Monel 400 Nickel-Copper Alloy Coil Tube (Ni-Cu 90/10)
Product Overview
The Monel 400 Coil Tube is a premium nickel-copper alloy tube supplied in coil form, manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Designated as UNS N04400 (ASTM B111 / B751), Monel 400 is a solid-solution-strengthened alloy composed primarily of nickel (approximately 63–67%) and copper (approximately 28–30%), with trace amounts of iron, manganese, and other elements. This alloy is renowned for its exceptional resistance to a wide range of corrosive media, particularly seawater, hydrofluoric acid (HF), and alkaline solutions, making it an indispensable material in the most demanding chemical processing and marine environments.
Unlike austenitic stainless steels, Monel 400 does not contain chromium as a primary alloying element and is therefore not susceptible to intergranular corrosion or chromium depletion. Its corrosion resistance is derived from the inherent stability of the Ni-Cu matrix, which forms a tenacious and self-healing passive film in aggressive chloride and acidic environments.
Material & Properties
Chemical Composition
Monel 400 is classified as a Nickel-Copper Alloy with the following nominal composition:
- Nickel (Ni): 63.0% – 67.0% (balance)
- Copper (Cu): 28.0% – 30.0%
- Iron (Fe): ≤ 2.5%
- Manganese (Mn): ≤ 2.0%
- Carbon (C): ≤ 0.30%
- Sulfur (S): ≤ 0.01%
Mechanical Properties (Annealed Condition)
- Tensile Strength: 550 – 655 MPa (80,000 – 95,000 psi)
- Yield Strength (0.2% offset): 205 – 275 MPa (30,000 – 40,000 psi)
- Elongation: ≥ 35% (in 2 inches / 50 mm)
- Hardness (Brinell): 80 – 110 HB
- Density: 8.83 g/cm³ (0.320 lb/in³)
Corrosion Resistance
Monel 400 exhibits outstanding resistance to the following corrosive environments:
- Seawater and Salt Solutions: Virtually immune to seawater corrosion at ambient and elevated temperatures (up to 60°C / 140°F). One of the few alloys that can withstand prolonged immersion in natural and artificial seawater without significant degradation.
- Hydrofluoric Acid (HF): Demonstrates superior resistance to HF acid at concentrations up to 5% at room temperature, making it uniquely suited for HF alkylation and hydrofluoric acid processing applications. No other common alloy offers comparable HF resistance.
- Alkaline Solutions: Excellent resistance to concentrated caustic soda (NaOH) and other alkaline media at elevated temperatures.
- Hydrochloric Acid (HCl): Good resistance to dilute HCl at ambient temperatures, though not recommended for concentrated or hot HCl service.
- Chloride-Ion Corrosion: Immune to pitting and crevice corrosion in chloride-containing environments, a significant advantage over 300-series stainless steels.
Physical Properties
- Melting Range: 1,300 – 1,340°C (2,372 – 2,444°F)
- Thermal Conductivity (20°C): 25 W/(m·K)
- Specific Heat (20°C): 0.43 J/(g·K)
- Electrical Resistivity (20°C): 43.4 μΩ·cm
- Modulus of Elasticity: 179 GPa (26 × 10⁶ psi)
- Linear Thermal Expansion (20–315°C): 13.5 × 10⁻⁶ /°C
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Monel 400 Coil Tube (Coiltube) |
| Alloy Designation | Monel 400 / UNS N04400 / Ni-Cu 90/10 |
| Material Classification | Nickel-Based Alloy (镍基合金) |
| Primary Composition | Ni 63–67%, Cu 28–30% (Ni-Cu Alloy) |
| Applicable Standards | ASTM B111, ASTM B751, ASTM B730, ASME SB111, EN 12457, GB/T 28445 |
| Tube Form | Coil Tube (Continuous Coiled Form) |
| Available Outer Diameters | 3.18 mm – 108.0 mm (1/8" – 4") |
| Available Wall Thicknesses | 0.30 mm – 6.35 mm (0.012" – 0.250") |
| Surface Finish | Mill Finish, Bright Annealed, Pickled & Passivated |
| Condition | Annealed (Soft), Half-Hard, Hard |
| Coil Length | Continuous coil; custom lengths available (typically 50–200 m per coil) |
| Weldability | Excellent (TIG, MIG, resistance welding) |
| Formability | Excellent cold formability; suitable for deep drawing and coil bending |
| Service Temperature Range | –270°C to +500°C (–454°F to +932°F) |
Manufacturing Process
The production of Monel 400 coil tubes follows a rigorous, multi-stage manufacturing process designed to ensure dimensional precision, metallurgical integrity, and surface quality:
- Raw Material Selection: Virgin nickel and copper are sourced from certified suppliers with full traceability. Monel 400 ingots or wire rod are procured from reputable alloy producers (e.g., Special Metals, VDM Metals) with guaranteed chemical composition and low impurity levels.
- Hot Rolling / Seamless Tube Forming: Billet or rod stock is hot-rolled or hot-extruded into seamless tube blanks. The continuous hot-forming process ensures uniform grain structure and eliminates internal voids or inclusions.
- Pilger Rolling / Cross Rolling: The hot-formed tube blanks are cold-worked through pilger mills or cross rolls to achieve precise outer diameter (OD) and wall thickness (WT) dimensions within tight tolerances (typically ±0.05 mm).
