Stainless 304 vs 316 CNC Machining — EU Cost and Application Guide 2026
The 304 vs 316 decision is a €1–€4 per-part question on most CNC jobs, and the wrong default costs money every time. This guide uses current EU workshop data to show when the 316 premium is earned.
Price snapshot — EU workshop median, Q2 2026
| Quantity | 304 €/part | 316 €/part | Premium |
|---|---|---|---|
| 1–10 | €42 | €56 | +33% |
| 11–100 | €24 | €34 | +42% |
| 101–500 | €16 | €22 | +38% |
| 500+ | €11 | €16 | +45% |
The 316 premium is real and larger than aluminum 6061 vs 7075. Two drivers: raw material cost (molybdenum content makes 316 ~30% more expensive per kg) and slower machining speed (316 work-hardens more aggressively, tool life is 30% shorter).
When 316 is genuinely required
- Chloride exposure — marine environments, coastal outdoor, de-icing salt, some industrial chemistry. 304 pits; 316 doesn't.
- Pharmaceutical / food-contact at elevated temperatures — 304 is food-safe at room temperature; 316 is required above ~60°C contact.
- Medical devices — implantable: 316L specifically (low carbon). Non-implantable: 304 is often fine.
- Certain acids and brines — sulfuric acid above 15% concentration, bromide solutions.
When 304 is correct and people still spec 316 "just in case"
- Indoor mounting brackets
- Decorative trim
- Kitchen equipment for dry or low-moisture contact
- Industrial fasteners in non-corrosive environments
- Most architectural hardware
The "just in case" pattern is where engineers inherit templates and cost goes up 40% for nothing.
Machinability considerations
304 is moderately difficult to machine (free-machining 303 exists for the worst cases). 316 is harder — slower feeds, more tool consumption, longer cycle time.
If you're doing high-feature counts or tight tolerances, factor an additional 5–8% surcharge on top of the material delta for 316 vs 304.
The 316L question
316L = 316 with lower carbon content (≤0.03%). Used for:
- Welded parts (reduces sensitization)
- Medical implants (required by standards)
- Some high-temperature service
For CNC-machined non-welded parts, 316 standard is usually fine. 316L adds ~5–10% cost for no benefit unless the application specifically demands it.
EU-specific considerations
- 316L is the default for medical device CE marking — don't try to use 304 to save cost on medical work, it will fail certification.
- Food-contact certification (1935/2004, 10/2011) — both 304 and 316 qualify, but 316 is required for high-chloride foods (marine proteins, pickled products).
- Pharma (3-A, FDA) — 316L is effectively required for process equipment contact surfaces.
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