TOBO Industrial (Shanghai) Co., Ltd., a leading manufacturer and global supplier of precision-engineered metal products, has announced the expansion of its advanced alloy portfolio with the introduction of Alloy CuNi 90/10 (UNS C70600) Cold-Drawn Seamless Tubes. Engineered for the most demanding marine, offshore, energy, and industrial processing applications, these tubes combine exceptional corrosion resistance with the superior structural integrity of cold-drawn seamless construction.
The Material of Choice for Aggressive Environments
At the heart of this new product line is the UNS C70600 (CuNi 90/10) alloy, a material long trusted in marine and offshore engineering. Comprising approximately 90% copper and 10% nickel with controlled additions of iron and manganese, it delivers a unique combination of properties that make it superior to conventional materials in challenging service conditions.
Unrivaled Seawater Corrosion Resistance: C70600 exhibits extremely low general corrosion rates in seawater, typically below 0.025 mm per year . It provides exceptional protection against pitting, crevice corrosion, and stress-corrosion cracking—common failure modes in chloride-rich environments .
Natural Biofouling Resistance: The alloy's surface chemistry inherently inhibits the adhesion and growth of marine organisms, such as barnacles and mussels, reducing maintenance requirements and preserving hydraulic efficiency in seawater systems .
Good Mechanical Properties: With tensile strength ranging from 275-370 MPa in the annealed condition to 480 MPa in hard-drawn tempers, and elongation of 20-40%, C70600 maintains excellent formability and durability across a wide temperature range .
Thermal and Mechanical Stability: The alloy performs reliably from cryogenic conditions up to 371°C, with no low-temperature embrittlement, making it suitable for heat exchangers and condensers .
Proven Longevity: Systems utilizing C70600 components have demonstrated service lives exceeding 30-40 years in marine environments, offering exceptional total cost of ownership despite higher initial material costs .
The Integrity of Cold-Drawn Seamless Construction
A pivotal aspect of this product launch is the cold-drawn seamless manufacturing process. The production begins with hot extrusion of cast billets, followed by cold working (cold drawing) and annealing operations. Cold drawing involves pulling the tube through a die to reduce its diameter and wall thickness while improving dimensional accuracy and surface finish . Intermediate annealing at 650-750°C relieves internal stresses and restores ductility for subsequent processing .
This multi-stage cold-working process results in:
Homogeneous Microstructure: Uniform grain structure around the entire circumference provides consistent mechanical strength and corrosion resistance .
Superior Dimensional Precision: Tolerances as tight as ±0.05mm on wall thickness ensure perfect fit in system assemblies .
Enhanced Fatigue Resistance: Absence of weld defects and associated heat-affected zones results in superior resistance to vibration and pressure cycling, essential for dynamic offshore and power generation environments .
Improved Flow Performance: Smooth internal surface minimizes friction and turbulence, reducing pumping energy requirements .
Quality Assurance and Compliance
TOBO's seamless tubes are manufactured and tested to meet rigorous international standards, including ASTM B111 / ASME SB111 for seamless condenser tubes and ASTM B466 / ASME SB466 for seamless pipe . Each production batch undergoes comprehensive quality verification, including chemical composition analysis (Ni 9.0-11.0%, Fe 1.0-1.8%, Mn ≤1.0%), mechanical testing, eddy current testing per ASTM E243, hydrostatic pressure testing, and flattening and expansion tests per ASTM B153 .
Certification options include Mill Test Certificates (MTCs) and EN 10204 Type 3.2 certification through independent third-party inspection by agencies such as SGS, BV, or TUV upon request .
Industry Applications Across Critical Sectors
These high-performance seamless tubes serve essential functions across multiple industries:
Marine and Offshore Engineering: Seawater cooling systems, ballast water management, fire-fighting pipelines, and subsea equipment .
Power Generation: Steam condenser tubing, feedwater heaters, and auxiliary cooling circuits in coastal and nuclear power plants .
Desalination and Water Treatment: Multi-stage flash (MSF) evaporator tube bundles, reverse osmosis (RO) plant piping, and brine heater sections .
Chemical and Petrochemical Processing: Heat exchanger tubes and process piping handling corrosive media .
Conclusion: The Trusted Standard for Corrosion-Resistant Piping
The introduction of TOBO's Alloy CuNi 90/10 (C70600) Cold-Drawn Seamless Tubes represents a significant advancement in materials technology. By combining the proven corrosion resistance of copper-nickel alloy with cold-drawn seamless construction and rigorous quality assurance, TOBO provides engineers and procurement specialists with a reliable solution for the most challenging fluid transport applications.
About TOBO Industrial (Shanghai) Co., Ltd.
TOBO is a professional manufacturer and exporter of precision-engineered metal products based in Shanghai, China. With robust production capacity and a commitment to metallurgical excellence, TOBO serves customers worldwide across marine, energy, chemical, and industrial sectors, specializing in copper-nickel alloys, nickel alloys, and stainless steels.