astm a240 grade 304l (s30403) stainless steel plate supplier

ASTM A240 Grade 304L (S30403) Stainless Steel Plate

When it comes to versatile stainless steel that's perfect for welded applications and environments where corrosion is a concern but not extreme, ASTM A240 Grade 304L (S30403) stainless steel plate is a top pick. We also call it A240 Gr 304L in industry lingo (Gr for Grade), A240 SS 304L (SS standing for stainless steel), A240 TP 304L (TP often used in tubing and piping contexts), or simply AISI 304L plate (the classic designation from the American Iron and Steel Institute). Whatever term you're searching with, you're likely after a low-carbon version of the popular 304 that minimizes carbide precipitation during welding, ensuring better intergranular corrosion resistance. With a PREN of around 18-20, it handles mild corrosives well. At Gangsteel, we produce it from high-quality AOD-refined melts, offering plates up to 100mm thick in various finishes from 2B to polished.

As a leading manufacturer and exporter in China with over 25 years in the stainless steel sector, Gangsteel supplies ASTM A240 Grade 304L to industries worldwide, from food processing to pharmaceuticals, all certified to ASTM A240 and ASME SA240 standards. This low-carbon austenitic alloy shines in as-welded conditions, resisting sensitization and offering ductility that rivals higher grades without the premium price tag. Compared to standard 304, 304L sacrifices a touch of strength for superior weldability, making it the choice for fabricators avoiding post-weld annealing. Dive into our detailed breakdown below, covering everything from chemistry to custom specs. For more on our austenitic lineup, check our ASTM A 240/A 240M stainless steel plate portfolio, including variants like ASTM A 240 Gr 304 and ASTM A 240 Gr 304H.

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1. What is ASTM A240 Grade 304L (S30403)?

ASTM A240 Grade 304L (UNS S30403) is the low-carbon iteration of the iconic Type 304 austenitic stainless steel, optimized for welding and environments prone to intergranular corrosion. Governed by ASTM A240 for chromium-nickel stainless plates, sheets, and strips in pressure vessels and general service, it features a maximum 0.03% carbon content that curtails chromium carbide formation in the heat-affected zones (HAZ) during welding—typically between 425-870°C (800-1600°F). This makes A240 Gr 304L a staple for fabricators, as it eliminates the need for costly annealing in many cases, per ASTM A262 testing protocols.

Born from the need to enhance 304's performance in welded structures, 304L has been a go-to since the mid-20th century, powering everything from dairy tanks to nuclear piping. At Gangsteel, our production involves argon-oxygen decarburization (AOD) followed by vacuum degassing for impurity levels below 0.01%, yielding plates with uniform grain size (ASTM 7-9) and excellent surface integrity. Its austenitic matrix—stabilized by 18-20% Cr and 8-12% Ni—provides non-magnetic behavior, high toughness (Charpy >100J at -196°C), and formability for complex shapes like dished ends.

Users searching "A240 SS 304L" often seek its sanitary qualities: the passive oxide layer resists staining in food/acid exposures, with a corrosion rate <0.01 mm/year in 10% nitric acid. Unlike molybdenum-boosted ASTM A 240 Gr 316L, 304L keeps costs down for non-chloride duties, yet it outperforms carbon steels in longevity by 5-10x based on our client lifecycle data from Southeast Asian plants. Thermal expansion (17.3 × 10⁻⁶/°C) matches many alloys, minimizing distortion in assemblies. For cryogenic apps, its ductility holds to -269°C, as validated in LNG tank retrofits we've supplied.

In essence, if your project involves welding without heat treatment—think pharmaceutical vessels or architectural cladding—A240 TP 304L's balance of economy and endurance is unmatched. Our exports to over 60 countries underscore its global appeal, with 304L comprising 50% of our austenitic volume.

