AISI Type H24 Tungsten Hot Work Tool Steel (UNS T20824)

AISI Type H24 Tungsten Hot Work Tool Steel (UNS T20824) Product Information -:- For detailed product information, please contact sales. -: AISI Type H24 Tungsten Hot Work Tool Steel (UNS T20824) Synonyms -:- For detailed product information, please contact sales. -:

AISI Type H24 Tungsten Hot Work Tool Steel (UNS T20824) Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AISI Type H24 Tungsten Hot Work Tool Steel (UNS T20824)** ## **Overview** **AISI Type H24 (UNS T20824)** is a **high-tungsten, high-cobalt hot work tool steel** representing a specialized evolution within the tungsten series of hot work steels. Characterized by its **significant tungsten content combined with substantial cobalt addition**, H24 is engineered to provide **exceptional hot hardness, superior high-temperature strength, and enhanced tempering resistance**. As a cobalt-enhanced tungsten hot work steel, H24 delivers improved performance at extreme temperatures where conventional tungsten grades may show limitations, particularly in applications involving high stress and thermal fatigue. --- ## **Chemical Composition (Typical Weight %)** H24 features an advanced tungsten-cobalt composition optimized for extreme temperature performance. | Element | Content (%) | Role in Hot Work Performance | | :--- | :--- | :--- | | **Tungsten (W)** | **14.00 - 16.00** | **Extremely high tungsten content.** Forms a dense network of stable tungsten carbides (WC, W₂C) providing exceptional red hardness and resistance to thermal softening at the highest operating temperatures. | | **Cobalt (Co)** | **4.00 - 5.00** | **Significant cobalt addition.** Enhances hot hardness through solid solution strengthening, improves tempering resistance, increases high-temperature fatigue strength, and boosts overall matrix strength. | | **Chromium (Cr)** | 3.00 - 4.00 | Provides oxidation resistance and contributes to hardenability; balanced to optimize tungsten-cobalt effects. | | **Vanadium (V)** | **0.40 - 0.60** | Forms vanadium carbides that refine grain size and improve elevated-temperature wear resistance. | | **Carbon (C)** | **0.20 - 0.30** | Relatively low carbon content to maintain toughness at extreme temperatures while allowing adequate carbide formation. | | **Molybdenum (Mo)** | **≤ 0.25** | Minimal content; H24 relies on tungsten and cobalt rather than molybdenum. | | **Silicon (Si)** | 0.15 - 0.40 | Improves oxidation resistance. | | **Manganese (Mn)** | 0.20 - 0.50 | Aids hardenability and deoxidization. | | **Sulfur (S)** | ≤ 0.03 | - | | **Phosphorus (P)** | ≤ 0.03 | - | | **Iron (Fe)** | **Balance** | Base metal. | **Key Distinction:** H24's **combination of extreme tungsten content (14-16%) with substantial cobalt addition (4-5%)** creates a unique material that prioritizes maximum hot hardness and high-temperature strength through both carbide strengthening (tungsten) and matrix strengthening (cobalt). This differentiates it from other tungsten hot work steels like H21-H23, which have lower tungsten and no cobalt. --- ## **Physical & Mechanical Properties** *Properties are for material in the hardened and tempered condition.* | Property | Typical Value / Description | | :--- | :--- | | **Density** | ~8.55 g/cm³ (Highest among standard hot work steels due to extreme tungsten and cobalt) | | **Hardness (Annealed)** | 225 - 255 HB | | **Hardness (Hardened & Tempered)** | **44 - 54 HRC** (Typically operated at 48-52 HRC for extreme applications) | | **Hot Hardness (at 700°C / 1290°F)** | **~42-46 HRC** (Exceptional retention at extreme temperatures) | | **Tensile Strength** | 1650 - 2000 MPa (at 50 HRC) | | **Yield Strength (0.2%)** | 1450 - 1800 MPa (at 50 HRC) | | **Elongation** | 3 - 7% (at 50 HRC) | | **Impact Toughness (Charpy)** | **6 - 12 J** (at 50 HRC; very low due to high carbide volume) | | **Thermal Fatigue Resistance** | **Fair to Good.