Bronze Flanged Bolts – Silicon Bronze Flanged Bolts

Premium-Quality Bronze Flanged Bolts and Silicon Bronze Flanged Bolts for Superior Corrosion Resistance and Strength

We are one of the leading manufacturers and exporters of Bronze flanged bolts and Silicon Bronze flanged bolts from India. We have been supplying high-quality corrosion-resistant fasteners to the world market for many decades. Our precision-engineered Bronze and Silicon Bronze flanged bolts represent the pinnacle of fastener technology for marine, industrial, and architectural applications where exceptional corrosion resistance is critical. These specialized fasteners combine the superior corrosion resistance of Bronze alloys with an integrated flange that provides enhanced load distribution, eliminating the need for separate washers while preventing surface damage to the joined materials. Manufactured to exacting standards using premium-grade Bronze alloys, our flanged bolts deliver reliable performance in the most demanding environments, including saltwater exposure, chemical processing, and outdoor architectural applications where standard fasteners would quickly deteriorate.

The integrated flange design of our Bronze flanged head bolts  and Silicon Bronze bolts serves multiple purposes, providing increased bearing surface to distribute clamping force more evenly, reducing the risk of galvanic corrosion by minimizing contact with dissimilar metals, and offering excellent sealing properties in applications where water or fluid ingress is a concern. Each bolt undergoes rigorous quality control throughout the manufacturing process, ensuring dimensional accuracy, material integrity, and superior finish. The combination of premium Bronze alloys, precision manufacturing, and comprehensive quality assurance makes our flanged bolts the preferred choice for applications where failure is simply not an option.

Material Grades and Properties for Bronze Flanged Bolts

Our Bronze flanged bolts and Silicon Bronze flanged bolts are manufactured using premium-grade Bronze alloys carefully selected for specific application requirements:

Key Material Properties by Application:

Silicon Bronze (C65500) is our most popular alloy for flanged bolts in marine applications due to its excellent combination of corrosion resistance, strength, and machinability. Its composition of approximately 97% Copper and 3% Silicon produces a material that resists dezincification while maintaining excellent mechanical properties and developing an attractive patina over time.

All our Bronze materials comply with international standards including ASTM B98/B150/B171, ISO 426-1/426-2, DIN 17662/17663, BS 2874/2875, and JIS H3250.

Manufacturing Processes

Our Bronze flanged bolts and Silicon Bronze flanged bolts undergo sophisticated manufacturing processes to ensure precision, consistency, and superior quality:

Material Sourcing and Verification The manufacturing process begins with careful sourcing of premium-grade Bronze alloy bar stock from approved suppliers. Each batch of raw material undergoes rigorous testing and certification to verify chemical composition, mechanical properties, and compliance with applicable standards. This careful material selection ensures the final product meets the demanding requirements for corrosion resistance and mechanical strength that our customers expect.

Blank Preparation and Forming The manufacturing process continues with precision cutting of Bronze bar stock to specified lengths, allowing for proper material distribution during the forming process. For larger diameter flanged bolts (≥M12), we utilize a hot forging process, where the material is heated to optimal temperature and formed using precision dies that create the integrated flange and shape the bolt head in a single operation. For smaller diameter flanged bolts (≤M10), we employ cold heading, which enhances the material’s mechanical properties through work hardening while forming the integrated flange and bolt head.

Thread Formation Following head forming, the bolt blanks undergo precision thread rolling or thread cutting, depending on size and application requirements. Thread rolling is our preferred method for most flanged bolts, as it produces stronger threads with continuous grain flow and work-hardened surfaces that enhance fatigue resistance. For specialized thread forms or larger sizes, we utilize precision thread cutting on CNC machines. Each thread is carefully formed to meet exact specifications for thread profile, pitch, and tolerances according to international standards.

Heat Treatment Selected Bronze alloys undergo specific heat treatment processes to optimize mechanical properties and ensure dimensional stability. This may include solution annealing, stress relief treatment, and controlled cooling, all carefully monitored and documented to ensure consistent results. Our heat treatment processes are tailored to each alloy’s specific requirements, enhancing strength, ductility, and corrosion resistance as needed for the intended application.

