platforms require cooling and heat transfer systems that can perform under saline, acidic, and variable temperature conditions.
Traditional materials like stainless steel often fall short due to pitting and crevice corrosion, especially when exposed to stagnant seawater or cleaning acids. As a result, nickel-based alloys have become the preferred choice for critical marine applications.
Market trends indicate a rising demand for superalloys with enhanced corrosion performance and long-term cost efficiency. In this context, Hastelloy C-276 stands out for its exceptional chemical resistance, while still maintaining machinability and weldability.
DLX Alloy has taken this a step further by investing in advanced tube-drawing and precision annealing technology, producing tubing with optimized grain structure, minimal inclusions, and consistent mechanical properties—essential for safety-critical marine systems.
Our research and development team continuously refines alloy chemistry and surface finishing to improve anti-fouling performance and heat transfer efficiency, making DLX C-276 tubes a smart and durable choice for next-generation marine cooling applications.
DLX Company Advantages
Integrated Production Line – From melting and extrusion to final polishing, DLX controls every stage of production.
Vacuum Melting & Refining – Ensures low carbon and sulfur levels for superior corrosion resistance.
Precision Tube Drawing – Consistent OD and wall thickness for precise system integration.
Mirror-Finished Inner Surface – Ra ≤ 0.4μm finish enhances cooling flow and resists fouling.
Customized Sizes & Shapes – Available in straight, coiled, or bent configurations for design flexibility.
Strict Testing Standards – Hydrostatic, eddy current, ultrasonic, and dimensional inspections for each batch.
Quick Lead Time & Global Delivery – Optimized logistics support for marine and offshore projects.
Engineering Support – Corrosion analysis, design consultation, and technical documentation available.
With these capabilities, DLX Alloy has earned a reputation for delivering high-performance tubing solutions that meet demanding standards in energy, marine, and industrial sectors.
Technical Comparison Table
| Property / Alloy | Hastelloy C-276 (UNS N10276) | Inconel 625 (UNS N06625) | 316L Stainless Steel | Duplex 2205 Stainless |
|---|---|---|---|---|
| Nickel Content (%) | ~57 | 58 | 10–12 | 5–6 |
| Molybdenum (%) | 16 | 9 | 2–3 | 3–3.5 |
| Chromium (%) | 15.5 | 21 | 17–18 | 22 |
| Corrosion Resistance (Seawater) | Excellent | Good | Fair | Good |
| Pitting Resistance Equivalent (PREN) | >70 | ~45 | ~25 | ~35 |
| Max Operating Temp (°C) | 1100 | 980 | 900 | 950 |
| Weldability | Excellent | Excellent | Excellent | Good |
| Ideal Applications | Marine Cooling, Chemical Systems | Offshore, Aerospace | Food, Industrial | Oil & Gas, Marine |
About Us:
Our 12,000㎡ factory is equipped with complete capabilities for research, production, testing, and packaging. We strictly adhere to ISO 9001 standards in our production processes, with an annual output of 1,200 tons. This ensures that we meet both quantity and quality demands. Furthermore, all products undergo rigorous simulated environment testing including high temperature, high pressure, and corrosion tests before being dispatched, ensuring they meet customer specifications.
For all our clients, we offer timely and multilingual after-sales support and technical consulting, helping you resolve any issues swiftly and efficiently.
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We support all kinds of testing:
1. What makes Hastelloy C-276 ideal for seawater cooling systems?
Its resistance to chlorides, oxidizing agents, and localized corrosion ensures long-term reliability in marine environments.
2. How does DLX maintain corrosion resistance during production?
We use vacuum melting, controlled annealing, and acid cleaning to eliminate inclusions and maintain chemical stability.
3. Are DLX’s C-276 tubes suitable for high-pressure systems?
Yes, the tubes are tested up to 6000 psi, ensuring safe operation in pressurized coolant circuits.
4. Can they be used in both stagnant and flowing seawater?
Absolutely. The alloy’s pitting and crevice resistance make it suitable for both dynamic and static seawater conditions.
5. What surface finishes are available?
We offer polished, bright annealed, or passivated surfaces, with Ra ≤ 0.4 μm for clean fluid flow.
6. Are DLX tubes compatible with other materials?
Yes, C-276 can be integrated with titanium or Inconel systems using appropriate fittings and welding techniques.
7. What quality certifications does DLX Alloy hold?
All production is ISO 9001 certified and compliant with ASTM and ASME material standards.
8. How does DLX ensure delivery quality and consistency?
Through 100% NDT testing, dimensional verification, and individual batch traceability documentation.
