Stainless steel grades table: AISI and EN numbers

Short answer: the most common stainless steel grades are AISI 304 (EN 1.4301, also called 18/8), AISI 316L (EN 1.4404, molybdenum-alloyed, often called acid-resistant) and AISI 430 (EN 1.4016, ferritic). The AISI number is the American designation and the EN number the European one (EN 10088). The table below shows which number matches which grade and what it is used for.

Stainless steel grades table

Chemical composition

Values are EN 10088-2 limits for sheet and strip. The actual composition of a delivered batch is shown on its material certificate.

What do 18/8 and 18/10 mean?

18/8 means about 18 % chromium and 8 % nickel, in practice grade AISI 304 / EN 1.4301. 18/10 is a name for the same grade family with nickel near the upper limit of the standard, used mostly for cookware. Neither is a separate standard grade.

304 or 316?

The key difference is molybdenum: 2 to 2.5 % molybdenum improves resistance to chlorides and pitting corrosion. Indoors and for food contact 304 is usually enough; where salt, moisture or chemicals are present, choose 316L. Full comparison: AISI 304 vs AISI 316.

What does the L mean?

L stands for low carbon: a carbon content of at most 0.030 %. Low carbon reduces chromium carbide formation in the heat-affected zone of a weld, so 304L and 316L suit welded structures. Material is often dual-certified (for example 1.4301/1.4307) and then meets the requirements of both grades.

Is stainless steel magnetic?

The austenitic grades 304 and 316L are practically non-magnetic when annealed, but cold working such as bending or rolling can make them slightly magnetic. Ferritic 430 is always magnetic. A magnet is therefore not a reliable way to identify a grade: check the grade on the material certificate.

How to choose a grade

• Indoors, dry conditions and decorative parts: 430 or 304.

• Food, kitchens and general fabrication: 304.

• Welded structures: 304L or 316L.

• Outdoors, coastal sites, salts and chlorides: 316L.

• Process piping and chemicals: 316L.

• In your enquiry, state the grade with both its AISI and EN number, the product form, dimensions, finish and the certificate you need, for example EN 10204 3.1.

Grades from Kominox

Kominox supplies stainless steel grades 304, 316L and 430 as well as aluminium, in a range of finishes. Material certificates are available on request. Request a quote

Frequently asked questions

What is EN 1.4301?

EN 1.4301 (X5CrNi18-10) is the European number for the stainless steel that matches AISI 304. It is the most common stainless steel, also known as 18/8.

What is EN 1.4404?

EN 1.4404 (X2CrNiMo17-12-2) matches AISI 316L. It is a low-carbon molybdenum-alloyed stainless steel with 2 to 2.5 % molybdenum.

Is 18/8 the same as AISI 304?

In practice, yes. 18/8 describes about 18 % chromium and 8 % nickel, which matches AISI 304 / EN 1.4301.

What is the difference between 304 and 304L?

304L has a carbon content of at most 0.030 %, while the limit for 304 is 0.07 %. Lower carbon improves corrosion resistance after welding.

Which EN number matches AISI 430?

AISI 430 matches EN 1.4016 (X6Cr17). It is a ferritic, magnetic and nickel-free stainless steel.