Surface Treatment and Finishing After forming and threading, flanged bolts undergo a series of surface finishing operations to achieve the desired appearance and performance characteristics. This may include cleaning, polishing, passivation, or application of protective treatments. For marine applications, we may apply specialized anti-seize compounds to prevent galling and facilitate future maintenance. Each finishing process is carefully controlled to ensure consistent quality and appearance across production batches.

Quality Control and Inspection Throughout the manufacturing process, our flanged bolts undergo multiple inspection points to verify dimensions, thread quality, material integrity, and surface finish. We employ advanced measurement techniques including optical comparators, thread gauges, and coordinate measuring machines (CMM) to ensure every bolt meets exact specifications. Final inspection includes visual examination, dimensional verification, and random destructive testing to confirm mechanical properties and performance characteristics.

Documentation and Traceability Each production batch is fully documented and traceable from raw material to finished product. We maintain comprehensive records of material certifications, process parameters, inspection results, and test data to ensure complete traceability and quality assurance. This documentation is available to customers upon request, providing confidence in the quality and consistency of our Bronze flanged bolts.

Machinery and Equipment

Our manufacturing facility houses advanced machinery and equipment specifically optimized for producing high-quality Bronze and Silicon Bronze flanged bolts:

Forging and Forming Equipment:

• 200-ton hydraulic presses for hot forging operations
• 150-ton mechanical presses for cold heading
• Induction heating systems for precise temperature control
• Multi-station progressive headers for efficient production
• Specialized dies for integrated flange formation

Threading Equipment:

• SASPI thread rolling machines for precision thread formation
• CNC thread cutting machines for specialized thread profiles
• Thread rolling dies for various thread forms and sizes
• Thread verification systems for quality assurance
• Specialized tooling for Bronze alloys

Heat Treatment Equipment:

• Controlled atmosphere furnaces
• Solution annealing furnaces
• Stress relief furnaces
• Temperature-controlled quenching systems
• Thermal monitoring and recording systems

Inspection and Testing Equipment:

• Optical comparators for thread profile verification
• Coordinate measuring machines (CMM) for dimensional accuracy
• Thread gauges (Go/No-Go) for thread tolerance verification
• Hardness testing equipment (Brinell, Rockwell)
• Tensile testing machines for mechanical property verification
• Salt spray chambers for corrosion testing
• Metallographic examination equipment
• Surface roughness testers

Surface Treatment:

• Automated cleaning and passivation lines
• Polishing equipment for various finish requirements
• Anti-seize application systems
• Surface treatment verification equipment

Quality Control:

• Spectrographic analyzers for material composition verification
• Optical emission spectrometers
• Digital imaging systems for surface inspection
• Environmental chambers for accelerated testing
• Documentation and data management systems

Product Specifications

Our Bronze flanged bolts and Silicon Bronze flanged bolts are available in a comprehensive range of sizes and configurations to meet diverse application requirements:

Standard Dimensional Specifications:

Thread Types:

• Metric ISO (Coarse and Fine)
• Unified (UNC, UNF, UNEF)
• Whitworth (BSW, BSF)
• NPT and BSPT for pipe thread applications
• Custom thread profiles as required

Tolerance Specifications:

• Thread tolerance: 6g (external) per ISO 965-1
• Flange diameter tolerance: ±0.13mm for diameters up to 20mm, ±0.15mm for larger diameters
• Flange thickness tolerance: ±0.08mm
• Length tolerance: ±0.5mm for lengths up to 100mm, ±0.8mm for longer bolts
• Concentricity: 0.05mm TIR (Total Indicator Reading)
• Surface roughness: Ra 3.2 μm standard, Ra 1.6 μm for premium finish

Special Design Features:

• Serrated flange underside option for enhanced grip
• Underhead radius for stress distribution
• Full or partial thread options
• Custom flange geometries for specialized applications
• Drilled head option for safety wire applications
• Anti-vibration features available
• Custom head markings for traceability

