COMPREHENSIVE TECHNICAL ANALYSIS AND DATASHEET OF UNS C65500 HIGH SILICON BRONZE FASTENERS

UNS C65500, universally recognized as "High Silicon Bronze" or historically by the trade name Everdur, is the undisputed premier copper alloy for marine, architectural, and direct-burial environments. By alloying pure copper with approximately 3% Silicon and 1% Manganese, the metal undergoes significant solid-solution strengthening. This transforms a naturally soft metal into a high-strength fastener capable of matching the tensile yield thresholds of medium-carbon steel, all while maintaining the supreme corrosion resistance of pure copper.

Unlike stainless steel, which relies on a passive oxide layer and suffers severely from oxygen-starved "crevice corrosion" underwater, C65500 is inherently noble and stable in seawater, brine, and wastewater. Furthermore, its excellent weldability, stunning aesthetic patina, and totally non-magnetic nature make it the ultimate fastening solution for traditional wooden boat building, high-voltage substation grounding, and monumental architectural sculptures.

Silicon Bronze is highly trusted in mission-critical infrastructure where unseen failure (like underground grounding or underwater marine hardware) can be catastrophic. Ananka ensures every fastener lot is backed by rigorous, mill-level chemical traceability.

• EN 10204 Type 3.1: Certifies the mandatory 2.80–3.80% Silicon addition, verifies Manganese content for structural toughness, and confirms the half-hard or hard cold-worked temper mechanical limits.
• EN 10204 Type 3.2: Available upon request for heavy marine shipbuilding, offshore platforms, or municipal wastewater treatment contracts requiring third-party testing oversight.

The C65500 specification is defined by the absence of Zinc or Tin as primary hardeners, relying almost entirely on a heavy injection of Silicon (Si). This metallurgical profile ensures the alloy is completely immune to dezincification while maintaining excellent hot-forging and cold-heading formability.

• Marine & Boat Building: The global standard for wooden boat construction, through-hull fittings, and subsea hardware due to its immunity to crevice corrosion and high structural rigidity.
• Wastewater & Municipal Water Works: Sluice gate fasteners, pump hardware, and weir bolting where the metal must survive constant exposure to raw sewage, sulfides, and chlorides.
• Electrical Utility Grounding: Heavy-duty split bolts, ground clamps, and direct-burial substation fasteners that require corrosion-free longevity in highly acidic soils.

While C65500 exhibits steel-like tensile strength, it possesses a high coefficient of friction. When threading Silicon Bronze nuts onto Silicon Bronze bolts under high loads, severe thread galling (cold welding) can occur rapidly. Premium marine-grade anti-seize or Teflon-based lubricants are strictly mandatory during assembly.