AISI Type H23 Tungsten Hot Work Tool Steel Sheet,Plate (UNS T20823)

AISI Type H23 Tungsten Hot Work Tool Steel Sheet/Plate (UNS T20823) Product Information -:- For detailed product information, please contact sales. -: AISI Type H23 Tungsten Hot Work Tool Steel Sheet/Plate (UNS T20823) Synonyms -:- For detailed product information, please contact sales. -:

AISI Type H23 Tungsten Hot Work Tool Steel (UNS T20823) Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AISI Type H23 Tungsten Hot Work Tool Steel (UNS T20823)** ## **Overview** **AISI Type H23 (UNS T20823)** is a **high-tungsten, high-chromium hot work tool steel** that represents the pinnacle of the conventional tungsten-based hot work steel series. Characterized by its **exceptionally high tungsten content combined with elevated chromium levels**, H23 is engineered to deliver **unparalleled hot hardness, superior oxidation resistance, and excellent high-temperature stability**. As the most advanced standard tungsten hot work steel, H23 is designed for the most extreme thermal applications where both extreme temperature resistance and oxidation protection are critical requirements. --- ## **Chemical Composition (Typical Weight %)** H23 features an extreme tungsten-chromium composition optimized for maximum high-temperature performance. | Element | Content (%) | Role in Hot Work Performance | | :--- | :--- | :--- | | **Tungsten (W)** | **11.00 - 12.75** | **Maximum tungsten content in standard H-series.** Forms an extensive network of stable tungsten carbides (WC, W₂C) providing exceptional red hardness and resistance to thermal softening at extreme temperatures. | | **Chromium (Cr)** | **11.00 - 12.75** | **Exceptionally high chromium content.** Provides superior oxidation resistance, enhances hardenability, and contributes to hot strength through chromium carbide formation. Creates a unique high-tungsten, high-chromium synergy. | | **Vanadium (V)** | **0.75 - 1.25** | **Elevated vanadium content.** Forms ultra-hard vanadium carbides (VC) for exceptional wear resistance at elevated temperatures and significantly refines grain structure. | | **Carbon (C)** | **0.25 - 0.35** | Carefully balanced to maintain toughness at extreme temperatures while providing adequate matrix hardness. | | **Cobalt (Co)** | **≤ 0.50** (optional) | Occasionally added to enhance hot hardness and tempering resistance in premium grades. | | **Silicon (Si)** | 0.15 - 0.40 | Improves oxidation resistance and thermal fatigue properties. | | **Manganese (Mn)** | 0.20 - 0.50 | Aids hardenability and deoxidization. | | **Molybdenum (Mo)** | **≤ 0.25** | Minimal content; H23 relies exclusively on tungsten for high-temperature strength. | | **Sulfur (S)** | ≤ 0.03 | - | | **Phosphorus (P)** | ≤ 0.03 | - | | **Iron (Fe)** | **Balance** | Base metal. | **Key Distinction:** H23's **dual-high composition (11-12.75% W and 11-12.75% Cr)** creates a unique material that combines the **extreme hot hardness of tungsten steels with the oxidation resistance of high-chromium steels**. This makes H23 fundamentally different from other tungsten hot work steels like H21 or H22, which have much lower chromium contents. --- ## **Physical & Mechanical Properties** *Properties are for material in the hardened and tempered condition.* | Property | Typical Value / Description | | :--- | :--- | | **Density** | ~8.40 g/cm³ (Highest among standard hot work steels due to extreme tungsten content) | | **Hardness (Annealed)** | 220 - 250 HB | | **Hardness (Hardened & Tempered)** | **44 - 54 HRC** (Typically operated at 48-52 HRC for extreme applications) | | **Hot Hardness (at 700°C / 1290°F)** | **~40-44 HRC** (Exceptional retention at extreme temperatures) | | **Tensile Strength** | 1600 - 1950 MPa (at 50 HRC) | | **Yield Strength (0.2%)** | 1400 - 1750 MPa (at 50 HRC) | | **Elongation** | 4 - 8% (at 50 HRC) | | **Impact Toughness (Charpy)** | **8 - 15 J** (at 50 HRC; lowest among standard hot work steels) | | **Thermal Fatigue Resistance** | **Good.** Surprisingly good for a tungsten steel due to high chromium content and refined microstructure. | | **Oxidation Resistance** | **Excellent.