ss904L and s316l pipe supplier. Contact us to get free quote and sample!
Stainless steel 904L and 316L stainless steel pipes each have their own strengths and weaknesses. 316L stainless steel is suitable for cost-sensitive, general applications in normal corrosive environments. 904L stainless steel, with its excellent resistance to extreme corrosion, is irreplaceable in demanding, specialized applications. Our manufacturers can produce astm a240 904L seamless and welded pipes to meet industry requirements. Contact us market@htpipe.com for more information and a free quote!
uns n08904 and s31603 Chemical Composition
| Element (%) | 904L (UNS N08904) | 316L (UNS S31603) |
|---|---|---|
| Cr | 19-23 | 16-18 |
| Ni | 23-28 | 10-14 |
| Mo | 4.0-5.0 | 2.0-3.0 |
| Cu | 1.0-2.0 | ≤0.75 |
| C | ≤0.02 | ≤0.03 |
| PREN Value | ≥33 (Cr+3.3Mo+16N) | ≥24 |
s904l and s316l Mechanical & Physical Properties
| Property | 904L | 316L |
|---|---|---|
| Yield Strength (MPa) | ≥220 | ≥170 |
| Tensile Strength (MPa) | ≥490 | ≥485 |
| Hardness (HB) | 70-90 | 70-90 |
| Density (g/cm³) | 8.0 | 8.0 |
| Key Difference | Higher Mo/Cu enhance strength but increase work hardening | Easier cold forming |
Corrosion Resistance between ss904l and ss316l
(1) s904l and s316l in Acidic Environments
Sulfuric Acid (H₂SO₄):
904L: Resists boiling dilute sulfuric acid (≤40% concentration).
316L: Only suitable for <10% concentration below 40°C.
Phosphoric Acid (H₃PO₄):
904L: Withstands industrial phosphoric acid with fluoride impurities.
316L: Fluorides cause pitting.
Organic Acids (Acetic/Formic):
904L: Resists all concentrations.
316L: Limited to low/medium concentrations.
(2) stainless steel 904l and 316l in Chloride Environments
| Property | 904L | 316L |
|---|---|---|
| Pitting/Crevice Corr. | Seawater/salt spray resistant (≤40°C) | High risk in seawater |
| Stress Corrosion Cracking (SCC) | Safe below 50°C | Risk above 25°C |
(3) 904l steel pipe and s31603 pipe in Special Media
904L: Resists mixed acids (e.g., H₂SO₄ + Cl⁻) and slurry with solids.
316L: Suitable only for pure media.
When should I choose 904L?
Sulfuric acid environments: concentration > 10% or temperature > 40°C.
Mixed corrosive media: such as H₂SO₄ + Cl⁻ or fluoride-containing phosphoric acid.
Seawater systems: Long-term immersion or low-flow areas.
High-purity requirements: Pharmaceutical/semiconductor equipment (904L surface is more resistant to passivation).
