GNEE specializes in the production of ASTM A249 UNS N08904 (904L) ERW welded pipes, designed specifically for extreme corrosive environments.
Our 904L steel pipes are manufactured using precision ERW welding and a specific solution annealing process (minimum temperature of 1095°C), followed by rapid quenching to ensure that the weld zone has the same corrosion resistance as the base material. Compared to 316L stainless steel, 904L offers superior resistance to chloride stress corrosion cracking (SCC), pitting, and crevice corrosion.
904L stainless steel welded pipes contain ultra-low carbon content (≤0.02%) and a PREN value ≥36, offering outstanding resistance to pitting, crevice corrosion, and sulfuric acid corrosion. These pipes are suitable for applications such as phosphoric acid production, flue gas desulfurization (FGD), micro-saline or seawater cooling pipelines, and pharmaceutical heat exchangers.
We supply ASTM A249 TP904L welded pipes with an outside diameter range of 12.7–219.1mm, wall thickness from 1.0–8.0mm, and lengths of 2–6m or custom lengths. Tolerances are strictly controlled: outside diameter ±0.13mm and wall thickness ±10%. Each pipe undergoes 100% hydrostatic testing, ECT testing, and flattening/reverse bending tests to ensure welding integrity. Products comply with EN 10204 3.1 MTC standards.
ASTM A249 UNS N08904 Welded Steel Pipe Specification
| Item | Description |
|---|---|
| Material Grade | UNS N08904 (904L) |
| Standard | ASTM A249 / ASME SA249 |
| Type | Welded (ERW / EFW / TIG / Plasma) |
| Structure | High-alloy Austenitic Stainless Steel |
| Primary Use | Heat exchangers, condensers, and chemical processing in sulfuric/phosphoric acid environments |
| Outside Diameter (OD) | 1/8" to 5" (3.2mm to 127mm) |
| Wall Thickness (WT) | 0.015" to 0.320" (0.4mm to 8.1mm) |
| OD Tolerance | ±0.005 to ±0.015 inches (based on size) |
| WT Tolerance | ±10% or as specified in technical agreement |
| Length | Single Random, Double Random, or Fixed Length (Max 25m) |
904L SS Pipes,Tubes Chemical Properties
| Grade | C | Mn | Si | P | S | Cr | MO | Ni | CU | |
| 904L | Min | – | – | – | – | – | 19.0 | 4.00 | 23.00 | 1.00 |
| max | 0.20 | 2.00 | 1.00 | 0.045 | 0.035 | 23.0 | 5.00 | 28.00 | 2.00 |
SS 904L Mechanical Properties
| Density | 8.0 g/cm3 |
| Melting Point | 1454 °C (2650 °F) |
| Tensile Strength | Psi – 75000 , MPa – 515 |
| Yield Strength (0.2%Offset) | Psi – 30000 , MPa – 205 |
| Elongation | 35 % |
316L vs. 904L (UNS N08904)
| Feature | 316L | 904L (N08904) |
| Nickel Content | 10-14% | 23-28% |
| Copper Addition | No | 1.0 - 2.0% |
| Pitting Resistance (PREN) | 24 | 32-34 |
| Sulfuric Acid Resistance | Poor | Excellent |
| SCC Resistance | Moderate | High |
ASTM A249 UNS N08904 Welded Tubes Application
Chemical Industry: Widely used in the production and processing of phosphoric acid, sulfuric acid, and acetic acid.
Heat Exchanger and Condenser Tubes: Essential for power plants, oil refineries, and offshore platforms.
Pollution Control: Used in flue gas desulfurization (FGD) systems.
How does 904L stainless steel perform in sulfuric acid (H₂SO₄)?
904L stainless steel was originally developed specifically for resistance to sulfuric acid environments. Due to its copper content, it can form a stable protective film in reducing environments. It can withstand most concentrations of sulfuric acid, up to temperatures of 35-40°C. In the concentration range of 0% to 100%, its corrosion resistance is far superior to 316L stainless steel and even 2205 duplex stainless steel.
For standard stock sizes (typically including 19.05 mm (3/4 inch) and 25.4 mm (1 inch) outer diameters, and wall thicknesses from 1.24 mm to 2.11 mm), our lead time is highly efficient, taking only 7 to 15 days, including final 100% non-destructive testing and export preparation. For custom rolling or large project orders exceeding 30 tons, production lead times are typically 6 to 9 weeks.
Required Tests & Inspection (ASTM A249 Standard)
| Test Category | Description |
| Flattening Test | Ensuring the weld and base metal ductility. |
| Flaring Test | Expanding the tube end without cracking. |
| Flange Test | Testing the weld integrity under 90° bending. |
| Reverse Bend Test | Bending the weld zone to ensure full fusion and no defects. |
| Hydrostatic Test | 100% Pressure test (unless Eddy Current is substituted). |
| Eddy Current Test | According to ASTM E426 to detect surface/sub-surface defects. |
| Intergranular Corrosion | According to ASTM A262 Practice E (when requested). |
Packaging
Plastic Caps: Each tube is fitted with a secure plastic cap at both ends.
Individual Sleeving: Each 904L tube is individually sleeved in a PE plastic bag or woven mesh sleeve.
Hexagonal Bundles: High-strength steel strapping is used.
