Stainless Steel, Austenitic
304L Stainless Steel (S30403)
Low carbon chromium-nickel austenitic stainless steel.
Stainless steel types 1.4301 and 1.4307 are also known as grades 304 and 304L respectively. Type 304 is the most versatile and widely used stainless steel. It is still sometimes referred to by its old name 18/8 which is derived from the nominal composition of type 304 being 18% chromium and 8% nickel.
304L stainless steel is a low-carbon variant of 304 austenitic stainless steel. It is known for its excellent corrosion resistance, good mechanical properties, and superior weldability, particularly in applications where post-weld corrosion resistance is critical.
Type 304L is the low carbon version of 304. It is used in heavy gauge components for improved weldability. Some products such as plate and pipe may be available as “dual certified” material that meets the criteria for both 304 and 304L.
Quarto Plate is hot rolled plate over 12mm thick that has not been coiled during production. CPP is continuously produced plate up to 12mm thick that has been coiled during rolling. Sheet is cold rolled.
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Range
| Bar & Tube | Imperial Sizes | Metric Sizes |
| Round Bar | 3" - 16" | |
| Flat Bar | 20 x 10mm - 100 x 25mm | |
| Welded Ornamental Tube | 1⁄2" - 4" | 30mm - 50mm |
| Welded Tube | 1/"2 - 2" | 16mm - 50mm |
| Hygienic Tube | 3⁄4 " - 4" |
| Sheet/Plate | Sheet Size | Thicknesses |
| Polished Sheet | 2000 x 1000 | 0.7mm - 3.0mm |
| Polished Sheet | 2500 x 1250 | 0.7mm - 6.0mm |
| Polished Sheet | 3000 x 1500 | 1.0mm - 6.0mm |
| Polished Sheet (Circle) | 2500 x 1250 | 0.7mm - 1.5mm |
| Sheet Cold Rolled | 2500 x 1250 | 4.0mm - 6.0mm |
| Sheet Cold Rolled | 3000 x 1500 | 4.0mm - 6.0mm |
| Sheet Cold Rolled | 4000 x 2000 | 2.0mm - 6.0mm |
| CPP Plate ID Finish | 2000 x 1000 | 3.0mm - 6.0mm |
| CPP Plate ID Finish | 2500 x 1250 | 3.0mm - 12.0mm |
| CPP Plate ID Finish | 3000 x 1500 | 3.0mm - 12.0mm |
| CPP Plate ID Finish | 4000 x 1500 | 10.0mm - 12.0mm |
| CPP Plate ID Finish | 4000 x 2000 | 2.0mm - 12.0mm |
| Quarto Plate ID Finish | 5" - 125" | |
| Polished sheet sizes are for mirror and super mirror finishes. | ||
| Polished Sheet options available: 240 Silicon, 240 Grit and various coating including Fiber Optic Laser for one or two sides. | ||
PLEASE NOTE
If you do not see what you are looking for, please contact your local service centre with your specific requirements.
Related Specifications
Stainless steel grade 1.4307/304L also corresponds to the following designations but may not be a direct equivalent:
- S30403
- SUS 304L
- STS 304L
- S30403
- X2CrNi 19-11
- Z2CN 18-10
- 1.4306 / 1.4307
- 304S12
Properties
Chemical Composition
1.4307 Steel
EN 10088-3 & EN 10088-2
| Chemical Element | % Present |
| Carbon (C) | 0.00 - 0.03 |
| Chromium (Cr) | 17.50 - 19.50 |
| Manganese (Mn) | 0.00 - 2.00 |
| Silicon (Si) | 0.00 - 1.00 |
| Phosphorous (P) | 0.00 - 0.05 |
| Sulphur (S) | 0.00 - 0.02 |
| Nickel (Ni) | 8.00 - 10.50 |
| Nitrogen (N) | 0.00 - 0.11 |
| Iron (Fe) | Balance |
Mechanical Properties
Bar & Section Up to 160mm Diameter/Thickness
EN 10088-3
| Mechanical Property | Value |
| Proof Stress | 175 Min MPa |
| Tensile Strength | 500 to 700 MPa |
| Elongation A50 mm | 45 Min % |
| Hardness Brinell | 215 Max HB |
Sheet Up to 8mm Thick
EN 10088-2
| Mechanical Property | Value |
| Proof Stress | 220 Min MPa |
| Tensile Strength | 520 to 700 MPa |
| Elongation A50 mm | 45 Min % |
Plate From 8mm to 75mm Thick
EN 10088-2
| Mechanical Property | Value |
| Proof Stress | 200 Min MPa |
| Tensile Strength | 500 to 700 MPa |
| Elongation A50 mm | 45 Min % |
General Physical Properties
| Physical Property | Value |
| Density | 8.0 g/cm³ |
| Melting Point | 1450 °C |
| Thermal Expansion | 17.2 x 10-6/K |
| Modulus of Elasticity | 193 GPa |
| Thermal Conductivity | 16.2 W/m.K |
| Electrical Resistivity | 0.72 x 10-6 Ω .m |
Applications of 304L Stainless Steel
304L stainless steel is a low-carbon austenitic stainless steel known for its excellent corrosion resistance, high ductility, and superior weldability. Its low carbon content makes it ideal for welded components and equipment exposed to corrosive environments.
