ASTM A240 Type 309H Stainless Steel Sheet & Plate
What is ASTM A240 Type 309H Stainless Steel Sheet & Plate?
As a professional stainless steel supplier, SHH STEEL is pleased to offer ASTM A240 Type 309H Stainless Steel Sheet and Plate. Also known as UNS S30909, this grade is the high-carbon version of Type 309 designed specifically for continuous elevated-temperature service where enhanced creep resistance is required.
Compared with Type 309S, Type 309H has a controlled higher carbon content (0.04–0.10%) and must meet a mandatory grain size requirement of ASTM No. 7 or coarser. These features significantly improve high-temperature strength and long-term creep performance while retaining excellent oxidation resistance up to approximately 1000–1095°C.
SHH STEEL supplies ASTM A240 Type 309H in both sheet and plate forms, with thicknesses ranging from 0.5 mm to 100 mm. The material is typically delivered in the solution-annealed condition with full Mill Test Certificates (EN 10204 3.1). Custom sizes, surface finishes, and additional testing are available upon request.
ASTM A240 Type 309H Material Specification
ASTM A240 Type 309H stainless steel sheet and plate are produced in accordance with ASTM A240/A240M and ASME SA-240. This specification covers chromium-nickel stainless steel plate, sheet, and strip for pressure vessels and general applications, including high-temperature service.
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Primary Standard | ASTM A240 / ASME SA-240 Type 309H | Full compliance |
| Product Form | Sheet and Plate | Both available |
| Thickness Range | 0.5 mm – 100 mm | Custom sizes available |
| Width / Length | Up to 2500 mm / 12000 mm | Custom fabrication supported |
| Surface Finish | 2B, No.1, BA, HL | Multiple options |
| Heat Treatment Condition | Solution Annealed | Standard supply condition |
| Grain Size Requirement | ASTM No. 7 or coarser | Mandatory for Type 309H |
| Certification | EN 10204 3.1 / 3.2 | Available |
ASTM A240 Type 309H Chemical Composition
The chemical composition of ASTM A240 Type 309H is designed to provide high-temperature strength through controlled carbon content.
| Element | Content (%) | Standard Limit | Role |
|---|---|---|---|
| Carbon (C) | 0.04 – 0.10 | 0.04 – 0.10 | Improves high-temperature creep strength |
| Manganese (Mn) | ≤ 2.00 | 2.00 max | Deoxidation and strength |
| Phosphorus (P) | ≤ 0.045 | 0.045 max | Impurity control |
| Sulfur (S) | ≤ 0.030 | 0.030 max | Cleanliness |
| Silicon (Si) | ≤ 0.75 | 0.75 max | Oxidation resistance |
| Chromium (Cr) | 22.00 – 24.00 | 22.00 – 24.00 | High-temperature oxidation resistance |
| Nickel (Ni) | 12.00 – 15.00 | 12.00 – 15.00 | Austenite stability and high-temperature strength |
ASTM A240 Type 309H Mechanical Properties
In the solution-annealed condition, ASTM A240 Type 309H provides good room-temperature properties and superior high-temperature performance compared with lower-carbon grades.
| Property | Value | Test Method |
|---|---|---|
| Tensile Strength | ≥ 515 MPa (75 ksi) | ASTM A370 |
| Yield Strength (0.2% Offset) | ≥ 205 MPa (30 ksi) | ASTM A370 |
| Elongation in 50 mm | ≥ 40% | ASTM A370 |
| Hardness | ≤ 217 HB / ≤ 95 HRB | ASTM E10/E18 |
| Density | 8.00 g/cm³ | — |
| Grain Size | ASTM No. 7 or coarser | ASTM E112 |
Delivery Conditions
SHH STEEL supplies ASTM A240 Type 309H primarily in the solution-annealed and pickled condition. Common surface finishes include 2B, No.1, BA, and HL. Protective film can be applied on request.
Tolerances
Dimensional tolerances for ASTM A240 Type 309H sheet and plate follow ASTM A480/A480M requirements.
Thickness Tolerances Thickness tolerances vary by product form and thickness. Cold-rolled sheet has tighter controls, while hot-rolled plate follows the standard allowable deviations of ASTM A480. Tighter tolerances can be provided for special applications.
Width and Length Tolerances Standard width tolerance is typically +6 mm / 0 mm. Length tolerance for cut plates is normally +10 mm / 0 mm. Precision cutting and closer tolerances are available upon request.
Flatness Flatness is controlled according to ASTM A480. Improved flatness material can be supplied for critical fabrication requirements.
Edge Condition Sheet is usually supplied with mill edge or slit edge. Plate can be supplied with mill edge, sheared edge, or plasma/laser cut edge.
ASTM A240 Type 309H Weldability
ASTM A240 Type 309H can be welded using standard fusion welding processes such as GTAW (TIG), GMAW (MIG), and SMAW. Due to the higher carbon content, care should be taken to control heat input.
Matching or slightly over-alloyed filler metals (e.g., ER309 or ER309H) are commonly recommended. Preheating is generally not required. Post-weld cleaning and passivation are advised to restore optimum high-temperature performance. In critical high-temperature applications, the effect of welding on creep properties should be carefully evaluated.
Equivalent Material Grades Of ASTM A240 Type 309H
| Grade | Standard | Designation |
|---|---|---|
| Type 309H | ASTM A240 / ASME SA-240 | — |
| UNS S30909 | Unified Numbering System | S30909 |
| 1.4950 | EN 10028-7 / EN 10095 | X6CrNi23-13 |
| SUS309H | JIS (reference) | — |
| Similar Chinese grades | GB/T series | High-carbon 23Cr-13Ni types |
Applications
| Application Area | Typical Components / Uses |
|---|---|
| Furnace & Heat Treatment | Furnace parts, radiant tubes, muffles, retorts |
| Continuous High-Temperature Service | Components requiring long-term creep resistance |
| Power Generation | Boiler tube hangers, heat shields, structural supports |
| Chemical & Petrochemical | High-temperature process equipment |
| Kiln & Industrial Heating | Kiln components, calciner parts |
| General Elevated Temperature | Thermowells, anchor systems, furnace hardware |
Why Choose SHH STEEL
SHH STEEL is a reliable exporter of ASTM A240 Type 309H stainless steel sheet and plate. We provide competitive pricing, flexible custom sizes, multiple surface finishes, full grain size control, and complete Mill Test Certificates. Our team offers technical support for high-temperature material selection.
FAQ
- What is the main difference between 309S and 309H?Type 309H has a higher controlled carbon content (0.04–0.10%) and must meet a grain size requirement of ASTM No. 7 or coarser. These features provide better creep strength for continuous high-temperature service. Type 309S has lower carbon (≤0.08%) and no mandatory grain size requirement.
- Why is grain size important for Type 309H?Coarser grain size (ASTM No. 7 or coarser) improves high-temperature creep and rupture strength, which is critical for long-term elevated-temperature applications.
- What is the maximum continuous service temperature for ASTM A240 Type 309H?Approximately 1000–1035°C in continuous service, depending on the environment and stress conditions.
- What is the density of ASTM A240 Type 309H?Approximately 8.00 g/cm³.
Conclusion
ASTM A240 Type 309H Stainless Steel Sheet and Plate from SHH STEEL deliver enhanced high-temperature creep strength and oxidation resistance through controlled higher carbon content and mandatory grain size requirements. With strict quality control, flexible sizing, and professional export service, we provide reliable material for demanding continuous elevated-temperature applications worldwide.
Contact SHH STEEL today for your ASTM A240 Type 309H requirements.
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