Difference between AISI 316, AISI 316L and AISI 316LN Stainless Steel

What are AISI 316 (1.4401), AISI 316L (1.4404) and AISI 316LN (1.4406)?

AISI 316 (1.4401), AISI 316L (1.4404) and AISI 316LN (1.4406) are Cr-Ni-Mo austenitic stainless steels, which are commonly used due to their very good corrosion resistance in various aggressive environments.

Differences between AISI 316 (1.4401), AISI 316L (1.4404) and AISI 316LN (1.4406)

The main difference between AISI 316 (1.4401) stainless steel and AISI 316L (1.4404) stainless steel is the carbon content. The "L" stands for "low carbon" content.

Due to the lower carbon amount, AISI 316L (1.4404) stainless steel has a reduced risk of sensitization (grain boundary carbide precipitation). Yet, at the same time, it loses some of its strength.

AISI 316LN (1.4406) stainless steel is alloyed with nitrogen to compensate for the loss of strength.

Chemical Composition

 

AISI 316 (1.4401)

AISI 316L (1.4404)

AISI 316LN (1.4406)

Cr (Chromium)

16.5 – 18.5 %

16.5 – 18.5 %

16.5 – 18.5 %

Ni (Nickel)

10 - 13 %

10 - 13 %

10 – 12.5 %

Mn (Manganese)

≤ 2 %

≤ 2 %

≤ 2 %

Mo (Molybdenum)

2 – 2.5 %

2 – 2.5 %

2 – 2.5 %

Si (Silicon)

≤ 1 %

≤ 1 %

≤ 1 %

N (Nitrogen)

0.11 %

0.11 %

0.12-0.22 %

P (Phosphorus)

0.045 %

0.045 %

0.045 %

C (Carbon)

≤ 0.07 %

≤ 0.03 %

≤ 0.03 %

S (Sulphur)

0.03 %

0.02 %

0.015 %

 

Mechanical and Thermal Properties (typical values at 20ºC)

 

AISI 316 (1.4401)

AISI 316L (1.4404)

AISI 316LN (1.4406)

Density

8 g/cm³

8 g/cm³

8 g/cm³

Elastic modulus

193 GPa

193 GPa

200 GPa

Hardness, Brinell

215 Max HB

215 Max HB

220 Max HB

Tensile strength

500 - 700 MPa

520 - 680 MPa

580-780 MPa

Yield strength

200 MPa

220 MPa

205 MPa

Coefficient of thermal expansion

1.59*10-5 1/K

1.59*10-5 1/K

 

Thermal conductivity

16.3 W/(m·K)

16.3 W/(m·K)

15 W/(m·K)

Melting point

1400 °C

1400 °C

1400 °C

Common Applications of 316/316L/316LN Stainless Steel

  • Aerospace Structures
  • Base plates
  • Food processing equipment
  • Brewery equipment
  • Pulp and paper processing equipment
  • Oil & petroleum refining equipment
  • Chemical transportation containers
  • Soap and photographic handling equipment
  • Textile Industry Equipment
  • Architectural
  • Pharmaceutical processing equipment
  • Laboratory benches & equipment
  • Boat fittings
  • Heat exchangers

The main differences between 316, 316L and 316LN lies in their chemical composition. The "L" indicates lower carbon content, while the "N" in 316LN points to the higher nitrogen content.