Not all stainless steel is equal. In food packaging machines, the choice of steel grade determines corrosion resistance, durability and compliance with hygiene regulations. Using the wrong grade means rusting machines, contamination and non-compliance at inspections.
AISI 304 vs AISI 316L: practical differences
AISI 304 (18% Cr, 8% Ni) is the most common grade in food machines for general use. AISI 316L adds 2-3% molybdenum, which dramatically increases resistance to chloride corrosion (sea salt, chlorinated detergents, salt water). The L suffix indicates low carbon content, improving weldability and reducing sensitisation.
- AISI 304: resistant to atmospheric corrosion and many acids
- AISI 316L: resistant to chlorides, salt water, aggressive detergents
- AISI 316L mandatory: fish, marine environments, constant salt contact
- AISI 304 sufficient: dry products, bakery, fresh-cut without salt
- Surface finish: Ra ≤ 0.8 µm for food contact surfaces
Reference standards for food machines
Food packaging machines must comply with Machinery Directive 2006/42/EC (CE marking) and EC Regulation 1935/2004 on food contact materials. EHEDG (European Hygienic Engineering and Design Group) guidelines define construction principles for hygienic design.
- Dir. 2006/42/EC: mandatory CE marking, declaration of conformity
- EC Reg. 1935/2004: food contact materials, chemical inertness
- EHEDG: hygienic design — no accumulation zones, complete drainage
- IP65/IP67: protection against water and dust ingress
- NSF certification: North American standard (useful for US export)
What to check before purchasing a machine
Always request documentation certifying the steel grade used (material certificates EN 10204 type 3.1) and surface finish of contact parts. Verify the machine is supplied with the CE declaration of conformity and complete technical file.
- Material certificate EN 10204 type 3.1: mandatory for contact parts
- Surface roughness Ra: measurable with profilometer, ≤ 0.8 µm at contact
- CE declaration: mandatory legal document for EU market placement
- Operating manual in local language: mandatory for CE
Want to verify the hygienic compliance of your machines?
All EMA Pack machines are in AISI 304/316L with material certificates and CE marking. Contact us for technical documentation.
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