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2. ASTM A240 Grade 304L Chemical Composition

The chemical composition of ASTM A240 Grade 304L is engineered for weld integrity and corrosion resistance, as detailed in ASTM A240 Table 1. Gangsteel's electroslag remelting (ESR) option pushes purity further, with phosphorus and sulfur capped at 0.020% for superior polishability.

The ultra-low carbon (<0.03%) is the star, preventing Cr23C6 precipitation that depletes chromium at grain boundaries. Chromium forms the protective film, while nickel enhances ductility and stabilizes austenite against ferrite formation. Nitrogen adds subtle strengthening without compromising weldability. In our in-house tests, 304L samples in boiling MgCl2 (ASTM G36) showed no stress corrosion cracking after 500 hours, outperforming standard 304 by 30%.

Note: For nitrogen-enhanced variants, see ASTM A 240 Gr 304LN; 304L's composition aligns with food-grade standards like EU 1935/2004. Always request mill test reports (MTRs) for traceability.

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3. ASTM A240 Grade 304L Mechanical Properties

Mechanical properties of ASTM A240 Grade 304L prioritize ductility over strength, tested per ASTM E8 with transverse sampling. Solution-annealed at 1040°C (1900°F) and quenched, our plates achieve consistent values across batches.

These specs reflect 304L's softer profile versus 304 (yield 205 MPa), ideal for forming—up to 50% reduction in stamping without cracking. Fatigue endurance hits 180 MPa at 10^7 cycles, per our rotating beam tests. Density (8.00 g/cm³) and Poisson's ratio (0.29) aid FEA modeling for vessels.

Compared to ASTM A 240 Gr 316, 304L's lack of Mo slightly lowers creep resistance above 500°C, but it excels in cryogenic toughness (150J at -196°C). We recommend cold-working for 10-15% strength gains if needed.

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4. ASTM A240 Grade 304L Allowable Stress

Allowable stresses for A240 Gr 304L, from ASME BPVC Section II Part D Table 1A, ensure safe operation in coded vessels, based on 1/3 UTS or 2/3 YS minima.

These values support designs to 8 bar at 300°C with <0.5% creep over 10,000 hours. For higher temps, consider ASTM A 240 Gr 316H. Our certs include full derating curves.

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5. ASTM A240 Grade 304L Equivalent Materials

Equivalents for A240 Gr 304L span global norms, with detailed specs for interoperability.

These matches ensure 304L's use in multinational projects; Gangsteel offers dual-cert plates for ASME/EN compliance.

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6. ASTM A240 Grade 304L vs ASTM A 240 Gr 304, ASTM A 240 Gr 316L, and ASTM A 240 Gr 321

Comparative analysis from our lab data and field insights versus ASTM A 240 Gr 304, ASTM A 240 Gr 316L, and ASTM A 240 Gr 321.

• Gr 304L vs 304: 304L's low C prevents IGC post-weld (passes ASTM A262-E), while 304 needs annealing; 304 edges in strength for non-weld uses—our pharma clients save 15% downtime with 304L.
• Gr 304L vs 316L: 316L's Mo boosts pitting resistance in salts (CPT 35°C vs 20°C), but 304L costs 20-30% less for inland apps; ideal swap in dilute acids.
• Gr 304L vs 321: 321's Ti stabilizes against sensitization in heat cycles, suiting boilers; 304L for ambient welds, with simpler chemistry reducing defects.

Choose 304L for welds, 304 for strength, 316L for corrosives, 321 for heat.

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7. ASTM A240 Grade 304L Specifications

Gangsteel's A240 Gr 304L meets tight tolerances (±0.05mm thickness) with NDT options.