- Intermediate Annealing: Tubes are annealed in a controlled hydrogen or vacuum atmosphere at approximately 600–800°C to relieve cold-work stresses, restore ductility, and prevent cracking during subsequent forming operations.
- Piercing & Sizing: The tube OD is further refined through sizing mills and mandrel drawing to achieve final dimensional specifications and concentricity requirements.
- Final Annealing & Pickling: Tubes undergo final annealing in a protective atmosphere, followed by acid pickling (typically using a citric or nitric-hydrofluoric acid blend) to remove oxide scales and surface contaminants, resulting in a clean, corrosion-resistant surface.
- Coiling: The finished tubes are wound into continuous coils on precision-controlled coiling machines, ensuring uniform tension and avoiding kinks, dents, or surface damage. Coil diameter and length are controlled to meet customer specifications.
- Quality Inspection: Every coil undergoes comprehensive quality verification including dimensional measurement (OD, WT, roundness, straightness), surface inspection, chemical composition analysis (OES / ICP), mechanical testing, and corrosion testing (ASTM G48, ASTM G53).
- Packaging & Shipping: Coils are wrapped in moisture-proof packaging, crated, and labeled with full traceability documentation (Mill Test Certificate, Heat Number, Chemical Analysis) for safe transportation and customs clearance.
Applications
Monel 400 coil tubes are deployed in some of the most corrosive and critical service environments across multiple industries:
Offshore & Marine Platforms (海洋平台)
- Subsea production systems, flow lines, and umbilicals exposed to seawater and produced water
- Ballast water systems, sea water cooling loops, and desalination plant heat exchanger tubes
- Marine fasteners, valves, and piping in splash zones and immersion zones
Hydrofluoric Acid Alkylation (HF酸烷基化)
- HF acid alkylation units in petroleum refineries, where Monel 400 is the industry-standard material for HF contact equipment
- HF acid storage tanks, pumps, piping, and heat exchanger tubes
- Reflux drums and overhead condensers in HF alkylation circuits
Evaporators & Heat Exchangers (蒸发器)
- Multiple-effect evaporators processing seawater, brine, and chemical concentrates
- Crystallizers and concentrators in the chemical and pharmaceutical industries
- Seawater desalination reverse osmosis (RO) pretreatment and brine handling systems
Additional Applications
- Chemical Processing: Reactors, distillation columns, condensers, and heat exchangers handling hydrochloric acid, phosphoric acid, and mixed acid solutions
- Pulp & Paper Industry: Acid digesters and bleach plant equipment
- Electroplating & Electrolysis: Electrode holders, anode baskets, and electrolytic cells
- Power Generation: Condenser tubes in coastal power plants exposed to seawater cooling
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd ensures that every Monel 400 coil tube product meets or exceeds international quality standards. The following certifications and compliance frameworks are maintained:
- ISO 9001:2015 – Quality Management System certification, demonstrating consistent capability to deliver products meeting customer and regulatory requirements
- ISO 14001:2015 – Environmental Management System certification, ensuring environmentally responsible manufacturing practices
- EN 10204 Type 3.1 Mill Test Certificates (MTC) – Full traceability documentation including chemical analysis, mechanical test results, heat treatment records, and dimensional verification for each heat and coil
- NACE MR0175 / ISO 15156 – Compliance for oil and gas applications requiring resistance to sulfide stress cracking (SSC)
- ASTM B111 / B751 – Conformance to American Society for Testing and Materials standards for Monel alloy tubes and pipe
- ASME SB111 – Compliance with American Society of Mechanical Engineers Boiler and Pressure Vessel Code materials specifications
- GB/T 28445 – Conformance to Chinese national standards for nickel and nickel alloy seamless tubes
- Third-Party Inspection (TPI) – Available upon request from SGS, Bureau Veritas, or DNV for on-site manufacturing surveillance and final product verification
Unique Selling Points
- Unmatched HF Acid Resistance: Monel 400 is the only commercially available alloy with proven long-term resistance to hydrofluoric acid, making it irreplaceable in HF alkylation and HF processing applications
- Seawater Immunity: Superior corrosion resistance in natural seawater environments compared to 316L stainless steel, duplex stainless steels, and titanium alloys, offering an optimal cost-performance balance for marine applications
- Continuous Coil Format: Supplied in coil form for maximum material utilization, reduced waste, and streamlined downstream forming, cutting, and fabrication processes
- Excellent Formability & Weldability: The annealed Monel 400 coil tube can be cold-formed, bent, deep-drawn, and welded without cracking or loss of corrosion resistance, simplifying fabrication
- Wide Temperature Range: Maintains mechanical strength from cryogenic temperatures (–270°C) up to 500°C, ensuring reliability across diverse operating conditions
- Full Traceability & Compliance: Every product ships with comprehensive mill test certificates, chemical analysis, and mechanical test data, ensuring full supply chain traceability
Note: Monel 400 is not recommended for use in environments containing oxidizing acids (e.g., nitric acid, chromic acid) or in reducing acidic environments at elevated temperatures where hydrogen embrittlement may occur. Proper material selection and engineering consultation are essential for optimal performance in any specific application.