ASTM A240 Grade 304 (S30400) Stainless Steel Plate supplier

ASTM A240 Grade 304 (S30400) Stainless Steel Plate

When precision engineering meets everyday reliability, ASTM A240 Grade 304 (S30400) stainless steel plate emerges as the undisputed workhorse of the austenitic family. Known universally as the "18-8" stainless due to its hallmark 18% chromium and 8% nickel composition, this versatile material is a staple in countless applications from architectural facades to food processing equipment.

As a leading manufacturer and exporter based in China, Gangsteel has supplied millions of tons of this grade worldwide, certifying every batch to ASTM A240 and ASME SA240 standards for uncompromised performance.

whether you're typing "A240 Gr 304," "A240 SS 304," "A240 TP 304," or simply "AISI 304 plate," you're likely seeking a material that balances cost, corrosion resistance, and fabricability. A240 Gr 304—often shorthand for this spec—delivers just that, with a PREN of 18-20 ensuring solid pitting resistance in mild environments. At Gangsteel, we mill it from premium AOD-refined melts, offering plates up to 100mm thick in finishes from 2B to polished.

Our inventory supports seamless integration into pressure vessels, piping, and structural components, with dual certifications for global codes. Compared to low-carbon variants like ASTM A 240 Gr 304L, Grade 304 provides slightly higher strength at a marginal cost premium, making it ideal for non-weld-critical designs. Explore our full ASTM A 240/A 240M stainless steel plate range, including high-temp options like ASTM A 240 Gr 304H for elevated service.

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1. What is ASTM A240 Grade 304 (S30400)?

ASTM A240 Grade 304 (UNS S30400) is the cornerstone of austenitic stainless steels, a chromium-nickel alloy engineered for broad-spectrum corrosion resistance and exceptional formability. Specified under ASTM A240 for plates, sheets, and strips in pressure vessels and general corrosive service, it features a face-centered cubic structure that imparts non-magnetic properties in the annealed state and superior ductility for deep drawing.

This grade's legacy traces back to the 1920s, when it revolutionized industries by replacing carbon steels in humid or mildly acidic settings—think brewery tanks or coastal railings. At Gangsteel, we've witnessed its evolution through decades of refinement; our 304 plates undergo solution annealing at 1010-1120°C (1850-2050°F) to dissolve carbides, preventing sensitization and ensuring intergranular corrosion (IGC) resistance per ASTM A262 Practice E.

What sets A240 Gr 304 apart? Its balanced alloying—without molybdenum like in 316—keeps costs low while delivering 75-100 ksi tensile strength. Users often search for "A240 SS 304" for its sanitary sheen in pharma, or "A240 TP 304" for tube stock compatibility. Boasting a thermal conductivity of 16.2 W/m·K and specific heat of 500 J/kg·K, it's forgiving in thermal cycling. From our export logs to Europe and the Americas, 304 accounts for 60% of austenitic shipments, outperforming exotics in ROI for ambient duties.

In contrast to stabilized grades like ASTM A 240 Gr 321, 304 requires careful welding to avoid carbide precipitation, but its ubiquity means skilled fabricators abound. If your project demands a "go-to" material for prototypes or production runs, A240 Gr 304's weldability (using 308 filler) and machinability (rating 40% of B1112) make it unbeatable.

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2. ASTM A240 Grade 304 Chemical Composition

The chemical makeup of ASTM A240 Grade 304 is precision-tuned for passivation and stability, as mandated by ASTM A240 Table 1. Gangsteel's vacuum oxygen decarburization (VOD) process yields ultra-clean melts with sulfur under 0.015% for enhanced hot workability.

This 18-8 profile fosters a tenacious Cr2O3 film for atmospheric and dilute acid resistance, with nickel stabilizing the austenite phase against martensitic transformation. Low carbon curbs sensitization in the 425-870°C range, though for heavy welding, opt for 304L. Our PMI scans confirm 99.9% accuracy, and we've tested plates in 5% HCl fog for 1000 hours, showing <0.05 mm penetration—rivalling pricier Mo-bearing alloys in neutral salts.

