Silicon Bronze Hex Bolts

Comprehensive Overview of Marine-Grade Silicon Bronze Hex Bolts

We are a premier manufacturer and global exporter of Silicon Bronze Hex Bolts, specifically engineered from C65500 High Silicon Bronze A alloy to deliver unmatched performance in the most corrosive environments. For over three decades, we have been the trusted supplier for marine, offshore, and chemical industries worldwide. Our silicon bronze hex bolts are manufactured using precision cold-heading and thread-rolling technology, ensuring superior tensile strength, perfect thread form, and consistent quality. Renowned for their exceptional resistance to saltwater corrosion, high strength, and non-sparking safety, these bolts are the definitive choice for critical applications where failure is not an option. Our manufacturing process is certified under ISO 9001:2015, providing full traceability from raw material to finished bolt.

Silicon Bronze Hex Bolts – The Ultimate Marine Fastener

Silicon Bronze Hex Bolts, made from alloy C65500, represent the highest standard for fasteners in marine and other highly corrosive environments. This alloy provides a unique combination of very high corrosion resistance, excellent strength, and good machinability, making it the preferred choice for permanent and critical fastenings.

Applications of Silicon Bronze Hex Bolts

Marine & Shipbuilding: Hull fastenings, keel bolts, deck hardware, stern tubes, and through-hull fittings in both wooden and metal boats.
Offshore & Coastal Structures: Piers, docks, seawalls, and offshore platform components constantly exposed to salt spray and immersion.
Chemical Processing: Reactors, piping systems, and equipment handling corrosive chemicals, acids, and alkalis.
Architectural Restoration: Historic building restoration, monuments, and permanent outdoor structures where longevity and aesthetics are key.
Water Treatment: Plants, valves, and pipelines for potable water, wastewater, and desalination.

Silicon Bronze Alloy C65500 Specifications

Property	Specification	Value / Description
Alloy Designation	UNS C65500, High Silicon Bronze A	CuSi3Mn1
Tensile Strength	65,000 – 80,000 psi	(448 – 552 MPa)
Yield Strength (0.5% Ext)	30,000 psi (Min)	(207 MPa)
Elongation	40% (Min in 2″)	Excellent Ductility
Corrosion Resistance	Excellent	Superior to most copper alloys in seawater.
Non-Sparking Property	Yes	Safe for hazardous environments (ATEX).
Color	Rich, warm reddish-gold	Maintains appearance without painting.

Silicon Bronze Hex Bolt Technical Specifications

Parameter	Standard Grade	High-Strength Grade
Tensile Strength (MPa)	448 – 552	550 – 655
Yield Strength (MPa)	207 (Min)	345 (Min)
Proof Load Stress (MPa)	235 – 310	380 – 485
Hardness (Rockwell B)	80 – 95	90 – 100
Recommended Working Load	60-80% of Proof Load	60-80% of Proof Load

Standard Sizes: M6 to M36, 1/4″ to 1-1/2″ diameter. Lengths from 20mm to 300mm+.
Threads: Metric Coarse, Metric Fine, UNC, UNF, BSW, BSF. Custom threads available.
Standards: ASTM B124, ASME B18.2.1, ISO 4014, ISO 4017, DIN 933, DIN 931.
Head Marking: Can be marked with grade identifier and our manufacturer’s logo.

Manufacturing Processes & Quality Control

Our Silicon Bronze Hex Bolts are manufactured through a controlled process to ensure grain structure integrity and dimensional precision:

Wire Drawing: High-quality C65500 silicon bronze wire is drawn to precise diameters.
Cold Heading: The bolt blank is formed under high pressure in multi-station cold heading machines to create the hex head and shank. This process creates a stronger bolt than machining.
Thread Rolling: Precise threads are formed by rolling the blank between dies. This cold-forming process work-hardens the threads, resulting in superior strength and surface finish compared to cut threads.
Heat Treatment (Stress Relieving): For certain applications, bolts may undergo stress relieving to minimize internal stresses and prevent stress corrosion cracking.
Deburring & Finishing: Bolts are tumbled to remove sharp edges and ensure a smooth finish.
Quality Inspection: 100% dimensional checks, sample lot testing for mechanical properties, and visual inspection.
Packaging: Packed in corrosion-inhibiting VCI packaging for export.

