AISI Type H26 Tungsten Hot Work Tool Steel Flange (UNS T20826)

1,We Manufacturing processes are primarily classified into four types: 1:Forging, 2:Casting, 3:Cutting, 4:Rolling. 2,We can manufacture in accordance with these standards. Standards: GB Series (Chinese Standards), JB Series (Machinery Standards), HG Series (Chemical Industry Standards), ASME B16.5 (American Standards), BS4504 (British Standards), DIN (German Standards), and JIS (Japanese Standards). Internationally, there are two primary systems of pipe flange standards: the European system, represented by the German DIN standards (including those of the former Soviet Union), and the American system, represented by the US ANSI pipe flange standards. Other common standards include: the Chinese Ministry of Machinery Industry standards (JB series), the Ministry of Chemical Industry standards (HG series), the Chinese National Standard *GB/T 9112–9124-2010 Steel Pipe Flanges*, as well as US standards (ASME B16.5), British standards (BS4504), German standards (DIN), Japanese standards (JIS), and marine standards (CBM), among others. The nominal pressure ratings for the PN series are designated by "PN" and comprise the following nine levels: PN2.5, PN6, PN10, PN16, PN25, PN40, PN63, PN100, and PN160. The nominal pressure ratings for the Class series are designated by "Class" and comprise the following six levels: Class150, Class300, Class600, Class900, Class1500, and Class2500. Flange Classification 1. **According to Chemical Industry Standards:** Flanges are classified as follows: Plate Flat Welding Flange (PL), Necked Flat Welding Flange (SO), Necked Butt Welding Flange (WN), Integral Flange (IF), Socket Welding Flange (SW), Threaded Flange (Th), Butt Welding Ring Loose Flange (PJ/SE), Blind Flange (BL), Flat Welding Ring Loose Flange (PJ/PJ), and Lined Blind Flange (BL(s)). 2. **According to Petrochemical (SH) Industry Standards:** Flanges are classified as follows: Threaded Flange (PL), Butt Welding Flange (WN), Flat Welding Flange (SO), Socket Welding Flange (SW), Loose Flange (LJ), and Blind Flange (no specific designation). 3. **According to Machinery (JB) Industry Standards:** Flanges are classified as follows: Integral Flange, Butt Welding Flange, Plate Flat Welding Flange, Butt Welding Ring Plate Loose Flange, Flat Welding Ring Plate Loose Flange, Lap Joint Ring Plate Loose Flange, and Blind Flange. 4. **According to Connection Method/Type:** Flanges are classified as follows: Plate Flat Welding Flange, Necked Flat Welding Flange, Necked Butt Welding Flange, Socket Welding Flange, Threaded Flange, Blind Flange, Necked Butt Welding Ring Loose Flange, Flat Welding Ring Loose Flange, Ring-Type Joint (RTJ) Flange and Blind Flange, Large-Diameter Plate Flange, Large-Diameter High-Neck Flange, Figure-8 Blind Plate, Butt Welding Ring Loose Flange, etc. 5. **According to the Component Being Connected:** Flanges can be classified into Vessel Flanges and Pipe Flanges. 6. **According to Structural Type:** Flanges include Integral Flanges, Threaded Flanges, Flat Welding Flanges, Butt Welding Flanges, Lap Joint (Loose/Swivel) Flanges, and Blind Flanges. A flange—also referred to as a flange plate or rim—is a component used to connect shafts to one another, or, more commonly, to join the ends of pipes. Flanges are also utilized at the inlet and outlet ports of equipment to facilitate connections between two devices—for instance, the flange on a speed reducer. A "flange connection" or "flanged joint" refers to a detachable joint assembly comprising three interconnected elements—a flange, a gasket, and bolts—that together form a sealed structural unit. In the context of piping systems, a "pipe flange" specifically denotes a flange used for plumbing within the installation; when applied to equipment, it refers to the inlet or outlet flange of that specific device. Flanges feature a series of holes through which bolts are inserted to securely fasten the two flanges together, while a gasket placed between the flanges ensures a leak-proof seal. Flanges are broadly categorized into three types: threaded (screw-in) flanges, welded flanges, and clamp-type flanges. Flanges are invariably used in pairs; threaded flanges are suitable for low-pressure piping applications, whereas welded flanges are required for systems operating at pressures exceeding 4 kilograms per square centimeter. A sealing gasket is inserted between the two flange plates, which are then firmly secured using bolts. The thickness of a flange—as well as the specifications of the bolts used