Inconel 686 Plates | UNS N06686 Corrosion-Resistant Plates for Phosphoric Acid, FGD & Sour Marine Service
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A complex phosphate‑fertiliser and power‑cogeneration site in India had learned the hard way that “acid‑resistant” stainless steels and even conventional Ni‑Mo alloys could not survive long in mixed phosphoric and sulfuric acid reactors, FGD outlet ducts and brine‑laden desalination lines, where pH sat near 1 and chlorides regularly exceeded 50,000–100,000 ppm. Corrosion audit data showed wall‑losses approaching 0.5–1.0 mm/year in some sections and repeated leaks at weld heat‑affected zones, but when the most critical linings, tower sections and condenser plates were rebuilt in Inconel 686 Plates (UNS N06686, W.Nr. 2.4606), a single‑phase Ni‑Cr‑Mo‑W alloy described as having “outstanding resistance to general corrosion, stress‑corrosion cracking, and pitting and crevice corrosion” with PREN values around 51, corrosion rates in 80% sulfuric acid at 80°C of about 0.1 mm/year and Critical Pitting and Crevice Temperatures above 85°C in ASTM G48 ferric chloride testing, inspection intervals extended and unplanned leaks dropped to essentially zero in those upgraded circuits.
INCONEL alloy 686 (UNS N06686 / W.Nr. 2.4606) is a single‑phase, austenitic nickel‑chromium‑molybdenum‑tungsten alloy developed specifically to resist both strongly reducing and strongly oxidising mixed acid environments, especially those containing high halide levels. Its high nickel and molybdenum contents provide resistance in reducing media, high chromium content provides resistance to oxidising media and the combined molybdenum and tungsten additions give exceptional resistance to localised attack such as pitting and crevice corrosion, while very low iron and carbon contents and carefully controlled microstructure minimise intergranular precipitation and preserve corrosion resistance in weld heat‑affected zones.
For procurement heads, engineers, fabricators, OEMs and hardware or industrial supply stores serving chemical, oil & gas, marine, pharma and power‑generation sectors, this alloy is a strategic answer to “no‑go” corrosion envelopes where even 6Mo stainless, 904L and some Hastelloy‑type alloys struggle in hot, chloride‑rich, low‑pH conditions. Mechanical property data for plate and sheet show typical tensile strengths in the 720–760 MPa range, 0.2% yield strengths around 345–400 MPa, elongation levels of 40–70% and hardness below about 240 HBW, with plate test pieces (for example 6.35–12.7 mm thickness) achieving yield strengths from roughly 364 to 421 MPa, tensile strengths from about 722 to 848 MPa and elongations near 59–71%, which, combined with extremely low corrosion rates in 80% sulfuric acid at 80°C (~0.1 mm/year) and stable behaviour in simulated FGD acid mixtures at 85°C, make Inconel 686 plates a compelling upgrade where downtime is driven by corrosion rather than stress.
Aurico Alloys LLP can help as an affordable, authentic Inconel 686 Plates supplier, manufacturer and stockist in Mumbai, offering UNS N06686 / 2.4606 plate per ASTM B575 / ASME SB575 with EN 10204 3.1 Mill Test Certificates, NACE‑aligned options and cut‑to‑size service for phosphoric and sulfuric acid reactors, pharmaceutical waste treatment and distillation columns, FGD systems, desalination liners, offshore sour‑service structures and high‑precision instrumentation panels. This directly aligns with search intent such as “Inconel 686 plate suppliers in Mumbai for highly aggressive phosphoric and sulfuric acid reactors”, “Corrosion resistant Alloy 686 plates for pharmaceutical waste treatment and distillation columns”, “ASTM B575 Inconel 686 plate stockist for chemical processing equipment in India”, “Inconel 686 plate price per kg in Mumbai for multi-stage flash desalination liners”, “Inconel 686 plates for FGD systems in Indian thermal power plants”, “Marine grade Inconel 686 plates for subsea fasteners and salt-water splash zone protection” and “Leading Inconel 686 alloy plate dealers in Mumbai for extreme crevice corrosion resistance”.
High-quality Inconel 686 Plates ready for industrial use.
Specification Overview
| Supplier & Role | Aurico Alloys LLP – Inconel 686 plate suppliers in Mumbai for highly aggressive phosphoric and sulfuric acid reactors, pharmaceutical waste treatment columns, FGD system internals, desalination liners and offshore sour‑service equipment, supplying plate with EN 10204 3.1 MTCs and NACE‑compliant chemistry where required. |
|---|---|
| Alloy Description | Solid‑solution strengthened Ni‑Cr‑Mo‑W alloy with extremely low Fe and C, designed as a single‑phase austenitic alloy for outstanding resistance to general, pitting, crevice and stress‑corrosion cracking in mixed acid, high‑chloride and oxidising/reducing service. |
| UNS / Werkstoff / EN | UNS N06686, W.Nr. 2.4606; referenced in DIN/EN plate and sheet standards as a high‑alloy Ni‑Cr‑Mo‑W corrosion‑resistant grade. |
| Main Plate Standards | ASTM B575 / ASME SB575 for plate, sheet and strip of Ni‑Cr‑Mo and Ni‑Cr‑Mo‑W alloys including UNS N06686; DIN 17750/17752 temper F69 for plate and sheet; used alongside NACE MR0175/ISO 15156 where sour‑service compliance is required. |
| Thickness Range | 4.75 mm – 150 mm |
| Key Corrosion Focus | Resistance to reducing and oxidising acids, mixed acid solutions with high halides, pH ≈1 or less and chloride levels greater than 100,000 ppm, with high PREN (~51) and CPT/CCT above 85°C in acidified ferric chloride tests. |
| Target Industries | Chemical and fertiliser processing, phosphoric and sulfuric acid production, pharmaceutical waste treatment, pollution control (FGD, stack liners, incinerators), power‑generation and nuclear waste handling, marine and offshore oil & gas. |
UNS & Equivalent Grades
| 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 |
| Plate, sheet and strip specification | ASTM B575 / B906 |
Identifiers and physical constants for Inconel 686. A dash means no such designation is published for this grade.
