304L is the most versatile and widely used stainless steel. All plate and sheet at Castle Metals UK is certified to 304/304L.
Stainless Steel 304L is a sort after material for use in severely corrosive conditions, it is used in heavy gauge components for improved weldability, 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.
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Stainless steel 304L is a 18Cr-9Ni austenitic stainless steel. The grade contains small amount of ferrite (≈ 3%) after solution annealing (1000-1100°C - 1832-2012°F) and water quenching.
This kind of steel is one of the basic grades of the stainless steels range. Its low carbon content ensures better ductility and avoids the intergranular corrosion, even on welded pieces without ulterior water quenching.
Stainless steel 304L exhibits an austenitic microstructures free of deleterious carbide precipitations at grainboundaries.
304L is characterised by
- Basic corrosion resistance
- Resistance against intergranular corrosion
- High ductility
Standards
| EURONORM | 1.4003 X2CrNi12 |
|---|---|
| AFNOR | UNS S41003 |
| ASTM | UNS S41003 |
Chemical Analysis
| Typical values (weight %) | |||||
|---|---|---|---|---|---|
| C | Cr | NI | Mo | N | Others |
| 0.020 | 18.5 | 9.2 | - | 0.05 | - |
| PREN (%Cr+3.3%Mo+16%N) ≥ 18 | |||||
Nickel content may be modified to be conform to 1.4306 grade.
Mechanical Properties
| Tensile properties after water quenching | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| °C | °F | Minimum guaranteed values * | Typical values | El % | ||||||||||
| Y.S. 0.2% | Y.S. 1% | UTS | Y.S. 0.2% | Y.S. 1% | UTS | |||||||||
| MPa | Ksi | MPa | Ksi | MPa | Ksi | MPa | Ksi | MPa | Ksi | MPa | Ksi | |||
| 20 | 68 | 200 | 29 | 240 | 35 | 520/ 650 |
75/ 95 |
265 | 38 | 305 | 44 | 570 | 83 | 45 |
| 100 | 212 | 147 | 21 | 181 | 26 | 410 | 60 | 240 | 34 | 280 | 40 | 480 | 70 | 40 |
| 200 | 392 | 115 | 17 | 147 | 21 | 360 | 52 | 220 | 32 | 240 | 34 | 440 | 63 | 35 |
| 300 | 572 | 100 | 15 | 127 | 19 | 340 | 50 | 170 | 25 | 190 | 27 | 420 | 62 | 35 |
| 400 | 752 | 89 | 13 | 116 | 17 | 330 | 48 | 150 | 22 | 165 | 24 | 400 | 58 | 30 |
| 500 | 932 | 81 | 12 | 109 | 16 | 320 | 47 | 130 | 20 | 145 | 21 | 380 | 56 | 30 |
* Following EN 10088 hot rolled plates - The EN guaranteed values are valid for a thickness from 5-75mm. Mechanical properties are related to the thickness of the plate.
| Impact values: KCV ≥ 120 j/cm² (room temperature) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| °C | -196 | -20 | +20 | θ (°C) | 200 | 400 | 600 | ||||
| °F | -321 | -4 | 68 | θ (°F) | 392 | 752 | 1112 | ||||
| KCV (J/cm²) Minimum |
125 | 160 | 180 | Ageing H | 265 | 257 | 252 | ||||
| KCV (J/cm²) Typical |
220 | 250 | 250 | KCU (J/cm²) Transverse |
158 | 142 | 122 | ||||
Typical values
High toughness values at -269°C (-452°F) need specific melts (extra low ferrite content).
| Interval temper °C |
Thermal expansion αx10-6K-1 |
°C | °F | Resistivity (µΩ cm) |
Thermal conductivity (W.m-1.K-1) |
Specific heat (J.kg-1.K-1) |
Young modulus E (GPa) |
Shear modulus G (GPa) |
|---|---|---|---|---|---|---|---|---|
| 20-100 | 16 | 20 | 68 | 73 | 15 | 500 | 200 | 77 |
| 20-200 | 17 | 100 | 212 | 77 | 16 | 500 | 194 | 75 |
| 20-300 | 17 | 200 | 392 | 84 | 17.5 | 520 | 186 | 71 |
| 20-400 | 18 | 300 | 572 | 91 | 19 | 530 | 179 | 68 |
| 20-500 | 18 | 400 | 752 | 97 | 20.5 | 540 | 172 | 65 |
| 500 | 932 | 102 | 22 | 540 | 165 | 62 | ||
Corrosion Resistance
| Quality corrosion tests guaranteed (special request may be discussed) | |||
|---|---|---|---|
| TEST | Other name | Corrosion (1) | Results |
| ASTM A 262 A | Intergranular | Step or dual structure | |
| ASTM A 262 B | STREICHER | Intergranular | Not recommended |
| ASTM A 262 C | HUEY | Intergranular | < 0,6mm/year* |
| ASTM A 262 E DIN 50914 |
STRAUSS | Intergranular | No cracking after bending |
| ASTM G48 A | Pitting | Not recommended (typical CPT = 5°C-41°F) |
|
| ASTM G48 B | ASTM G78 | Crevice | Not recommended (typical CCT ≤ 0°C-32°F) |
(1) kind of corrosion mechanism investigated
* Using low ferrite grade.
The alloy is not really resistant to localised corrosion in chloride containing solutions. Pitting may occur even at low temperature (5-10°C - 41-50°F).
The alloy is very prone to stress corrosion cracking in chloride containing solution when temperature is higher than 50°C (122°F).
Applications
Stainless steel 304L is corrosion resistant in:
- Urban media
- Nitric solution, up to 55% weight, up to 80°C (176°F) (low ferrite)
- Most of diluted organic acids at moderate temperatures
- Most of food and pharmaceutical products
- Pure phosphoric acid
- Whatever concentration in cold solution
- Up to 10% diluted hot solution sulphuric or fluoridric acid traces increase the corrosion
- Caustic solutions free of chlorides or fluorides at medium temperatures
The alloys are not corrosion resistant in chloride containing solutions, even diluted, and in sulphuric acid media.
So, the main applications are:
- Food processing industry (excluding Cl - containing media)
- Diluted nitric acid solution
- Nuclear industry (special melts; please consult)
