INCONEL
Inconel 686 Tube
Ultra-high corrosion resistance nickel-chromium tube for aggressive chemical processing and seawater environments
Inconel 686 tube delivers exceptional resistance to aggressive chemical media including chlorides, sulfides, and oxidizing acids at elevated temperatures. Engineered for demanding chemical processing, offshore applications, and corrosive fluid transport where material failure risks catastrophic consequences.
Quick Specifications
- UNS Designation
- N06686
- Werkstoff Number
- 2.4606
- Form
- Seamless or Welded Tube
- Tensile Strength (at 20°C)
- 655 - 860 MPa
- Yield Strength (0.2% Offset)
- 310 MPa minimum
- Elongation
- 25% minimum
Standards & Certifications
Product Description
Inconel 686 is an advanced nickel-chromium-molybdenum alloy engineered to provide the most comprehensive corrosion resistance available for extreme chemical processing environments. The alloy combines high chromium and molybdenum content with carefully controlled nickel and iron levels to deliver exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride-bearing solutions, sulfurous environments, and mixed corrosive media. The tube form enables direct transmission of aggressive fluids while maintaining structural integrity and preventing leakage failures.
The tube manufacturing process employs seamless extrusion or welded construction with final heat treatment to optimize corrosion-resistance properties. The microstructure is precisely controlled to maintain high chromium and molybdenum in solid solution, providing exceptional pitting resistance number (PREN) of approximately 65, making it suitable for service in seawater, salt brines, and highly chloridized process streams. Every tube undergoes rigorous hydrostatic testing and surface inspection to ensure freedom from defects and leakage pathways.
Inconel 686 tubes are available in various outer diameters and wall thicknesses to accommodate diverse pressure ratings and flow requirements. The material's superior weldability, compared to higher-chromium specialty alloys, simplifies field installation and modifications. Whether for subsea heat exchangers, chlor-alkali process equipment, or high-pressure chemical reactors, the tube delivers unmatched corrosion protection and operational reliability.
With unparalleled resistance to the most aggressive corrosive environments encountered in industrial processing, offshore operations, and specialized chemical applications, Inconel 686 tube represents the pinnacle of corrosion-resistant materials. The alloy's proven service history in seawater desalination, offshore oil and gas processing, and hazardous chemical synthesis demonstrates its unmatched capability to prevent costly corrosion failures.
Specifications
| UNS Designation | N06686 |
| Werkstoff Number | 2.4606 |
| Form | Seamless or Welded Tube |
| Tensile Strength (at 20°C) | 655 - 860 MPa |
| Yield Strength (0.2% Offset) | 310 MPa minimum |
| Elongation | 25% minimum |
| Density | 8.45 g/cm³ |
| Melting Point | 1360 - 1395°C |
| Thermal Conductivity at 100°C | 12.6 W/m·K |
| Modulus of Elasticity | 215 GPa at 20°C |
| Pitting Resistance Equivalent (PREN) | ~65 |
| Maximum Service Temperature | 900°C (continuous) |
Chemical Composition
| Element | Content (%) |
|---|---|
| Nickel (Ni) | 48.0 - 54.0 |
| Chromium (Cr) | 20.0 - 23.0 |
| Molybdenum (Mo) | 15.0 - 17.0 |
| Iron (Fe) | 4.0 - 6.0 |
| Tungsten (W) | 3.0 - 4.2 |
| Carbon (C) | ≤ 0.05 |
| Manganese (Mn) | ≤ 1.0 |
| Cobalt (Co) | ≤ 2.5 |
| Silicon (Si) | ≤ 0.5 |
| Sulfur (S) | ≤ 0.010 |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength at 20°C | 655 - 860 MPa |
| Tensile Strength at 500°C | 520 - 620 MPa |
| Yield Strength (0.2% Offset) at 20°C | 310 MPa minimum |
| Yield Strength at 500°C | 250 MPa minimum |
| Elongation at 20°C | 25% minimum |
| Reduction of Area | 35% minimum |
| Hardness (Solution Annealed) | ≤ 255 HV |
| Impact Strength (Charpy V, 20°C) | ≥ 80 J |
Key Features & Advantages
Applications
Offshore Oil and Gas Processing
Manufacturing of subsea heat exchangers, process piping, and equipment for handling chloride-rich seawater in crude oil extraction and processing operations where corrosion failures would result in environmental and operational disasters.
Seawater Desalination Systems
Fabrication of heat exchanger tubing and process equipment for converting seawater to fresh water, where extreme chloride concentrations and thermal cycling demand materials with unmatched corrosion resistance.
Chemical Processing Reactors
Construction of reactor vessels, internal piping, and heat transfer equipment for synthesis of specialty chemicals, pharmaceuticals, and fine chemicals where corrosive media and elevated temperatures are inherent process requirements.
Chlor-Alkali Production Plants
Manufacturing of electrochemical cell internals, product pipelines, and brine handling equipment in chlorine and caustic soda production where extreme chloride exposure demands superior material integrity.
Biogas and Anaerobic Digestion Systems
Fabrication of heat exchanger and piping systems in biogas production facilities where sulfide-rich corrosive environments and mixed chemical exposure require exceptional corrosion resistance.
Acid and Pickling Process Equipment
Construction of product lines, heat exchangers, and process vessels for concentrated nitric acid, hydrochloric acid, and ferric chloride service where combined oxidizing/reducing conditions exceed capabilities of conventional materials.
Frequently Asked Questions
How does Inconel 686 compare to other corrosion-resistant alloys like Hastelloy in seawater applications?
Can Inconel 686 tubes be welded in the field, and what precautions are necessary?
What is the PREN value of Inconel 686, and why is it important for chloride environments?
Can Inconel 686 tubes be used for handling sulfide stress corrosion cracking (SSCC) environments?
What surface finish is recommended for Inconel 686 tubes to maximize corrosion resistance?
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