Stock & Product Availability
As an ASTM B575 / ASME SB575 Inconel 686 plate stockist in Mumbai, Aurico Alloys LLP can supply hot‑rolled and cold‑rolled plates for highly aggressive phosphoric and sulfuric acid reactors, pharmaceutical waste‑treatment vessels, distillation columns, FGD absorber and outlet‑duct liners and multi‑stage flash desalination panels, typically in solution‑annealed condition for optimum corrosion performance and fabricability. Plate data for DIN F69 temper list minimum yield strengths of about 310 MPa, tensile strengths above 690 MPa, elongation above 45% and hardness below 240 HBW, with measured plate properties exceeding these minima in many thickness ranges.
This inventory profile is aligned with search needs such as “Inconel 686 plate suppliers in Mumbai for highly aggressive phosphoric and sulfuric acid reactors”, “ASTM B575 Inconel 686 plate stockist for chemical processing equipment in India”, “Inconel 686 plate price per kg in Mumbai for multi-stage flash desalination liners”, “Inconel 686 plates for Flue Gas Desulfurization (FGD) systems in Indian thermal power plants”, “High-chromium Inconel 686 plate exporters in Mumbai for stack liners and ducting”, “ASME SB575 Inconel 686 alloy plates for hazardous waste incinerator scrubbers”, “Marine grade Inconel 686 plates for subsea fasteners and salt-water splash zone protection”, “Inconel 686 plate stockholders in Mumbai for offshore oil and gas sour service environments”, “Custom cut Inconel 686 plate sizes for oil refinery overhead condensers and piping” and “Inconel 686 cold rolled plates for high-precision chemical instrumentation in Maharashtra”.
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 & Physical Properties
| Property (Plate / Sheet) | Typical Value – Inconel 686 / UNS N06686 |
|---|---|
| Tensile Strength (room temp.) | Typical minimum around 720–760 MPa; some plate data show 722–848 MPa depending on thickness. |
| 0.2% Yield Strength (room temp.) | Typical minimum around 345–400 MPa; plate data show 364–421 MPa for 1.57–12.7 mm thickness. |
| Elongation | ≥40–45% minimum; measured plate elongations around 59–71% depending on gauge. |
| Hardness | Typically 200–250 HB, with specifications limiting hardness to below about 240 HBW for many plate tempers. |
| Pitting & Crevice Resistance | PREN ≈51 with Critical Pitting and Crevice Temperatures >85°C in 6% FeCl₃ (ASTM G48 C&D), indicating extremely high resistance to localised corrosion. |
| Acid Corrosion Rates | Corrosion rates reported around 0.1 mm/year in 80% H₂SO₄ at 80°C and low rates in mixed H₂SO₄/HCl/HF/HNO₃ FGD simulants at 85°C. |
Applications & Benefits
- Chemical & Pharma: Inconel 686 plates are used for highly aggressive phosphoric and sulfuric acid reactors, agitator baffles, pharmaceutical waste‑treatment vessels and distillation columns where mixed acids, halides and low pH rapidly attack stainless and many Ni‑Mo alloys.
- Pollution Control & Power: Alloy 686 plates suit FGD absorber linings, outlet‑duct sections, stack liners, hazardous‑waste incinerator scrubbers and nuclear waste containment hardware thanks to very low corrosion rates in FGD simulants and hot, contaminated acids.
- Marine & Oil & Gas: Marine‑grade Inconel 686 plates enable subsea fasteners, splash‑zone shields, marine heat‑exchanger plates, condenser tubes and offshore sour‑service fittings by combining high pitting resistance (PREN ~51) with stability in high‑chloride, low‑pH conditions.
- Sourcing & Compliance: Verified Inconel 686 plate exporters in India provide solution‑annealed hot‑rolled and cold‑rolled plates with EN 10204 3.1 MTCs, NACE or project‑specific corrosion test data and custom cutting for overhead condensers, piping spools and high‑precision chemical instrumentation in Maharashtra.
FAQ & Search Trends
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Conclusion
Inconel 686 Plates from Aurico Alloys LLP, supplied as UNS N06686 / W.Nr. 2.4606 plate to ASTM B575 / ASME SB575 requirements with EN 10204 3.1 Mill Test Certificates and project‑specific corrosion data, give chemical, oil & gas, marine, pharma and power‑generation uses a Ni‑Cr‑Mo‑W alloy that combines high strength with exceptional resistance to general, pitting, crevice and stress‑corrosion cracking in the most aggressive phosphoric, sulfuric, chloride‑rich and FGD environments are your most corrosion‑critical reactors, ducts, desalination lines and offshore assets still relying on borderline stainless and mid‑range nickel alloys instead of fully optimised Inconel 686 plates?