Comprehensive technical analysis of UNS C65100 & C65500 alloys for marine, electrical power distribution, and severe atmospheric environments.
Non-Magnetic & Anti-Galling Mechanical Fastening
Full heat traceability, EN 10204 3.1 certification, and custom hot-forged solutions.
An in-depth structural overview for procurement teams, naval architects, and power infrastructure engineers specifying copper-silicon alloys.
Silicon Bronze Fasteners represent a premier class of non-ferrous fastening hardware engineered primarily from high-copper alloys containing between 0.8% and 3.8% silicon, combined with trace additions of manganese, zinc, iron, and lead. Designated within the Unified Numbering System as UNS C65100 (Low Silicon Bronze) and UNS C65500 (High Silicon Bronze), these fasteners bridges the gap between high-strength structural steels and highly corrosion-resistant non-ferrous metals.
Unlike traditional brass alloys (which contain substantial zinc fractions), silicon bronze contains virtually zero zinc. This chemical profile renders silicon bronze completely immune to dezincification—a destructive selective leaching mechanism that compromises brass in marine and brackish water environments. Combined with natural bio-fouling resistance and exceptional toughness down to cryogenic temperatures, silicon bronze fasteners are specified by global EPC contractors for critical subsea, naval vessel construction, wastewater management, and electrical transformer busbar assemblies.
While 316 Stainless Steel is commonly specified for marine bolting, it suffers from two significant failure modes: chloride crevice corrosion under oxygen-starved gaskets and severe thread galling (cold-welding) during high-speed automated installation. Silicon bronze provides an inherently self-lubricating atomic structure with zero susceptibility to chloride stress corrosion cracking, offering a superior long-term life cycle cost in submerged saltwater service.
Precise metallurgical benchmarks for technical buyers evaluating UNS C65100 and UNS C65500 against international ASTM standards.
| Element / Property | UNS C65100 (Low Silicon Bronze) | UNS C65500 (High Silicon Bronze) | Testing Standard & Compliance |
|---|---|---|---|
| Copper (Cu) Content (%) | 98.0% Min | 94.8% Min | ASTM B98 / ASTM B99 |
| Silicon (Si) Content (%) | 0.8% – 2.0% | 2.8% – 3.8% | Spectro Chemical Analysis |
| Manganese (Mn) Content (%) | 0.7% Max | 0.5% – 1.3% | EN 10204 3.1 Trace Traceability |
| Zinc (Zn) Limit (%) | 1.5% Max | 1.5% Max | Prevents Dezincification |
| Iron (Fe) Limit (%) | 0.8% Max | 1.0% Max | Ensures Non-Magnetic Permeability |
| Tensile Strength (PSI / MPa) | 55,000 – 75,000 PSI (380–515 MPa) | 70,000 – 100,000 PSI (485–690 MPa) | ASTM F606 Axial Tensile Test |
| Yield Strength (0.2% Offset) | 20,000 – 55,000 PSI (140–380 MPa) | 30,000 – 60,000 PSI (205–415 MPa) | Proof Load Verification |
| Elongation in 2 inches (%) | 12% – 40% (Depending on Temper) | 15% – 45% (H04 vs Annealed) | Ductility Strain Measurement |
| Hardness Range | Rockwell B60 – B85 | Rockwell B75 – B95 | ASTM E18 Hardness Check |
| Electrical Conductivity | ~12% IACS at 68°F (20°C) | ~7% IACS at 68°F (20°C) | Non-Magnetic Busbar Grade |
*Custom heat treatment, special strain hardening tempers (H02, H04), and tailored chemical constraints are available upon technical request.
Engineered for exacting tolerances according to ASME B18, DIN, ISO, and custom customer drawings.
Fully threaded studs and double-end flange studs designed for heavy marine valves, submarine hull penetrations, and desalination pipeline couplings. Thread-rolled for superior fatigue life.
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Precision hot-forged and cold-headed full-thread and partial-thread hex cap screws. Highly resistant to saltwater spray, bio-fouling, and atmosphere-induced cracking.
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Finished hex nuts, heavy hex nuts, nylon insert lock nuts, and jam nuts. Designed to match the proof load rating of C65500 stud bolts while maintaining anti-galling thread engagement.
