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.
304L Stainless Steel Pipes and Tubes Product Range
304L Stainless Steel Pipes and Tubes Specifications: ASTM A269 / ASTM A312
304L Stainless Steel Pipes and Tubes Sizes (Seamless): 1/2" NB - 24" NB
304L Stainless Steel Pipes and Tubes Sizes (ERW): 1/2" NB - 24" NB
304L Stainless Steel Pipes and Tubes Sizes (EFW): 6" NB - 100" NB
304L Stainless Steel Pipes and Tubes Wall Thickness available:
Schedule 5S - Schedule XXS (heavier on request)
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Other Materials Testing:
NACE MR0175, H2 SERVICE, OXYGEN SERVICE, CRYO SERVICE, etc.
304L Stainless Steel Pipes and Tubes Dimensions:
All Pipes is manufactured and inspected/tested to the relevant standards including ASTM A269 / ASTM A312
Background 304L Stainless Steel
Grade 304 is the standard "18/8" stainless; it is the most versatile and most widely used stainless steel, available in a wider range of products, forms and finishes than any other. It has excellent forming and welding characteristics. The balanced austenitic structure of Grade 304 enables it to be severely deep drawn without intermediate annealing, which has made this grade dominant in the manufacture of drawn stainless parts such as sinks, hollow-ware and saucepans. For these applications it is common to use special "304DDQ" (Deep Drawing Quality) variants. Grade 304 is readily brake or roll formed into a variety of components for applications in the industrial, architectural, and transportation fields. Grade 304 also has outstanding welding characteristics. Post-weld annealing is not required when welding thin sections.
Grade 304L, the low carbon version of 304, does not require post-weld annealing and so is extensively used in heavy gauge components (over about 6mm). Grade 304H with its higher carbon content finds application at elevated temperatures. The austenitic structure also gives these grades excellent toughness, even down to cryogenic temperatures.
304L Stainless Steel Pipes and Tubes Composition
Typical compositional ranges for grade 304 stainless steels are given in table 1.
Table 1. Composition ranges for 304 grade stainless steel
Grade |
C |
Mn |
Si |
P |
S |
Cr |
Mo |
Ni |
N |
304 |
min.
max. |
-
0.08 |
-
2.0 |
-
0.75 |
-
0.045 |
-
0.030 |
18.0
20.0 |
- |
8.0
10.5 |
-
0.10 |
304L |
min.
max. |
-
0.030 |
-
2.0 |
-
0.75 |
-
0.045 |
-
0.030 |
18.0
20.0 |
- |
8.0
12.0 |
-
0.10 |
304H |
min.
max. |
0.04
0.10 |
-
2.0 |
-
0.75 |
-0.045 |
-
0.030 |
18.0
20.0 |
- |
8.0
10.5 |
- |
Mechanical Properties
Typical mechanical properties for grade 304 stainless steels are given in table 2.
Table 2. Mechanical properties of 304 grade stainless steel
Grade |
Tensile Strength (MPa) min |
Yield Strength 0.2% Proof (MPa) min |
Elongation (% in 50mm) min |
Hardness |
Rockwell B (HR B) max |
Brinell (HB) max |
304 |
515 |
205 |
40 |
92 |
201 |
304L |
485 |
170 |
40 |
92 |
201 |
304H |
515 |
205 |
40 |
92 |
201 |
| 304H also has a requirement for a grain size of ASTM No 7 or coarser. |
Physical Properties
Typical physical properties for annealed grade 304 stainless steels are given in table 3.
Table 3. Physical properties of 304 grade stainless steel in the annealed condition
Grade |
Density (kg/m3) |
Elastic Modulus (GPa) |
Mean Coefficient of Thermal Expansion (m/m/0C) |
Thermal Conductivity (W/m.K) |
Specific Heat 0-1000C (J/kg.K) |
Electrical Resistivity (n.m) |
0-1000C |
0-3150C |
0-5380C |
at 1000C |
at 5000C |
304/L/H |
8000 |
193 |
17.2 |
17.8 |
18.4 |
16.2 |
21.5 |
500 |
720 |
304L Stainless Steel Pipes and Tubes Grade Specification Comparison
Approximate grade comparisons for 304 stainless steels are given in table 4.
Table 4. Grade specifications for 304 grade stainless steel
Grade |
UNS No |
Old British |
Euronorm |
Swedish SS |
Japanese JIS |
BS |
En |
No |
Name |
304 |
S30400 |
304S31 |
58E |
1.4301 |
X5CrNi18-10 |
2332 |
SUS 304 |
304L |
S30403 |
304S11 |
- |
1.4306 |
X2CrNi19-11 |
2352 |
SUS 304L |
304H |
S30409 |
304S51 |
- |
1.4948 |
X6CrNi18-11 |
- |
- |
These comparisons are approximate only. The list is intended as a comparison of functionally similar materials not as a schedule of contractual equivalents. If exact equivalents are needed original specifications must be consulted. |
304L Stainless Steel Pipes and Tubes Corrosion Resistance
Excellent in a wide range of atmospheric environments and many corrosive media. Subject to pitting and crevice corrosion in warm chloride environments, and to stress corrosion cracking above about 600C. Considered resistant to potable water with up to about 200mg/L chlorides at ambient temperatures, reducing to about 150mg/L at 600C.
304L Stainless Steel Pipes and Tubes Heat Treatment
Solution Treatment (Annealing) - Heat to 1010-11200C and cool rapidly. These grades cannot be hardened by thermal treatment.
