Ss 1.4404 / 1.4435 grade

Stainless Steel Products

Ss 1.4404 / 1.4435 grade

Reliable Pipes & Tubes – Premium Manufacturer, Supplier & Exporter of Ss 1.4404 / 1.4435 Austenitic Stainless Steel

Reliable Pipes & Tubes is a leading supplier, stockist, and exporter of high-purity Ss 1.4404 / 1.4435 grade (EN standard 316L equivalents) products. Both grades are low-carbon molybdenum-bearing austenitic stainless steels designed to offer outstanding resistance to pitting, crevice corrosion, and intergranular corrosion. While they are highly similar, European standards make a strict distinction between the two, with 1.4435 serving as a high-molybdenum and high-nickel upgrade for the most demanding sanitary and high-purity processing sectors.

We supply Ss 1.4404 / 1.4435 pipes, sheets, plates, and custom-fabricated items with full material traceability (EN 10204 3.1 certificates). Our pharma-line and sanitary grade products are controlled to maintain low delta ferrite levels (<0.5% or <3%) to ensure electropolishability (Ra < 0.4µm) and eliminate the risk of rouging in high-purity water (WFI) loops.

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Standard Comparison: EN 1.4404 vs. EN 1.4435

Under the European Norm (EN) system, both 1.4404 and 1.4435 fall under the class of 316L austenitic stainless steel (UNS S31603 / TP316L). However, key differences in chemical composition lead to different performance profiles:

  • Molybdenum (Mo) Content: 1.4435 guarantees a higher molybdenum content (2.50% - 3.00%) compared to 1.4404 (2.00% - 2.50%), which boosts corrosion resistance.
  • Nickel (Ni) Content: 1.4435 features higher nickel (12.5% - 15.0%) compared to 1.4404 (10.0% - 13.0%), stabilizing the austenitic structure and minimizing delta ferrite.
  • Pitting Resistance (PREN): Due to the higher Mo content, 1.4435 achieves a PREN of 26 - 29 (compared to 1.4404's 23 - 26), offering superior protection in chloride-rich media and organic acids.
  • Delta Ferrite Levels: 1.4435 enables zero or extremely low ferrite content (<0.5%), crucial for preventing rouging and achieving smooth, mirror-like finishes after electropolishing (Ra < 0.4µm).

Chemical Composition Comparison (per EN 10088-3)

Element EN 1.4404 (%) EN 1.4435 (%) Key Differences
Carbon (C)≤0.030%≤0.030%Same (Low carbon limits carbide precipitation)
Silicon (Si)≤1.00%≤1.00%Same
Manganese (Mn)≤2.00%≤2.00%Same
Phosphorus (P)≤0.045%≤0.045%Same
Sulfur (S)≤0.015%≤0.015%Same (Low sulfur for optimal polishability)
Chromium (Cr)16.50 – 18.50%17.00 – 19.00%1.4435 is slightly higher
Molybdenum (Mo)2.00 – 2.50%2.50 – 3.00%1.4435 has higher Mo (Better pitting resistance)
Nickel (Ni)10.00 – 13.00%12.50 – 15.00%1.4435 has higher Ni (Stable austenite structure)
Nitrogen (N)≤0.11%≤0.11%Same
Iron (Fe)62.80 – 71.50%59.80 – 68.00%Balance

Mechanical Properties Comparison

Mechanical Property EN 1.4404 (316L) EN 1.4435 (316L)
Brinell Hardness (HB)190 to 270190
Elastic Modulus (GPa)200200
Elongation at Break (%)14 to 43%43%
Fatigue Strength (MPa)220 to 320220
Impact Strength (Charpy V-Notch, J)91 to 9390
Poisson's Ratio0.280.28
Shear Modulus (GPa)7878
Shear Strength (MPa)420 to 550420
Tensile Strength (UTS, MPa)600 to 900610
Yield Strength (Proof, MPa)240 to 570240

Thermal & Physical Properties Comparison

Thermal / Physical Property EN 1.4404 EN 1.4435
Density (g/cm³)7.97.9
Latent Heat of Fusion (J/g)290290
Max Temp: Corrosion (°C)410420
Max Temp: Mechanical (°C)950980
Melting Completion (Liquidus, °C)14401440
Melting Onset (Solidus, °C)14001400
Specific Heat Capacity (J/kg-K)470470
Thermal Conductivity (W/m-K)1515
Thermal Expansion (μm/m-K)1616
Electrical Conductivity (% IACS)2.3 (Volume), 2.6 (Weight)2.3 (Volume), 2.6 (Weight)
Thermal Diffusivity (mm²/s)4.04.0
Thermal Shock Resistance13 to 2014

Common Calculations & Structural Data

Property / Metric EN 1.4404 EN 1.4435
PREN (Pitting Resistance)2628
Resilience: Ultimate (MJ/m³)110 to 210210
Resilience: Unit Modulus (kJ/m³)140 to 800150
Stiffness to Weight: Axial / Bending14 / 25 points14 / 25 points
Strength to Weight: Axial21 to 32 points21 points
Strength to Weight: Bending20 to 26 points20 points
Embodied Carbon (kg CO₂/kg)3.84.1
Embodied Energy (MJ/kg)5257
Embodied Water (L/kg)150160

Applications Guide: Selecting the Right Grade

We recommend selecting the material grade based on your specific media and process requirements:

Use 1.4404 (Standard 316L) for:

  • Food & Beverage: Dairy processing lines, brewing tanks, soft drink distribution.
  • Personal Care: Lotions, cosmetics, soap, and shampoo manufacturing loops.
  • Standard Utilities: Compressed air pipelines, pre-filtration water networks.
  • General Process Industry: Light acid piping and general industrial environments where non-aggressive media is transferred.

Use 1.4435 (High-Purity / ASME BPE) for:

  • Pharmaceuticals: Active Pharmaceutical Ingredient (API) lines, injectable vaccine production loops.
  • Biotechnology: Bioreactors, fermentation vessels, cell culture media storage.
  • Semiconductors: Ultra-high purity (UHP) gas and chemical distribution systems.
  • WFI (Water for Injection) Systems: Re-circulating high-purity water loops where ferrite rouging is a severe concern.

Frequently Asked Questions (FAQs)

What makes 1.4435 more expensive than 1.4404?

1.4435 requires a higher minimum concentration of Nickel (up to 15.0%) and Molybdenum (up to 3.00%). The increased cost of these raw alloying elements results in a slightly higher base price (approx. 21% relative vs 19% relative for 1.4404).

Why is a low delta ferrite content important in pharmaceutical systems?

Delta ferrite particles act as initiation sites for "rouging" (reddish surface rust) in high-purity water loops. High nickel stabilization in 1.4435 keeps ferrite levels near-zero (<0.5%), ensuring superior corrosion resistance and a smoother surface finish after electropolishing.

Are these grades compatible with ASME BPE standards?

Yes, EN 1.4435 is widely used to comply with ASME BPE SF1 and SF4 pharmaceutical dimensional and surface finish specifications, providing the ultimate hygienic design.