904L Stainless Steel Bar

Diameter 20-150mm, strong acid resistant, pharmaceutical reactor shaft

904L super stainless steel bar is manufactured from 00Cr20Ni25Mo4.5Cu austenitic stainless steel, in compliance with ASTM A276 and GB/T 21832 standards.

  • Outstanding resistance to aggressive media

    Corrosion rate ≤0.1 mm/year in 50% H₂SO₄ (80℃), over 5 times better than 316L.

  • Resistance to high temperature & stress corrosion

    No stress corrosion cracking in chloride-containing environments at 200℃; service temperature range: -196℃ to 400℃.

  • Excellent formability

    Annealed hardness ≤220HB, comparable to 304 stainless steel; supports cold bending, welding, and complex processing.

Product Specifications

Chemical Composition (ASTM A276)
Element Content (%)
Cr 19.0–21.0
Ni 24.0–26.0
Mo 4.0–5.0
Cu 1.0–2.0
C ≤0.02
Physical & Mechanical Properties

Physical Properties

  • Density: 8.0 g/cm³ (slightly higher than 304 stainless steel at 7.93 g/cm³).

  • Melting Point: 1350–1400℃, ensuring good high-temperature performance; service temperature range: -196℃ to 400℃.

  • Thermal Conductivity: 12.9 W/(m·K) at 20℃, increasing to 18.0 W/(m·K) at 300℃.

  • Coefficient of Thermal Expansion: 15×10⁻⁶/K (20–100℃).

  • Magnetism: Non-magnetic in solution-annealed condition.

Mechanical Properties (Annealed Condition)

Property Value Advantage vs. 304 SS
Tensile Strength ≥490 MPa Comparable to 304 (≥520 MPa), but maintains strength better under severe corrosion.
Yield Strength ≥215 MPa Slightly higher than 304 (≥205 MPa); enhanced resistance under combined stress & corrosion.
Elongation ≥35% Similar to 304, ensuring excellent cold forming ability (bending, stretching).
Reduction of Area ≥50% Higher than 304; superior toughness, better impact resistance.
Brinell Hardness ≤220 HB Balanced hardness for machinability and wear resistance; more stable under corrosion.
Impact Toughness (-40℃) ≥27 J Maintains toughness at low temperatures (better than 304), suitable for polar environments.
Specifications & Supply Range

Diameter Range:

  • 5–30 mm: tolerance ±0.03 mm (cold-drawn bright bar)
  • 30–100 mm: tolerance ±0.08 mm (hot-rolled + annealed)
  • 100–200 mm: tolerance ±0.15 mm (forged + annealed)

Length: Standard 3–6 m; custom cutting available, tolerance ±5 mm.

Surface Finish:

  • Annealed condition: Black (hot-rolled) or Bright (cold-drawn, Ra ≤1.6 μm).
  • Optional passivation treatment: enhances corrosion resistance; salt spray test ≥1000 hours without rust spots.

Pricing Calculation

Workshop & Manufacturing Machine

Stainless Steel Bar Inventory Racking System

Spectrometer for Alloy Composition Analysis

Finished Stainless Steel Bars on Storage Racks

Palletized Stainless Steel Bars on Workshop Floor

Secured Stainless Steel Bar Bundles for Shipment

Forklift Loading Bundled Stainless Steel Bars into Freight Truck

Product Applications

  • Chemical Equipment

    Specification: Ø20–80 mm

    Advantage: Corrosion rate ≤0.1 mm/year in 50% H₂SO₄ (80℃), far superior to conventional stainless steels.

    Case: Reactor agitator shafts (Ø50 mm) in sulfuric acid plants maintain long-term stability; phosphoric acid transport pipelines (Ø60 mm) resist acid attack, ensuring process safety.

  • Marine Engineering

    Specification: Ø30–100 mm

    Advantage: Pitting potential ≥+400 mV in 3.5% NaCl; excellent crevice corrosion resistance.

    Case: Used in seawater desalination units (e.g., RO membrane support shafts Ø80 mm), ensuring continuous operation; offshore platform bridge supports (Ø100 mm) withstand salt spray and seawater corrosion, ensuring structural safety.

  • Pharmaceutical Industry

    Specification: Ø10–50 mm

    Advantage: High surface finish, meets GMP requirements.

    Typical Cases: Stirring rods (Ø20 mm) in crystallizers prevent contamination; pharmaceutical transfer pipes (Ø30 mm) ensure product purity.

  • Environmental Equipment

    Specification: Ø20–60 mm

    Advantage: Excellent resistance in acidic, chloride-rich wastewater.

    Typical Cases: Aerator drive shafts (Ø40 mm) in wastewater treatment plants provide stable operation; spray pipes (Ø50 mm) in flue gas treatment resist acidic exhaust and spray liquid corrosion.

FAQ

What is 904L stainless steel bar known for?

904L is known for its exceptional resistance to strong acids and chloride-induced corrosion.

What applications commonly require 904L stainless steel bars?

Chemical processing equipment, offshore structures, heat exchangers, and pressure components.

Does 904L stainless steel offer good weldability?

Yes. With proper welding procedures, 904L maintains corrosion resistance after welding.

How does 904L compare to duplex stainless steel bars?

904L excels in corrosion resistance, while duplex grades offer higher mechanical strength.

Are inspection and certification available for 904L bars?

Yes. MTC, PMI testing, and third-party inspection can be provided.

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