Products Description

ASTM A182 F55 Stainless Steel Forged Fittings & Flanges are high-end forging-grade super duplex stainless steel, strictly adhering to the ASTM A182/A182M high-temperature forged pipe fittings, flanges, and valves standards. Manufactured using a 1100–1140℃ solution annealing + rapid water quenching process, they are specifically designed for extreme operating conditions involving high chloride ions, high pressure, and acid corrosion, and are widely used in high-requirement, high-end engineering projects such as marine oil and gas, seawater desalination, and fine chemicals.

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Element

Element	Content Range	Alloy Function
Carbon (C)	≤0.03%	Low carbon content reduces the risk of intergranular corrosion
Chromium (Cr)	24.0~26.0%	Forms a passive film to provide general corrosion resistance
Nickel (Ni)	6.0~8.0%	Stabilizes austenite phase and improves material toughness
Molybdenum (Mo)	3.0~4.0%	Greatly enhances resistance to chloride pitting and crevice corrosion
Nitrogen (N)	0.20~0.30%	Strengthens the matrix and raises the Pitting Resistance Equivalent Number (PREN)
Copper (Cu)	0.50~1.00%	Unique alloying element, notably improves corrosion resistance to reducing acids such as dilute sulfuric acid and phosphoric acid
Tungsten (W)	0.50~1.00%	Unique alloying element, reinforces resistance to crevice corrosion especially in hot seawater service
Manganese (Mn), Silicon (Si), Phosphorus (P), Sulfur (S)	Mn≤1.00%, Si≤1.00%, P≤0.035%, S≤0.015%	Strict impurity control for enhanced anti-corrosion performance

Key Advantages

Superior Corrosion Resistance:

Completely surpasses ordinary stainless steel and duplex stainless steel, resisting high-chloride seawater and brine erosion; outstanding resistance to chloride stress corrosion cracking (SCC), suitable for sulfur-containing oil and gas environments, and applicable to acidic oil and gas fields.

High Mechanical Strength, Allowing for Lightweight Design:

Yield strength is nearly three times that of 316L austenitic stainless steel. Under the same pressure rating, flanges/fittings can be made with thinner walls, reducing overall equipment weight and saving project material costs; ample safety margin for deformation and burst resistance under high-pressure conditions.

Superior Plasticity and Toughness, Facilitating Processing and Construction:

Minimum elongation of 25%, higher than F53's 15%, making cold forging, machining, beveling, and flange sealing surface finishing easier; stable weldability, compatible with ER2594 welding consumables, eliminating the need for post-weld heat treatment, reducing on-site construction costs.

Highly Recognized in Marine Engineering:

Certified by NORSOK for North Sea offshore platforms, it is the designated high-end material for North Sea oil fields, subsea pipelines, offshore drilling platforms, and high-pressure components in seawater desalination. Its lifespan after long-term immersion in seawater far exceeds that of conventional stainless steel, significantly reducing the frequency of maintenance and replacement.

Excellent Thermal Conductivity and Expansion Performance:

With a higher thermal conductivity than austenitic stainless steel and a lower coefficient of thermal expansion, it experiences less thermal stress under high-temperature alternating temperature conditions. This reduces the likelihood of sealing leaks due to thermal expansion and contraction during long-term flange use.

Typical Application Scenarios

Offshore Oil and Gas Platforms / Subsea Wellheads: High-pressure flanges, pipe fittings, and forgings for downhole acidic conditions;

Seawater Desalination Projects: High-pressure pump bodies, high-pressure pipeline flanges, and reverse osmosis high-pressure components;

Chemical Industry: Dilute sulfuric acid and phosphoric acid production units, pickling equipment, and reducing acid delivery pipe fittings and valves;

Marine Equipment: Marine seawater systems and high-pressure connectors for ballast pipelines;

Geothermal, Saline Wastewater, and Power Plant Desulfurization: High-pressure components for high-salinity wastewater treatment.