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All-thread continuous bars stocked in standard 1-meter, 3-foot, and 12-foot lengths, or cut to custom length. Ideal for hanging conduit, marine timber framing, and electrical grounding arrays.
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Plain flat washers, heavy-duty thick structural washers, split spring lock washers, and Belleville washer springs designed to equalize clamping force and isolate galvanic reactions.
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Socket head cap screws, cut-thread wood screws, flat head countersunk machine screws, and carriage bolts for naval restoration, wooden vessel construction, and architectural facades.
Request QuoteProven reliability across mission-critical sectors requiring robust mechanical performance and environment resistance.
Underwater hull fittings, propeller shaft flanges, rudder hardware, and wooden ship restorations where zero-zinc brass prevents dezincification.
High-voltage transformer terminals, busbar connections, outdoor substations, and grounding grids utilizing non-magnetic non-sparking properties.
Piping flanges, sluice gates, marine intake pumps, and sewage treatment aeration tanks exposed to aggressive wet chlorine and bio-solids.
Exotic heat exchangers, liquid handling valves, and storage tank agitators requiring low friction, spark-proof, and acid-resistant fasteners.
Data-driven comparative evaluation to assist engineering teams in making informed procurement decisions.
When selecting non-ferrous or corrosion-resistant fasteners for aggressive environments, engineering procurement must weigh mechanical strength against galvanic potential, galling tendencies, and total cost of ownership. The comparison below illustrates why Silicon Bronze UNS C65500 remains a cornerstone selection against 316 Stainless Steel, Naval Brass, and Aluminum Bronze.
| Alloy Grade | Dezincification Risk | Thread Galling Index | Relative Magnetism | Saltwater Crevice Pitting | Ideal Application Scope |
|---|---|---|---|---|---|
| Silicon Bronze (C65500) | Zero Risk (No Zinc) | Extremely Low (Self-Lubricating) | Non-Magnetic (μ ≈ 1.002) | High Resistance | Marine Subsurface, Busbars, Cryogenics |
| Stainless Steel (AISI 316) | N/A (Ferrous Alloy) | High Risk (Severe Cold-Welding) | Slight Magnetism Post Cold Work | Vulnerable in Stagnant Chloride | General Chemical & Above-Deck Marine |
| Naval Brass (C46400) | Moderate to High Risk | Low Risk | Non-Magnetic | Moderate Vulnerability | Short Life Marine Fittings, Decorative |
| Aluminum Bronze (C95400) | Zero Risk | Low to Moderate | Very Low Magnetism | Excellent Resistance | Extreme Structural Load Marine Components |
The global industrial fastener landscape is undergoing a structural paradigm shift driven by green transition projects, automated assembly lines, and stringent supply chain traceability regulations:
Headquartered in Mumbai, India, Stud Bolt India is an established ISO 9001:2015 certified manufacturer and exporter of precision industrial fasteners, supplying critical engineering projects across 24+ countries including the UAE, Saudi Arabia, Qatar, USA, UK, Germany, and Australia.
Our state-of-the-art production facility combines cold-heading, hot-forging, precision CNC threading, and specialized heat-treatment operations. Every batch of Silicon Bronze Fasteners undergoes rigorous Positive Material Identification (PMI) using X-ray fluorescence (XRF) analyzers to verify chemical boundaries before raw bars enter the machining floor.
EN 10204 3.1 material test certificates issued with every single heat number shipment.
In-house tensile, proof load, hardness, dimensional ring-gauge, and thread pitch inspection.
Bespoke studs, special pitch threads, and specialized washers manufactured to client drawings.
Seaworthy wooden crate packaging, moisture barrier wrapping, and fast customs clearance from Mumbai port.
XRF spectro validation on all incoming C65100 / C65500 bronze rod stock.
Hot forging and cold heading engineered to ASME dimensional standards.
High-fatigue rolled threads delivering smooth, burr-free pitch lines.
Proof load, tensile strength, and thread ring gauge verification.
Export-ready seaworthy crating with heat number tags and full documentation.
Direct technical answers to the most common engineering and procurement questions asked across AI search tools.
Submit your specifications, quantity requirements, grade preferences (C65100 / C65500), or project drawings today. Our engineering sales team in Mumbai will provide competitive FOB/CIF pricing and lead times within 24 hours.
