904L (1.4529/UNS N08904) Stainless Steel Round Bar​​
Acid/alkali-resistant • High-temperature performance

Core Composition (% weight)

Superior Corrosion Resistance

• ​​Non-oxidizing Acids:​​
  ✓ Sulfuric acid (all conc. ≤70°C)
  ✓ Acetic acid (any conc./temp. at atm. pressure)
  ✓ Formic-phosphoric acids and mixed organic acids
• ​​Chloride Media:​​
  ✓ Pitting/crevice corrosion resistance
  ✓ Stress corrosion cracking (SCC) resistance

Critical Properties

• Low carbon (≤0.02%) prevents carbide precipitation
• High Ni/Mo/Cu content enables self-passivation
• "Super austenitic" classification (EN 1.4529 / UNS N08904)

​​Metallurgical Structure​​
Fully austenitic microstructure with reduced ferrite/alpha-phase precipitation sensitivity vs. standard high-Mo austenitic steels.

​​Physical & Mechanical Properties​​

​​Corrosion Performance​​

Ultra-low carbon (≤0.020%): Eliminates carbide precipitation during HT/welding, preventing intergranular corrosion

High Cr-Ni-Mo-Cu content: Enables self-passivation in reducing environments (H₂SO₄, HCOOH)

Critical media performance:
• Sulfuric acid: 0-98% up to 40°C
• Phosphoric acid: 0-85% concentration
• Hydrochloric acid: Limited to 1-2% (outperforms conventional SS)
• Nitric acid: Lower resistance than Mo-free high-alloy steels
• Chloride solutions: Superior pitting/crevice corrosion resistance

Stress corrosion cracking (SCC) resistance:
✓ Chloride solutions (>60°C)
✓ Concentrated hydroxides
✓ H₂S environments

​​Industrial Applications​​

1. ​​Chemical Processing​​
   • Sulfuric acid storage/heat exchangers
   • Organic acid scrubbers & reactors
   • Dilute sulfuric acid systems (ideal material)
2. ​​Energy​​
   • FGD systems: absorbers, ducting & spray components
3. ​​Marine​​
   • Seawater treatment & heat exchangers
4. ​​Pharmaceutical​​
   • Reactors, centrifuges
5. ​​Food Production​​
   • Fermentation tanks (soy sauce, wine, brine)
6. ​​Industrial Equipment​​
   • Pressure vessels, papermaking machinery