AISI Type H19 Chromium Hot Work Tool Steel Sheet,Plate (UNS T20819)

AISI Type H19 Chromium Hot Work Tool Steel Sheet/Plate (UNS T20819) Product Information -:- For detailed product information, please contact sales. -: AISI Type H19 Chromium Hot Work Tool Steel Sheet/Plate (UNS T20819) Synonyms -:- For detailed product information, please contact sales. -:

AISI Type H19 Chromium Hot Work Tool Steel (UNS T20819) Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AISI Type H19 Chromium Hot Work Tool Steel (UNS T20819)** ## **Overview** **AISI Type H19 (UNS T20819)** is a **premium, high-tungsten, high-cobalt chromium hot work tool steel** engineered for the most demanding high-temperature applications. Characterized by its **exceptional combination of tungsten (for hot hardness), cobalt (for high-temperature strength), and chromium (for oxidation resistance)**, H19 delivers superior performance in extreme thermal environments. This grade represents the pinnacle of traditional hot work steel technology, offering **maximum resistance to thermal softening, excellent creep resistance, and good wear characteristics** at temperatures where conventional hot work steels would rapidly degrade. --- ## **Chemical Composition (Typical Weight %)** H19 features an advanced tungsten-cobalt-chromium composition optimized for extreme temperature service. | Element | Content (%) | Role in Hot Work Performance | | :--- | :--- | :--- | | **Tungsten (W)** | **3.75 - 4.50** | **Primary high-temperature strengthening element.** Forms stable tungsten carbides (WC, W₂C) that provide exceptional red hardness and resist softening at extreme temperatures. | | **Cobalt (Co)** | **4.00 - 4.50** | **Critical high-temperature strengthener.** Enhances hot hardness, improves tempering resistance, strengthens the matrix through solid solution strengthening, and boosts high-temperature fatigue resistance. | | **Chromium (Cr)** | 4.00 - 4.75 | Provides oxidation resistance, moderate hardenability, and contributes to hot strength through chromium carbide formation. | | **Vanadium (V)** | 1.75 - 2.20 | **Elevated vanadium content.** Forms ultra-hard vanadium carbides (VC) for exceptional wear resistance at elevated temperatures and refines grain structure. | | **Carbon (C)** | 0.32 - 0.45 | Balanced to provide adequate hardness while maintaining toughness at extreme temperatures. | | **Molybdenum (Mo)** | **≤ 0.25** | Minimal content; H19 relies on tungsten and cobalt rather than molybdenum for high-temperature properties. | | **Silicon (Si)** | 0.80 - 1.20 | Increases resistance to thermal fatigue and oxidation. | | **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:** H19's **combination of tungsten, cobalt, and elevated vanadium** creates a synergistic effect that provides **unparalleled high-temperature performance** among chromium-based hot work steels. The cobalt addition is particularly significant, as it substantially improves hot hardness without forming carbides, instead strengthening the matrix through solid solution effects. --- ## **Physical & Mechanical Properties** *Properties are for material in the hardened and tempered condition (typical operating hardness 46-50 HRC).* | Property | Typical Value / Description | | :--- | :--- | | **Density** | ~8.05 g/cm³ (Higher than conventional hot work steels due to tungsten and cobalt) | | **Hardness (Annealed)** | 220 - 250 HB | | **Hardness (Hardened & Tempered)** | **44 - 54 HRC** (Typically operated at 48-52 HRC for extreme hot work) | | **Hot Hardness (at 650°C / 1200°F)** | **~40-44 HRC** (Exceptional retention of hardness at extreme temperatures) | | **Tensile Strength** | 1600 - 1900 MPa (at 50 HRC) | | **Yield Strength (0.2%)** | 1400 - 1700 MPa (at 50 HRC) | | **Elongation** | 5 - 9% (at 50 HRC) | | **Impact Toughness (Charpy)** | 8 - 18 J (at 50 HRC) | | **Thermal Fatigue Resistance** | **Good.** Adequate for many applications but may be inferior to H13 in severe thermal cycling due to different carbide structure. | | **Thermal Conductivity** | **~24.5 W/m·K** at 20°C (Lower than molybdenum-based grades) | | **Coefficient of Thermal Expansion** | ~11.8 × 10⁻⁶/°C (20-500°C) | | **Maximum Continuous Service Temperature** | **~650°C (1200°F)** (Among the highest for chromium hot work steels) | | **Creep Resistance** | **Excellent.** Superior resistance to deformation under sustained high-temperature stress. | | **Machinability (Annealed)** | **Poor** (~40% of 1% carbon steel). Difficult due to high alloy content. | | **Grindability** | **Poor to Very Poor.** Hard vanadium carbides increase grinding difficulty. | --- ## **Heat Treatment Guidelines** Precise heat treatment is critical to develop H19's full high-temperature potential. | Process | Parameters | Special Considerations for H19 | | :--- | :--- | :--- | | **Annealing** | Heat to 870-900°C (1600-1650°F), slow furnace cool to 480°C (900°F) at ≤15°C/hr, then air cool. | Results in ~235 HB for machining. | | **Stress Relieving** | 650-675°C (1200-1250°F) for 2 hrs, air cool. | Essential after rough machining due to high alloy content. | | **Preheating** | **Double preheat:** 650°C (1200°F) and 850°C (1560°F). | Critical to prevent thermal shock and cracking. | | **Austenitizing** | **1050-1090°C (1920-1995°F).