1. Chemical and Petrochemical Industry
Storage tanks and pressure vessels
Piping systems for acids and corrosive liquids
Heat exchangers and condensers
2. Food and Beverage Industry
Food processing equipment and containers
Brewing, dairy, and pharmaceutical machinery
Tanks, pipelines, and fittings requiring hygienic surfaces
3. Architectural and Decorative Applications
Cladding and exterior panels
Handrails, trims, and decorative fixtures
Kitchen and household appliances
4. Medical and Pharmaceutical Equipment
Surgical instruments and medical devices
Sterile processing equipment
Laboratory benches and components
5. Industrial Applications
Pumps, valves, and fasteners in corrosive environments
Components in wastewater treatment systems
General manufacturing equipment exposed to moisture or mild chemicals
Summary
304L stainless steel is widely used in applications requiring excellent corrosion resistance, high weldability, and good formability. Its ability to resist intergranular corrosion after welding makes it ideal for chemical, food, pharmaceutical, architectural, and industrial applications.
Characteristics of 304L Stainless Steel
304L stainless steel is a low-carbon variant of 304 austenitic stainless steel, offering excellent corrosion resistance, good mechanical properties, and enhanced weldability. It is widely used in applications where post-weld corrosion resistance is important.
1. Chemical Composition
Low carbon content (≤0.03%) to minimize sensitization during welding.
Contains chromium (18–20%) and nickel (8–12%).
Trace elements enhance corrosion resistance and mechanical stability.
2. Corrosion Resistance
Excellent resistance to oxidation, general corrosion, and mild acid attack.
Resistant to intergranular corrosion after welding, unlike standard 304 stainless steel.
Suitable for food, chemical, and pharmaceutical environments.
3. Mechanical Properties
Good tensile strength and yield strength.
High ductility and toughness, even at low temperatures.
Maintains excellent properties over a wide range of temperatures.
4. Fabrication and Formability
Excellent cold working and forming characteristics.
Can be welded easily with minimal risk of corrosion in the heat-affected zone.
Suitable for deep drawing, bending, and stamping.
5. Heat and Temperature Resistance
Performs well in moderate heat applications.
Retains strength and corrosion resistance under normal service temperatures.
6. Applications
Food processing equipment and storage tanks
Chemical and pharmaceutical equipment
Architectural and decorative components
Piping, valves, and tanks requiring high weld integrity
Summary
304L stainless steel is characterized by excellent corrosion resistance, good mechanical properties, high ductility, and superior weldability. Its low carbon content ensures post-weld corrosion protection, making it ideal for chemical, food, pharmaceutical, and industrial applications.
Additional Information
Weldability
Weldability of 304L Stainless Steel
304L stainless steel is a low-carbon austenitic stainless steel that offers excellent weldability. The reduced carbon content (<0.03%) minimizes the risk of sensitization and intergranular corrosion in the heat-affected zone (HAZ) after welding, making 304L ideal for welded assemblies in corrosive environments.
1. Compatible Welding Processes
TIG (GTAW): Ideal for precision welding of thin sections.
MIG (GMAW): Common for thicker sections and high-productivity applications.
Shielded Metal Arc Welding (SMAW): Suitable for field and maintenance welding.
Resistance Welding: Spot and seam welding are effective for sheet and thin components.
2. Carbon Content Benefits
The low carbon content reduces the likelihood of chromium carbide precipitation.
Prevents sensitization in welded or heat-affected zones, maintaining corrosion resistance without the need for post-weld annealing.
3. Filler Material Selection
Matching filler metals such as ER308L are recommended to maintain corrosion resistance and mechanical properties.
Low-carbon fillers are preferred for thicker sections or critical applications.
4. Heat Input and Distortion
Austenitic stainless steels, including 304L, have high thermal expansion, which can lead to distortion.
Moderate heat input and proper welding sequence help minimize warping and residual stresses.
