astm a240 grade 321h (s32109) stainless steel plate supplier

ASTM A240 Grade 321H (S32109) Stainless Steel Plate

When engineering demands a stainless steel that combines high-temperature creep resistance with titanium stabilization to combat sensitization in welded high-heat applications like boiler tubes or petrochemical reformers, ASTM A240 Grade 321H (S32109) stainless steel plate emerges as a high-carbon, stabilized austenitic powerhouse. We also call it A240 Gr 321H in technical discussions (Gr for Grade), A240 SS 321H (SS as in stainless steel),

A240 TP 321H (TP for tubing plate, prevalent in pressure vessel specs), or the classic AISI 321H plate (the American Iron and Steel Institute tag that persists). Whatever variation you entered in your search, you're likely pursuing a material with elevated carbon (0.04-0.10%) for enhanced rupture strength at 500-900°C, plus titanium (4xC min) to bind carbides and prevent IGC—delivering a PREN of ~19-21 for moderate corrosion resistance in oxidizing environments. At Gangsteel, we melt it via AOD with precise Ti additions, rolling plates up to 100 mm thick in finishes from No.1 to polished.

Drawing on over 25 years as a leading Chinese manufacturer and exporter, Gangsteel supplies ASTM A240 Grade 321H to power generation, aerospace, and chemical industries worldwide, dual-certified to ASTM A240 and ASME SA240 for seamless code compliance. This high-carbon variant of 321 boosts short-time tensile strength for sustained thermal loads, resisting sigma phase and embrittlement where low-carbon grades soften. It's a budget-savvy alternative to nickel superalloys in carburizing or sulfidizing atmospheres. Delve into our detailed analysis below. Check our extensive ASTM A 240/A 240M stainless steel plate offerings, including stabilized cousins like ASTM A 240 Gr 321 and molybdenum-stabilized ASTM A 240 Gr 316Ti.

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1. What is ASTM A240 Grade 321H (S32109)?

ASTM A240 Grade 321H (UNS S32109) is a high-carbon, titanium-stabilized austenitic stainless steel under ASTM A240 for chromium-nickel plates, sheets, and strips in pressure vessels, boilers, and elevated-temperature corrosive service. Optimized for ASME code applications, its 0.04-0.10% carbon elevates carbide formation for superior creep and stress-rupture strength at 600-900°C (1112-1652°F), while titanium (4xC min) forms stable TiC carbides to prevent chromium depletion and IGC in sensitized zones—allowing as-welded use without annealing in many scenarios. This grade is engineered for prolonged thermal exposure, resisting oxidation scaling up to 925°C intermittent.

Evolving from 321 to meet 1970s refinery demands for hotter, longer service, 321H has become essential in superheater tubes and catalytic converters. At Gangsteel, we use electroslag remelting for homogeneous Ti distribution, yielding grain size ASTM 5-7 and minimal intermetallics for peak toughness. The 17-19% Cr and 9-12% Ni matrix ensures non-magnetic behavior, high ductility (elongation >40%), and formability for complex bends. Thermal expansion (17.2 × 10⁻⁶/°C) and conductivity (16.1 W/m·K) facilitate bimetallic welds with low distortion.

Users searching “A240 SS 321H” often seek its thermal superiority: it holds 180 MPa rupture at 650°C/10,000 hours, 20-30% better than 321, per our creep tests. Weld with 347 or 321 filler; solution anneal at 1050-1150°C for optimal properties. Compared to ASTM A 240 Gr 304H, 321H adds Ti for weld stability without Mo’s chloride focus—PREN ~19-21 suits mild acids.

For setups with cyclic heating and moderate corrosion—like ethylene furnaces or aircraft afterburners—A240 TP 321H’s blend of creep resistance and affordability often triples lifespan versus carbon steels, as validated in our Gulf client audits.

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2. ASTM A240 Grade 321H Chemical Composition

The chemical profile of ASTM A240 Grade 321H is tuned for high-temp durability, per Table 1. Gangsteel’s vacuum degassing hits tight C and Ti for maximum stabilization.

Elevated C promotes strengthening carbides; Ti binds excess to avert IGC. Low P/S enhance weldability. Our exposures in boiling CuSO4-H2SO4 (ASTM A262-B) confirm <0.03 mm/year penetration post-sensitization.

Note: Higher C than ASTM A 240 Gr 321 for creep; no Mo like 316Ti. MTRs include Ti/C ratio.

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3. ASTM A240 Grade 321H Mechanical Properties

Properties focus on thermal strength, annealed at 1050-1150°C.

High C boosts creep 20% over 321; rupture >160 MPa at 650°C/10,000h. Fatigue 200 MPa at 10^7 cycles post-anneal.

Vs ASTM A 240 Gr 316H, similar heat strength but no Mo—better for dry oxidation.

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4. ASTM A240 Grade 321H Allowable Stress

ASME Table 1A for design.

High C/Ti enable stresses 10-20% above 304H at 600°C. Certs with deratings.