** Soak: 20-30 min/inch. | **High temperature required** to dissolve tungsten and vanadium carbides; use protective atmosphere. | | **Quenching** | **Oil quench** (preferred) or air quench. | Oil quenching ensures maximum hardness; air quenching suitable for complex shapes. | | **Tempering** | **Double or triple temper at 600-650°C (1110-1200°F)** for 2+ hours each. | **High tempering temperatures required** to develop optimal properties; must temper well above intended service temperature. | --- ## **Product Applications** H19 is specialized for the most demanding high-temperature applications where conventional hot work steels fail. ### **Primary Hot Work Applications:** 1. **High-Temperature Forging Dies:** For forging of superalloys, titanium alloys, and high-temperature steels (650-950°C workpiece temperatures). 2. **Hot Extrusion Tooling:** For extrusion of nickel-based alloys, stainless steels, and other high-temperature materials. 3. **Die Casting Dies for High Melting Point Alloys:** Such as brass, bronze, and copper-based alloys. 4. **Hot Work Tools for Aerospace Components:** For forming high-temperature aerospace alloys. 5. **Isothermal Forging Dies:** Where dies are maintained at high temperatures (500-650°C) during prolonged forging operations. 6. **Hot Piercing Punches and Mandrels:** For piercing high-temperature metals. 7. **Tools for Powder Metallurgy Hot Pressing:** Dies and punches for high-temperature powder compaction. ### **Industry Usage:** - **Aerospace Component Manufacturing** (turbine blades, engine components) - **High-Temperature Alloy Forging** - **Specialty Metal Extrusion** - **Power Generation Equipment Manufacturing** - **Advanced Materials Processing** --- ## **International Standards & Cross-Reference** AISI H19 is a specialized grade with specific international equivalents. | Standard | Designation | Equivalent / Similar Grade | | :--- | :--- | :--- | | **AISI/SAE (USA)** | **H19** | - | | **UNS (USA)** | **T20819** | - | | **ASTM (USA)** | A681 | Grade H19 | | **Europe (EN)** | **~1.2606** | X30WCrV5-3 (Approximate; different composition) | | **Germany (DIN)** | **~1.2606** | X30WCrV5-3 | | **Japan (JIS)** | **Not standard** | - | | **ISO** | **~35WCrV5** | - | | **UK (BS)** | **BH19** | - | **Important Note:** True chemical equivalents to AISI H19 are uncommon in international standards due to its specific cobalt-tungsten-vanadium balance. The European DIN 1.2606 has different alloy levels but represents a similar high-performance hot work steel concept. H19 remains primarily an AISI standard grade. --- ## **Technical Comparison: H19 vs. Other High-Temperature Hot Work Steels** | Property | **H19 (UNS T20819)** | **H13 (UNS T20813)** | **H21 (UNS T20821)** | | :--- | :--- | :--- | :--- | | **Cobalt Content** | **4.00-4.50%** | 0% | 0% | | **Tungsten Content** | 3.75-4.50% | 0% | **8.00-10.00%** | | **Vanadium Content** | **1.75-2.20%** | 0.80-1.20% | 0.30-0.60% | | **Hot Hardness (at 650°C)** | **40-44 HRC** | 30-32 HRC | **42-46 HRC** | | **Toughness (at 48 HRC)** | 8-18 J | **25-40 J** | 10-20 J | | **Creep Resistance** | **Excellent** | Good | Very Good | | **Maximum Service Temperature** | **~650°C (1200°F)** | ~540°C (1000°F) | **~650°C (1200°F)** | | **Relative Cost** | **Highest** | Moderate | High | | **Primary Application** | **Extreme temp forging** | **General-purpose** | **High-temp forging** | --- ## **Advantages & Considerations** ### **Advantages:** 1. **Exceptional Hot Hardness:** Superior resistance to softening at extreme temperatures (up to 650°C continuous). 2. **Excellent Creep Resistance:** Maintains dimensional stability under sustained high-temperature stress. 3. **Good High-Temperature Wear Resistance:** Elevated vanadium content provides excellent abrasion resistance at temperature. 4. **Superior High-Temperature Fatigue Strength:** Cobalt addition improves resistance to thermal and mechanical fatigue at high temperatures. 5. **Good Oxidation Resistance:** Chromium content provides protection against high-temperature oxidation. ### **Considerations:** 1. **High Cost:** Tungsten, cobalt, and vanadium are expensive alloying elements. 2. **Low Toughness:** Limited impact resistance at room temperature; requires careful handling and design. 3. **Complex Heat Treatment:** Requires precise control of high-temperature processing. 4. **Poor Machinability & Grindability:** Difficult and expensive to fabricate. 5. **Limited Availability:** Specialized grade with limited stock and long lead times. 6. **Specific Application Focus:** Over-engineered for most applications; only justified for extreme conditions. --- ## **Metallurgical Characteristics** ### **Cobalt Strengthening Mechanisms:** 1. **Solid Solution Strengthening:** Cobalt atoms in the matrix impede dislocation movement at high temperatures. 