Type 304L stainless steel is an iron-based austenitic steel grade containing 18 Cr 8 Ni content, it is the low carbon version of 304 alloy, the “L” stands for LOW carbon (max 0.035%) in 304L, and the lower carbon content helps minimize and eliminate carbide precipitation during the welding process, and improve corrosion resistance, 304L grade has slightly lower mechanical properties than the standard 304 grade, but very similar to type 304, it has good fabrication, outstanding formability characteristics and versatility. The austenitic stainless steel 304L is also known in Europe as 1.4307 stainless steel.
304L Stainless Steel Composition
The chemical composition of 304L stainless steel consists of 18-20% chromium and 8-12% nickel content, combined with a maximum of 0.03% carbon, 2% manganese, 1% silicon, 0.11% nitrogen, 0.045% phosphorus, and 0.03% sulfur, compared to 304 stainless steel, these two alloys are very similar, but there is one key difference in carbon content, the maximum carbon content in 304 0.08%.
The typical chemical composition for this grade is given in the table below, together with composition limits given for the product according to different standards. The required standard will be fully met as specified on the order.
| Standard | Grade | C | Mn | P | S | Si | Cr | Ni | N |
|---|---|---|---|---|---|---|---|---|---|
| ASTM A240 | 304L | ≤0.030 | ≤2.00 | 0.045 | 0.030 | 1.0 | 18.0-20.0 | 8.0-12.0 | ≤0.10 |
| ASTM A312 | TP304L | ≤0.035 | ≤2.00 | 0.045 | 0.030 | 1.0 | 18.0-20.0 | 8.0-12.0 | ≤0.10 |
| EN 10028-7 | 1.4307 | ≤0.030 | ≤2.00 | 0.045 | 0.030 | 1.0 | 17.5-19.5 | 8.0-10.5 | ≤0.10 |
| EN 10088-2 | 1.4307 | ≤0.030 | ≤2.0 | 0.045 | 0.030 | 1.0 | 17.5-19.5 | 8.0-10.5 | ≤0.10 |
| EN 10088-3 | 1.4307 | ≤0.030 | ≤2.00 | 0.045 | 0.030 | 1.0 | 17.5-19.5 | 8.0-10.5 | ≤0.10 |
| EN 10088-4 | 1.4307 | ≤0.030 | ≤2.0 | 0.045 | 0.030 | 1.0 | 17.5-19.5 | 8.0-10.5 | ≤0.10 |
304L Stainless Steel Mechanical Properties
304L grade has slightly lower mechanical properties than the standard 304 grade, this means that 304L stainless steel is weaker than the standard 304 alloys, but it is still widely used in many applications, It can be used at low temperatures down to -196 °C/384.8 °F even in welded structures. Moderate strengths can be reached at elevated temperatures (~550 °C/1022 °F). Temperatures for excessive scaling are close to 850 °C/1562 °F.
| Standard | Grade | Yield Strength | Tensile Strength | Elongation | Hardness | Hardness |
|---|---|---|---|---|---|---|
| MPa | MPa | %, Min | Rockwell, HRB | HB, Maz | ||
| ASTM A240 | 304L | ≥ 170 | ≥ 485 | 35 | 92 | 201 |
| EN 10028-7 | 1.4307 | ≥ 220 | 520-700 | 35 | 215 | |
| EN 10088-2 | 1.4307 | ≥ 220 | 520-700 | 35 | 215 | |
| EN 10088-4 | 1.4307 | ≥ 220 | 520-700 | 35 | 215 |
304L Stainless Steel Equivalent
- UNS S30403
- DIN 1.4307
- EN X5CrNi18-10
- JIS SUS304L
- GB 022Cr19Ni10
304L Stainless Steel Physical Properties
| Physical Properties | Value |
|---|---|
| Density, g/cm3 (lb/in3) | 7.93 (0.286) |
| Melting point, °C (°F) | 1400-1450 (2550-2650) |
| Specific heat capacity, J/kg·K (Btu/lb ·°F) | 500 (0.12) at 20 °C (68 °F) |
| Electrical resistivity, μΩ·m | 0.72 at 20 °C (68 °F) |
| Conductivity, %, IACS | 2.5 |
| Magnetic permeability | 1.02 (Approximate) |
| Elastic modulus (Modulus of Elasticity), GPa (106 psi) | 193 (28) |
| Thermal diffusivity, mm2/s (in2/s) | 3.84 (0.006) |
| Thermal conductivity, W/m·K (Btu/ft·h·°F) | 16.2 (9.4) at 100 °C (212 °F) |
| 21.5 (12.4) at 500 °C (932 °F) | |
| Coefficient of thermal expansion (CTE), 10-6/K (μin./in·°F) | 17.2 (9.6) at 0-100 °C (32-212 °F) |
| 17.8 (9.9) at 0-315 °C (32-600 °F) | |
| 18.4 (10.2) at 0-538 °C (32-1000 °F) |
304L Stainless Steel Characteristics
- Low carbon content eliminates carbon precipitation in the welding process
- Is preferred for use in environments sufficiently corrosive to cause intergranular corrosion of welds and heat-affected zones on susceptible alloys.
- Good oxidation resistance in intermittent service to 1600°F and in continuous service to 1690°F.
- Excellent welding properties; post-weld annealing is not required when welding thin sections.
