What is ASTM A240 type 316h material?

What is ASTM A240 type 316h material?

When queries like "What is ASTM A240 type 316h material?" arise from engineers, fabricators, or procurement experts, they often point to ASTM A240 Grade 316H (UNS S31609), a high-carbon, molybdenum-bearing austenitic stainless steel plate, sheet, or strip designed for high-temperature service with enhanced creep resistance.

ASTM A240/A240M is the standard specification for chromium and chromium-nickel stainless steel plate, sheet, and strip for pressure vessels and general applications, and Type 316H modifies the base 316 by raising carbon to 0.04-0.10% to improve strength at elevated temperatures above 500°C (932°F) while maintaining excellent corrosion resistance in chloride and acidic environments. As a premier manufacturer and exporter in China, Gangsteel produces ASTM A240 Type 316H material, certified to both ASTM A240 and ASME SA240, with a focus on carbon uniformity for optimal thermal performance.

Type 316H is the "high-carbon" variant of 316, adding strength for applications like furnace parts, heat exchangers, and chemical processing equipment where sustained heat could cause deformation in lower-carbon grades. It offers a PREN of 24-26 for superior pitting resistance compared to 304 grades, and its austenitic structure ensures non-magnetic properties, high ductility, and toughness from -196°C to 925°C intermittent.

At Gangsteel, we refine 316H via AOD + electroslag remelting for precise carbon (0.05-0.08%) and low inclusions, rolling plates up to 100 mm thick in finishes like No.1 and 2B. Priced at USD 4.5-12 per kg in November 2025 (or $4500-12000 per metric ton), it's a premium choice for thermal-corrosive duties. This guide covers its composition, properties, equivalents, and more. For our high-temp molybdenum grades, browse the ASTM A 240/A 240M stainless steel plate portfolio, including ASTM A 240 Gr 316H and low-carbon ASTM A 240 Gr 316L.

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1. What is A240 Grade 316H (S31609)?

A240 Grade 316H is a high-carbon version of the molybdenum-alloyed austenitic stainless steel Type 316, specified under ASTM A240/A240M for enhanced high-temperature performance in pressure vessels, boilers, and corrosive service. The "H" indicates high carbon (0.04-0.10%), which promotes carbide formation to pin grain boundaries, boosting creep and rupture strength at temperatures above 500°C where standard 316 might soften. This makes it ideal for furnace parts, heat exchangers, and chemical reactors exposed to sustained thermal loads and mild corrosives.

Evolving from 316 to meet ASME boiler code needs for hotter service, 316H has been key since the 1970s in power and petrochemical sectors. At Gangsteel, we produce it from electric arc furnace melts with vacuum degassing for carbon precision, achieving grain size ASTM 5-7 for toughness. The austenitic matrix—16-18% Cr, 10-14% Ni, 2-3% Mo—provides non-magnetic behavior, ductility (elongation ≥40%), and formability. It resists scaling to 925°C intermittent, with conductivity 14.6 W/m·K and expansion 16.5 × 10⁻⁶/°C for assembly stability.

Often called "AISI 316H plate," it requires welding with 316H filler and post-weld anneal for thick sections to mitigate sensitization risk from high carbon. Compared to ASTM A 240 Gr 316 (C ≤0.08%), 316H trades weld ease for 20-30% better creep. For stabilized heat, see ASTM A 240 Gr 321H.

In refineries or power plants, A240 316H's thermal prowess extends life 30-50% over 316 in heat-corrosive zones, per our Middle East client reports.

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2. A240 Grade 316H Chemical Composition

The composition of A240 Grade 316H is tailored for high-temp corrosion resistance, per ASTM A240 Table 1.

High C strengthens at heat; Mo boosts PREN to 24-26 for chlorides. Low P/S aid workability. Gangsteel keeps C 0.05-0.08% for balance, with <0.05 mm/year in phosphoric acid.

Note: Vs ASTM A 240 Gr 316L (low C), 316H for creep not welds. MTRs with spectro.

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3. A240 Grade 316H Mechanical Properties

Mechanics prioritize thermal strength, annealed at 1040-1175°C.

High C retains >60% strength at 600°C, creep rupture ≥180 MPa at 650°C/10,000h. Fatigue 220 MPa at 10^7 cycles.

Vs ASTM A 240 Gr 316, 20% better creep. Machinability 40% of B1112.

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4. A240 Grade 316H Allowable Stress

Stresses per ASME BPVC Table 1A.

High C enables 10-20% higher than 316L at heat. Certs with deratings.

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5. A240 Grade 316H Equivalent Materials

Equivalents for sourcing.

Gangsteel dual-certs.

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6. A240 Grade 316H vs A240 Gr 316, A240 Gr 316L, and A240 Gr 321H

Vs ASTM A 240 Gr 316, ASTM A 240 Gr 316L, ASTM A 240 Gr 321H.

