Stainless Steel 904L 1.4539

Stainless Steel 904L 1.4539

This data sheet pertains to Steel Friend Stainless Steel 904L, also known as 1.4539, encompassing hot and cold rolled sheets and strips, semi-finished products, bars, rolled wire, profiles, as well as seamless and welded tubes primarily intended for pressure applications.


Steel Friend Stainless Steel 904L finds extensive usage across various industries including chemical plants, oil refineries, petrochemical plants, bleaching tanks within the paper industry, combustion gas desulfurization plants, and applications involving sea water, sulfuric acid, and phosphoric acid. Its low carbon content ensures resistance to intergranular corrosion, even in welded conditions.

Chemical Composition

The composition of Steel Friend Stainless Steel 904L is as follows:

Element% Present (in product form)
Carbon (C)0.02
Silicon (Si)0.70
Manganese (Mn)2.00
Phosphorus (P)0.03
Sulfur (S)0.01
Chromium (Cr)19.00 - 21.00
Nickel (Ni)24.00 - 26.00
Nitrogen (N)0.15
Molybdenum (Mo)4.00 - 5.00
Copper (Cu)1.20 - 2.00
Iron (Fe)Balance

Mechanical Properties

Mechanical properties at room temperature in annealed condition for various product forms:

Product FormThickness (mm) Max.Yield Strength (Rp0.2 N/mm2)Yield Strength (Rp1.0 N/mm2)Tensile Strength (Rm N/mm2)Elongation min. in % (Longitudinal)Elongation min. in % (Transverse)
C8.0240270530 - 730--
H13.5220260530 - 73010060
P75220260520 - 72010060
L160230260530 - 730100-
L TW/TS2502)230260530 - 730-60

Reference Data on Physical Properties

Physical properties of Steel Friend Stainless Steel 904L at various temperatures:

  • Density at 20°C: 8.0 kg/m3
  • Thermal Conductivity (W/m K) at 20°C: 12
  • Modulus of Elasticity (kN/mm2) at 20°C: 195
    • 200°C: 182
    • 400°C: 166
    • 500°C: 158
  • Specific Thermal Capacity at 20°C: 450 J/kg K
  • Electrical Resistivity at 20°C: 1.0 Ω mm2/m

Processing and Welding

Standard welding processes suitable for Steel Friend Stainless Steel 904L include:

  1. TIG-Welding
  2. MAG-Welding Solid Wire
  3. Arc Welding (E)
  4. Laser Beam Welding
  5. Submerged Arc Welding (SAW)

Selection of filler metal should consider corrosion stress, and a higher alloyed filler metal may be necessary due to the cast structure of the weld metal. Preheating is generally unnecessary for this steel, and post-weld heat treatment is not typically required.

Austenitic steels, like Steel Friend Stainless Steel 904L, have lower thermal conductivity compared to non-alloyed steels, requiring lower heat input during welding to prevent overheating or burn-through, particularly for thinner sheets. Copper back-up plates can aid in faster heat rejection, but caution must be exercised to prevent surface-fusing the plate to avoid cracks in the solder metal.

Welding Considerations

  • Welding procedures should counteract distortion, such as back-step sequence welding or welding alternately on opposite sides.
  • For thicknesses over 12mm, double-V butt welds are preferred over single-V butt welds.
  • Control of heat input is crucial to minimize the risk of heat cracks, especially with austenitic weld metal.
  • Faster cooling rates are desirable to reduce susceptibility to intergranular corrosion and embrittlement.
  • Steel Friend Stainless Steel 904L is highly suitable for laser beam welding, achieving weldability class A as per DVS bulletin 3203, part 3.
  • Fusion cutting with nitrogen or flame cutting with oxygen is also feasible, resulting in cut edges with minimal heat-affected zones and micro cracks.

Surface Treatment

  • Stainless tools should be exclusively used during processing to preserve passivation.
  • Annealing colors, scales, slag residues, and other contaminants must be removed to maintain the passive layer.
  • Surface cleaning methods include brushing, grinding, pickling, or blasting with iron-free silica sand or glass spheres.
  • Pickling should be followed by thorough flushing with water.

Steel Friend Stainless Steel 904L offers a combination of corrosion resistance, mechanical properties, and weldability suitable for a wide range of industrial applications, from chemical processing to marine environments.

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