** Comparable to stainless steels at high temperatures due to high chromium content. | | **Thermal Conductivity** | **~22.5 W/m·K** at 20°C (Lowest among hot work steels) | | **Coefficient of Thermal Expansion** | ~11.5 × 10⁻⁶/°C (20-500°C) | | **Maximum Continuous Service Temperature** | **~700°C (1290°F)** (Highest among standard AISI hot work steels) | | **Specific Heat Capacity** | 460 J/kg·K | | **Machinability (Annealed)** | **Poor** (~35% of 1% carbon steel). Very difficult due to extreme alloy content. | | **Grindability** | **Very Poor.** Extremely challenging due to high volume of hard carbides. | --- ## **Heat Treatment Guidelines** Extreme precision in heat treatment is required to realize H23's full potential. | Process | Parameters | Critical Considerations for H23 | | :--- | :--- | :--- | | **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 ~235 HB; full spheroidization is essential. | | **Stress Relieving** | 650-700°C (1200-1290°F) for 2-4 hrs, slow cool. | Mandatory after any significant machining. | | **Preheating** | **Triple preheat:** 400°C (750°F), 650°C (1200°F), and 850°C (1560°F). | Essential to prevent thermal shock and cracking. | | **Austenitizing** | **1150-1200°C (2100-2190°F).** Soak: 20-40 min/inch. | **Extreme temperature required;** must use vacuum or protective atmosphere to prevent catastrophic decarburization. | | **Quenching** | **Oil quench** (40-60°C oil with vigorous agitation) or **air quench** for complex shapes. | High-pressure gas quenching recommended for optimal results. | | **Tempering** | **Triple temper at 620-680°C (1150-1255°F)** for 2+ hours each. Cryogenic treatment (-80°C) between tempers is beneficial. | **Must temper immediately** after reaching room temperature; high temperatures develop peak secondary hardening. | --- ## **Product Applications** H23 is reserved for the most extreme high-temperature applications where no other standard hot work steel can survive. ### **Primary Hot Work Applications:** #### **1. Extreme Temperature Forging:** - **Dies for superalloy forging** (Inconel 718, Waspaloy, Rene alloys) at 700-950°C - **Isothermal forging dies** maintained at 650-750°C - **Hot die forging tools** for titanium alloys (Ti-6Al-4V) - **Precision forging dies** for aerospace components #### **2. High-Temperature Extrusion:** - **Extrusion dies for nickel-based superalloys** - **Mandrels and liners** for high-temperature alloy extrusion - **Tools for glass extrusion** at extreme temperatures #### **3. Specialty High-Temperature Applications:** - **Hot isostatic pressing (HIP) tooling** - **Die casting dies for copper and copper-beryllium alloys** - **Tools for powder metallurgy** at extreme temperatures - **Glass molding and forming tools** requiring maximum temperature resistance - **Hot work tools for refractory metals** (molybdenum, tungsten) ### **Specific Industry Usage:** - **Aerospace & Defense** (jet engine components, rocket parts) - **Power Generation** (gas turbine components, high-temperature valves) - **Advanced Materials Research & Development** - **Specialty Metal Processing** (superalloy, refractory metal processing) - **Nuclear Industry** (high-temperature tooling) --- ## **International Standards & Cross-Reference** H23 is a highly specialized grade with specific international recognition. | Standard | Designation | Equivalent / Similar Grade | | :--- | :--- | :--- | | **AISI/SAE (USA)** | **H23** | - | | **UNS (USA)** | **T20823** | - | | **ASTM (USA)** | A681 | Grade H23 | | **Europe (EN)** | **~1.2606** | X32CrMoCoV3-3-3 (Approximate; different composition) | | **Germany (DIN)** | **~1.2606** | X32CrMoCoV3-3-3 | | **Japan (JIS)** | **Not standard** | - | | **ISO** | **~35WCr12** | - | | **UK (BS)** | **BH23** | - | | **China (GB)** | **4Cr3Mo3W4V** (Similar concept) | - | **Important Note:** True chemical equivalents to AISI H23 are exceptionally rare in international standards due to its unique high-tungsten, high-chromium composition. Most "equivalents" are actually similar-concept grades with different alloy balances. H23 remains a specialized AISI grade with limited global standardization. --- ## **Technical Comparison: H23 vs. Other Extreme Hot Work Steels** | Property | **H23 (UNS T20823)** | **H21 (UNS T20821)** | **H13 (UNS T20813)** | | :--- | :--- | :--- | :--- | | **Tungsten Content** | **11.00-12.75%** | 8.00-10.00% | 0% | | **Chromium Content** | **11.00-12.75%** | 3.00-3.75% | 4.75-5.50% | | **Hot Hardness (at 700°C)** | **~40-44 HRC** | ~36-38 HRC | ~28-30 HRC | | **Maximum Service Temp** | **~700°C (1290°F)** | ~650°C (1200°F) | ~540°C (1000°F) | | **Oxidation Resistance** | **Excellent** | Fair | Very Good | | **Toughness (at 50 HRC)** | 8-15 J | **15-25 J** | **20-35 J** | | **Thermal Conductivity** | ~22.5 W/m·K | ~24.0 W/m·K | **~28.0 W/m·K** | | **Relative Cost** | **Highest** | High | Moderate | | **Primary Application** | **Extreme temp + oxidation** | **High-temp forging** | **General-purpose** | --- ## **Advantages & Considerations** ### **Advantages:** 1. **Maximum Hot Hardness:** Unparalleled resistance to softening at temperatures up to 700°C. 2. **Superior Oxidation Resistance:** Excellent protection against high-temperature oxidation due to high chromium content. 