If you import stainless steel 304 vs 316 from China by the container — for food equipment, chemical processing, marine and coastal structures, architecture, or metal fabrication — the real question is not "which grade do I pick" but "will I actually receive the grade I paid for". This is for wholesale B2B buyers (from 5 tonnes / one 20-foot container), not retail. Short answer: the difference between 304 and 316 is molybdenum, and the biggest risk on the Chinese market is grade substitution. Below is how to choose the right steel and how to control it.
304 vs 316: the real difference
Both are austenitic chromium-nickel stainless steel, but they behave very differently in aggressive environments.
- 304 (18/8) — roughly 18% chromium, 8% nickel. The general-purpose workhorse: food equipment, kitchens, tanks, decorative parts, indoor structures.
- 316 — the same base plus 2–3% molybdenum. That molybdenum is what delivers resistance to chlorides and pitting (localized) corrosion. It is the "marine" grade: coastlines, salt water, chemical plants, pharma, swimming pools.
The key difference in one sentence: if the part contacts chlorides, salt, sea air, or aggressive chemicals, you need 316; for everything else 304 is usually enough, and it is noticeably cheaper.
304L, 316L, and why 201 is a trap
- 304L / 316L — low-carbon versions ("L" = low carbon). They matter when parts are welded: low carbon prevents intergranular corrosion in the weld zone. For welded marine or chemical equipment, specify 316L, not plain 316.
- 201 — a manganese stainless steel. Part of the nickel is replaced by manganese and nitrogen, so it is significantly cheaper, slightly magnetic, and looks almost identical to 304 — but its corrosion resistance is lower. 201 has legitimate uses (decorative and household items in dry environments); the problem is that it is often sold as 304.
For customs, stainless flat-rolled product typically falls under HS headings 7219 / 7220 (hot-rolled and cold-rolled sheet/strip of corrosion-resistant steel, of width ≥600 mm and <600 mm respectively). The exact code depends on form and dimensions and affects duty and paperwork.
The central risk: grade substitution in China
This is why this article is worth reading. Two typical substitutions occur on the Chinese market:
- 201 or off-spec sold as 304 — the buyer pays for 304, receives manganese steel, and it starts rusting within a year.
- 304 sold as 316 — visually identical, the certificate looks "right", but there is no molybdenum, and the part fails in a marine environment.
You cannot tell these grades apart by eye. The classic "sample OK, batch defective" trap applies in full force here: the sample is fine, but the container is a different alloy. So the grade must be measured, not merely declared.
How to verify batch composition
Do not rely on the seller's word. The working toolkit:
- Mill Test Certificate (MTC / EN 10204 3.1) — must include the heat's chemical analysis: Cr, Ni, Mo, Mn, C. For 316, the Mo column must read ~2–3%; if molybdenum is 0, it is not 316. How to read and cross-check the certificate is covered in our guide to the Mill Test Certificate for China steel. Remember: paper can be forged, so an MTC is necessary but not sufficient.
- Portable XRF / PMI spectrometer at inspection — a handheld analyzer shows the real Cr, Ni, Mo content in seconds, right at the warehouse or in the container. This is the most reliable way to catch substitution before shipment. Order an independent quality inspection in China with a mandatory PMI grade test.
- Molybdenum spot test — a chemical field test that distinguishes 316 from 304 by its reaction to molybdenum. A cheap on-site check, though less precise than XRF.
- Why the "magnet test" is unreliable — the common myth is that stainless "is not magnetic". In reality, cold-worked (bent, cut, drawn) 304 becomes slightly magnetic, and 201 is also mildly magnetic. A magnet will not separate 201 from 304, let alone 304 from 316. Never accept a batch "because the magnet doesn't stick".
Pricing: 316 costs more, 201 costs less
Stainless prices move with nickel and the quotes on the London Metal Exchange, so we give ratios rather than fixed numbers (as of 2026):
- 316 costs notably more than 304 — the extra nickel and molybdenum typically add tens of percent. Do not be surprised when 316L is materially more expensive than 304.
- 201 is cheaper than 304 — which is exactly why it gets slipped in. If a "304" quote is suspiciously low, that is your first signal to verify the grade.
- Supplier type matters too: factory vs trader affects both price and your control over the melt.
For composition benchmarks, use ASTM A240 (the specification for stainless sheet/plate for pressure vessels and general use) and the equivalent ISO standards. Verify the supplier's legal entity in the state registry at gsxt.gov.cn.
Which grade for which application
- Food equipment, kitchens, tanks (dry / non-saline) — 304 / 304L.
- Marine, coastal, chemical, pharma, pools — 316 / 316L.
- Welded structures — always the "L" grade (304L or 316L).
- Decorative, dry-environment, budget parts — 201 is acceptable, but only knowingly and at a price below 304.
We run the full cycle: factory sourcing, verification, PMI grade control, and logistics. See our stainless steel sourcing line and the broader guide to importing steel from China.
Request a price and grade verification
Send us the grade (304 / 304L / 316 / 316L), the product form, thickness, and volume — we will quote the container price from the factory and include a PMI grade test in the pre-shipment inspection. Email contact@silkwaysourcing.com or WhatsApp +380 97 883 4765.
