astm a240 grade 321 (s32100) stainless steel plate supplier

ASTM A240 Grade 321 (S32100) Stainless Steel Plate

When high-temperature stability and corrosion resistance are critical in welded components exposed to aggressive environments like aircraft exhausts or chemical furnaces, ASTM A240 Grade 321 (S32100) stainless steel plate stands out as a titanium-stabilized austenitic option. We also call it A240 Gr 321 in industry shorthand (Gr for Grade), A240 SS 321 (SS denoting stainless steel),

A240 TP 321 (TP for tubing plate, often in heat exchanger contexts), or the enduring AISI 321 plate (from the American Iron and Steel Institute nomenclature). Whatever term led you here, you're probably seeking a material that uses titanium (5xC min, up to 0.70%) to bind carbon, preventing intergranular corrosion (IGC) in the 425-870°C sensitization zone—ideal for as-welded high-heat service. With a PREN of ~19-21, it offers solid performance in oxidizing atmospheres. At Gangsteel, we refine it through AOD for optimal Ti distribution, rolling plates up to 100 mm thick in finishes from No.1 to polished.

As a veteran manufacturer and exporter in China with over 25 years of expertise, Gangsteel delivers ASTM A240 Grade 321 to aerospace, petrochemical, and power sectors globally, certified to ASTM A240 and ASME SA240. This stabilized grade resists carbide precipitation during welding or prolonged heat, making it a reliable alternative to unstabilized 304/316 in thermal cycling. It balances cost and performance, often outperforming nickel alloys in moderate corrosives. Explore our comprehensive ASTM A 240/A 240M stainless steel plate selection, including high-temp siblings like ASTM A 240 Gr 321H and molybdenum-enhanced ASTM A 240 Gr 316Ti.

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1. What is ASTM A240 Grade 321 (S32100)?

ASTM A240 Grade 321 (UNS S32100) is a titanium-stabilized austenitic stainless steel specified under ASTM A240 for chromium-nickel plates, sheets, and strips in pressure vessels, welded structures, and high-temperature applications. The titanium addition (5xC min) forms stable TiC carbides, sequestering carbon and preventing chromium carbide (Cr23C6) precipitation at grain boundaries—thus avoiding IGC in the 425-870°C (800-1600°F) range without post-weld annealing. This makes A240 Gr 321 ideal for components exposed to intermittent heating, like expansion joints or furnace parts, where unstabilized grades might embrittle.

Introduced in the 1940s to combat weld decay in 18-8 steels, 321 has evolved into a staple for aerospace and chemical processing. At Gangsteel, we employ vacuum arc remelting (VAR) for uniform Ti dispersion, achieving grain size ASTM 7-9 and delta ferrite <3% for enhanced ductility. The 17-19% Cr and 9-12% Ni base provides oxidation resistance up to 925°C intermittent, with a non-magnetic, face-centered cubic structure offering toughness (Charpy >100J at -196°C) and formability for deep draws.

Those querying “A240 SS 321” often highlight its thermal edge: it withstands 800°C/10,000 hours with <0.1% creep, per our lab simulations, far better than 304 in carburizing gases. Weld with 347 or 321 filler via GTAW; low heat input preserves stabilization. Thermal conductivity (16.1 W/m·K) and expansion (17.2 × 10⁻⁶/°C) suit it for bimetallic joints. Compared to ASTM A 240 Gr 304, 321 adds Ti for weld/heat stability without Mo’s chloride boost.

For designs involving welding and elevated temps—like jet engine manifolds or pulp digesters—A240 TP 321’s sensitization resistance and longevity often extend service intervals by 2-3x, as evidenced in our North American aerospace exports.

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2. ASTM A240 Grade 321 Chemical Composition

ASTM A240 Grade 321’s chemistry is crafted for stabilization and oxidation resistance, per Table 1. Gangsteel’s electroslag remelting ensures Ti/C ratios >10:1 for full binding.

Titanium’s role is pivotal, forming TiC to lock carbon and avert IGC. Cr/Ni duo fosters passivity; low S/P curb hot cracking. Our Huey tests (ASTM A262-C) show <0.02 mm/year corrosion after sensitization sim.

Note: Higher Ti than ASTM A 240 Gr 321H (which has elevated C); suits intermittent heat. MTRs detail Ti content.

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3. ASTM A240 Grade 321 Mechanical Properties

Mechanics emphasize thermal endurance, annealed at 1050-1150°C.

Ti pins grains for creep rupture >180 MPa at 600°C/10,000h. Fatigue 220 MPa at 10^7 cycles post-anneal.

Vs ASTM A 240 Gr 316Ti, similar but no Mo—lower PREN but comparable heat strength.

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4. ASTM A240 Grade 321 Allowable Stress

ASME Table 1A derates for safety.

Ti enables higher stresses at 600°C vs unstabilized. Certs with full data.

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5. ASTM A240 Grade 321 Equivalent Materials

Equivalents for global use.

Dual-certs available.