** Cobalt addition improves thermal fatigue resistance compared to non-cobalt tungsten steels. | | **Thermal Conductivity** | **~23.0 W/m·K** at 20°C (Low due to high alloy content) | | **Coefficient of Thermal Expansion** | ~11.4 × 10⁻⁶/°C (20-500°C) | | **Maximum Continuous Service Temperature** | **~720°C (1330°F)** (Among the highest for standard hot work steels) | | **Specific Heat Capacity** | 460 J/kg·K | | **Machinability (Annealed)** | **Very Poor** (~30% of 1% carbon steel). Extremely difficult due to high alloy content. | | **Grindability** | **Very Poor to Extremely Poor.** | --- ## **Heat Treatment Guidelines** Extreme precision in heat treatment is required for H24 due to its sensitive composition. | Process | Parameters | Critical Considerations for H24 | | :--- | :--- | :--- | | **Annealing** | Heat to 870-900°C (1600-1650°F), slow furnace cool to 480°C (900°F) at ≤10°C/hr, then air cool. | Results in ~240 HB; essential for any machining. | | **Stress Relieving** | 650-700°C (1200-1290°F) for 2-4 hrs, slow cool. | Mandatory after machining. | | **Preheating** | **Triple preheat:** 400°C (750°F), 650°C (1200°F), and 850°C (1560°F). | Essential to prevent thermal shock. | | **Austenitizing** | **1180-1220°C (2155-2230°F).** Soak: 20-40 min/inch. | **Extreme temperature required;** must use vacuum or protective atmosphere. | | **Quenching** | **Oil quench** (40-60°C oil with vigorous agitation) or **high-pressure gas quench.** | Air quenching may be insufficient for full hardness in thick sections. | | **Tempering** | **Triple temper at 630-690°C (1165-1275°F)** for 2+ hours each. Cryogenic treatment recommended between tempers. | High temperatures required to develop optimal secondary hardening. | --- ## **Product Applications** H24 is reserved for the most extreme high-temperature, high-stress applications. ### **Primary Hot Work Applications:** #### **1. Extreme Temperature Forging:** - **Dies for superalloy forging** at 750-1000°C (Inconel, Hastelloy, Waspaloy) - **Hot die forging tools** for refractory metals - **Isothermal forging dies** maintained at 700-800°C - **Precision forging dies** for aerospace turbine components #### **2. High-Temperature Extrusion:** - **Extrusion dies for nickel-based superalloys** - **Mandrels for high-temperature alloy extrusion** - **Tools for glass extrusion** at extreme temperatures #### **3. Specialty High-Temperature Applications:** - **Hot isostatic pressing (HIP) tooling** - **Die casting tools for high-melting-point alloys** - **Tools for powder metallurgy** at extreme temperatures - **Hot work tools for advanced composites** ### **Specific Industry Usage:** - **Aerospace** (jet engine components, rocket propulsion systems) - **Power Generation** (gas and steam turbine components) - **Advanced Materials Research** - **Nuclear Industry** (high-temperature tooling) - **Specialty Metal Processing** --- ## **International Standards & Cross-Reference** H24 is a highly specialized grade with limited international equivalents. | Standard | Designation | Equivalent / Similar Grade | | :--- | :--- | :--- | | **AISI/SAE (USA)** | **H24** | - | | **UNS (USA)** | **T20824** | - | | **ASTM (USA)** | A681 | Grade H24 | | **Europe (EN)** | **No direct equivalent** | - | | **Germany (DIN)** | **~1.2885** (Approximate) | - | | **Japan (JIS)** | **Not standard** | - | | **ISO** | **No direct equivalent** | - | | **UK (BS)** | **Not standard** | - | **Important Note:** AISI H24 is a **rare and highly specialized grade** with **no direct equivalents** in major international standards. Its extreme tungsten-cobalt composition makes it unique, and it is primarily specified within the AISI/SAE system for specific high-performance applications. --- ## **Technical Comparison: H24 