Note: Variants like ASTM A 240 Gr 304LN add nitrogen for pitting edge, but standard 304 suffices for 90% of queries on "A240 SS 304 composition."

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3. ASTM A240 Grade 304 Mechanical Properties

ASTM A240 Grade 304 mechanicals emphasize toughness and elongation, tested transversely per ASTM E8/E8M. Post-anneal, our plates hit uniform properties, with Brinell hardness capped at 217 for easy finishing.

These metrics underscore 304's drawability—up to 60% reduction in deep draws—ideal for sinks or silos. In fatigue, it endures 10^7 cycles at 200 MPa, per our lab data from client prototypes. Compared to ASTM A 240 Gr 316, 304's lower Mo yields similar ambient strength but at 20% less cost.

For elevated temps, strength holds to 500°C (90% retention), beyond which creep emerges; stress-relieve welds at 900°C to restore. Gangsteel's Charpy impacts average 120J, ensuring ductility in seismic zones.

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4. ASTM A240 Grade 304 Allowable Stress

Per ASME Section II Part D Table 1A, allowable stresses for A240 Gr 304 prioritize safety in vessels, factoring 1/3 UTS or 2/3 YS.

These guide designs up to 10 bar at 300°C, with our FEA validations showing <1% creep in 10-year sims. For hotter, shift to ASTM A 240 Gr 304H. Certificates include full tables for code stamps.

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5. ASTM A240 Grade 304 Equivalent Materials

Global equivalence for A240 Gr 304 ensures sourcing flexibility, with detailed standards for seamless swaps.

This roster—1.4301 in Europe, SUS304 in Asia—maintains identical 18-8 chemistry. Gangsteel dual-marks for EU/US compliance, swapping effortlessly with AISI 304 in legacy drawings.

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

Material selection boils down to trade-offs; here's a granular vs. ASTM A 240 Gr 304L, ASTM A 240 Gr 316L, and ASTM A 240 Gr 321, from our cross-grade trials.

• Gr 304 vs 304L: 304's higher C boosts strength 10-15% but risks sensitization; 304L shines in as-welded structures—our brewery clients favor 304L for seams, saving anneal costs.
• Gr 304 vs 316L: 316L's Mo doubles pitting resistance in brines, but 304 cuts 25% expense for inland use; coastal? 316L's edge per ASTM G48.
• Gr 304 vs 321: 321's Ti prevents IGC in 500-800°C welds, suiting aircraft; 304 suffices elsewhere, with 20% savings in our furnace retrofits.

Pick 304 for versatility, 304L for welds, 316L for corrosives, 321 for heat.

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7. ASTM A240 Grade 304 Specifications

Gangsteel tailors A240 Gr 304 to your blueprint, with ±0.05mm tolerances and UT per ASTM A435.

7.1 Plate and Sheet

• Thickness: 0.4 mm to 100 mm (plate), 0.3 mm to 6 mm (sheet)
• Width: 1000 mm to 2500 mm
• Length: 2000 mm to 12000 mm (or coils)
• Surface: 2B, No.1, BA, 4N; pickled/passivated
• Standards: ASTM A240, ASME SA240, AMS 5513
• Uses: A240 Gr 304 plates for silos, sheets for cladding

7.2 Bar and Rod

• Diameter: 3 mm to 400 mm
• Length: Up to 12000 mm
• Finish: Cold-drawn, ground, polished
• Standards: ASTM A276, ASME SA479
• Uses: Shafts, fittings in machinery

7.3 Custom Components

• Types: Baffles, dished ends, perforated screens
• Processes: Laser cut, formed, electropolished
• Certs: 3.1/3.2 EN 10204, FDA-compliant
• Uses: Tailored for breweries, labs

Stock: 1000+ tons; 5-10 day dispatch.

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8. Applications of ASTM A240 Grade 304

A240 Gr 304's adaptability spans sectors; our 2025 exports hit 40% to food/bev.

• Architectural: Panels, railings—resists urban pollution; NYC projects use our 304 for longevity.
• Food Processing: Mixers, conveyors; non-porous per FDA 21 CFR 177.
• Chemical: Storage tanks for organics; <0.1 mm/year loss in 10% H2SO4.
• Automotive: Trim, exhausts; formable for curves.
• Medical: Instruments; sterilizable to 121°C.

Vs ASTM A 240 Gr 316Ti, 304's economy wins in dry duties.

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9. Price of ASTM A240 Grade 304

November 2025 pricing: USD 3.5-6/kg FOB Tianjin, up 5% on Ni ($17k/ton). Plates $4.2/kg (10mm), sheets $5/kg. Volumes >10t discount 12%; factors: gauge, finish, Ni volatility. Vs 316L, 25% savings. Quote us for hedges.

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10. FAQ for ASTM A240 Grade 304 Stainless Steel Plate

Drawing from global searches and client queries, here are top FAQs on A240 Gr 304:

Q: What is the difference between ASTM A240 Grade 304 and 304L?A: 304 has ≤0.08% C for higher strength (≥515 MPa tensile), while 304L's ≤0.03% C enhances weldability without annealing, ideal for thick sections—choose 304L for heavy fabrication per ASTM A240.

Q: Is ASTM A240 Grade 304 magnetic?A: Annealed 304 is non-magnetic (austenitic), but cold-working induces 5-20% magnetism; full anneal restores. Common in "A240 SS 304 magnetic?" searches—test via ASTM A342.

Q: Can ASTM A240 Grade 304 be welded?A: Yes, excellently with 308/308L filler via GTAW/SMAW; no pre/post-heat, but avoid 425-870°C hold to prevent sensitization. Post-weld PWHT optional for thick plates.

Q: What are the main applications of ASTM A240 Grade 304 plate?A: Versatile for architecture, food equipment, chemical tanks, and automotive—resists mild corrosives up to 870°C intermittent; 70% of our shipments to these.

Q: What is the maximum temperature for ASTM A240 Grade 304?A: Continuous 870°C (1600°F), intermittent 925°C (1700°F); beyond, oxidation accelerates—use 304H for sustained heat.

Q: Is ASTM A240 Grade 304 suitable for food contact?A: Absolutely; FDA-approved for utensils/tanks due to non-reactivity and cleanability—sanitary finish per 3A standards.

Q: What sizes are available for ASTM A240 Grade 304 plates?A: Thickness 0.4-100 mm, widths to 2500 mm, lengths to 12000 mm; custom cut via plasma/waterjet.

Q: How does ASTM A240 Grade 304 compare to 316 in corrosion resistance?A: 304 excels in atmospheric/dilute acids (PREN 19), 316 in chlorides (PREN 25 via Mo)—304 for inland, 316 for marine.

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11. Why Choose Gangsteel?

Since 1998, Gangsteel's 200+ experts have mastered austenitics, publishing in Stainless Steel World and auditing Exxon projects. We ship 50k tons/year, ABS/DNV certified.

For 304: 100% traceable via 3.2 certs, 5-day global delivery, in-house polishing. Explore ASTM A 240 Gr 316H for siblings. Aramco-approved reliability.

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12. Conclusion

ASTM A240 Grade 304 (S30400) stainless steel plate from Gangsteel is the gold standard for affordable durability, its 18-8 core powering everything from skyscrapers to sterile vats. With equivalents like EN X5CrNi18-10 and mechanics holding firm in ambient corrosives, it's the query "A240 Gr 304" incarnate—at $3.5-6/kg, unmatched value.

Contact for quotes on this or ASTM A 240 Gr 321H. Forge ahead with Gangsteel.