Applications and Industries

Our Bronze flanged bolts and Silicon Bronze flanged bolts are utilized across numerous industries where corrosion resistance and long service life are critical:

Marine and Shipbuilding

Bronze flanged bolts excel in marine environments due to their exceptional resistance to saltwater corrosion. The integrated flange provides excellent load distribution for hull fittings, deck hardware, and underwater components. Silicon Bronze flanged bolts are particularly valued for their superior resistance to dezincification and biofouling in seawater applications. Common applications include:

Through-hull fittings and sea cocks where the flange creates an enhanced seal against water ingress, propeller shaft couplings that benefit from the superior torque distribution of the flanged design, rudder assembly connections that require both strength and corrosion resistance, deck hardware mounting including cleats, winches, and rails where the flange prevents damage to gelcoat or teak decking, and marine engine component assembly where the fasteners must withstand both corrosion and vibration.

Architectural and Historical Restoration

The aesthetic appeal, corrosion resistance, and historical authenticity of Bronze and Silicon Bronze flanged bolts make them ideal for architectural applications and historical restoration projects. The flange provides excellent load distribution on fragile or historical materials while offering an attractive appearance for exposed fasteners. These bolts are commonly used in coastal architecture where saltwater exposure demands corrosion resistance, historical building restoration where period-appropriate fasteners enhance authenticity, outdoor structures including pergolas, gazebos, and bridges that are exposed to weather, decorative ironwork where the fastener becomes part of the visible design, and custom furniture and fixtures requiring both strength and aesthetic appeal.

Chemical Processing and Industrial Applications

The chemical resistance of Bronze alloys makes flanged bolts excellent choices for chemical processing equipment and industrial applications where exposure to corrosive substances is a concern. The flange distributes clamping force over a larger area, reducing the risk of leakage and improving seal integrity. Our Bronze flanged bolts are widely used in chemical pump assembly where the flange enhances sealing around gaskets, valve body assembly requiring both strength and chemical resistance, heat exchanger mounting that benefits from the flange’s load distribution, processing equipment in food and beverage industries where contamination concerns preclude zinc-containing fasteners, and pharmaceutical manufacturing equipment where material compatibility and cleanliness are paramount.

Renewable Energy Systems

The long service life and reliability of Bronze flanged bolts make them excellent choices for renewable energy systems, particularly in harsh environments like offshore wind or tidal power installations. The flange design enhances load distribution and reduces maintenance requirements for components that may be difficult to access. Applications include solar panel mounting systems in coastal environments where corrosion resistance is essential, offshore wind turbine components exposed to constant saltwater spray, tidal power generation equipment subjected to continuous submersion in seawater, hydroelectric facility components where both freshwater corrosion and structural integrity are concerns, and battery storage systems where electrical conductivity and long service life are required.

Water Management and Infrastructure

Bronze flanged bolts provide excellent service in water management systems and infrastructure, where their corrosion resistance and sealing capabilities deliver reliable long-term performance. The flange design helps create more effective seals in piping systems and fluid handling equipment. Common applications include water treatment facility components where chemical resistance is essential, irrigation system components exposed to constant moisture and soil chemicals, municipal water distribution systems requiring long service life and safety, flood control mechanisms subjected to periodic submersion, and water feature construction in architectural and landscape designs where aesthetics and durability are equally important.

Oil and Gas Industry

The exceptional corrosion resistance and mechanical reliability of Bronze and Silicon Bronze flanged bolts make them valuable in specific oil and gas applications, particularly in offshore or coastal facilities where saltwater exposure is a concern. The flange design enhances load distribution and improves sealing in critical connections. Our flanged bolts are used in offshore platform components exposed to constant saltwater spray, valve assemblies in seawater-cooled systems, fire suppression system components requiring both reliability and corrosion resistance, non-critical instrumentation mounting in marine environments, and electrical junction boxes where the flange enhances sealing against moisture ingress.

Performance Metrics

Our Bronze flanged bolts and Silicon Bronze flanged bolts deliver exceptional performance across key metrics:

Mechanical Performance:

Corrosion Performance: