Copper Nickel Nuts & Bolts (90/10 & 70/30)| UNS C70600 / C71500
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Copper Nickel Nuts & Bolts (90/10 & 70/30) | UNS C70600 / C71500 Brochure
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Descriptions
At Navkar Metal Syndicate, we manufacture and supply precision-engineered Cupronickel fasteners — including nuts, bolts, studs, screws, and washers — in both 90/10 (UNS C70600) and 70/30 (UNS C71500) alloys. Designed specifically for marine, offshore, power generation, and seawater-exposed systems, these fasteners combine exceptional corrosion resistance, mechanical strength, and anti-fouling performance.
Ideal for applications demanding long-term reliability, leak-proof assembly, and low maintenance, our Cu-Ni fasteners are available in a wide range of head styles (hex, socket/allen, cap, flange, countersunk) and thread forms (metric coarse/fine and unified/inch). Each lot is fully traceable and supplied with Mill Test Certificates (MTCs) as per EN 10204 3.1, ensuring complete transparency and quality assurance.
Navkar Metal Syndicate also offers custom sizes, special coatings, and project-specific certification for international EPC, shipbuilding, and industrial installations. All products are packed in export-grade seaworthy packaging with clear heat number identification and inspection reports on request.
- Available in 90/10 (C70600) and 70/30 (C71500) Cupronickel alloys
- Excellent resistance to seawater, chlorides, and bio-fouling
- Head styles: Hex, Socket, Flange, Cap, Countersunk, Square
- Threads: Metric (M6–M48) & Unified (UNC/UNF/BSW)
- Certifications: EN 10204 3.1 / 3.2 with TPI (Lloyd’s, DNV, BV, SGS)
- Applications: Condensers, pumps, heat exchangers, desalination, shipboard systems
Navkar Metal Syndicate — Trusted worldwide for Cu-Ni marine fasteners combining precision, performance, and corrosion-proof engineering.
Chemical Composition
| Element | 90/10 (C70600) | 70/30 (C71500) |
|---|---|---|
| Copper (Cu) | ~ 86.0 – 90.0% | ~ 65.0 – 70.0% |
| Nickel (Ni) | ~ 9.0 – 11.0% | ~ 29.0 – 33.0% |
| Iron (Fe) | ~ 0.8 – 1.8% | ~ 0.4 – 1.0% |
| Manganese (Mn) | ≤ 1.0% | ≤ 1.0% |
| Lead (Pb) | ≤ 0.02% | ≤ 0.02% |
| Zinc (Zn) | ≤ 0.5% | ≤ 0.5% |
| Balance | Copper | Copper |
Mechanical & Corrosion Properties — Cupronickel Fasteners
| Grade | Condition | Tensile Strength (UTS) | 0.2% Proof / Yield | Hardness (HV) | Corrosion / Seawater Performance |
|---|---|---|---|---|---|
| 90/10 (C70600) | Annealed / Soft | 275 – 360 MPa | 90 – 160 MPa | 80 – 110 | Very good general seawater resistance; low uniform corrosion; good resistance to biofouling & pitting; suitable for moderate flow service. |
| 90/10 (C70600) | Forged / Cold-Worked | 350 – 500 MPa | 200 – 350 MPa | 110 – 200 | Maintains excellent seawater resistance; suitable for marine bolting applications; reliable under moderate erosion or velocity conditions. |
| 70/30 (C71500) | Annealed / Soft | 345 – 420 MPa | 120 – 200 MPa | 95 – 130 | Excellent seawater resistance; lower corrosion rate than 90/10; highly resistant to pitting, crevice corrosion & biofouling in warm or polluted seawater. |
| 70/30 (C71500) | Forged / Cold-Worked | 420 – 600 MPa | 220 – 400 MPa | 130 – 240 | Exceptional seawater & erosion-corrosion resistance; preferred for high-velocity or high-pressure service; ideal for critical offshore bolting. |
Note: Values are typical for fastener-grade Cu-Ni materials and may vary based on size, product form, and fabrication method. Mechanical and corrosion properties conform to ASTM B151 / B151M, ASTM B151 / ASME SB151, and related specifications.
Applications
Navkar Metal Syndicate manufactures Cupronickel Nuts and Bolts in 90/10 (UNS C70600) and 70/30 (UNS C71500) alloys for demanding marine, offshore, and process industry environments. These fasteners are specifically designed to provide reliable, maintenance-free performance in seawater and high-chloride systems, combining mechanical strength with outstanding corrosion resistance.
- Marine construction and shipbuilding — deck fittings, hull hardware, and underwater structures
- Offshore oil & gas platforms, risers, and structural bolting assemblies
- Seawater piping, condenser assemblies, and heat exchanger connections
- Desalination plants, seawater intake structures, and evaporator units
- Pumps, valves, and chemical processing equipment in chloride-bearing environments
- Power generation systems — cooling water lines and turbine casings
- Critical structural joints where long-term anti-fouling and corrosion resistance are essential
- Naval and defense projects — preferred for non-magnetic and anti-spark applications
Our Copper Nickel 90/10 and 70/30 nuts, bolts, studs, and washers are widely used in shipyards, offshore refineries, desalination EPCs, and marine equipment manufacturing due to their proven resistance to seawater corrosion, pitting, and stress cracking. Each fastener is precision-machined, tested, and supplied with Mill Test Certificates (EN 10204 3.1) for complete traceability.
