Type 304L Stainless Steel

Type 304L is a lower carbon variant of Grade 304 – the steel can be welded without the resulting issue of carbon precipitation (precipitation of chromium carbide as heat is applied during the welding process which depletes the chromium element of the steel thus reducing its anti-corrosive/oxidation effectiveness).

As a result, Type 304L stainless steel is a sort after material for use in severely corrosive conditions. Weld annealing is only necessary in applications where stress loads are excessive.

This steel Grade is found in a variety of commercial sectors, particularly in the chemical industry.

Benefits of using 304L Stainless Steel

  • Low carbon content eliminates carbon precipitation in the welding process
  • Can be used in severe corrosive environments
  • Weld annealing only required in high stress applications
  • Very similar to Type 304

304 & 304L plate and pipes have similar properties and in certain cases are stocked with Dual Certification, where it is concluded that each item has properties and a composition which comply with both steel types. Grade 304H cannot be included in this equation due to the steel’s higher carbon content which is intended for use in elevated temperature applications.

Mechanical Properties of 304L

Description Type 304L
Proof Stress 0.2% (MPa) 170
Tensile strength (MPa) 485
Elongation A5 (%) 40
Hardness HB: 201
HRB: 92

Chemical Composition of 304L

UNS No S30403
EN 1.4301
AISI 304
Carbon (C) 0.03
Silicon (Si) 0.75
Manganese (Mn) 2.00
Phosphorus (P) 0.045
Sulphur (S) 0.030
Chromium (Cr) 18.00 – 20.00
Molybdenum (Mo)  
Nickel (Ni) 8.00 – 12.00
Nitrogen (N) 0.10