Is SUS304 stainless steel food grade?
Jun 19, 2025
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If you are sourcing SUS304 stainless steel for food processing equipment, kitchenware, beverage systems, or sanitary applications, the answer is generally YES. SUS304 is one of the most widely used food-contact grade stainless steel grades globally. However, qualifying as "food grade" depends on more than just the material designation itself. Compliant food-grade SUS304 products must also meet strict requirements regarding chemical composition, corrosion resistance, surface finish, manufacturing quality, and relevant food-contact regulations.
What is SUS304 Stainless Steel?
SUS304 (equivalent to AISI 304 / EN 1.4301) typically contains 18%–20% Chromium and 8%–10.5% Nickel, delivering exceptional corrosion resistance, ease of cleaning, and long-term stability in most food processing environments. For professional procurement managers, selecting the right SUS304 supplier requires verifying Mill Test Certificates (MTC), conducting Positive Material Identification (PMI) testing, and focusing on surface roughness, passivation processes, and lot traceability-rather than simply competing on the lowest price.
What Is SUS304 Stainless Steel Equivalent to?
| Standard | Grade Designation |
|---|---|
| JIS | SUS304 |
| ASTM | AISI 304 / UNS S30400 |
| EN | 1.4301 / X5CrNi18-10 |
| GB | 06Cr19Ni10 |
SUS304 Stainless Steel Chemical Composition
The food-grade rating of SUS304 stems directly from its austenic alloy formulation. Chromium creates a passive chromium-oxide film ($Cr_2O_3$) that prevents rust, while Nickel preserves structural integrity and acid resistance during food processing.
| Element | JIS SUS304 (Standard Range) | AISI 304 Equivalent | Role in Food Safety & Processing |
| Chromium (Cr) | 18.00% – 20.00% | 17.50% – 19.50% | Forms passive oxide layer to block corrosion |
| Nickel (Ni) | 8.00% – 10.50% | 8.00% – 10.50% | Enhances acid/alkali resistance and durability |
| Carbon (C) | ≤ 0.08% | ≤ 0.07% | Prevents carbide precipitation during welding |
| Manganese (Mn) | ≤ 2.00% | ≤ 2.00% | Improves hot workability and tensile strength |
| Silicon (Si) | ≤ 1.00% | ≤ 0.75% | Deoxidizer in steelmaking process |
| Phosphorus (P) | ≤ 0.045% | ≤ 0.045% | Strictly capped to maintain material purity |
| Sulfur (S) | ≤ 0.030% | ≤ 0.015% | Capped to ensure corrosion resistance |
Why Is SUS304 Considered Food Grade?
SUS304 is classified as a food-grade material due to its composition of 18%–20% chromium and 8%–10.5% nickel (the "18/8" grade). The chromium content enables the formation of a self-healing passive oxide layer (Cr₂O₃) that effectively prevents corrosion, rusting, and the leaching of heavy metals, while the nickel enhances acid resistance, allowing the material to withstand exposure to acidic foods (pH > 3.0). With a smooth surface finish (Ra ≤ 0.8 μm) that resists bacterial adhesion, the material fully complies with FDA 21 CFR 175.300 and EU 1935/2004 food safety standards.
Global Compliance Standards for Procurement Managers
When importing SUS304 products or raw materials, verifying chemical composition alone is insufficient. B2B buyers must inspect supplier compliance certificates matching destination market regulations:
United States (FDA): Compliance with FDA 21 CFR 175.300 (GRAS - Generally Recognized As Safe for food contact surfaces).
European Union (EU): Adherence to Regulation (EC) No 1935/2004 and CM/Res(2013)9 heavy metal leaching limits (Lead, Cadmium, Nickel migration test).
China (GB): Certification under GB 4806.9-2016 (National Food Safety Standard for Food Contact Metal Materials).
Sanitation Standards: 3-A Sanitary Standards (USA) for dairy and beverage processing equipment designs.
Food Grade SUS304 Surface Finish Requirements
For food contact applications, surface quality is as important as chemical composition.
| Surface Finish | Typical Roughness | Application |
|---|---|---|
| 2B | Ra ≤0.4–0.8 μm | General food equipment |
| BA | Ra ≤0.2–0.4 μm | Kitchen appliances |
| No.4 | Ra ≤0.8 μm | Food preparation surfaces |
| EP | Ra ≤0.2 μm | Pharmaceutical / sanitary systems |
SUS304 Food Grade Applications
| Industry | Products |
|---|---|
| Food Processing | Tanks, conveyors, mixers |
| Beverage | Brewing tanks, pipelines |
| Dairy | Milk storage equipment |
| Kitchen | Sinks, tables, cookware |
| Pharmaceutical | Clean equipment |
| Catering | Food preparation surfaces |
To help tailor this information, are you looking for SUS304 applications for a specific commercial project, or do you need help comparing it against grade 316 for a high-salt or acidic environment?