Navkar Metal Syndicate — your trusted partner for corrosion-proof fastening solutions in global marine, desalination, and offshore energy projects.
Types of Cupronickel Nuts & Bolts
| Nuts | Bolts & Screws | Other Forms |
|---|---|---|
| Hex Nuts, Heavy Hex, Square Nuts, Cap Nuts, Castle/Slotted Nuts, Flange Nuts, Eye Nuts | Hex Head Bolts, Heavy Hex Bolts, Flange Bolts, Timber Bolts, Stud Bolts, Set Screws, Eye Bolts | Washers (Flat/Spring), Threaded Rods/Studs, Custom CNC Turned Fasteners |
Standards & International Equivalents:
Navkar Metal Syndicate supplies Cupronickel 90/10 (C70600) and Cupronickel 70/30 (C71500) nuts, bolts, and fasteners manufactured in accordance with leading global standards to ensure compatibility with international marine, power, and industrial projects.
| Standard / Specification | 90/10 (Cu-Ni 90/10) | 70/30 (Cu-Ni 70/30) |
|---|---|---|
| UNS Designation | C70600 | C71500 |
| ASTM / ASME Standards | ASTM B151 / B151M, B122 / B171 ASME SB151 / SB171 |
ASTM B151 / B171 / B122 ASME SB151 / SB171 |
| EN / European Standards | EN 12163, EN 1652, CW352H | EN 12163, EN 1652, CW354H |
| British Standards (BS) | BS CN102 | BS CN107 |
| DIN / WNR | 2.0872 | 2.0882 |
| ISO Equivalents | CuNi10Fe1Mn | CuNi30Mn1Fe |
| Military / Defense Specs | MIL-C-15726 (for Cu-Ni alloys) | MIL-DTL-24202, MIL-F-1183, MIL-C-15726F |
All Cu-Ni nuts, bolts, and washers are produced in compliance with international standards for marine, offshore, and industrial applications, ensuring dimensional accuracy, chemical consistency, and long-term corrosion resistance.
Common Names & International Identifiers
Navkar Metal Syndicate manufactures and supplies Cupronickel 90/10 and Cupronickel 70/30 nuts, bolts, studs, and washers recognized under multiple international designations. These identifiers help ensure global compatibility, traceability, and compliance for marine and industrial fastening systems.
| Category | 90/10 Cu-Ni (C70600) | 70/30 Cu-Ni (C71500) |
|---|---|---|
| Common Names | Cupronickel 90/10, Copper-Nickel 10%, CuNi10Fe1Mn | Cupronickel 70/30, Copper-Nickel 30%, CuNi30Mn1Fe |
| Trade Designations | UNS C70600, CW352H (EN), BS CN102 | UNS C71500, CW354H (EN), BS CN107 |
| CDA Alloy Number | 706 | 715 |
| DIN / WNR | 2.0872 | 2.0882 |
| ISO / EN Equivalent | CuNi10Fe1Mn | CuNi30Mn1Fe |
| Typical Designation in Marine Industry | Cu-Ni 90/10 Marine Grade Fasteners | Cu-Ni 70/30 High Strength Marine Fasteners |
These designations are recognized globally by shipbuilders, desalination plant engineers, and offshore contractors to identify Cupronickel fasteners used in seawater, chemical, and structural applications.
Common Product Forms & Dimensions
Navkar Metal Syndicate offers a comprehensive range of Cupronickel Fasteners — including Nuts, Bolts, Studs, Screws, and Washers — in both 90/10 (UNS C70600) and 70/30 (UNS C71500) grades. Designed for marine, offshore, and industrial applications, each fastener is precision-machined for high corrosion resistance, excellent mechanical strength, and dimensional accuracy.
Bolt Types
- Hex Head Bolts (Full Thread / Half Thread)
- Socket Head Cap Screws (Allen Bolts)
- Flange Bolts & Serrated Flange Bolts
- Eye Bolts & Lifting Bolts
- Square Head Bolts
- Carriage Bolts / Cup Head Bolts
- Machine Screws & Stud Bolts
- Anchor Bolts & Foundation Bolts
- Custom Non-Standard Bolts for Marine Hardware
Nut Types
- Hex Nuts / Heavy Hex Nuts
- Nylock Nuts (Self-Locking)
- Jam Nuts / Thin Nuts
- Square Nuts
- Dome (Cap) Nuts
- Flange Nuts / Serrated Flange Nuts
- Castle Nuts / Slotted Nuts
- Wing Nuts
- Eye Nuts & Lifting Nuts
Washer Types
- Flat Washers
- Spring / Lock Washers
- Sealing Washers (CuNi Alloy)
- Plain / Chamfered Washers
- Machined Precision Washers
- Custom Profiled Washers for Marine Use
Available Sizes
- Metric Threads: M2 to M100
- Imperial / Inch Threads: 1/8″ to 4″ UNC, UNF, BSW, BSF
- Lengths: 10 mm to 500 mm (custom on request)
- Standards: DIN, ISO, ASTM, BS, ANSI, NPT
- Finishes: Natural Cu-Ni, Polished, Passivated, Coated
- Threads: Metric Coarse/Fine, Unified, BSP, or Custom
All Cupronickel fasteners are manufactured to international standards with full Mill Test Certificates (MTCs), traceable heat numbers, and export-grade packing for global marine and industrial projects.
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