TOBO Industrial (Shanghai) Co., Ltd., a leading manufacturer and global supplier of precision-engineered metal products, has announced the expansion of its high-performance flange portfolio with the introduction of Copper Nickel (Cu-Ni) alloy flanges manufactured to the rigorous ASTM B151 / ASME SB151 standard. The comprehensive product line includes both 90/10 (UNS C70600) and 70/30 (UNS C71500) grades, featuring Raised Face (RF) and Welding Neck configurations with Class 300 pressure ratings. These premium flanges deliver exceptional corrosion resistance and structural integrity for the most demanding marine, offshore, power generation, and chemical processing applications worldwide.
The ASME SB151 Standard: The Quality Benchmark for CuNi Flanges
The ASME SB151 / ASTM B151 standard is the globally recognized specification for copper-nickel alloy plate, sheet, strip, and rolled bar, which serves as the foundation for high-quality forged flange manufacturing. This standard ensures:
Chemical Composition Verification: Strict control of alloy ratios—for C70600 (90/10): Ni 9.0-11.0%, Fe 1.0-1.8%; for C71500 (70/30): Ni 29.0-33.0%, Fe 0.4-1.0%—essential for optimal corrosion resistance
Mechanical Property Validation: Confirmation of minimum tensile strength (C70600: 275-570 MPa, C71500: 380-620 MPa), yield strength, and elongation requirements
Dimensional Accuracy: ASME B16.5 compliance ensures tight tolerances for perfect fit in system assemblies
Pressure Integrity: Class 300 rating provides robust performance for moderate to high-pressure applications
Material Excellence: C70600 and C71500 Copper-Nickel Alloys
C70600 (90/10 Copper-Nickel) – The Versatile Workhorse:
The 90/10 alloy, comprising approximately 90% copper and 10% nickel with 1.0-1.8% iron, is the most widely used wrought copper alloy for marine engineering applications. Key characteristics include:
Excellent Seawater Corrosion Resistance: Exhibits extremely low general corrosion rates in seawater, typically below 0.025 mm per year, significantly outperforming standard stainless steels in chloride-rich environments
Natural Biofouling Resistance: The alloy's surface chemistry inherently inhibits marine growth, reducing maintenance requirements by up to 60% compared to alternative materials
Good Mechanical Properties: Minimum tensile strength of 275 MPa (annealed) to 570 MPa (hard-drawn), with elongation of 30-45%
Thermal Conductivity: Approximately 44 W/m·K, ideal for heat exchanger and condenser applications
Applications: Seawater cooling systems, desalination plants, marine piping, and power plant condensers
C71500 (70/30 Copper-Nickel) – The Premium Grade:
The 70/30 alloy contains 29-33% nickel with 0.4-1.0% iron, delivering enhanced properties for the most demanding service conditions:
Superior Corrosion Resistance: Of all commercial copper alloys, C71500 offers the best resistance to aqueous corrosion, with high resistance to stress corrosion cracking and impingement attack
Exceptional Strength: Minimum tensile strength of 380 MPa (annealed) to 620 MPa (hard-drawn), significantly stronger than the 90/10 grade
High-Temperature Stability: Maintains mechanical properties in continuous service up to 400°C
Excellent Fatigue Resistance: Superior resistance to cyclic loading and thermal fatigue
Applications: Offshore oil and gas platforms, naval vessels, chemical processing equipment, and critical heat exchangers
Flange Design: RF and Welding Neck Configurations
The product line focuses on two of the most robust and widely used flange types:
Welding Neck Flanges (WN): Recognized as the strongest and most reliable configuration for high-pressure, high-temperature, and cyclic loading services. The tapered hub provides optimal stress distribution, making it the first choice for critical process lines, offshore platform piping, and shipboard systems where joint integrity is paramount.
Raised Face (RF) Flanges: The most common facing for general service, providing an effective sealing surface for a wide variety of gasket types. The raised face concentrates gasket pressure while protecting the flange faces from damage.