to fasten it—vary depending on the specific pressure rating required for the application. When connecting equipment such as water pumps or valves to piping systems, the corresponding connection points on these devices are often manufactured in the shape of a matching flange; this method of attachment is also referred to as a "flange connection." Generally, any connecting component that utilizes bolts to join and seal the perimeters of two flat surfaces—such as the joints in ventilation ducts—is termed a "flange"; such components may collectively be classified as "flange-type parts." However, since such a connection often constitutes merely a *portion* of a larger device—for instance, the interface between a flange and a water pump—it would be inappropriate to classify the entire water pump itself as a "flange-type part." Conversely, smaller components—such as valves—that feature such flanged interfaces may indeed be appropriately categorized as "flange-type parts." -:- For detailed product information, please contact sales. -: AISI Type H26 Tungsten Hot Work Tool Steel Flange (UNS T20826) Product Information -:- For detailed product information, please contact sales. -: AISI Type H26 Tungsten Hot Work Tool Steel Flange (UNS T20826) Synonyms -:- For detailed product information, please contact sales. -:

AISI Type H26 Tungsten Hot Work Tool Steel (UNS T20826) Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AISI Type H26 Tungsten Hot Work Tool Steel (UNS T20826)** ## **Overview** **AISI Type H26 (UNS T20826)** is a **very high-tungsten, chromium-based hot work tool steel** representing one of the final members of the traditional tungsten series hot work steels. Characterized by its **substantial tungsten content with balanced chromium and vanadium additions**, H26 is engineered to provide **exceptional hot hardness and high-temperature stability** for demanding thermal applications. This grade bridges the gap between conventional tungsten hot work steels and more specialized compositions, offering a balanced approach to extreme temperature service with particular emphasis on wear resistance at elevated temperatures. --- ## **Chemical Composition (Typical Weight %)** H26 features a high-tungsten composition with carefully balanced supporting elements. | Element | Content (%) | Role in Hot Work Performance | | :--- | :--- | :--- | | **Tungsten (W)** | **17.00 - 19.00** | **Exceptionally high tungsten content.** Forms a dense, stable network of tungsten carbides (WC, W₂C) providing maximum red hardness and resistance to thermal softening. | | **Chromium (Cr)** | **3.75 - 4.50** | Provides essential oxidation resistance, contributes to hardenability, and forms chromium carbides that complement the tungsten carbide network. | | **Vanadium (V)** | **0.75 - 1.25** | **Significant vanadium content.** Forms ultra-hard vanadium carbides (VC) for enhanced wear resistance at high temperatures and refines grain structure. | | **Carbon (C)** | **0.45 - 0.55** | **Higher carbon than other tungsten H-grades.** Provides increased carbide volume for better wear resistance while maintaining adequate toughness. | | **Molybdenum (Mo)** | **≤ 0.50** | Minimal; H26 relies primarily on tungsten for high-temperature properties. | | **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 | - | | **Cobalt (Co)** | **0%** | Notably absent; distinguishes H26 from cobalt-containing grades like H24/H25. | | **Iron (Fe)** | **Balance** | Base metal. | **Key Distinction:** H26's **very high tungsten content (17-19%) with zero cobalt** distinguishes it from the cobalt-enhanced tungsten grades (H24, H25). This creates a material that relies exclusively on carbide strengthening (tungsten and vanadium carbides) rather than combined carbide and matrix (cobalt) strengthening. The **higher carbon content (0.45-0.55%)** compared to other tungsten H-grades also provides greater carbide volume for enhanced wear resistance. --- ## **Physical & Mechanical Properties** *Properties are for material in the hardened and tempered condition.* | Property | Typical Value / Description | | :--- | :--- | | **Density** | ~8.80 g/cm³ (Very high due to extreme tungsten content) | | **Hardness (Annealed)** | 235 - 265 HB | | **Hardness (Hardened & Tempered)** | **46 - 56 HRC** (Typically operated at 50-54 HRC for hot work) | | **Hot Hardness (at 650°C / 1200°F)** | **~44-48 HRC** (Exceptional retention at high temperatures) | | **Tensile Strength** | 1650 - 2000 MPa (at 52 HRC) | | **Yield Strength (0.2%)** | 1450 - 1800 MPa (at 52 HRC) | | **Elongation** | **3 - 7%** (at 52 HRC; low due to high carbide volume) | | **Impact Toughness (Charpy)** | **6 - 12 J** (at 52 HRC; very low - characteristic limitation) | | **Thermal Fatigue Resistance** | **Fair to Good.