Stainless Steel Grade AISI 316/316L

AISI 316/AISI 316L (1.4401/1.4404/V4A)

Different grades of stainless steel are distinguished according to their chemical composition. Depending on the amounts of special additives contained in the steel alloy, the different proportions determine the physical properties of the material and therefore its possible applications.

One of the most popular stainless steel grade for applications in architecture, industry and especially in the chemical industry is the material AISI 316 or AISI 316L.

What is stainless steel AISI 316/AISI 316L?

AISI 316/AISI 316L, also known in German-speaking countries as "Edelstahl 1.4401/1.4404" and "V4A", is a higher-quality alloy compared to the material AISI 304 ("1.4301" and “V2A” in German-speaking countries) with added molybdenum and an increased chromium and nickel content, which means that the material has a higher resistance to corrosion. The addition of molybdenum makes this stainless steel more corrosion and oxidation resistant and very suitable for applying for instance in areas near the sea or in a slightly alkaline environment. This material is easy to process, form and weld.

The abbreviation AISI stands for "American Iron and Steel Institute", which set up the certain standards to which stainless steel grades AISI 304, AISI 316 and AISI 316L should correspond.

The ending "L" has been added to some of the alloys. When comparing AISI 316 and AISI 316L we can see quite identical chemical compositions. However, there is a significant difference – L stands for "low" in relation to the slightly lower carbon content.

V4A, X2CrNiMo17-12-2, 1.4404 – Synonyms of AISI 316/AISI 316L

The stainless steel AISI 316/AISI 316L has become a popular material in today's markets and is being manufactured in various countries around the globe. The rules for forming its name, which consists of alphabetical and numerical symbols, are governed by the regulations and ordinances of each country. In the USA as well as in European and non-European countries, different specific designations systems are used for this stainless steel grade.

Below mirrorINOX would like to give a rough overview of the different names of this material and their origin.

1.4404

1.4404 is the numeric designation for this grade of austenitic stainless steel according to the European Standard, where for the exact designation of material, experts use this option (as for other grades the designations for instance 1.4301, 1.4571 or 1.4404 are preferred).

V4A

Already before the end of the 19th century, it was discovered that the corrosion resistance of steel could be improved by adding nickel and chromium. The decisive step was taken in Germany in 1912. By adding nickel and chromium and by means of the right heat treatment, the optimal combination of excellent corrosion resistance and good mechanical properties was achieved for the first time.

The abbreviations "V2A" and "V4A" consist of the letters "V" for the German word "Versuch" (which means "trial", "test", "experiment") and the letter "A" for "Austenit” ("austenite") plus the figures 2 and 4 indicating the ordinal number of the successful tests in which the inventors reached the required properties of the alloy. These designations are very common in colloquial language of German-speaking countries and some others.

X2CrNiMo17-12-2

The historical German name for AISI 316L is "X2CrNiMo17-12-2". This classification was developed by the German Institute for Standardization (Deutsche Institut für Normung), which is colloquially often referred to as "according to DIN standards" or simply "according to DIN".

The characters X2 in this classification mean that the material contains less than 0.03 percent by weight of carbon that improves significantly the weldability of the material. (For your information: X5 stands for less than 0.07 wt%, X10 – less than 0.10 wt%).

Further symbols in this designation indicate the mass fraction of the alloy elements chromium, nickel and molybdenum in the steel composition, namely: chromium 17.5 wt%, nickel 12.5 wt% and molybdenum 2.5 wt%.

Stainless steel AISI 316/AISI 316L: Properties

The stainless steel with the material number AISI 316/AISI 316L is characterized by excellent resistance to various aggressive media, heat resistance and higher expansion rate. It is much more stable, for example when used in an environment with salty or acidic air.

AISI 316/1.4404 has excellent mechanical and anti-corrosive properties even at more extreme temperatures. AISI 316 is easy to process and to weld, has increased ductility and better formability.

Is AISI 316/AISI 316L magnetic?

The material AISI 316/AISI 316L is rather non-magnetic or only very weakly magnetic.

The magnetic/non-magnetic properties of the stainless steel depend on the nickel content in its composition. Only when the nickel content is reduced to 9 % or less does the stainless steel begin to magnetise, even if it is austenitic stainless steel.