Fixturing and tack welding can further reduce distortion during fabrication.
5. Post-Weld Treatment
Post-weld annealing is usually not required for corrosion resistance due to low carbon content.
Stress relief may be applied in critical applications where dimensional stability or high-temperature service is required.
6. Applications Leveraging Weldability
Chemical and food processing equipment
Pressure vessels and piping systems
Architectural structures
Heat exchangers and tanks requiring welded assemblies
Summary
304L stainless steel provides excellent weldability due to its low carbon content, enabling strong, corrosion-resistant welds without the need for extensive post-weld heat treatment. Proper filler selection, heat control, and welding technique ensure reliable performance in industrial, chemical, and architectural applications.
Fabrication
Fabrication of 304L Stainless Steel
304L stainless steel is a low-carbon austenitic stainless steel widely used for its excellent corrosion resistance, weldability, and formability. It is highly versatile and can be fabricated using standard metalworking processes.
1. Forming
Cold Forming:
304L has excellent cold formability, making it suitable for bending, rolling, stamping, and deep drawing.
Work hardening occurs during deformation, so intermediate annealing may be necessary for extensive forming.
Hot Forming:
Hot working can be performed at 1010–1175°C (1850–2150°F) to shape thick or complex components.
Produces uniform mechanical properties and reduces the effects of work hardening.
2. Cutting and Shearing
Can be cut using shears, saws, laser cutting, or waterjet cutting.
Sharp tools and proper feeds are recommended to minimize work hardening and ensure smooth edges.
3. Machining
304L is moderately difficult to machine due to its toughness and tendency to work harden.
Carbide tooling is preferred for high-speed cutting.
Coolants and cutting fluids help control heat and extend tool life.
4. Welding
304L exhibits excellent weldability thanks to its low carbon content.
Prevents chromium carbide precipitation and intergranular corrosion in welded areas.
Common processes: TIG (GTAW), MIG (GMAW), SMAW, and resistance welding.
Filler metals such as ER308L are recommended for maintaining corrosion resistance.
5. Cold Working
Cold working increases strength via work hardening.
Extensive deformation reduces ductility, so solution annealing may be performed to restore formability for subsequent fabrication.
6. Surface Finishing
Can be supplied in various finishes, including 2B (mill finish), BA (bright annealed), and polished.
Cold working may require additional finishing to achieve desired surface aesthetics or corrosion resistance.
7. Applications Leveraging Fabrication
Chemical and food processing equipment
Pressure vessels, piping systems, and tanks
Architectural panels and structural components
Heat exchangers and welded assemblies
Summary
304L stainless steel is highly versatile and easy to fabricate, offering excellent cold and hot formability, machining, and welding properties. Its low carbon content ensures corrosion resistance is maintained during welding and forming, making it ideal for industrial, chemical, architectural, and food processing applications.
Hot Working
Hot Working of 304L Stainless Steel
304L stainless steel is a low-carbon austenitic stainless steel with excellent hot workability, allowing it to be formed, rolled, or forged at elevated temperatures. Hot working reduces work hardening and improves ductility, toughness, and uniformity in mechanical properties.
1. Recommended Hot Working Temperature
Typical range: 1010–1175°C (1850–2150°F)
Working above this range may cause grain growth, reducing toughness.
Working below this range increases flow stress and the risk of cracking.
2. Suitable Hot Working Processes
Hot Rolling: For sheets, plates, strips, and structural components
Hot Forging: For high-strength or complex-shaped parts
Hot Extrusion: For rods, tubes, and profiles
Hot Pressing/Forming: For thick or large components that are difficult to cold-work
3. Advantages of Hot Working
Reduces the effects of work hardening compared to cold working
Enhances ductility and toughness
Produces uniform grain structure and mechanical properties
Enables fabrication of large, thick, or complex components
4. Post-Hot Working Treatments
Annealing may be applied to relieve residual stresses and restore ductility.
Pickling or passivation enhances surface corrosion resistance after hot working.
5. Applications Leveraging Hot Working
Structural components in industrial machinery
Automotive and aerospace parts
Pressure vessels and piping
Large sheets, plates, or complex forms requiring elevated-temperature shaping
Summary
304L stainless steel demonstrates excellent hot workability, allowing rolling, forging, extrusion, and forming at 1010–1175°C. Hot working improves ductility, reduces work hardening, and ensures uniform mechanical properties while preserving corrosion resistance, making it ideal for industrial, structural, and high-performance applications.