3. **Exceptional High-Temperature Stability:** Maintains properties during prolonged exposure to extreme temperatures. 4. **Good Wear Resistance at Extreme Temperatures:** High vanadium content provides excellent abrasion resistance. 5. **Unique Alloy Synergy:** The tungsten-chromium combination provides properties unattainable with either element alone. ### **Considerations:** 1. **Very Low Toughness:** Extremely brittle at room temperature; requires meticulous handling and design. 2. **Extremely Complex Heat Treatment:** Demands precise control of extreme processing temperatures. 3. **Very High Cost:** Among the most expensive standard tool steels due to high tungsten and chromium content. 4. **Poor Thermal Conductivity:** Lowest among hot work steels, leading to severe thermal gradients. 5. **Extremely Poor Machinability:** Among the most difficult steels to machine and grind. 6. **Limited Availability:** Very specialized with long lead times and minimal stock. 7. **Specific Application Focus:** Only justifiable for the most extreme applications. --- ## **Metallurgical Characteristics** ### **Dual-High Alloy System:** 1. **Tungsten-Chromium Synergy:** Creates a complex carbide system with both W-rich and Cr-rich carbides. 2. **Microstructural Stability:** Exceptional resistance to carbide coarsening and matrix recovery at high temperatures. 3. **Oxidation Mechanism:** Forms a protective Cr₂O₃ scale at high temperatures, unlike other tungsten steels. ### **Unique Microstructure:** - **Complex Carbide Network:** Multiple carbide types (WC, W₂C, Cr₇C₃, Cr₂₃C₆, VC) in a refined distribution. - **Matrix Composition:** High alloy content in solid solution provides exceptional high-temperature strength. - **Grain Structure:** Extremely fine grain size due to vanadium's grain-refining effects. --- ## **Special Processing & Fabrication** ### **Forging (Extreme Care Required):** - **Start Forging:** 1150-1200°C (2100-2190°F) - **Finish Forging:** ≥1050°C (1920°F) - **Cooling:** Very slow furnace cool (≤15°C/hour) with isothermal holds ### **Machining (Extremely Difficult):** - **CBN or PCD tools mandatory** - **Very conservative parameters:** Low speeds, moderate feeds - **High-pressure coolant** with proper filtration - **Frequent tool changes** due to extreme abrasiveness ### **Grinding (Specialized Equipment Required):** - **Diamond wheels essential** - **Very light infeeds** (≤0.010 mm/pass) - **Copious coolant** with precise temperature control - **Frequent dressing** to maintain wheel sharpness --- ## **Surface Treatments & Enhancement** ### **Essential Treatments:** 1. **Pre-oxidation:** Intentional oxidation to form protective scale before service. 2. **Aluminizing or Chromizing:** Diffusion coatings for enhanced oxidation resistance. 3. **Thermal Barrier Coatings:** For applications above 750°C. 4. **Specialized PVD Coatings:** Multilayer coatings for specific applications. ### **Treatment Benefits:** - **Extended tool life** in oxidizing environments - **Reduced soldering and galling** - **Improved thermal insulation** in extreme applications - **Enhanced performance** beyond base material limits --- ## **Economic & Selection Considerations** ### **When H23 is Justified:** 1. Operating temperatures consistently exceed 650°C 2. Oxidation is a significant failure mode with other materials 3. Tool failure causes catastrophic production losses 4. No alternative material provides adequate service life 5. Budget supports premium tooling costs ### **Cost-Benefit Analysis:** - **Initial Cost:** 3-5× higher than H13 - **Processing Cost:** 2-3× higher than conventional hot work steels - **Potential Tool Life:** 5-10× longer than H13 in appropriate applications - **ROI:** Positive only in very