ASTM A240 Type 800H Stainless Steel Sheet & Plate
What is ASTM A240 Type 800H Stainless Steel Sheet?
As a professional stainless steel and nickel alloy supplier and China Mill-Direct Supply / Mill Direct Exporter, SHH STEEL is pleased to present ASTM A240 Type 800H Stainless Steel Sheet & Plate, commonly known as Alloy 800H or Incoloy 800H (UNS N08810).
Alloy 800H is the controlled high-carbon version of Alloy 800. It features a carbon content of 0.05–0.10%, restricted aluminum + titanium content, and a mandatory coarse grain size. These controls significantly improve creep and stress-rupture strength at elevated temperatures compared with standard Alloy 800, while retaining excellent resistance to oxidation, carburization and high-temperature corrosion.
Although Alloy 800H is most accurately specified under ASTM B409 / ASME SB-409, it is frequently requested under the ASTM A240 Type 800H designation in projects that also use A240 stainless grades. It is the preferred material for long-term high-temperature service in heat exchangers, furnace components, petrochemical processing equipment, power generation piping and industrial heating systems where creep strength is critical.
SHH STEEL supplies Alloy 800H / Type 800H sheet and plate as true Mill Direct Supply. This enables competitive pricing, consistent quality, full heat traceability and reliable delivery. Material is supplied in the solution-annealed condition with controlled grain size to meet the requirements of the grade.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Primary Designation | Alloy 800H / UNS N08810 (commonly requested as ASTM A240 Type 800H) | Full compliance |
| Related Standards | ASTM B409 / ASME SB-409, ASTM B408 | Available |
| Product Form | Sheet, Plate | Available |
| Delivery Condition | Solution Annealed (controlled grain size) | Standard |
| Thickness Range | 1 mm – 80 mm (thicker available on request) | Custom sizes supported |
| Width | Up to 2000–3000 mm | Available |
| Length | Up to 12000 mm or cut-to-length | Available |
| Surface Finish | No.1, and others on request | Available |
| Certification | EN 10204 3.1 / Mill Test Certificate | Available |
Chemical Composition
Heat Analysis (typical for UNS N08810 / Alloy 800H):
| Element | Content (%) |
|---|---|
| Nickel (Ni) | 30.00 – 35.00 |
| Chromium (Cr) | 19.00 – 23.00 |
| Iron (Fe) | ≥ 39.50 (balance) |
| Carbon (C) | 0.05 – 0.10 |
| Manganese (Mn) | ≤ 1.50 |
| Silicon (Si) | ≤ 1.00 |
| Copper (Cu) | ≤ 0.75 |
| Aluminum (Al) | 0.15 – 0.60 |
| Titanium (Ti) | 0.15 – 0.60 |
| Al + Ti | 0.30 – 1.20 |
| Sulfur (S) | ≤ 0.015 |
Product Analysis follows the permissible variations of the applicable ASTM/ASME specifications.
The higher and controlled carbon content (0.05–0.10%), together with restricted Al + Ti and mandatory coarse grain size, are the key features that give Alloy 800H its superior creep and rupture strength at elevated temperatures.
Mechanical Properties
Room-Temperature Mechanical Properties (Solution Annealed Condition, typical)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 520 MPa (75 ksi) |
| Yield Strength (0.2%) | ≥ 205 MPa (30 ksi) |
| Elongation (in 50 mm) | ≥ 30% |
| Hardness | ≤ 185 HB |
| Grain Size | ASTM No. 5 or coarser |
Elevated-Temperature Performance Alloy 800H is specifically designed for superior creep and stress-rupture strength in the temperature range of approximately 600–1100°C. It is the preferred grade when long-term high-temperature strength under load is required.
Physical Properties
- Density: 7.94 g/cm³
- Melting Range: approximately 1350–1400°C
- Magnetic: Generally non-magnetic in the annealed condition
Material Comparison
| Grade / Alloy | Carbon / Special Control | Primary Advantage | Typical Preference |
|---|---|---|---|
| Alloy 800 | ≤ 0.10% (no grain control) | Good high-temp strength & oxidation resistance | General high-temperature service |
| Alloy 800H / Type 800H | 0.05–0.10% + grain size control | Superior creep & rupture strength | Long-term high-temp pressure service |
| Alloy 800HT | Controlled C + optimized Al+Ti | Maximum high-temperature strength | Most demanding creep applications |
| A240 Type 310H | 0.04–0.10% | Excellent oxidation resistance | High-temp oxidizing atmospheres |
| Alloy 625 | High Mo + Nb | Outstanding corrosion + high strength | Severe corrosive high-temp service |
Alloy 800H is selected when the design requires higher allowable stresses at elevated temperature than standard Alloy 800. For the absolute highest creep strength, Alloy 800HT is preferred. Related high-temperature stainless grades include astm a240 type 310h stainless steel sheet plate and astm a240 type 310s stainless steel sheet plate.
Corrosion Resistance
Alloy 800H offers the same excellent resistance to oxidation, carburization and high-temperature corrosion as Alloy 800. The controlled composition maintains good structural stability and resistance to embrittlement during long-term elevated-temperature exposure.
It also provides good resistance to many aqueous corrosive media and has useful resistance to chloride stress corrosion cracking due to its high nickel content.
Heat Treatment
Alloy 800H is supplied in the solution-annealed condition with controlled grain size.