Heat Resistance
Heat Resistance of 304L Stainless Steel
304L stainless steel is a low-carbon austenitic stainless steel with good high-temperature properties, suitable for service in moderately elevated temperatures. Its low carbon content minimizes sensitization and maintains corrosion resistance during prolonged heat exposure.
1. Continuous Service Temperature
Suitable for continuous service in oxidizing atmospheres up to ~870°C (1600°F).
Prolonged exposure to temperatures above this range may lead to oxidation scaling and reduced mechanical properties.
2. Intermittent Exposure
Can tolerate intermittent heating up to ~925°C (1700°F) without significant degradation.
Useful for components subjected to occasional thermal cycles.
3. Oxidation Resistance
Forms a protective chromium oxide layer in oxidizing atmospheres.
Prevents scaling and surface deterioration in moderate temperature service.
Not suitable for strongly oxidizing or sulfidizing environments at very high temperatures.
4. Thermal Effects on Mechanical Properties
Maintains good tensile strength and ductility up to moderate temperatures.
Prolonged exposure to high heat may reduce work-hardening effects in cold-worked material.
Grain growth can occur if improperly annealed at elevated temperatures.
5. Applications Related to Heat Resistance
Heat exchangers and furnace components
Tanks and piping exposed to moderate high temperatures
Food and chemical processing equipment requiring heat exposure
Welded assemblies operating at elevated temperatures
6. Comparison to Other Austenitic Grades
Heat resistance is slightly lower than 321 or 347 stainless steels for long-term high-temperature service.
304L is chosen for applications emphasizing corrosion resistance and weldability rather than extreme high-temperature strength.
Summary
304L stainless steel provides good heat resistance, suitable for continuous service up to ~870°C and intermittent exposure up to ~925°C. Its low carbon content preserves corrosion resistance and prevents sensitization, making it ideal for welded assemblies and moderately high-temperature industrial applications.
Machinability
Machinability of 304L Stainless Steel
304L stainless steel is a low-carbon austenitic stainless steel that is moderately difficult to machine. Its toughness, work-hardening tendency, and low thermal conductivity require careful selection of tooling, cutting parameters, and cooling methods to achieve efficient machining and good surface finish.
1. Work-Hardening Behavior
304L exhibits work hardening during cutting, especially when using slow feed rates or worn tooling.
Hardened surfaces increase cutting forces and accelerate tool wear.
Continuous and smooth cutting helps minimize work-hardening.
2. Tooling Recommendations
Carbide tooling is preferred for high-speed and high-volume machining.
High-speed steel (HSS) tools can be used at lower cutting speeds.
Tools with positive rake angles reduce cutting forces and heat generation.
3. Cutting Speeds and Feeds
Slower cutting speeds than carbon steels are recommended.
Use moderate to heavy feeds to maintain continuous chip flow and prevent local work-hardening.
4. Cooling and Lubrication
Austenitic stainless steels have low thermal conductivity, causing heat buildup at the cutting zone.
Flood coolant, cutting oils, or high-pressure lubricants help reduce heat, extend tool life, and improve surface finish.
5. Chip Formation
Chips are usually tough and stringy, which can be difficult to remove.
Use chip breakers or specially designed inserts to manage chip evacuation effectively.
6. Surface Finish
Good surface finishes are achievable with sharp tools, proper feeds, and effective cooling.
Avoid dwelling or pauses on the workpiece, as these can create hardened spots and reduce finish quality.
Summary
304L stainless steel has moderate machinability, requiring sharp tools, controlled cutting parameters, and proper cooling to counteract work-hardening and achieve high-quality finished components. Its low carbon content helps maintain corrosion resistance in welded and machined parts, making it suitable for industrial, chemical, and food-processing applications.
Corrosion Resistance
Corrosion Resistance of 304L Stainless Steel
304L stainless steel is a low-carbon austenitic stainless steel known for its excellent corrosion resistance in a wide range of environments. Its low carbon content minimizes chromium carbide precipitation during welding, maintaining corrosion resistance in welded and heat-affected areas.
1. General Corrosion Resistance
Resists oxidation and general corrosion in atmospheric, industrial, and mildly corrosive environments.
Performs well in food, chemical, and pharmaceutical applications where hygiene and corrosion resistance are critical.
2. Resistance to Intergranular Corrosion
Low carbon (<0.03%) prevents chromium carbide precipitation during welding.
Protects against sensitization in the heat-affected zone (HAZ) and welded areas.
Eliminates the need for post-weld solution annealing in most applications.
3. Resistance to Chlorides
Moderately resistant to chloride-induced pitting and crevice corrosion, though less resistant than Mo-bearing grades like 316.
