Cast Stainless Steel HK40, UNS J94204

Cast Stainless Steel HK40, UNS J94204 Product Information -:- For detailed product information, please contact sales. -: Cast Stainless Steel HK40, UNS J94204 Synonyms -:- For detailed product information, please contact sales. -:

Cast Stainless Steel HK40, UNS J94204 Product Information -:- For detailed product information, please contact sales. -: ### **Technical Data Sheet: Cast Stainless Steel HK40 (UNS J94204)** **Product Overview** UNS J94204 is the Unified Numbering System designation for the cast stainless steel commonly known as HK40. This high-carbon, austenitic heat-resistant alloy is part of the 25Cr-20Ni family and represents one of the most widely used materials for high-temperature applications. The alloy combines excellent oxidation resistance with outstanding creep and rupture strength, making it particularly suitable for components operating under heavy mechanical loads in extreme temperature environments up to 1150°C (2100°F). --- #### **1. International Standards & Designations** UNS J94204 is recognized across multiple international standards systems: | Standard Organization | Designation | | :--- | :--- | | **UNS (Unified Numbering System)** | **J94204** | | **ACI/SFSA (USA)** | **HK-40** | | **ASTM International** | A297 Grade HK40 | | **ASTM International** | A351/A351M Grade HK40 | | **European Norm (EN)** | 1.4848 | | **German (DIN)** | G-X 40 CrNiSi 25-12 | | **Japanese (JIS)** | SCH 22 | --- #### **2. Chemical Composition (Weight %)** The chemical composition of UNS J94204 is critical to its 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 Features:** - **High Carbon Content**: Provides superior creep strength through solid solution strengthening and carbide formation - **Chromium-Rich**: Ensures exceptional oxidation and carburization resistance - **Nickel-Stabilized Austenite**: Maintains structural stability under thermal cycling --- #### **3. Typical Physical & Mechanical Properties** **Physical Properties:** - **Density**: 7.78 g/cm³ - **Melting Range**: 1350-1400°C (2460-2550°F) - **Thermal Conductivity**: 14.0 W/m·K at 100°C - **Specific Heat**: 500 J/kg·K - **Coefficient of Thermal Expansion**: 16.0 × 10⁻⁶ /K (20-100°C) - **Modulus of Elasticity**: 200 GPa at 20°C **Mechanical Properties (Room Temperature):** - **Tensile Strength**: 620 MPa minimum - **Yield Strength (0.2% Offset)**: 310 MPa minimum - **Elongation**: 10% minimum in 2 inches - **Hardness**: 170-240 HB **High-Temperature Capabilities:** - **Maximum Service Temperature**: 1150°C (2100°F) in oxidizing atmospheres - **Creep Strength**: Excellent long-term load-bearing capacity - **Oxidation Resistance**: Superior performance in direct-fired service - **Thermal Fatigue Resistance**: Good resistance to thermal cycling --- #### **4. Product Applications** UNS J94204 is specified for critical high-temperature components across multiple industries: **Petrochemical Industry:** - Steam methane reformer tubes and headers - Ethylene cracking furnace components - Pressure vessel parts for refinery applications **Heat Processing Equipment:** - Radiant tubes for carburizing and annealing furnaces - Furnace retorts, muffles, and trays - Heat treatment fixtures and baskets **Power Generation:** - Waste-to-energy plant components - Biomass boiler parts - High-temperature valve bodies and fittings **Other Applications:** - Glass manufacturing hardware - Cement plant preheater components - Chemical processing reactor parts --- #### **5. Fabrication Characteristics** **Casting Performance:** - Excellent castability with good fluidity - Suitable for both static and centrifugal casting processes - Minimal tendency for hot tearing **Machining:** - Difficult to machine due to work-hardening tendency - Requires carbide tools and rigid setups - Recommended slow speeds with heavy feeds **Welding:** - Weldable using SMAW, GTAW, and GMAW processes - Matching filler metals (ENiCrFe-3 type) recommended - Post-weld heat treatment at 1150-1200°C essential **Heat Treatment:** - Solution annealing temperature: 1150-1200°C (2100-2200°F) - Rapid cooling (water quench or fast air) required - Stress relieving generally not recommended --- **Technical Notes:** - UNS J94204 demonstrates superior carbon stability compared to lower-grade alloys - The high carbon content provides excellent resistance to sigma phase formation - Proper heat treatment is crucial for maximizing service life - Component design should consider thermal expansion characteristics This data is provided for informational purposes only. For critical applications, consult the relevant ASTM specifications and qualified metallurgical engineering resources. -:- For detailed product information, please contact sales. -: Cast Stainless Steel HK40, UNS J94204 Specification Dimensions Size： Diameter 20-1000 mm Length <4218 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, UNS J94204 Properties -:- For detailed product information, please contact sales. -:

Applications of Cast Stainless Steel HK40, UNS J94204 -:- For detailed product information, please contact sales. -: Chemical Identifiers Cast Stainless Steel HK40, UNS J94204 -:- For detailed product information, please contact sales. -:

Packing of Cast Stainless Steel HK40, UNS J94204 -:- 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 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 689 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