904L Stainless Steel (UNS N08904) is a super austenitic stainless steel containing:

• Chromium: 14.0-18.0%
• Nickel: 24.0-26.0%
• Molybdenum: 4.5%

This low-carbon, high-nickel, molybdenum-enhanced alloy demonstrates exceptional passivation capability and corrosion resistance.

• Acid Resistance: Excellent performance in sulfuric acid (<70°C), all concentrations/temperatures of acetic acid (atmospheric pressure), and formic-acetic acid mixtures
• Chloride Resistance: Superior resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride media
• General Corrosion: Proven resilience in phosphoric acid and other non-oxidizing acids

Metallurgical Structure: Fully austenitic structure with reduced sensitivity to ferrite/alpha phase precipitation compared to conventional high-molybdenum austenitic steels.

Physical/Mechanical Properties:

• Density: 8.0 g/cm³
• Tensile Strength: ≥520 MPa
• Elongation: ≥35%

• Ultra-low carbon (≤0.020%) prevents carbide precipitation during heat treatment/welding
• High Cr-Ni-Mo-Cu content enables passivation even in reducing environments
• Demonstrated performance in specific media:
  • Sulfuric acid: ≤40°C at 0-98% concentration
  • Phosphoric acid: Excellent in 0-85% pure acid
  • Chloride solutions: Superior pitting/crevice corrosion resistance
• Limited hydrochloric acid use (≤2% concentration) with performance exceeding conventional grades

• Chemical Processing: Reactors, acid storage/transport, scrubbers
• Power Generation: Flue gas desulfurization systems
• Marine Engineering: Seawater heat exchangers/processing
• Petrochemical: Reactors, H₂S-resistant equipment
• Food/Pharma: Fermentation vessels, centrifuges, reactors
• Pulp & Paper: Chemical processing equipment