Suitable for freshwater, mild saltwater, and general chemical exposure, but not for highly concentrated chloride solutions.
4. High-Temperature Corrosion
Continuous service up to ~870°C (1600°F) in oxidizing atmospheres.
Intermittent service up to ~925°C (1700°F).
Low carbon content helps maintain corrosion resistance in high-temperature welding applications.
5. Applications Leveraging Corrosion Resistance
Pressure vessels, tanks, and piping in chemical and food-processing industries
Architectural structures and cladding exposed to weather
Heat exchangers and boilers
Welded assemblies in corrosive environments
6. Comparison to Other Austenitic Grades
Better resistance to intergranular corrosion than 304 due to low carbon content.
Slightly lower chloride resistance than 316 or 317 stainless steels.
Preferred for welded assemblies and environments where corrosion resistance and weldability are both critical.
Summary
304L stainless steel provides excellent general and intergranular corrosion resistance, particularly in welded structures, thanks to its low carbon content. It is suitable for a broad range of industrial, chemical, food-processing, and architectural applications, combining durability, hygiene, and reliability in corrosive environments.
Heat Treatment
Heat Treatment of 304L Stainless Steel
304L stainless steel is a low-carbon austenitic stainless steel that is not hardened by heat treatment. Instead, heat treatment is used primarily to restore ductility, relieve residual stresses, and maintain corrosion resistance, particularly after cold working or welding.
1. Solution Annealing
Purpose:
Restore ductility after cold working
Relieve residual stresses
Dissolve any chromium carbides formed during improper heating
Temperature Range: 1010–1120°C (1850–2050°F)
Cooling: Rapid air or water quenching to maintain a fully austenitic structure
Effect:
Returns mechanical properties to the annealed condition
Maintains corrosion resistance due to low carbon content
2. Stress Relief
Purpose: Reduce residual stresses from forming, bending, or welding
Temperature Range: 450–650°C (840–1200°F)
Effect: Minimizes distortion and reduces the risk of stress corrosion cracking without significantly altering mechanical properties
3. Cold-Worked Condition Considerations
Cold working increases strength but decreases ductility.
Intermediate solution annealing may be performed to restore formability for subsequent fabrication steps.
4. Post-Weld Heat Treatment
Usually not required for corrosion resistance due to low carbon content (<0.03%).
Stress relief annealing may be applied in critical high-temperature or dimension-sensitive applications.
5. Limitations
Heat treatment does not significantly increase hardness; 304L relies on cold working for strengthening.
Prolonged exposure to temperatures above ~500°C may slightly reduce cold work strengthening effects.
Summary
Heat treatment of 304L stainless steel is primarily for stress relief, ductility restoration, and maintaining corrosion resistance. Solution annealing and controlled stress relief ensure optimal mechanical and chemical performance, making 304L ideal for welded, cold-worked, and moderately high-temperature applications.
Cold Working
Cold Working of 304L Stainless Steel
304L stainless steel is a low-carbon austenitic stainless steel with excellent cold-working characteristics. Cold working increases strength and hardness through work hardening, while maintaining good corrosion resistance and ductility.
1. Work-Hardening Behavior
304L work-hardens during cold deformation, increasing tensile and yield strength.
Excessive cold working reduces ductility, so intermediate annealing may be required for extensive forming.
2. Common Cold Working Processes
Rolling: For sheets, strips, and plates
Drawing: For wires, tubes, and rods
Bending and Forming: For clips, brackets, and structural components
Stamping and Deep Drawing: For intricate parts or industrial components
3. Mechanical Properties Control
Cold working allows adjustment of tensile strength, yield strength, and hardness.
Extensive cold working may necessitate solution annealing to restore ductility before further processing.
4. Effect on Corrosion Resistance
304L’s low carbon content prevents chromium carbide precipitation, maintaining corrosion resistance even after significant cold work.
Unlike standard 304, 304L is highly resistant to intergranular corrosion in welded or heavily worked areas.
5. Post-Forming Considerations
Solution annealing may be applied for stress relief and restoring formability if multiple cold-forming steps are required.
Cold working may induce slight magnetism due to minor martensitic transformation, but this is typically negligible.
6. Applications Leveraging Cold Work
Springs, clips, and fasteners
Structural components requiring higher strength
Tubes, rods, and wire for chemical and food processing
Components requiring formability combined with corrosion resistance
Summary
304L stainless steel exhibits excellent cold-working properties, allowing increased strength through work hardening while maintaining corrosion resistance. Proper management of deformation and intermediate annealing ensures high-quality, durable components for industrial, chemical, food-processing, and structural applications.