specific, high-value applications --- ## **Modern Alternatives & Complements** ### **Competing Technologies:** 1. **Nickel-based Superalloys:** For temperatures above 750°C 2. **Molybdenum Alloys (TZM):** For high-temperature strength and conductivity 3. **Ceramic Tooling:** For specific extreme temperature applications 4. **Advanced Coating Systems:** On less expensive substrates 5. **Powder Metallurgy Tool Steels:** For improved toughness at high hardness ### **H23's Niche:** Despite alternatives, H23 maintains relevance for: - **Applications requiring both extreme temperature and oxidation resistance** - **Legacy systems** where redesign is impractical - **Specific processes** where its unique properties are irreplaceable - **Research applications** requiring known, characterized materials --- ## **Maintenance & Life Extension** ### **Critical Practices:** 1. **Gradual Preheating:** Heat to 400-500°C over several hours 2. **Temperature Uniformity:** Ensure even heating before service 3. **Regular Thermal Cycling Management:** Control heating and cooling rates 4. **Surface Condition Monitoring:** Regular inspection for oxidation and damage 5. **Preventive Re-conditioning:** Surface refurbishment before catastrophic failure ### **Failure Prevention:** - **Avoid thermal shock** at all costs - **Prevent localized overheating** - **Maintain surface integrity** - **Control operating environment** (atmosphere, contaminants) --- ## **Future Outlook & Evolution** While H23 represents a historical peak in traditional hot work steel development, its future involves: 1. **Premium Processing:** ESR, VAR, and powder metallurgy versions 2. **Micro-alloying Enhancements:** Trace element additions for property improvements 3. **Hybrid Systems:** H23 bases with advanced coating technologies 4. **Digital Integration:** Sensor-equipped tools for condition monitoring 5. **Sustainable Alternatives:** Development of reduced-critical-element versions --- ## **Conclusion** **AISI Type H23 Tungsten Hot Work Tool Steel (UNS T20823)** represents the **absolute zenith of traditional tungsten-based hot work steel technology**, offering a **unique combination of extreme hot hardness and exceptional oxidation resistance** through its unprecedented high-tungsten, high-chromium composition. As the **most capable standard hot work steel for extreme temperature applications**, H23 delivers **unmatched performance in environments where both thermal softening and oxidation would rapidly destroy conventional tool steels**. While its **extreme brittleness, formidable processing challenges, and prohibitive costs** restrict its use to highly specialized applications, H23 provides **indispensable value in specific niches** involving superalloy processing, extreme temperature forming, and oxidizing high-temperature environments. For engineers facing **thermal challenges beyond the capabilities of H13, H21, or even nickel-based alloys**, H23 offers a **proven, if demanding, solution** that has served critical industries for decades. In an era of increasing thermal demands and advanced materials processing, H23 continues to demonstrate that **carefully balanced extreme alloying** can create materials capable of withstanding conditions that approach the fundamental limits of ferrous metallurgy. It stands as both a **testament to traditional metallurgical excellence** and a **benchmark against which modern alternatives must be measured**, maintaining its status as the ultimate conventional hot work steel for the most extreme thermal applications. -:- For detailed product information, please contact sales. -: AISI Type H23 Tungsten Hot Work Tool Steel (UNS T20823) Specification Dimensions Size： Diameter 20-1000 mm Length <6696 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 H23 Tungsten Hot Work Tool Steel (UNS T20823) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Type H23 Tungsten Hot Work Tool Steel Sheet,Plate (UNS T20823) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Type H23 Tungsten Hot Work Tool Steel Sheet,Plate (UNS T20823) -:- For detailed product information, please contact sales. -:

Packing of AISI Type H23 Tungsten Hot Work Tool Steel Sheet/Plate (UNS T20823) -:- 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 Sheet/Plate 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 3167 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