One of the most common misconceptions I encounter in my 20 years of trading stainless steel is the belief that "304" automatically means "Food Grade."
You might see the label "18/8" and assume it is safe for food contact.
The reality is: While all Food Grade stainless steel is 304, not all 304 stainless steel is strictly Food Grade.
If you are manufacturing kitchenware, medical devices, or food processing machinery, understanding this distinction is critical to avoiding compliance issues.
1. The Standard 304: The "18/8" Workhorse
First, let's look at the basics.
Grade 304 (Density: 7.93 g/cm³) is the most widely used stainless steel globally. It is famous for its 18/8 composition:
Chromium: 18% min
Nickel: 8% min
It offers excellent corrosion resistance, withstands high temperatures up to 800°C, and is easy to stamp or bend. For most industrial applications-like architecture, auto parts, or furniture-standard 304 is perfect.
2. The "Food Grade" Difference: It's About Impurities
So, what makes "Food Grade" special?
According to international standards, ordinary 304 allows for certain fluctuations in chemical composition as long as Ni > 8% and Cr > 18%.
However, Food Grade 304 has stricter controls on Heavy Metals.
Lead & Manganese: Food grade materials strictly limit the content of harmful precipitates (like lead) that could leach into food during heating.
Composition Range: While standard 304 might have a wider tolerance, food-grade sourcing often requires tighter adherence to the 18% Cr / 8% Ni ratio to ensure stability.
Key Takeaway: If your project requires FDA or CE food certification, you must specify "Food Grade" when ordering, not just "304".
3. Decoding the Labels: 304 vs. SUS304 vs. 06Cr19Ni10
When you receive a Mill Test Certificate (MTC), you might see different names. Are they the same?
Basically, yes, but they refer to different national standards:
304: This usually refers to the ASTM standard (USA), such as ASTM A240 (Plate/Sheet) or ASTM A276 (Bars).
SUS304: This indicates the JIS standard (Japan).
06Cr19Ni10: This is the chemical name under the GB standard (China).
Pro Tip: To ensure you are getting real 304, checking the standard is not enough. You must verify the Chemical Analysis (Ni ≥ 8.0%).
4. Can 304 Rust? (Maintenance Advice)
Many clients ask: "If I buy 304, will it stay shiny forever?"
The answer is: It depends on the environment.
Although 304 has excellent corrosion resistance in the atmosphere, it is not invincible.
Clean Indoor Air: 304 will last indefinitely.
Coastal/Polluted Areas: If used in heavy industrial zones or near the sea, 304 can suffer from corrosion (rust spots) due to chloride ions.
Recommendation: For coastal/marine environments, we strongly recommend upgrading to Grade 316. If you must use 304 outdoors, it requires frequent washing to remove dust and corrosive particles.
Conclusion
Don't let a labeling technicality ruin your product line.
Need standard 304 for construction? We have it.
Need certified Food Grade 304 with strict heavy metal control? We supply that too.
Not sure which one you need?
[Contact our engineering team today] and we will help you select the right material according to ASTM/JIS standards.
Email：ru@gneesteelgroup.com
Phone：+8615824687445