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5. ASTM A240 Grade 321H Equivalent Materials

International matches.

Dual-certs for global codes.

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

Detailed vs ASTM A 240 Gr 321, ASTM A 240 Gr 316H, ASTM A 240 Gr 304H.

• Gr 321H vs 321: 321H’s higher C boosts creep 20% for sustained heat; same stabilization—use 321H for continuous >600°C.
• Gr 321H vs 316H: Both high-C; 316H’s Mo adds chloride resistance (PREN 25 vs 19)—321H for dry oxidation, 316H wet + heat.
• Gr 321H vs 304H: Both high-C; 321H’s Ti prevents IGC in welds/heat—superior for sensitized zones.

Opt for 321H in hot stabilized, 321 general, 316H corrosives, 304H economy.

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7. ASTM A240 Grade 321H Specifications

Tailored with ±0.1 mm precision.

7.1 Plate and Sheet

• Thickness: 3-100 mm (plate), 0.5-6 mm (sheet)
• Width: 1000-2500 mm
• Length: 2000-12000 mm/coils
• Surface: No.1, 2B, annealed
• Standards: ASTM A240, ASME SA240, AMS 5570
• Uses: Plates for tubesheets, sheets for liners

7.2 Bar and Rod

• Diameter: 10-300 mm
• Length: Up to 6000 mm
• Finish: Hot-forged, peeled
• Standards: ASTM A276, ASME SA479
• Uses: Valve stems, fasteners

7.3 Custom Components

• Types: Heads, flanges
• Processes: Rolled, machined
• Certs: EN 10204 3.2, NACE
• Uses: Custom for power plants

400 tons stock; 10-15 day turnaround.

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8. Applications of ASTM A240 Grade 321H

321H suits high-heat stabilized:

• Power Generation: Superheater tubes; creeps low to 800°C.
• Petrochemical: Reformers; carburization resistant.
• Aerospace: Afterburners; thermal fatigue tolerant.
• Heat Treatment: Fixtures; cyclic stable.
• Chemical: Acid lines; IGC-free.

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

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9. Price of ASTM A240 Grade 321H

As of November 2025, A240 Gr 321H prices range USD 3.5-5.5 per kg FOB, with hot-rolled at $3.5-4.5/kg per ton equivalents, influenced by Ni (~$17k/ton) and Ti premium. Bulk >5t discounts 10-15%. Gangsteel provides hedging.

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10. FAQ for ASTM A240 Grade 321H Stainless Steel Plate

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

A: Grade 321H has a higher carbon content (0.04-0.10% vs ≤0.08% in 321), which improves high-temperature creep and rupture strength for continuous service above 600°C, while both share titanium stabilization for IGC resistance; 321H is preferred for sustained thermal loads like boilers, with 20% better creep performance.

Q: Is ASTM A240 Grade 321H good for high temperatures?

A: Yes, it's designed for continuous 870°C and intermittent 925°C; high carbon enhances carbide pinning for creep resistance (180 MPa at 650°C/10,000h), and titanium prevents sensitization—ideal for furnaces and reformers in oxidizing atmospheres.

Q: What welding filler for ASTM A240 Grade 321H?

A: Use ER347 or ER321 filler for GTAW/SMAW; low heat input (1.0-1.5 kJ/mm) preserves stabilization; post-weld anneal at 1050-1150°C recommended for thick sections to optimize properties and avoid IGC.

Q: Can ASTM A240 Grade 321H resist corrosion?

A: Moderately; good in oxidizing acids and atmospheres (<0.1 mm/year in 10% HNO3), but limited in chlorides (PREN 19)—use for dry high-temp corrosives; Ti ensures weld zones remain resistant.

Q: Is ASTM A240 Grade 321H magnetic?

A: Non-magnetic annealed; cold work can induce 5-10% martensite for slight magnetism—anneal at 1050°C to restore full austenite.

Q: What sizes for ASTM A240 Grade 321H plates?

A: 3-100 mm thick, widths to 2500 mm, lengths to 12000 mm; custom with ±0.1 mm tolerance.

Q: How does 321H compare to 316H in high temp?

A: Both high-C for creep; 316H’s Mo adds chloride resistance (PREN 25 vs 19), better for wet + heat; 321H excels in dry oxidation and carburization without Mo cost.

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11. Why Choose Gangsteel?

Gangsteel’s 25+ years, 500+ experts, and Ti-stab tech affirm reliability. 100k tons/year exports, LR/TUV certified. For 321H: 100% PMI, custom annealing, global stock. See ASTM A 240 Gr 316. Trusted by GE, Aramco.

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12. Conclusion

ASTM A240 Grade 321H (S32109) from Gangsteel is the high-carbon, Ti-stabilized austenitic for enduring hot corrosive battles, its creep strength dominating power and petrochemical fields. Aligning with EN X8CrNiTi18-10 and thermal mechanics, at $3.5-5.5/kg in November 2025, it’s high-value engineering. Contact for quotes on this or ASTM A 240 Gr 304LN. Power forward with Gangsteel.