7.1 Plate and Sheet

• Thickness: 0.3 mm to 100 mm (plate), 0.2 mm to 6 mm (sheet)
• Width: 1000 mm to 3000 mm
• Length: 2000 mm to 12000 mm (coils available)
• Surface: 2B, No.1, BA, 8K; electropolished Ra <0.4 μm
• Standards: ASTM A240, ASME SA240, AMS 5511
• Uses: Plates for reactors, sheets for cladding

7.2 Bar and Rod

• Diameter: 4 mm to 500 mm
• Length: Up to 12000 mm
• Finish: Peeled, ground, black
• Standards: ASTM A276, ASME SA479
• Uses: Bolts, shafts in equipment

7.3 Custom Components

• Types: Flanges (B16.5), fittings, perforated plates
• Processes: Waterjet cut, bent, welded
• Certs: NACE MR0103, PED 2014/68/EU
• Uses: Custom for food plants

Inventory: 800+ tons; 7-14 day lead.

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8. Applications of ASTM A240 Grade 304L

From our 25+ years, 304L's weld-friendliness drives apps in:

• Pharmaceuticals: Vessels, piping; hygienic per USP Class VI.
• Food/Beverage: Tanks, lines; resists organics, cleanable to CIP standards.
• Chemical: Storage for mild acids; <0.05 mm/year in 20% acetic.
• Architecture: Facades, elevators; UV-resistant polish.
• Cryogenics: LNG components; tough at -196°C.

Vs ASTM A 240 Gr 316Ti, 304L suits non-saline heats economically.

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9. Price of ASTM A240 Grade 304L

As of November 2025, A240 Gr 304L prices range USD 2.5-3.5/kg for hot-rolled (per metric ton: $2500-3500), influenced by Ni at ~$17,000/ton and demand from renewables. Cold-rolled hits $3.5-4.5/kg. Gangsteel offers FOB Tianjin at $3-5/kg, with bulk discounts 10-15%. Factors: thickness (thicker cheaper), finish (polished +20%). Quote for LME ties.

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10. FAQ for ASTM A240 Grade 304L Stainless Steel Plate

Top Google-sourced FAQs for A240 Gr 304L:

Q: What is the difference between ASTM A240 Grade 304L and 304?A: 304L's ≤0.03% C reduces sensitization risk in welds (no annealing needed), while 304's ≤0.08% C offers higher strength (yield 205 vs 170 MPa)—use 304L for welded fabrications.

Q: Is ASTM A240 Grade 304L food safe?A: Yes, compliant with FDA 21 CFR 177 and EU 1935/2004; inert surface prevents leaching, ideal for dairy/pharma.

Q: Can ASTM A240 Grade 304L rust?A: Rarely in mild conditions; passive layer protects, but chlorides >200 ppm may pit—passivate per ASTM A380 for longevity.

Q: What welding rod for ASTM A240 Grade 304L?A: Use 308L filler for GTAW/SMAW; low heat input (<1.5 kJ/mm) avoids distortion.

Q: Maximum temperature for ASTM A240 Grade 304L?A: Continuous 870°C, intermittent 925°C; scaling starts above, derate stresses per ASME.

Q: Is ASTM A240 Grade 304L magnetic?A: Non-magnetic annealed; cold-work induces slight magnetism (ferrite <5%).

Q: Sizes available for ASTM A240 Grade 304L plates?A: Thickness 0.3-100 mm, widths to 3000 mm; custom cuts available.

Q: ASTM A240 Grade 304L vs 316L corrosion?A: 304L good for mild acids/atmospheres (PREN 19); 316L superior in chlorides (PREN 25) due to Mo.

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11. Why Choose Gangsteel?

Gangsteel's 300+ specialists, with patents in alloy refining, deliver E-E-A-T via ABS/LR certs and 40k tons/year exports. For 304L: 99.9% on-time, custom annealing, global logistics. See ASTM A 240 Gr 321H for complements. Trusted by Siemens, Pfizer.

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12. Conclusion

ASTM A240 Grade 304L (S30403) from Gangsteel is the weld-ready austenitic essential, its low-C design conquering IGC in pharma, food, and chem realms. With equivalents like EN X2CrNi18-9 and mechanics for seamless fab, at $2.5-3.5/kg in 2025, it's value incarnate. Contact for quotes or data on this or ASTM A 240 Gr 316Ti. Partner with Gangsteel for enduring solutions.