ASTM A182 F304N
ASTM A182 F304N Flanges & Fittings
ASTM A182 F304N is a nitrogen-strengthened version of 304 stainless steel, offering enhanced mechanical strength, pitting & crevice corrosion resistance, and improved toughness compared to standard 304 and 304L grades.
Nitrogen addition increases austenitic stability, enabling higher strength without the risk of carbide precipitation. This grade is widely used in critical piping systems, chemical plants, marine applications, food processing, and high-purity industrial processes.
It is supplied in forged condition for manufacturing flanges, forged fittings, valves, and pressure-bearing components.
Key Features
Enhanced yield & tensile strength due to nitrogen addition
Excellent pitting & crevice corrosion resistance
Superior toughness and ductility
Great resistance to chloride-induced stress corrosion cracking
Good weldability and fabrication characteristics
Suitable for medium-to-high corrosion environments
Maintains strength at cryogenic & elevated temperatures
Technical Specification
| Property | Description |
|---|---|
| Standard | ASTM A182 |
| Grade | F304N |
| UNS | S30451 |
| Material | Nitrogen-Alloyed Austenitic Stainless Steel |
| Forms | Forged Flanges, Fittings, Valves, Components |
| Delivery Condition | Forged / Rolled / Heat-treated |
| Ratings | Class 150 to 2500 / PN 6 – PN 400 |
Equivalent Grades
| Standard | Equivalent Designation |
|---|---|
| UNS | S30451 |
| EN | 1.4949 (Similar nitrogen alloyed grade) |
| WNR | — |
| ASTM | A182 F304N |
| ASME | SA182 F304N |
| JIS | SUS304N |
Available Sizes
| Product | Size Range |
|---|---|
| Forged Fittings | ½″ to 4″ (DN15 – DN100) |
| Flanges | ½″ to 48″ (DN15 – DN1200) |
| Pressure Class | 150#, 300#, 600#, 900#, 1500#, 2500# |
| Wall Thickness | SCH 10 – XXS |
Chemical Composition
| Element | Min | Max |
|---|---|---|
| Carbon (C) | — | 0.08 |
| Chromium (Cr) | 18.0 | 20.0 |
| Nickel (Ni) | 8.0 | 11.0 |
| Nitrogen (N) | 0.10 | 0.16 |
| Manganese (Mn) | — | 2.00 |
| Silicon (Si) | — | 1.00 |
| Phosphorus (P) | — | 0.045 |
| Sulfur (S) | — | 0.030 |
| Iron (Fe) | Balance | Balance |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | 580 MPa (Min) |
| Yield Strength | 260 MPa (Min) |
| Elongation | 35% (Min) |
| Hardness | 95 HRB Max |
Physical Properties
| Property | Value |
|---|---|
| Density | 8.0 g/cm³ |
| Melting Point | 1400–1450°C |
| Modulus of Elasticity | 193 GPa |
| Thermal Expansion | 17.2 µm/m°C |
| Thermal Conductivity | 14–16 W/m-K |
Type ASTM A182 F304N Flanges & Fittings
Corrosion Resistance
Better localized corrosion resistance compared to 304/304L
Strong resistance to marine atmospheres
High resistance to chloride stress corrosion cracking
Ideal for chemical processing, food, and pharma environments
Heat Resistance
Suitable for elevated temperature service
Oxidation resistance up to 870°C
Maintains mechanical integrity in thermal cycling conditions
Heat Treatment
| Process | Condition |
|---|---|
| Solution Annealing | 1010–1120°C followed by rapid cooling |
| Hardening | Not hardenable by heat treatment (cold-working only) |
Welding
Good weldability with TIG / MIG / SMAW / SAW
Low-carbon filler recommended if maximum corrosion resistance is required
Post-weld annealing recommended for critical services
Fabrication
Excellent formability and machining behavior
Cold working increases strength further
No pre-heating required
Applications
Chemical Processing & Petrochemical Plants
Marine & Offshore Pipelines
Food & Beverage Industry
Pharmaceutical & Biotech Plants
Heat Exchangers & Pressure Vessels
Desalination Units
Piping Systems for Nitrogen-Rich Media
LNG & Cryogenic Applications