N08904 (904L) Super Austenitic Stainless Steel Comprehensive Characteristics Analysis

N08904 (corresponding to 904L, European standard 1.4539) is a high-alloy super austenitic stainless steel. Through the coordinated design of high molybdenum (Mo), copper (Cu) and nickel (Ni), it shows excellent performance in strong acid, chloride and high temperature complex corrosion environments. It is an ideal corrosion-resistant material in the chemical, marine and energy fields.

Implementation standards:

ASTM A240/ASME SA-240, ASTM A276, ASTM A182/ASME SA-182, ASTM A312/ASMES A312, ASTM B625/ASME B625, ASTM B673/ASME B673

Internationally known as: 904L, Al-904L, UNS N08904, SUS890L, F904L, W.-Nr. 1.4539, NAS 255, 00Cr20Ni25Mo4.5Cu

Key performance indicators

1. Corrosion resistance:

Acidic medium: Excellent overall corrosion resistance in ≤40% sulfuric acid (≤50℃), phosphoric acid, and dilute hydrochloric acid, better than 316L and 317L;

Chloride environment: Pitting resistance equivalent index (PREN=Cr+3.3Mo+16N) ≥35, resistant to seawater and salt spray corrosion, suitable for marine engineering.

2. Mechanical properties:

Tensile strength at room temperature ≥490MPa, yield strength ≥220MPa, elongation ≥35%, with both high strength and plasticity.

3. Physical properties:

Density 7.95-8.24g/cm³, melting point 1300-1390℃, non-magnetic, short-term use temperature up to 400℃, long-term service recommended ≤250℃135.

N08904 (904L) is widely used in the following scenarios due to its excellent corrosion resistance:

1. Chemical and petrochemical: sulfuric acid reactors, phosphoric acid evaporators, acetic acid storage tanks, strong acid corrosion resistance and intergranular corrosion resistance;

2. Marine engineering: seawater desalination equipment, marine pumps and valves, submarine pipelines, resistance to chloride ion pitting and seawater erosion;

3. Environmental protection and energy: flue gas desulfurization (FGD) systems, nuclear waste treatment containers, resistance to mixed acid (H₂SO₄+Cl⁻) media;

4. Oil and gas: oil and gas field pipelines containing hydrogen sulfide (H₂S), acidic oil well equipment, resistance to sulfide stress corrosion cracking (SSCC)