ASTM A403 WP904L
ASTM A403 WP904L Pipe Fittings
ASTM A403 WP904L is a high-alloy austenitic stainless steel grade designed for severe corrosion environments, particularly in sulfuric acid, phosphoric acid, and chloride-rich atmospheres. Known for its low carbon content and high nickel-chromium-molybdenum composition, Grade WP904L delivers exceptional resistance to pitting, stress corrosion cracking, and crevice corrosion.
These fittings are extensively used in chemical industries, seawater systems, pharmaceuticals, and oil & gas processing plants where superior durability and corrosion resistance are required.
Key Features
Excellent resistance to sulfuric, phosphoric & hydrochloric acids
High resistance to pitting & crevice corrosion
Low carbon content prevents carbide precipitation & sensitization
Strong mechanical strength & toughness
Suitable for high-temperature & high-pressure pipe systems
Long service life in aggressive environments
Technical Specification Table
| Specification | Details |
|---|---|
| Standard | ASTM A403 / ASME SA403 |
| Grade | WP904L |
| Material | Stainless Steel 904L |
| Process | Seamless / Welded / Fabricated |
| Schedule | SCH 5S, 10S, 20S, 40S, 80S, 160S, XXS |
| Size Range | ½” to 48” |
| Type | Buttweld Pipe Fittings |
Equivalent Grades
| Standard | Grade |
|---|---|
| UNS | N08904 |
| WNR | 1.4539 |
| JIS | SUS 904L |
| BS | 904S13 |
Available Sizes
Buttweld Fittings: ½” to 48”
Thickness: SCH 5S to XXS
Formats: LR/SR Elbows, Equal/Reducing Tees, Concentric/Eccentric Reducers, End Caps, Stub Ends, Pipe Bends
Chemical Composition (% max)
| Element | Content |
|---|---|
| C | ≤ 0.020 |
| Mn | ≤ 2.00 |
| Si | ≤ 1.00 |
| P | ≤ 0.045 |
| S | ≤ 0.035 |
| Cr | 19.0 – 23.0 |
| Ni | 23.0 – 28.0 |
| Mo | 4.0 – 5.0 |
| Cu | 1.0 – 2.0 |
| Fe | Balance |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength | ≥ 490 MPa |
| Yield Strength | ≥ 220 MPa |
| Elongation | ≥ 35% |
| Hardness | ≤ 90 HRB |
Types of ASTM A403 WP904L Fittings
ASTM A403 WP904L Elbow
ASTM A403 WP904L Tee
ASTM A403 WP904L Reducers
ASTM A403 WP904L Caps
ASTM A403 WP904L Cross Fittings
ASTM A403 WP904L Nipples
ASTM A403 WP904L Couplings
ASTM A403 WP904L Stub Ends
Corrosion Resistance
Excellent in chloride environments
Superior resistance to sulfuric & phosphoric acid
Highly resistant to pitting & crevice corrosion
Ideal for marine & acidic environments
Heat Resistance
Performs well up to 400–450°C
Maintains structural stability and oxidation resistance at high temperature
Heat Treatment
Solution Annealing: 1090°C – 1175°C
Rapid quenching recommended
No post-weld heat treatment required
Weldability
Excellent weldability using TIG/MIG/SAW
Use matching 904L filler metal for maximum corrosion resistance
Low carbon reduces risk of sensitization during welding
Fabrication
Good formability & machinability
Heavy duty cutting tools recommended due to work-hardening tendency
Suitable for deep drawing, bending & forming
Applications
Chemical & Petrochemical Plants
Seawater & Marine Applications
Oil & Gas Refineries
Fertilizer Industry
Pulp & Paper Processing
Pharmaceutical & Food Processing
Heat Exchangers & Pressure Vessels
Desalination Plants
Acid Production Units