ASTM A387 Alloy Steel Foil/Strip, Grade 91

ASTM A387 Alloy Steel Foil, Grade 91 Product Information -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel Foil, Grade 91 Synonyms -:- For detailed product information, please contact sales. -:

ASTM A387 Alloy Steel, Grade 91 Product Information -:- For detailed product information, please contact sales. -: ### **Product Introduction: ASTM A387/A387M Alloy Steel, Grade 91** **1. Overview** ASTM A387 Grade 91 is a high-strength chromium-molybdenum-vanadium alloy steel plate designed for service in welded pressure vessels and other high-temperature applications. It is a creep-strength enhanced ferritic (CSEF) steel, offering significantly superior mechanical properties and creep resistance at elevated temperatures (up to ~600°C / 1112°F) compared to traditional Cr-Mo grades like Grade 22 or Grade 5. Its development allows for the design of thinner-walled, more efficient pressure vessels and components in critical service. **2. Key International Standards** * **Primary Standard:** **ASTM A387/A387M** - Standard Specification for Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum. * This standard covers the chemical, mechanical, and mandatory heat treatment requirements. * **Dimensional & General Requirements:** * **ASTM A20/A20M** - Standard Specification for General Requirements for Steel Plates for Pressure Vessels. * **Equivalent Standards:** * **EN / DIN:** X10CrMoVNb9-1 (Material No. 1.4903) * **JIS:** SCMV 29 (Not an exact equivalent, but similar application) * **ASME:** SA-387 Gr. 91 (The ASME code case version for boiler and pressure vessel construction). **3. Chemical Composition (Weight %)** The composition of Grade 91 is precisely controlled, with microalloying elements like Vanadium, Niobium, and Nitrogen being critical for its enhanced strength. | Element | Composition (%) | | :--- | :--- | | Carbon (C) | 0.08 - 0.12 | | Manganese (Mn) | 0.30 - 0.60 | | Phosphorus (P), max | 0.020 | | Sulfur (S), max | 0.010 | | Silicon (Si) | 0.20 - 0.50 | | Chromium (Cr) | 8.00 - 9.50 | | Molybdenum (Mo) | 0.85 - 1.05 | | Vanadium (V) | 0.18 - 0.25 | | Niobium (Nb) | 0.06 - 0.10 | | Nitrogen (N) | 0.03 - 0.07 | | Nickel (Ni), max | 0.40 | | **Chromium Equivalent** | **~8.5** | | **Nickel Equivalent** | **~0.5** | *Note: The balance between these elements is crucial for achieving the desired tempered martensite microstructure and precipitation strengthening.* **4. Mechanical & Physical Properties** Grade 91 is **mandatorily supplied in the Normalized and Tempered condition**. The typical normalizing temperature is 1040-1080°C (1904-1976°F) followed by air cooling, and tempering at 730-780°C (1346-1436°F). **Mechanical Properties (at room temperature):** | Property | Value | | :--- | :--- | | Tensile Strength | 585 - 760 MPa (85 - 110 ksi) | | Yield Strength (min) | 415 MPa (60 ksi) | | Elongation in 2 in. (50 mm), (min) | 20% | | **Hardness (typical)** | **~190-250 HB** | **Approximate Physical Properties:** * **Density:** 7.73 g/cm³ (0.279 lb/in³) * **Melting Point:** ~ 1470 - 1510 °C (2678 - 2750 °F) * **Modulus of Elasticity:** 200 GPa (29 x 10⁶ psi) at 20°C * **Thermal Conductivity:** ~ 26.0 W/m·K (at 100°C) * **Coefficient of Thermal Expansion:** ~ 11.5 x 10⁻⁶ /K (20-100°C) * **Poisson's Ratio:** 0.27 - 0.30 *Note: Physical properties, especially modulus of elasticity and thermal conductivity, change significantly with temperature and must be used from validated high-temperature data sheets for design.* **5. Product Applications** ASTM A387 Gr. 91 is used in the most demanding high-temperature and high-pressure applications across the energy sector. Its primary use is where superior creep strength allows for significant weight and wall thickness reduction. * **Power Generation:** Superheater and reheater headers, main steam pipelines, high-temperature turbines, and boilers in ultra-supercritical (USC) power plants. * **Petroleum Refining:** Hydroprocessing reactors (especially in severe service), high-pressure heat exchangers, and transfer lines. * **Chemical & Petrochemical:** High-temperature reactors and vessels where creep deformation is a design-limiting factor. **6. Key Characteristics & Advantages** * **Exceptional Creep Strength:** Offers the highest allowable stress values among Cr-Mo steels at temperatures above 500°C (932°F), enabling more efficient, thinner-walled designs. * **High-Temperature Oxidation Resistance:** The 9% Chromium content provides good resistance to scaling and oxidation in steam and flue gas environments. * **Thermal Fatigue Resistance:** Good resistance to damage from thermal cycling due to its lower thermal expansion coefficient and high thermal conductivity compared to austenitic stainless steels. * **Critical Fabrication Consideration - Weldability:** While weldable, Grade 91 requires strict control. It is essential to use matching filler metals (e.g., ER90S-B9, E9015-B9), mandatory pre-heating (200-300°C), and a strict Post-Weld Heat Treatment (PWHT) at ~760°C to achieve the required tempered martensite structure and avoid premature failure in service. In summary, **ASTM A387 Grade 91** is a premier creep-strength enhanced ferritic steel that is a cornerstone material for modern, high-efficiency power generation and high-pressure petrochemical equipment, offering an optimal balance of high-temperature strength and fabricability. -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel, Grade 91 Specification Dimensions Size： Diameter 20-1000 mm Length <4376 mm Size:We can customized as required Standard： Per your request or drawing We can customized as required Properties（Theoretical） Chemical Composition -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel, Grade 91 Properties -:- For detailed product information, please contact sales. -:

Applications of ASTM A387 Alloy Steel Foil, Grade 91 -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A387 Alloy Steel Foil, Grade 91 -:- For detailed product information, please contact sales. -:

Packing of ASTM A387 Alloy Steel Foil/Strip, Grade 91 -:- For detailed product information, please contact sales. -: Standard Packing: -:- For detailed product information, please contact sales. -: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and Steel Foil/Strip drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 847 gallon liquid totes Special package is available on request. E FORUs’ is carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition