Inconel 825 Knife Gate Valves

Falcon Inconel 825 Knife Gate Valves

Advanced Resistance to Sulfuric Acid and Stress Corrosion Cracking

Falcon Inconel 825 Knife Gate Valves are engineered for aggressive chemical processing and oil and gas applications where resistance to both oxidizing and reducing acids is required. Utilizing Alloy 825 (UNS N08825), these valves provide exceptional stability against sulfuric and phosphoric acids, as well as chloride-induced stress corrosion cracking.

1. The Inconel 825 Advantage

The specific balance of Nickel, Iron, and Chromium, with additions of Molybdenum and Copper, gives Inconel 825 unique properties:

• Sulfuric Acid Resistance: Excellent performance in sulfuric acid environments at various concentrations and temperatures.

• Chloride Immunity: The high nickel content provides nearly total immunity to chloride-ion stress-corrosion cracking.

• Non-Pitting: Molybdenum and Chromium additions provide superior resistance to pitting and crevice corrosion compared to 316/317 stainless steels.

• Intergranular Stability: Stabilized with Titanium to resist intergranular attack after welding or exposure to high temperatures.

2. Engineering & Design Features

• Heavy-Duty Solid Gate: Every Falcon 825 valve features a solid (not clad) Inconel gate, precision-ground to ensure a smooth, low-friction seal against the packing and seats.

• Superior Gland Sealing: Outfitted with high-performance PTFE or Graphite-based packing, reinforced to prevent fugitive emissions in volatile chemical lines.

• Erosion-Resistant Deflector Cones: Optional C276 or Stellite-coated deflector cones can be added to protect the 825 body when handling abrasive acidic slurries.

• Flexible Seat Options: Choose between EPDM/Viton for bubble-tight liquid service or Metal-to-Metal for high-solids/slurry applications.

3. Technical Specifications

Parameter	Specification Details
Material Grade	Inconel 825 (ASTM A494 Grade CU5MCuC / UNS N08825)
Pressure Ratings	ASME B16.34 Class 150, 300, 600
Size Range	2" (DN50) to 48" (DN1200)
Design Standards	MSS SP-81, ASME B16.5, API 598
Temperature Range	-29°C to +540°C (1000°F)

4. Primary Industry Applications

Falcon Inconel 825 valves are the industry standard for:

• Oil & Gas (Sour Service): Handling "Sour" gas containing $H_2S$, $CO_2$, and chlorides (NACE MR0175/ISO 15156 compliant).

• Chemical Processing: Production of sulfuric acid, phosphoric acid, and ammonium sulfate.

• Nuclear Fuel Reprocessing: Handling the complex radioactive and acidic waste streams.

• Pollution Control: Exhaust systems and scrubbers where sulfuric acid condensation is a constant threat.

• Pickling Operations: Specifically in steel processing lines utilizing hot sulfuric acid baths.

Quality & Verification Benchmarks

To guarantee the performance of our Inconel 825 builds, Falcon provides:

1. Titanium Verification: PMI testing to ensure the correct Titanium-to-Carbon ratio for stabilization.

2. Pressure Testing: Each valve undergoes hydrostatic shell testing at $1.5 \times$ the rated pressure and pneumatic seat testing per API 598.

3. Dye Penetrant Inspection: All critical welds and sealing surfaces are checked for microscopic surface flaws.

4. Traceability: Full EN 10204 3.1 Material Test Reports for all pressure-containing components.

Technical Comparison: Inconel 825 vs. Alloy 20

While both materials are specifically designed to survive sulfuric acid, they have different "thresholds" of performance. Alloy 20 is often called the "Sulfuric Acid Alloy," but Inconel 825 offers a wider range of protection in more complex environments.

 Chemical Composition & Strength

Feature	Alloy 20 (CN7M)	Inconel 825 (CU5MCuC)
Nickel Content	~32-38%	~38-46% (Higher)
Primary Focus	Pure Sulfuric Acid ($H_2SO_4$).	Sulfuric Acid + Chlorides + High Temps.
SCC Resistance	Good.	Superior (Due to higher Nickel).
Pitting Resistance	Moderate.	Better (Higher Molybdenum/Nickel).
Titanium Stabilized	No (usually Niobium).	Yes