• 316H vs 316: 316H high C for 20% better creep; same corrosion—316H for sustained heat.
• 316H vs 316L: 316L low C for welds; 316H stronger for non-weld thermal.
• 316H vs 321H: Both high-C; 316H Mo for chlorides, 321H Ti for stab in acids.

Choose 316H for hot corrosives, 316 ambient, 316L welds, 321H stab.

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7. A240 Grade 316H Specifications

Gangsteel supplies with ±0.1 mm tolerances.

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 5573
• Uses: Plates for headers, sheets for baffles

7.2 Bar and Rod

• Diameter: 10-300 mm
• Length: Up to 6000 mm
• Finish: Forged, ground
• Standards: ASTM A276, ASME SA479
• Uses: Shafts, bolts

7.3 Custom Components

• Types: Nozzles, flanges
• Processes: Rolled, machined
• Certs: EN 10204 3.2, NACE
• Uses: Custom for petrochemical

500 tons stock; 10-15 days.

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8. Applications of A240 Grade 316H

316H for high-heat corrosives:

• Petrochemical: Reformers; creeps low in hydrocarbons.
• Power: Boiler tubes; oxidation to 800°C.
• Chemical: Reactors; acids/chlorides.
• Heat Treatment: Fixtures; cyclic.
• Aerospace: Turbine parts; strength.

Vs 316L, 316H for sustained heat.

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9. Price of A240 Grade 316H

November 2025: USD 4.5-12/kg FOB, hot-rolled ~$4.5-6/kg ($4500-6000/MT), per data. Mo/Ni affect; high C premium 10%. Gangsteel discounts bulk.

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10. FAQ for A240 Grade 316H Stainless Steel Material

Q: What is the difference between A240 316H and 316?

A: A240 316H has higher carbon (0.04-0.10% vs ≤0.08% in 316), which enhances creep and rupture strength for continuous high-temperature service above 500°C, such as in furnaces or reactors; both share the same molybdenum for corrosion resistance (PREN 24-26), but 316H may require annealing after welding to prevent sensitization, while standard 316 offers better ambient weldability without the thermal focus.

Q: Is A240 316H suitable for high temperatures?

A: Yes, it's optimized for temperatures up to 925°C intermittent or 870°C continuous, where its elevated carbon promotes carbide formation for superior creep resistance (e.g., holding 80 MPa stress at 600°C with minimal deformation over 10,000 hours), outperforming low-carbon variants in oxidizing or mildly reducing atmospheres like those in petrochemical reformers or power boilers.

Q: What welding tips for A240 316H?

A: Use 316H or 317L filler metals with GTAW or SMAW methods, keeping heat input low (<1.5 kJ/mm) to minimize distortion and carbide precipitation; post-weld solution annealing at 1040-1175°C followed by rapid quench is recommended for sections over 6mm to restore corrosion resistance and avoid intergranular attack, as per AWS guidelines and ASTM A262 testing.

Q: Can A240 316H be used in corrosive environments?

A: Yes, it provides excellent resistance to pitting and crevice corrosion in chlorides and acids (PREN 24-26), with <0.05 mm/year loss in phosphoric or sulfuric environments; however, its high carbon may increase sensitization risk in weld zones without annealing, so it's best for combined high-temperature and moderate corrosive duties like chemical reactors.

Q: Is A240 316H magnetic?

A: It is non-magnetic in the annealed condition due to its fully austenitic structure, but heavy cold working can induce up to 10-15% martensite, causing slight magnetism; full solution annealing at 1040°C restores the non-magnetic properties, which is important for applications like MRI equipment or non-sparking tools.

Q: What sizes are available for A240 316H plates?

A: Standard thicknesses range from 3mm to 100mm for plates and 0.5mm to 6mm for sheets, with widths up to 2500mm and lengths to 12000mm; custom sizes and coiled sheets are available, with tolerances as tight as ±0.1mm via plasma or waterjet cutting for precision components.

Q: How does A240 316H compare to 321H?

A: Both are high-carbon for creep resistance, but 316H includes 2-3% molybdenum for superior pitting in chlorides (PREN 24-26 vs 18-20), making it better for wet high-temperature environments like acid reactors; 321H uses titanium for stabilization against polythionic acids, so choose 316H for chloride exposure and 321H for dry or sulfurous heat.

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11. Why Choose Gangsteel?

Gangsteel’s 25+ years, 500+ experts deliver E-E-A-T. 120k tons/year, ABS/TUV certified. For 316H: 100% PMI, custom annealing, global delivery. Explore ASTM A 240 Gr 316Ti.

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12. Conclusion

ASTM A240 Type 316H material is the high-carbon, Mo-alloyed austenitic stainless for high-temp corrosion resistance in furnaces and reactors. With equivalents like EN 1.4919 and mechanics for enduring heat, at $4.5-12/kg in 2025, it’s strategic value. Contact Gangsteel for quotes or data on this or ASTM A 240 Gr 304H. Build resiliently.