Corrosion Resistance
304L stainless steel has excellent corrosion resistance, It can withstand many organic and sufficiently diluted mineral acids depending on the temperature of the solution. Due to its low carbon content, the risk of sensitization for intergranular corrosion after welding is strongly reduced when compared to other austenitic CrNi standard grades with normal carbon content.
304L is preferred for use in environments sufficiently corrosive to cause intergranular corrosion of welds and heat-affected zones on susceptible alloys.
In aqueous solutions containing halogenides, e.g. chlorides or bromides, pitting and crevice corrosion may occur depending on halogenide concentration, temperature, pH value, concentration of oxidizing compounds, and crevice geometry, if applicable.
304L steel has lower carbon content, the risks of chrome carbide precipitation are much minimized, and it may show a lower corrosion rate than the higher carbon Alloy 304.
Welding
304L/4307 has excellent weldability and is suitable for the full range of conventional welding methods (like MMA, MIG, MAG, TIG, SAW, LBW, or RSW), except gas welding.
Core 304L/4307 has about 50% higher thermal expansion and lower heat conductivity compared to carbon steels. This means that larger deformation and higher shrinkage stresses may result from welding.
Post-weld heat treatment is generally not required. In special cases where there is a high risk of stress corrosion cracking or fatigue, stress relief treatment may be considered.
To fully restore the corrosion resistance of the weld seam, the weld discoloration should be removed by pickling and passivation.
304L Stainless Steel Forms
304L Stainless Steel Specifications
- ASTM A240/ASME SB240, Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
- ASTM A480, Standard Specification for General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel Plate, Sheet, and Strip
- EN 10088-2, Stainless steels. Technical delivery conditions for sheet/plate and strip of corrosion-resisting steels for general purposes
- EN 10088-3, Stainless steels. Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products of corrosion-resisting steels for general purposes
- EN 10088-4, Stainless steels. Technical delivery conditions for sheet/plate and strip of corrosion-resisting steels for construction purposes
- EN 10088-5, Stainless steels. Technical delivery conditions for bars, rods, wire, sections and bright products of corrosion-resisting steels for construction purposes
- ASTM A249, Standard Specification for Welded Austenitic Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes
- ASTM A213, Standard Specification for Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes
- ASTM A312, Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes
- ASTM A276, Standard Specification for Stainless Steel Bars and Shape
Applications
Chemical Industry
304L SS is used to manufacture chemical reactors, tanks, pipes and fittings, etc. Because of its good corrosion resistance, it can be used for storing and transporting a variety of chemicals.
Food Processing and Medical Devices.
304L SS used in the manufacture of food processing equipment, medical devices, and surgical instruments, etc., and its non-toxic, corrosion-resistant, easy-to-clean features Ensure the safety and hygiene of food and medical devices 2. In addition, 304L stainless steel is also used to manufacture building materials and decorations, such as doors, windows, handrails, railings, staircases and other indoor and outdoor decorations, as well as components in architectural structure, which is widely used for its beauty, durability, and easy to clean 2.
IMarine Engineering
304L SS is used to manufacture ships, offshore platforms, etc. It’s good corrosion resistance and oxidation resistance can withstand the corrosion and erosion of the marine environment.2 Finally,
Automotive industry
304L SS is used to manufacture automotive exhaust pipes, fuel pipes, gearboxes, turbines and turbine housings, etc. Its good mechanical properties and corrosion resistance improve the life span of the automotive components and the efficiency of use.
304L vs 316L stainless steel, What is the difference?
304L and 316L stainless steels are austenitic steel grades with low carbon content (max 0.03%), but 304L stainless steel contains 18-20% chromium and 8-11% nickel while 316 stainless steel contains 16-18% chromium, 10-12% nickel, and 2-3% molybdenum, the main difference between 304L and 316L stainless steel is that 316L stainless steel has 2-3% of molybdenum content, which makes 316L better corrosion resistant than 304L, and 316L is suitable for application of chloride environment, but 316L is more expensive.
304L vs 304 stainless steel, What is the difference?
304 and 304L are austenitic stainless steel grades, the difference between 304 stainless steel and 304L is in carbon element, 304 has a max of 0.07% carbon but 304L has a max of 0.03%, this difference in composition makes a difference in properties, 304L has a lower tensile strength of 485 Mpa compared to 304 (515 Mpa). 304L is easier to weld, but its primary advantage is lesser carbide precipitation, improving corrosion resistance. In practice, both 304 and 304L can be used for many of the same applications, dual certified stainless steel is available, and 304L/4307 is often dual-certified as EN 1.4301/1.4307, ASTM Type 304/304L.
FAQ
304L stainless steel is about 50-80 USD/tonne more expensive than 304 stainless steel，304L is an ultra-low carbon stainless steel with a carbon content of less than 0.03 percent, while 304 has a carbon content of less than 0.08 percent. The lower carbon content makes 304L superior in welding performance and resistance to intergranular corrosion.
Stainless steel 304 and 304L may look similar, but there are subtle differences in carbon content, usage and price. When choosing the material to be used, the selection should be made according to the specific use environment and requirements to meet your needs.
304L is an ultra-low carbon stainless steel, where the carbon content is reduced to less than 0.03 percent. This is done to avoid intergranular corrosion and theoretically provides greater resistance to stress corrosion than 304. 304H has a higher carbon content, at least 0.04%, which contributes to the strength of the material at high temperatures. It has higher short and long-term creep strength and is more resistant to sensitization than 304L.