Cast Stainless Steel Rod/Bar HK40, ASTM A351M

Cast Stainless Steel Rod HK40, ASTM A351M Product Information -:- For detailed product information, please contact sales. -: Cast Stainless Steel Rod HK40, ASTM A351M Synonyms -:- For detailed product information, please contact sales. -:

Cast Stainless Steel HK40, ASTM A351M Product Information -:- For detailed product information, please contact sales. -: ### **Technical Data Sheet: Cast Stainless Steel HK40 (ASTM A351M Grade HK40)** **Product Overview** Cast Stainless Steel HK40, conforming to the ASTM A351M standard, is a high-carbon, austenitic heat-resistant alloy. It is a widely used material for components that require exceptional strength and resistance to oxidation (scaling) and carburization at elevated temperatures. The "HK" designation originates from the Alloy Casting Institute (ACI), and the "40" refers to its nominal carbon content of approximately 0.40%. **ASTM A351M** specifically covers the requirements for austenitic steel castings for pressure-containing parts in high-temperature service, making HK40 a prime choice for critical valves, fittings, pumps, and vessel components in demanding industrial environments. --- #### **1. International Standards & Designations** HK40 is recognized globally under the following standard specifications. Its primary identity for static pressure-containing castings is ASTM A351M. | Standard Organization | Designation | Scope / Note | | :--- | :--- | :--- | | **ASTM International** | **A351/A351M Grade HK40** | **Primary Standard for Pressure Castings** | | **ASTM International** | A297 Grade HK40 | For general heat-resistant castings | | **UNS (Unified Numbering System)** | **J94204** | Unified Number | | **ACI / SFSA (USA)** | **HK-40** | Common Trade Designation | | **European Norm (EN)** | **G-X 40 CrNiSi 25-12** | Similar designation, note carbon difference | | **Japanese (JIS)** | **SCH 22** | JIS G5121 | --- #### **2. Chemical Composition (Weight % per ASTM A351M)** The chemical composition is strictly controlled by the ASTM A351M specification to ensure high-temperature performance. | Element | Composition (%) | | :--- | :--- | | **Carbon (C)** | 0.35 - 0.45 | | **Chromium (Cr)** | 23.0 - 27.0 | | **Nickel (Ni)** | 19.0 - 22.0 | | **Silicon (Si)** | 1.75 max | | **Manganese (Mn)** | 1.50 max | | **Phosphorus (P)** | 0.04 max | | **Sulfur (S)** | 0.04 max | | **Iron (Fe)** | Balance | **Key Composition Rationale:** * **High Chromium (Cr):** Provides superior resistance to oxidation and carburization by forming a stable, self-healing chromium oxide (Cr₂O₃) layer on the surface at temperatures up to 1150°C. * **High Nickel (Ni):** Stabilizes the austenitic matrix, providing high-temperature strength, ductility, and resistance to thermal cycling and creep deformation. * **Higher Carbon (C):** Compared to HK30, the increased carbon content (0.35-0.45%) significantly enhances high-temperature strength and creep resistance through solid solution strengthening and the formation of stable carbides within the austenitic structure. --- #### **3. Typical Physical & Mechanical Properties** **Physical Properties (At Room Temperature):** * **Density:** 7.75 - 7.80 g/cm³ * **Melting Range:** ~1350 - 1400 °C (2460 - 2550 °F) * **Specific Heat:** 500 J/kg·K * **Thermal Conductivity:** ~14.0 W/m·K (at 100°C) * **Coefficient of Thermal Expansion:** ~16.0 x 10⁻⁶ /K (20 - 100°C) **Room Temperature Mechanical Properties (Per ASTM A351M - Heat-Treated Condition):** * **Tensile Strength:** 620 MPa (90 ksi) min * **Yield Strength (0.2% Offset):** 310 MPa (45 ksi) min * **Elongation (% in 2in/50mm):** 10% min **High-Temperature Performance (Key Characteristics):** * **Maximum Service Temperature:** Up to **1150°C (2100°F)** in oxidizing environments. * **Oxidation Resistance:** Excellent, suitable for long-term service in furnace atmospheres. * **Creep & Rupture Strength:** Outstanding resistance to deformation under stress at high temperatures. HK40 offers superior short-term and long-term creep strength compared to HK30, making it suitable for heavily loaded components. * **Carburization Resistance:** Good resistance to attack from carbon-rich atmospheres. --- #### **4. Product Applications** ASTM A351M HK40 is predominantly used for **statically cast pressure-containing parts** that must withstand severe thermal and mechanical stress. Its primary applications are in: * **Petrochemical & Refining:** * Tube headers and return bends for reformer furnaces. * Valve bodies, pump casings, and fitting for high-temperature process streams. * Manifolds and reactor components. * **Heat Treatment & Industrial Furnaces:** * Fixtures, jigs, and trays for carburizing and annealing. * Burner nozzles and furnace components. * **Power Generation:** * Components for boiler systems, such as damper links and supports. * Parts for waste-to-energy and biomass incineration plants. --- #### **5. Fabrication & Heat Treatment** * **Casting Process:** Produced via static sand casting or investment casting processes to create complex shapes like valves and pumps, as covered by ASTM A351M. * **Machining:** Difficult due to its austenitic structure, high strength, and abrasiveness from carbides. Requires rigid setups, slow speeds, high feeds, and carbide tooling. * **Welding:** Weldable using shielded metal arc welding (SMAW) or gas tungsten arc welding (GTAW) with matching or over-alloyed filler metals (e.g., ENiCrFe-3). Pre-heating is generally not required. **Post-weld heat treatment (Solution Annealing) is typically mandatory** to restore corrosion and oxidation resistance by re-dissolving carbides precipitated in the heat-affected zone. * **Heat Treatment:** Per ASTM A351M, castings are supplied in the **heat-treated condition**. The standard treatment is **Solution Annealing** at a minimum temperature of **1150°C (2100°F)**, followed by rapid cooling (quenching in water or rapid air) to achieve optimal properties. --- **Disclaimer:** This data sheet provides typical information and values. The properties of the final product can be influenced by casting parameters, section size, and heat treatment cycles. For critical design and procurement, the complete and latest version of the **ASTM A351M** specification must be consulted. -:- For detailed product information, please contact sales. -: Cast Stainless Steel HK40, ASTM A351M Specification Dimensions Size： Diameter 20-1000 mm Length <4216 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. -: Cast Stainless Steel HK40, ASTM A351M Properties -:- For detailed product information, please contact sales. -:

Applications of Cast Stainless Steel Rod HK40, ASTM A351M -:- For detailed product information, please contact sales. -: Chemical Identifiers Cast Stainless Steel Rod HK40, ASTM A351M -:- For detailed product information, please contact sales. -:

Packing of Cast Stainless Steel Rod HK40, ASTM A351M -:- 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 Rod 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 687 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