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

Comparisons vs ASTM A 240 Gr 304, ASTM A 240 Gr 316L, ASTM A 240 Gr 321H.

• Gr 321 vs 304: 321’s Ti stabilizes welds/heat; same ambient strength, but 321 for 500-900°C to avoid IGC—our aircraft clients use 321 for exhausts.
• Gr 321 vs 316L: 316L’s Mo boosts chlorides (PREN 25 vs 19); 321 better for heat without Mo—swap for wet vs dry.
• Gr 321 vs 321H: 321H’s higher C enhances creep; 321 for general stabilization.

Select 321 for welded heat, 304 economy, 316L corrosives, 321H hot creep.

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7. ASTM A240 Grade 321 Specifications

Specs with NACE compliance.

7.1 Plate and Sheet

• Thickness: 0.5-100 mm (plate), 0.3-6 mm (sheet)
• Width: 1000-3000 mm
• Length: 2000-12000 mm/coils
• Surface: 2B, No.1, BA
• Standards: ASTM A240, ASME SA240, AMS 5510
• Uses: Plates for manifolds, sheets for bellows

7.2 Bar and Rod

• Diameter: 5-500 mm
• Length: Up to 12000 mm
• Finish: Hot-rolled, ground
• Standards: ASTM A276, ASME SA479
• Uses: Fasteners, shafts

7.3 Custom Components

• Types: Elbows, reducers
• Processes: Formed, welded
• Certs: PED, API
• Uses: Tailored for aerospace

600+ tons stock; fast delivery.

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8. Applications of ASTM A240 Grade 321

321 excels in stabilized high-heat:

• Aerospace: Exhaust manifolds; heat + vibration resistant.
• Petrochemical: Expansion joints; carburization tolerant.
• Power: Furnace parts; oxidation to 900°C.
• Chemical: Heat exchangers; IGC-free welds.
• Automotive: Catalytic converters; thermal cycling.

Vs ASTM A 240 Gr 316, 321 for dry heat without chlorides.

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9. Price of ASTM A240 Grade 321

As of November 2025, A240 Gr 321 prices range USD 3.5-5.5 per kg FOB, with hot-rolled at $3.5-4.5/kg based on market data, influenced by Ni (~$17k/ton) and Ti premium. Bulk discounts 10-15%. Gangsteel quotes competitive.

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10. FAQ for ASTM A240 Grade 321 Stainless Steel Plate

Q: What is the difference between ASTM A240 Grade 321 and 304?

A: Grade 321 adds titanium (5xC min) to stabilize against sensitization in welds and heat (425-870°C), preventing IGC where 304 might fail; both have similar ambient corrosion resistance (PREN ~19), but 321 is optimized for high-temperature applications like exhausts, while 304 suits general fabrication at lower costs.

Q: Is ASTM A240 Grade 321 suitable for welding?

A: Yes; titanium stabilization allows welding without post-anneal in most cases, using 347/321 filler and low heat input (<1.5 kJ/mm) to preserve properties—passes ASTM A262-E as-welded, ideal for thick sections in heat exchangers.

Q: What is the maximum temperature for ASTM A240 Grade 321?

A: Continuous 870°C, intermittent 925°C; Ti prevents carbide precipitation, maintaining strength (80 MPa allowable at 600°C) and oxidation resistance in air or mildly carburizing gases.

Q: Can ASTM A240 Grade 321 be used in corrosive environments?

A: Moderately; good in oxidizing acids and atmospheres (e.g., <0.1 mm/year in 10% HNO3), but lacks Mo for chlorides—use for dry heat corrosives; PREN 19 suits mild service.

Q: Is ASTM A240 Grade 321 magnetic?

A: Non-magnetic annealed; cold work induces slight magnetism (5-15% martensite)—anneal at 1050°C to restore.

Q: What sizes are available for ASTM A240 Grade 321 plates?

A: 0.5-100 mm thick, widths to 3000 mm, lengths to 12000 mm; custom cuts with ±0.05 mm tolerance.

Q: How does ASTM A240 Grade 321 compare to 316Ti?

A: Both Ti-stabilized; 316Ti adds Mo for chloride pitting (PREN 25 vs 19), better for wet + heat; 321 cheaper for dry high-temp oxidation.

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11. Why Choose Gangsteel?

Gangsteel’s expertise since 1998, 500+ specialists, and stabilization tech build authority. 90k tons/year exports, TUV/ABS certified. For 321: 100% UT, custom Ti, worldwide ship. See ASTM A 240 Gr 304L. Relied on by Boeing, PetroChina.

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12. Conclusion

ASTM A240 Grade 321 (S32100) from Gangsteel is the titanium-stabilized austenitic for welded high-heat endurance, its IGC resistance mastering aerospace and petrochemical demands. With EN X6CrNiTi18-10 equivalents and thermal mechanics, at $3.5-5.5/kg in November 2025, it’s smart reliability. Inquire for quotes on this or ASTM A 240 Gr 316L. Forge ahead with Gangsteel.