2. **Matrix Stabilization:** Increases the stability of tempered martensite at elevated temperatures. 3. **Carbide Modification:** Influences the precipitation and distribution of alloy carbides during tempering. 4. **Recovery Resistance:** Retards the recovery and recrystallization processes that lead to softening. ### **Microstructural Stability:** H19's combination of tungsten, cobalt, and vanadium creates an exceptionally stable microstructure at high temperatures: - **Carbide Coarsening Resistance:** Tungsten and vanadium carbides resist growth during prolonged high-temperature exposure. - **Matrix Stability:** Cobalt stabilizes the tempered martensite matrix against recovery processes. - **Grain Boundary Strengthening:** Alloying elements segregate to grain boundaries, improving high-temperature properties. --- ## **Special Processing & Fabrication** ### **Forging and Hot Working:** - **Forging Temperature:** 1100-1150°C (2010-2100°F) - **Finishing Temperature:** ≥950°C (1740°F) - **Cooling:** Very slow cooling after forging (furnace cool or bury in insulating material) ### **Heat Treatment Optimization:** 1. **For maximum hot hardness:** Austenitize at 1080°C, oil quench, triple temper at 620-640°C 2. **For better toughness:** Austenitize at 1060°C, air quench, double temper at 600-620°C 3. **For complex shapes:** Use vacuum or high-pressure gas quenching ### **Surface Treatments:** - **Nitriding:** Highly effective for improving surface hardness and wear resistance - **PVD Coatings:** TiAlN, AlCrN, or CrN coatings can enhance performance in specific applications - **Oxidation Treatments:** Can improve high-temperature oxidation resistance --- ## **Economic & Selection Considerations** ### **Cost-Benefit Analysis:** H19 should only be considered when: 1. Operating temperatures exceed 600°C continuously 2. Conventional hot work steels (H13, H21) fail prematurely due to thermal softening 3. Tool life improvement justifies the 3-5x higher material cost 4. Production volumes or component values warrant premium tooling 5. Tool failure would cause significant downtime or safety concerns ### **Life Cycle Costing:** While H19 has higher initial costs, its extended tool life in appropriate applications can result in lower cost per part produced, especially in high-volume or high-value manufacturing. --- ## **Modern Alternatives & Comparisons** While H19 remains a viable option, modern alternatives include: 1. **Premium ESR/VAR H13:** For applications up to 550°C 2. **H10A/H10B:** Modified grades with enhanced properties 3. **Nickel-based superalloys:** For extreme temperatures (>700°C) 4. **Ceramic or cermet tooling:** For specific high-temperature applications --- ## **Conclusion** **AISI Type H19 Chromium Hot Work Tool Steel (UNS T20819)** represents the **apex of traditional chromium-based hot work steel technology**, engineered to withstand the most extreme thermal environments encountered in metal forming operations. Its **advanced tungsten-cobalt-vanadium alloy system** provides **unparalleled hot hardness, creep resistance, and high-temperature stability** among standard hot work steels, making it the material of choice for applications involving sustained exposure to temperatures up to 650°C. While its **high cost, fabrication challenges, and limited toughness** restrict its use to specialized applications, H19 delivers **exceptional performance where conventional hot work steels fail**. For tooling engineers working with **superalloys, high-temperature aerospace materials, or other extreme thermal applications**, H19 provides a **proven, high-performance solution** that bridges the gap between conventional tool steels and exotic high-temperature materials. In an era of increasingly demanding manufacturing requirements, H19 continues to serve critical roles in aerospace, power generation, and advanced materials processing industries, demonstrating that well-designed traditional alloy systems remain relevant for the most challenging high-temperature applications. Its continued use in specialized applications underscores the enduring value of targeted alloy development for extreme service conditions. -:- For detailed product information, please contact sales. -: AISI Type H19 Chromium Hot Work Tool Steel (UNS T20819) Specification Dimensions Size： Diameter 20-1000 mm Length <6692 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 H19 Chromium Hot Work Tool Steel (UNS T20819) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Type H19 Chromium Hot Work Tool Steel Sheet,Plate (UNS T20819) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Type H19 Chromium Hot Work Tool Steel Sheet,Plate (UNS T20819) -:- For detailed product information, please contact sales. -:

Packing of AISI Type H19 Chromium Hot Work Tool Steel Sheet/Plate (UNS T20819) -:- 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 3163 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