Recommended Solution Annealing Parameters
- Temperature range: 1125 – 1175°C (typically 1150°C)
- Holding (soaking) time: Sufficient to achieve full solution and uniform grain size (typically 30–90 minutes depending on thickness)
- Cooling: Rapid cooling (water quench or accelerated air cool) to retain the desired microstructure
The higher annealing temperature and controlled cooling are essential to achieve the coarse grain size (ASTM No. 5 or coarser) required for optimum creep strength.
Surface Finishes
| Finish | Description | Typical Use / Keywords |
|---|---|---|
| No.1 | Hot-rolled, solution annealed and descaled | A240 Type 800H No.1 / Alloy 800H No.1 – most common for industrial and pressure vessel plate |
| Special | Ground or custom finishes | A240 Type 800H Special – on request |
SHH STEEL regularly supplies Alloy 800H / Type 800H in No.1 finish and can provide other finishes according to project requirements.
Tolerances
Dimensional tolerances for ASTM A240 Type 800H / Alloy 800H sheet & plate generally follow ASTM B409 / ASME SB-409 and related standards.
Typical available size range:
- Thickness: 1 mm – 80 mm (thicker plates available on request)
- Width: up to 2000–3000 mm
- Length: up to 12000 mm or cut-to-length
Thickness, width, length and flatness tolerances are controlled within standard limits. Tighter tolerances can be arranged. SHH STEEL provides precise dimensional control for both standard and custom-size Alloy 800H sheet and plate.
Equivalent Material Grades
| Grade / Designation | Standard / UNS | Notes |
|---|---|---|
| Alloy 800H | UNS N08810 | Standard high-creep grade |
| Alloy 800HT | UNS N08811 | Further optimized for maximum strength |
| Alloy 800 | UNS N08800 | Standard (lower creep strength) |
| 1.4958 / X5NiCrAlTi31-20 | EN | European equivalent |
| NCF 800H | JIS | Japanese equivalent |
Related grades frequently evaluated include Alloy 800, Alloy 800HT, and high-temperature stainless grades such as astm a240 type 310h stainless steel sheet plate.
Applications
Alloy 800H / ASTM A240 Type 800H is selected for long-term high-temperature service where creep strength is critical. Typical applications of A240 Type 800H / Alloy 800H include:
| Industry / Sector | Typical Components / Equipment (with keywords) |
|---|---|
| Heat Exchangers | Alloy 800H / A240 Type 800H heat exchanger tubesheets, shells and high-temp components |
| Petrochemical & Refining | A240 Type 800H furnace components, transfer piping, reactors |
| Power Generation | Alloy 800H superheater, reheater and high-temperature piping |
| Industrial Furnaces | A240 Type 800H radiant tubes, muffles, fixtures and retorts |
| Chemical Processing | Alloy 800H high-temperature process equipment and vessels |
| Power & Energy | A240 Type 800H components requiring long-term creep resistance |
| Heat Treatment Equipment | Alloy 800H high-temperature fixtures and baskets |
Why Choose SHH STEEL
SHH STEEL is a China Mill-Direct Supply and Mill Direct Exporter of stainless steel and nickel alloy plate. We maintain long-term cooperation with major mills and supply Alloy 800H / ASTM A240 Type 800H with the following advantages:
- Competitive mill-direct pricing
- Consistent quality, controlled grain size and complete heat traceability
- Full Mill Test Certificates (EN 10204 3.1)
- Flexible dimensions and surface finishes (including A240 Type 800H No.1)
- Technical support for high-temperature and creep-resistant material selection
- Reliable worldwide logistics and export documentation
FAQ
- What is the main difference between Alloy 800 and Alloy 800H?Alloy 800H has a controlled higher carbon content (0.05–0.10%), restricted Al + Ti, and mandatory coarse grain size, giving it significantly better creep and rupture strength at elevated temperatures. SHH STEEL recommends 800H when long-term high-temperature strength under load is required.
- When should I choose Alloy 800HT instead of 800H?Alloy 800HT has further optimized aluminum + titanium content for even higher creep strength. SHH STEEL can supply both grades and assist with material selection based on design temperature and stress requirements.
- Is Alloy 800H / ASTM A240 Type 800H magnetic?It is generally non-magnetic in the solution-annealed condition. SHH STEEL supplies fully annealed material.
- What is the density of Alloy 800H?7.94 g/cm³. SHH STEEL provides material certificates confirming physical and mechanical properties.
- Can SHH STEEL supply dual-certified material?Yes, SHH STEEL commonly supplies Alloy 800H with dual certification to ASTM B409 / ASME SB-409 and other required standards.
Conclusion
ASTM A240 Type 800H / Alloy 800H (UNS N08810) Stainless Steel Sheet & Plate is a high-carbon, grain-size-controlled nickel-iron-chromium alloy specifically engineered for superior creep and rupture strength at elevated temperatures, while retaining excellent oxidation and carburization resistance. It is the material of choice for long-term high-temperature pressure service in heat exchangers, petrochemical equipment, power generation and industrial furnaces.
As a professional China Mill-Direct Supply and Mill Direct Exporter, SHH STEEL provides high-quality Alloy 800H / ASTM A240 Type 800H sheet and plate with competitive pricing, full certification and complete technical support.
Contact SHH STEEL today for stock availability, surface finish options (including A240 Type 800H No.1), Alloy 800HT options, or a competitive quotation.
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