SUS304 vs SUS316 Food Grade Stainless Steel
Many buyers compare SUS304 with SUS316 because both are used in food industries.
| Comparison | SUS304 | SUS316 |
|---|---|---|
| Chromium | 18–20% | 16–18% |
| Nickel | 8–10.5% | 10–14% |
| Molybdenum | None | 2–3% |
| Corrosion Resistance | Excellent | Superior |
| Salt Resistance | Medium | Excellent |
| Cost | Lower | Higher |
| Common Application | General food equipment | Marine, chemical, high chloride food |
SUS304 vs. SUS316 Food-Grade Stainless Steel: How to Choose?
For standard daily food processing applications, SUS304 stainless steel is recommended; however, if the equipment requires frequent contact with salt, acidic substances, or harsh cleaning chemicals, an upgrade to SUS316 stainless steel is advisable. Both SUS304 and SUS316 are FDA-certified, food-safe, and chemically stable materials, meaning they do not leach harmful toxins into food under normal operating conditions. The primary differences between the two lie in their chemical composition and their resistance to harsh environments.
Food-Grade SUS304 Suppliers and Manufacturers
Our SUS304 products comply with international standards for food-contact materials. We provide Material Test Certificates (MTC) and can facilitate third-party testing (e.g., SGS, TUV, BV) to ensure the material is free from harmful heavy metal leaching and is safe for food processing and storage.
We specialize in supplying high-quality 2B and BA finishes characterized by extremely low surface roughness (Ra). This ensures a hygienic surface that is easy to clean and resistant to bacterial growth-critical factors for food-grade applications.
Food-grade SUS304 specifications
| Product Form | Available Dimensions / Specs | Primary Surface Finish |
| Stainless Steel Coil | Thickness: 0.3mm - 3.0mm | 2B, BA, No.4 |
| Stainless Steel Sheet/Plate | Thickness: 0.3mm - 20mm | 2B, BA, No.4, HL |
| Stainless Steel Pipe/Tube | OD: 6mm - 630mm; WT: 0.5mm - 20mm | Pickled, Polished, Sanitary |
| Stainless Steel Strip | Width: 10mm - 600mm | Slit edge, 2B/BA |
To implement this technical specification more effectively, could you please clarify:
What specific product or equipment are you designing or evaluating (e.g., storage tanks, basins, or piping)?
What operating environment will it be exposed to (such as temperature range, or contact with cleaning chemicals or salt)?
Quality Control:
Each coil and sheet undergoes precise chemical composition analysis to ensure a balanced ratio of nickel (8–10.5%) and chromium (18–20%). This imparts superior corrosion resistance, enabling the material to withstand exposure to acidic food substances and cleaning agents.
Professional Export Packaging:
To prevent scratches, corrosion, or contamination during transit, we employ high-standard export packaging solutions, including PVC protective film, moisture-proof paper wrapping, and fumigation-free wooden pallets.
FAQ
Q1: Is SUS304 the same as 18/8 stainless steel?
Yes. The term "18/8" refers to a nominal composition of 18% chromium and 8% nickel, which aligns with the basic chemical composition of JIS SUS304 and AISI 304.
Q2: Is SUS304 stainless steel safe for food contact?
Yes. SUS304 is widely used in food-contact applications due to its chromium-nickel composition, corrosion resistance, and easy-to-clean surface. However, buyers should still verify that the final product complies with relevant food-contact safety standards.
Q3: Is SUS304 better than SUS316 for food processing equipment?
Not necessarily. SUS304 is suitable for most standard food applications; however, SUS316-which contains molybdenum-offers superior performance in environments involving salt, acids, marine conditions, or chemical corrosion.
Q4: Which SUS304 surface finish is best for food processing equipment?
For general food equipment, 2B or BA finishes are typically chosen. For pharmaceutical applications or those requiring high hygiene standards, electropolished surfaces with lower Ra values (surface roughness) are commonly selected.
Q5: Will SUS304 rust when exposed to food processing chemicals?
It can rust under certain conditions. Although SUS304 offers excellent resistance to organic acids (such as citric acid and acetic acid), prolonged exposure to high concentrations of chlorides (e.g., brine, bleach, or hot saline solutions) may cause pitting corrosion. For high-salinity processing environments, SUS316L is recommended instead.
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