Class 300 Pressure Rating: Engineered for Reliability
The Class 300 pressure rating, defined by ASME B16.5, provides robust performance for a wide range of moderate to high-pressure applications. This rating ensures:
Pressure-Temperature Capability: Suitable for demanding marine, offshore, and industrial services where standard Class 150 ratings may be insufficient
Enhanced Safety Margins: The heavier flange construction provides additional strength and reliability for critical system connections
Global Compatibility: ASME B16.5 standards ensure dimensional interchangeability with components from any compliant manufacturer worldwide
Forged Construction: The Integrity Advantage
TOBO's CuNi flanges are manufactured through precision hot forging processes, ensuring superior material properties compared to cast alternatives:
Refined Grain Structure: Forging aligns the metal's grain flow to follow the shape of the flange, eliminating porosity and internal voids common in castings
Superior Strength and Density: The homogeneous microstructure provides higher mechanical strength, better impact resistance, and greater ductility
Enhanced Fatigue Resistance: Essential for components in systems experiencing constant thermal expansion and pressure cycling
100% Non-Destructive Testing: Comprehensive inspection including ultrasonic examination and positive material identification (PMI) verifies quality
Industry Applications Across Critical Sectors
These high-performance CuNi flanges serve essential functions across multiple critical sectors:
Marine and Shipbuilding:
Seawater cooling systems for main engines and auxiliary equipment
Ballast water management and fire-fighting pipelines
Heat exchanger and condenser connections
Naval vessel systems requiring maximum reliability
Offshore Oil and Gas:
Seawater injection lines for reservoir pressure maintenance
Topside and subsea cooling water systems on platforms and FPSOs
Firewater systems and process piping
Desalination and Water Treatment:
Multi-stage flash (MSF) evaporator connections
Reverse osmosis (RO) plant high-pressure piping
Brine heater and heat recovery sections
Power Generation:
Steam condenser tubing in coastal and nuclear power plants
Feedwater heaters and heat exchangers
Cooling water systems for thermal power stations
Chemical and Process Industries:
Heat exchanger connections for corrosive media
Process piping in chemical plants handling aggressive fluids
Pollution control systems and industrial water treatment
Manufacturing Excellence and Quality Assurance
TOBO's state-of-the-art manufacturing facility in Shanghai employs advanced production processes to ensure consistent quality. Quality assurance protocols include:
Material Certification: Mill Test Reports (MTRs) verifying chemical composition and mechanical properties, with EN 10204 3.1 and 3.2 certification available
Dimensional Verification: Precision measurement ensuring compliance with ASME B16.5 specifications
Non-Destructive Testing: 100% radiographic or ultrasonic examination available for critical applications
Hydrostatic Testing: Verification of pressure integrity per applicable standards
Third-Party Inspection: DNV, ABS, LR, BV, SGS inspection available upon request
TOBO operates in accordance with ISO 9001:2015 quality management systems, ensuring consistent product quality and complete traceability for regulated industries.
Economic Advantages and Lifecycle Value
While CuNi alloys command a higher initial material cost compared to carbon steel, the Total Cost of Ownership (TCO) presents compelling economic justification:
Extended Service Life: 30-50 year service life in seawater applications eliminates frequent replacement cycles
Reduced Maintenance: Natural corrosion and biofouling resistance minimize cleaning requirements, chemical treatments, and inspection frequency
Operational Reliability: Prevention of corrosion-related failures avoids costly unplanned downtime
Lower Total Cost of Ownership: Despite premium initial investment, the combination of longevity and reduced maintenance delivers superior long-term value
Global Standards Compliance
TOBO's CuNi flanges meet or exceed international requirements:
ASME SB151 / ASTM B151: Standard specification for copper-nickel alloy plate and sheet
ASME B16.5: Dimensional standards for pipe flanges and flanged fittings
ASME B16.47: For large diameter flanges where applicable
NACE MR0175 / ISO 15156: For sour service applications where required
EN 1092-1: For European market requirements
Conclusion: Setting the Standard for Critical Connections
The introduction of ASTM B151 / ASME SB151 Copper-Nickel 90/10 and 70/30 RF and Welding Neck Class 300 Flanges represents TOBO's commitment to providing comprehensive, high-performance solutions for the most demanding fluid transport applications. By combining the proven corrosion resistance of copper-nickel alloys with forged construction, rigorous quality assurance, and full international certification, TOBO enables engineers, system designers, and project managers to specify with confidence for critical marine, offshore, and industrial applications.
Whether specified for seawater cooling systems on offshore platforms requiring C70600, critical naval applications demanding C71500, or high-pressure process connections in chemical facilities, these flanges deliver the durability, reliability, and performance that modern industry demands.
About TOBO Industrial (Shanghai) Co., Ltd.
TOBO is a professional manufacturer and exporter of precision-engineered metal products based in Shanghai, China. Established in 1998, the company operates multiple manufacturing facilities with over 260 workers and 45 technicians, producing 60,000 tons of pipe fittings annually. With robust production capacity and a commitment to metallurgical excellence, TOBO serves customers worldwide across marine, energy, chemical, and industrial sectors. The company specializes in copper-nickel alloys, stainless steels, duplex steels, nickel alloys, and associated products for demanding applications, with strict quality control and complete traceability.