Materials guide
AISI 304 or 316 stainless steel for laser cutting: how to choose
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Why the choice of alloy matters
When designing a stainless steel component to be laser cut, choosing between AISI 304 and AISI 316 is not just a matter of price: it affects how long the part will last, how well it resists specific operating environments and, as a result, the overall cost of the project once future maintenance or replacement is taken into account. The two alloys laser cut in a very similar way, so the decision should be made upstream, based on where and how the part will be used.
The two alloys compared
AISI 304 and AISI 316 are both austenitic stainless steels, the most widely used family in sheet metal fabrication thanks to their combination of corrosion resistance, workability and relatively low cost compared with other stainless alloys.
The main chemical difference is molybdenum: AISI 316 typically contains between 2% and 3%, while AISI 304 contains none. Molybdenum significantly improves resistance to pitting and chloride corrosion, which is exactly the type of corrosive attack typical of saline and marine environments or contact with aggressive chemicals.
Otherwise, the two alloys share a similar basic structure: AISI 304 contains about 18% chromium and 8-10% nickel, while AISI 316 contains about 16-18% chromium and 10-14% nickel — slightly more than 304. These elements provide the “baseline” corrosion resistance common to all austenitic steels.
Comparison table
| Property | AISI 304 | AISI 316 |
|---|---|---|
| Molybdenum | None | Present (~2-3%) |
| General corrosion resistance | Good | Excellent |
| Resistance to chlorides and saline environments | Limited | High |
| Indicative cost | Lower | Higher |
| Typical applications | Furniture, household appliances, indoor food use, general fabrication | Marine, chemical, pharmaceutical, shipbuilding, swimming pools |
| Laser cutting behaviour | Excellent, clean edge | Excellent, clean edge |
| Bending and welding | Standard for austenitic steels | Standard for austenitic steels |
As far as the laser cutting itself is concerned, the two alloys behave almost identically: both cut well with very similar power and speed settings. Edge quality depends more on the assist gas than on the alloy — nitrogen gives a “bright”, oxide-free edge, while oxygen leaves a slightly oxidised edge but cuts faster and more economically on thicker material.
Thicknesses that can be laser cut
Both alloys are available and can be laser cut in a similar range of thicknesses, roughly from 0.8 to 8 mm, which covers the vast majority of light fabrication, technical furniture and industrial components. For non-standard thicknesses, availability depends on the sheet supplier.
Choosing by sector
- Food and pharmaceutical: AISI 304 is widely used for equipment and surfaces in contact with food in indoor environments. 316 becomes preferable when frequent washing with saline or chlorine solutions is expected, or in environments with stricter hygiene requirements.
- Furniture and design: for furniture, interior accessories and household appliances, AISI 304 offers an excellent balance of appearance, durability and cost.
- Marine or coastal environments: chlorides in the air and in brackish water make AISI 316 the recommended choice to avoid localised corrosion over time.
- Chemical and industrial sector: where aggressive chemicals or corrosive atmospheres are present, AISI 316 ensures a longer component life.
- Construction and outdoor fabrication: for structures continuously exposed to the weather, especially in polluted urban or industrial areas, AISI 316 offers greater safety margins than 304.
How to choose: quick checklist
- Will the part be exposed to chlorides, salt spray or marine environments? If so, go for AISI 316.
- Is the component intended for indoor use in a controlled environment (furniture, non-aggressive food use, household appliances)? AISI 304 is generally sufficient.
- Is frequent washing with chemicals or chlorine expected? Consider AISI 316.
- Is budget a tight constraint and the operating environment not aggressive? AISI 304 offers the best balance of performance and cost.
- If in doubt, always check the material data sheet and, if necessary, ask your supplier for a heat certificate.
Frequently asked questions
- Is AISI 316 always a better choice than 304?
- No. 316 offers superior corrosion resistance, especially where chlorides are present, but it costs more. For indoor, furniture or food applications not in direct contact with saline or aggressive chemical environments, AISI 304 is generally an adequate and more economical choice.
- How much more does AISI 316 cost than 304?
- The price difference depends on the supplier and on raw material market trends, but 316 costs noticeably more than 304 for the same thickness, mainly because of the molybdenum in the alloy. For an up-to-date estimate on your project, it's always best to request a specific quote.
- Do AISI 304 and 316 bend and weld the same way?
- Yes, both alloys are austenitic stainless steels and behave similarly in bending and welding. The main differences concern corrosion resistance, not mechanical workability.
- How can I tell whether an existing part is AISI 304 or 316?
- They cannot be told apart with certainty by eye: you need specific tests, such as dedicated chemical reagents or spectrometric analysis, or the supplier's documentation. If the part comes from a traceable supply, the technical data sheet or heat certificate shows the exact alloy designation.
- Do I need a material certificate for laser-cut stainless steel?
- It depends on the sector and the end use. For food, pharmaceutical or regulated applications it's common to request a 3.1 certificate according to EN 10204, which certifies the composition and properties of the material used.