Quality Assurance Tests:

Dimensional Verification: Go/No-Go gauges for threads, micrometer checks for head dimensions, length, and shank diameter.
Proof Load Testing: Sample bolts are tested to a specified proof load (typically 2x Working Load Limit) without permanent deformation.
Tensile Testing: Destructive testing on sample lots to verify ultimate tensile and yield strength.
Hardness Testing: Rockwell or Vickers hardness tests to verify material temper.
Material Certification: Mill Test Certificates (MTC) provided for all raw material lots, confirming alloy composition per ASTM B124.
Salt Spray Testing: Periodic corrosion resistance testing per ASTM B117 standards (typically 500+ hours without failure).

Frequently Asked Questions (FAQ)

Q1: Why is Silicon Bronze (C65500) considered the best for marine applications?
Silicon Bronze offers an unmatched combination of very high corrosion resistance (superior to other bronze alloys in seawater), high strength, and excellent resistance to stress corrosion cracking and dezincification. It is the benchmark material for critical marine fastenings like wooden boat hulls and permanent coastal structures.

Q2: Are silicon bronze hex bolts stronger than stainless steel bolts?
While high-grade stainless steel (like 316) has a higher ultimate tensile strength, Silicon Bronze C65500 is stronger than standard 304 stainless steel and offers sufficient strength for most marine and industrial applications. Its key advantage is maintaining this strength while being completely corrosion-resistant in saltwater and non-sparking.

Q3: Can you supply matching Silicon Bronze Hex Nuts?
Yes, we are a full-service manufacturer and can supply matching silicon bronze hex nuts in the same C65500 alloy. This ensures optimal performance and prevents galvanic corrosion between the bolt and nut. We provide nuts per standards like ASME B18.2.2, ISO 4032, and DIN 934.

Q4: What is the maximum working temperature for these bolts?
Silicon bronze bolts retain their strength at elevated temperatures better than many aluminum alloys. They are generally suitable for continuous service up to 250°C (480°F). For higher temperatures, specific high-temperature copper alloys should be considered.

Q5: Do silicon bronze bolts gall like stainless steel?
Silicon bronze has excellent anti-galling properties, significantly better than stainless steel. This makes them much less likely to seize during installation or disassembly, especially in threaded connections. The use of an anti-seize compound is still recommended in extreme cases.

Why Choose Our Silicon Bronze Hex Bolts?

Pure C65500 Alloy: We use only certified C65500 alloy, not cheaper alternatives, ensuring you get the true marine-grade performance you pay for.
Precision Cold Forming: Our cold heading and thread rolling process creates bolts with superior grain flow, resulting in higher fatigue life and tensile strength compared to machined bolts.
Full Traceability: From certified silicon bronze wire to finished bolts, we maintain full traceability and provide all necessary documentation, including MTCs and test reports.
Complete Size Range: We cater to both metric and imperial standards and can produce custom diameters, lengths, and thread pitches.
Proven Marine Performance: Our bolts are used in some of the world’s most demanding marine environments, from superyachts to commercial shipping.
Competitive Global Pricing: As a manufacturer based in India, we offer high-quality silicon bronze fasteners at competitive prices, providing excellent value for global customers.

Call to Action – Contact Us Today

Secure your critical marine and industrial applications with the reliability of genuine silicon bronze hex bolts. Contact us for a prompt quote or technical consultation.

Request a Quote: Email your specifications, standards, and quantities to sales@jambrass.com for a detailed quotation within 24 hours.
Call Us Directly: Speak with our marine fastener experts at +91-22-43449300 / +91-22-43449323 (Monday-Saturday, 9:00 AM – 6:00 PM IST).
Visit Our Offices:
- Office Address: 1406, 14th Floor, Dalamal Tower, Nariman Point, Mumbai – 400021, Maharashtra, India
- Factory Address: Plot 10B, GIDC Industrial Estate, Shanker Tekari, Udyognagar, Jamnagar, Gujarat, India – 361004
Samples Available: Contact us to request samples for your evaluation and testing.