AISI 316/AISI 316L usually contains between 10 and 13 wt% of nickel, which makes this steel basically non-magnetic. Due to its lower carbon content, AISI 316L/1.4404 is however easier to machine and to weld than the otherwise equivalent stainless steel AISI 316/1.4401.

Density of Stainless steel AISI 316L

The density of the material AISI 316L is 8,0 kg/dm³ and the electrical resistance at 20 °C is 0.75 (Ω·mm²/m).

Tensile strength of Stainless steel AISI 316L

The tensile strength and other mechanical or physical properties are presented in the chart below:

Mechanical properties of Stainless steel AISI 316 at 20 °C/ 68 °F

Value

0.2 % Yield strength Rp 0.2 (N/mm2)

> 190 N/mm²

1.0 % Yield strength Rp 1.0 (N/mm2)

250

Tensile strength, Rm N/mm2

520-670

Elongation at break A5 (%)

40 / 30

lengthwise / crosswise

Notched impact strength ISO-V (J)

100 J / 60

lengthwise / crosswise

Physical properties of Stainless steel AISI 316

Value

Density, kg/dm3

7.95

Hardness HB

< 215

Is the material magnetic?

No, not regularly

Is the material polishable?

Yes, it can be polished very well

Material temperature

1 % Yield strength of Stainless steel,
Rp 1.0

Tensile strength of Stainless steel,
Rm

100 / 212 °C/°F

>= 199 / >= 28.9 N / mm² / ksi

430 / 62.4 N / mm² / ksi

200 / 392 °C/°F

>= 167 / >= 24.2 N / mm² / ksi

390 / 56.6 N / mm² / ksi

300 / 572 °C/°F

>= 145 / >= 21.0 N / mm² / ksi

380 / 55.1 N / mm² / ksi

400 / 752 °C/°F

>= 135 / >= 19.6 N / mm² / ksi

380 / 55.1 N / mm² / ksi

500 / 932 °C/°F

>= 128 / >= 18.6 N / mm² / ksi

360 / 52.2 N / mm² / ksi

Chemical composition of Stainless Steel AISI 316
Chemical elements

C

Si

Mn

P

S

Cr

Mo

Ni

Min %

16.50

2.00

10.00

Max %

0.030

1.00

2.00

0.045

0.015

18.50

2.50

13.00

Applications and fields where stainless steel AISI 316/AISI 316L can be used

Due to its properties, AISI 316/AISI 316L is used in many fields and sectors of industries: in the architecture or construction industry for façades, roofs, all types of cladding and other architectural elements, especially for outdoor and technical applications, for example, for the construction of specialised industrial plants in the chemical, food, paper and cellulose production, mining, pharmaceutical and petrochemical industries for the construction of containers, silos, vessels, tanks, pipes, and much more.

Everything you need to know about AISI 316L in one table

Designations and general descriptions of Stainless steel AISI 316L

EN European Norms

X2CrNiMo17-12-2

AISI American Iron and Steel Institute

AISI 316L

UNS Unified Numbering System for Metals and Alloys

S 31603
Grade TP 316L

AFNOR Association française de normalisation

X2CrNiMo17-12-2 / NF EN 10028-7 (01/2000) (FR)

BS British Standards

X2CrNiMo17-12-2 / B.S. EN 10028-7 (01-2000) (GB)

Mill designation

V4A Supra NK

Density, kg/dm³

7.95

Hardness HB

< 215

Type of alloy

Nickel-chromium-molybdenum steel

Groupe

Stainless steels
Rust and acid-proof steels

Class

Austenitic stainless steel

Corrosion

Resistant to intergranular corrosion

Description

Austenitic stainless steel AISI 316 has a good acid resistance

Stainless steel grades we are processing

mirrorINOX processes the surfaces of stainless steels using traditionally established and proven metal processing technologies, as well as the newest and most advanced ones.

We very often refine the more common stainless steels such as 1.4016, AISI 304 (1.4301) and AISI 316L (1.4404), but also the less conventional, rarer grades such as 1.4435, 1.4571, 1.4509. We are even treating special stainless steels such as 1.4462 ("Duplex") and 1.4410 ("Super Duplex").

We look forward to your inquiry – whatever stainless steel grade you require!

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