Inconel 686 Tube Supplier, Stockist and Exporter
Table of Contents
Aurico Alloys LLP supplies Inconel 686 tube (N06686, Werkstoff 2.4606), seamless to ASTM B622 and welded to ASTM B626, from Mumbai to customers across India and in more than 40 export markets.
686 tube goes into the heat exchanger that has already eaten a 625 or C-276 bundle. Hot acid condensate carrying chlorides or fluorides, mixed oxidising and reducing acids, bleach-plant liquors – these are the process sides where its 15–17% molybdenum and 3.0–4.4% tungsten on a 19–23% chromium base hold out, and where a tube failure means a shutdown rather than a repair.
Sizes and Specifications
| Grade | Inconel 686 |
|---|---|
| UNS number | N06686 |
| Werkstoff (W.Nr.) | 2.4606 |
| Specifications | ASTM B622 (seamless pipe and tube); ASTM B626 (welded tube) |
| Size range | Outside diameter 3.0 mm to 254 mm with wall thickness 0.5 mm to 15 mm, in seamless and welded construction, random or cut lengths up to 6 m and longer to order. |
| Condition and finish | Supplied annealed and pickled, bright annealed or polished, in straight lengths, U-bends and coiled tubing for instrumentation. |
| Certification | EN 10204 3.1 mill test certificate; 3.2 and third-party inspection on request |
Equivalent Grades & Standards
| Property | Value |
|---|---|
| UNS number | N06686 |
| Werkstoff / EN number | 2.4606 |
| Density | 8.73 g/cm3 |
| Melting range | 1338-1380 °C |
| Electrical resistivity | 1.237 µΩ·m |
| Magnetic permeability (at 200 oersted / 15.9 kA/m) | 1.0001 |
| Pipe and tube specification | ASTM B619 / B622 / B626 |
Identifiers and physical constants for Inconel 686. A dash means no such designation is published for this grade.
Chemical Composition
| Element | Min (%) | Max (%) |
|---|---|---|
| Chromium (Cr) | 19.0 | 23.0 |
| Molybdenum (Mo) | 15.0 | 17.0 |
| Tungsten (W) | 3.0 | 4.4 |
| Titanium (Ti) | 0.02 | 0.25 |
| Iron (Fe) | — | 2.0 |
| Carbon (C) | — | 0.01 |
| Manganese (Mn) | — | 0.75 |
| Sulfur (S) | — | 0.02 |
| Silicon (Si) | — | 0.08 |
| Phosphorus (P) | — | 0.04 |
| Nickel (Ni) | — | Balance |
Composition limits for Inconel 686. These are specification limits for the grade, not measured values for a lot; the mill test certificate supplied with your order states the actual analysis.
Mechanical and Physical Properties
Annealed 686 tube runs around 720 MPa tensile. It is a solid-solution alloy supplied solution annealed, with carbon held to 0.01% maximum, which limits carbide precipitation in the heat-affected zone – the reason tube-to-tubesheet welds keep their corrosion resistance.
Industry Applications
Why Inconel 686 tube
Specify 686 tube when the exchanger has a failure history in 625 or C-276, or when the process chemistry is known to be beyond them – not as a default, because it costs more. Seamless tube to B622 and welded tube to B626 are both available: B626 tube is made by automatic welding without filler metal and supplied solution annealed, and is intended for heat-exchanger and condenser service, so welded tube is a sound and often cheaper choice for a bundle.
| Industry | Typical use |
|---|---|
| Chemical processing | Heat exchangers in mixed-acid and halide-bearing process streams. |
| Waste treatment | Coolers and condensers handling acid condensate from incineration. |
| Pulp and paper | Exchangers in chlorine dioxide bleaching plant. |
| Oil and gas | High-chloride sour-service exchanger tube; the alloy is approved under NACE MR0175. |
Testing and Certification
Tube ships with an EN 10204 3.1 mill test certificate stating heat number, chemical analysis and mechanical properties. We add hydrostatic and ultrasonic testing, positive material identification and ASTM G28 intergranular corrosion testing on request, can certify to NACE MR0175 / ISO 15156, and arrange third-party release under our ISO 9001:2015 system.
Frequently Asked Questions
Request a Quotation
Send your size, quantity and specification and we will come back with price and lead time, usually the same working day. Call +91 7977 88 6611 or email info@auricoalloys.com.