In the pharmaceutical industry, 304 and 316L stainless steel have significantly different application scenarios due to differences in chemical composition and performance.
The following is a comparative analysis of material properties, corrosion resistance, compliance requirements and specific application scenarios:
| Element | 304 Stainless Steel (UNS S30400 / EN 1.4301) | 316L Stainless Steel (UNS S31603 / EN 1.4404) |
|---|---|---|
| Carbon (C) | ≤ 0.08% | ≤ 0.03% |
| Manganese (Mn) | ≤ 2.00% | ≤ 2.00% |
| Phosphorus (P) | ≤ 0.045% | ≤ 0.045% |
| Sulfur (S) | ≤ 0.030% | ≤ 0.030% |
| Silicon (Si) | ≤ 1.00% | ≤ 1.00% |
| Chromium (Cr) | 18.0–20.0% | 16.0–18.0% |
| Nickel (Ni) | 8.0–11.0% | 10.0–14.0% |
| Molybdenum (Mo) | Not Present | 2.0–3.0% |
| Nitrogen (N) | ≤ 0.10% | ≤ 0.10% |
304 stainless steel has moderate corrosion resistance to common dilute acids and alkalis (e.g., hydrochloric acid, sodium hydroxide solutions), as well as organic solvents like ethanol. It is also more cost-effective than 316L.
Typical Applications:
Purified Water (PW) distribution systems where chloride content ≤ 0.2 ppm
Ventilation and HVAC condensate piping in non-sterile areas (no direct contact with drug products
316L stainless steel contains molybdenum, offering significantly better resistance than 304 to chloride ions (e.g., in WFI with ≤ 0.2 ppm Cl⁻), sulfur-containing compounds (e.g., sodium sulfide solutions), and high-temperature steam.
Typical Applications:
Water for Injection (WFI) systems
Pure steam pipelines used for sterilization
Aseptic production lines, such as piping for lyophilizers and mixing tanks
Chloride-containing pharmaceutical solutions, such as sodium chloride injections and cephalosporin-based antibiotic solutions
FDA 21 CFR Part 177.2400 compliant: Approved for general food contact applications.
Suitable for non-sterile formulations or low-risk areas (e.g., ISO Class 9 / Grade D cleanrooms).
Must meet GMP traceability requirements, including provision of COA (Certificate of Analysis) for material verification.
USP Class VI Certified: Ensures the material is non-cytotoxic and suitable for direct contact with sterile drug products.
ASME BPE (BioProcessing Equipment) compliant: Required in biopharmaceutical systems for control of surface roughness (Ra ≤ 0.4 μm) and high-quality welds.
ISO 10993 Biocompatibility Tested: Passed cytotoxicity and sensitization tests to prevent contamination of drug products.
Typically finished with Mechanical Polishing (MP):
Internal surface roughness: Ra ≤ 0.8 μm
External surface roughness: Ra ≤ 1.6 μm
Suitable for systems that are frequently dismantled and manually cleaned, such as those used in oral liquid production.
Weld areas require passivation (e.g., with nitric acid) to enhance corrosion resistance over long-term use.
Preferred finish: Electropolishing (EP):
Internal surface roughness: Ra ≤ 0.4 μm
Creates a dense, uniform passive film, improving corrosion resistance by over 30% compared to 304.
Ideal for CIP (Clean-in-Place) or SIP (Steam-in-Place) systems in sterile production.
Smooth internal surfaces reduce the risk of bacterial biofilm formation and ensure higher sanitary performance.
1.If you're currently evaluating sanitary piping materials for pharmaceutical applications, choosing the right stainless steel grade is critical to long-term process reliability and GMP compliance.
2.Whether you're upgrading existing systems or building new production lines, our expert team can help you select the optimal solution-be it cost-effective 304 or high-purity 316L.
3.Contact us today for material certificates, surface finish options, and a custom quote tailored to your cleanroom needs.
.jpg)
.jpg)
.jpg)
.jpg)