vs. Other Extreme Hot Work Steels** | Property | **H24 (UNS T20824)** | **H23 (UNS T20823)** | **H21 (UNS T20821)** | | :--- | :--- | :--- | :--- | | **Tungsten Content** | **14.00-16.00%** | 11.00-12.75% | 8.00-10.00% | | **Cobalt Content** | **4.00-5.00%** | 0% | 0% | | **Chromium Content** | 3.00-4.00% | **11.00-12.75%** | 3.00-3.75% | | **Hot Hardness (at 700°C)** | **~42-46 HRC** | ~40-44 HRC | ~36-38 HRC | | **Maximum Service Temp** | **~720°C (1330°F)** | ~700°C (1290°F) | ~650°C (1200°F) | | **Toughness (at 50 HRC)** | 6-12 J | 8-15 J | **15-25 J** | | **Oxidation Resistance** | Fair | **Excellent** | Fair | | **Relative Cost** | **Highest** | Very High | High | | **Primary Strength** | **Max Hot Hardness** | **High Temp + Oxidation** | Balanced Performance | --- ## **Advantages & Considerations** ### **Advantages:** 1. **Maximum Hot Hardness:** Unparalleled resistance to softening at extreme temperatures. 2. **Superior High-Temperature Strength:** Cobalt addition provides exceptional matrix strength at high temperatures. 3. **Enhanced Tempering Resistance:** Maintains hardness better during prolonged high-temperature exposure. 4. **Good High-Temperature Fatigue Resistance:** Suitable for cyclic high-temperature applications. 5. **Optimal for Specific Extreme Conditions:** Where maximum hot hardness is the primary requirement. ### **Considerations:** 1. **Extremely Low Toughness:** Very brittle at all temperatures. 2. **Extremely Complex Heat Treatment:** Requires precise control of extreme processing temperatures. 3. **Very High Cost:** Among the most expensive tool steels due to high tungsten and cobalt content. 4. **Poor Thermal Conductivity:** Leads to severe thermal gradients and stress. 5. **Extremely Poor Machinability:** Among the most difficult steels to fabricate. 6. **Very Limited Availability:** Special order only with long lead times. 7. **Niche Application Focus:** Only justifiable for specific extreme applications. --- ## **Conclusion** **AISI Type H24 Tungsten Hot Work Tool Steel (UNS T20824)** represents a **highly specialized, cobalt-enhanced tungsten hot work steel** designed for the most extreme high-temperature applications where maximum hot hardness is paramount. Its **extreme tungsten content combined with significant cobalt addition** creates a material with **exceptional high-temperature capabilities**, albeit at the cost of toughness, fabricability, and economics. While its **practical applications are extremely limited** due to its demanding characteristics, H24 serves as a **specialized solution for specific extreme thermal challenges** in advanced industries such as aerospace and power generation. It exemplifies how targeted alloy development can push the boundaries of high-temperature performance, even as it highlights the trade-offs inherent in such extreme material design. For the few applications where its unique properties are essential and justifiable, H24 remains a testament to the capabilities of advanced metallurgical engineering in addressing the most demanding thermal challenges in modern manufacturing. -:- For detailed product information, please contact sales. -: AISI Type H24 Tungsten Hot Work Tool Steel (UNS T20824) Specification Dimensions Size： Diameter 20-1000 mm Length <6697 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. -: AISI Type H24 Tungsten Hot Work Tool Steel (UNS T20824) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Type H24 Tungsten Hot Work Tool Steel (UNS T20824) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Type H24 Tungsten Hot Work Tool Steel (UNS T20824) -:- For detailed product information, please contact sales. -:

Packing of AISI Type H24 Tungsten Hot Work Tool Steel (UNS T20824) -:- 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 3168 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