** Adequate for many applications but challenged by low thermal conductivity. | | **Thermal Conductivity** | **~21.5 W/m·K** at 20°C (Very low due to extreme alloy content) | | **Coefficient of Thermal Expansion** | ~11.2 × 10⁻⁶/°C (20-500°C) | | **Maximum Continuous Service Temperature** | **~680°C (1255°F)** | | **Specific Heat Capacity** | 460 J/kg·K | | **Machinability (Annealed)** | **Extremely Poor** (~20-25% of 1% carbon steel). Exceptionally difficult. | | **Grindability** | **Extremely Poor.** Among the most challenging steels to grind. | --- ## **Heat Treatment Guidelines** H26 requires extreme care in heat treatment due to its high alloy content and sensitivity. | Process | Parameters | Critical Considerations for H26 | | :--- | :--- | :--- | | **Annealing** | Heat to 870-900°C (1600-1650°F), slow furnace cool to 480°C (900°F) at ≤8°C/hr, then air cool. | Results in ~250 HB; essential for any machining attempts. | | **Stress Relieving** | 650-700°C (1200-1290°F) for 3-4 hrs, slow furnace cool. | Mandatory after machining to prevent stress-induced cracking. | | **Preheating** | **Triple preheat:** 400°C (750°F), 650°C (1200°F), and 850°C (1560°F). | Critical to prevent thermal shock during high-temperature austenitizing. | | **Austenitizing** | **1220-1260°C (2230-2300°F).** Soak: 20-40 min/inch. | **Extreme temperature required** to dissolve tungsten carbides; vacuum atmosphere essential. | | **Quenching** | **Oil quench** with vigorous agitation or **high-pressure gas quench.** | Rapid cooling necessary; air quenching generally insufficient for full hardness. | | **Tempering** | **Triple temper at 630-680°C (1165-1255°F)** for 2+ hours each. Cryogenic treatment between tempers recommended. | High tempering temperatures required; must begin tempering immediately after quenching. | --- ## **Product Applications** H26 is specialized for extreme high-temperature applications requiring maximum hot hardness without cobalt. ### **Primary Hot Work Applications:** #### **1. High-Temperature Forging:** - **Dies for high-alloy steel forging** at 600-750°C - **Hot die forging tools** for nickel-based alloys - **Forging dies for specialized high-temperature materials** #### **2. Hot Extrusion Tooling:** - **Extrusion dies for copper and copper alloys** - **Mandrels for high-temperature extrusion** - **Tools for specialized metal extrusion processes** #### **3. Wear-Intensive High-Temperature Applications:** - **Hot work tools subject to severe abrasion** at elevated temperatures - **Die casting tools for abrasive high-temperature alloys** - **Tools for hot powder compaction** of hard materials ### **Specific Industry Usage:** - **Specialty Metal Forging** (high-alloy steels, certain superalloys) - **Non-Ferrous Metal Processing** (copper, brass industries) - **Advanced Materials Manufacturing** - **Research & Development** in high-temperature tooling --- ## **International Standards & Cross-Reference** H26 is a highly specialized grade with limited international recognition. | Standard | Designation | Equivalent / Similar Grade | | :--- | :--- | :--- | | **AISI/SAE (USA)** | **H26** | - | | **UNS (USA)** | **T20826** | - | | **ASTM (USA)** | A681 | Grade H26 | | **Europe (EN)** | **No equivalent** | - | | **Germany (DIN)** | **No equivalent** | - | | **Japan (JIS)** | **No equivalent** | - | | **ISO** | **No equivalent** | - | | **UK (BS)** | **No equivalent** | - | **Critical Note:** **AISI H26 has no direct international equivalents.** Its extreme tungsten content without cobalt creates a unique composition that falls outside standard international tool steel classifications. It is essentially exclusive to the AISI/SAE system and is rarely specified even within that framework. --- ## **Technical Comparison: H26 vs. Other Tungsten Hot Work Steels** | Property | **H26 (UNS T20826)** | **H21 (UNS T20821)** | **H23 (UNS T20823)** | | :--- | :--- | :--- | :--- | | **Tungsten Content** | **17.00-19.00%** | 8.00-10.00% | 11.00-12.75% | | **Cobalt Content** | **0%** | 0% | 0% | | **Chromium Content** | 3.75-4.50% | 3.00-3.75% | **11.00-12.75%** | | **Carbon Content** | **0.45-0.55%** | 0.25-0.35% | 0.25-0.35% | | **Hot Hardness (at 650°C)** | **~44-48 HRC** | ~40-44 HRC | ~42-46 HRC | | **Wear Resistance** | **Best** (high carbon + vanadium) | Good | Very Good | | **Toughness (at 52 HRC)** | 6-12 J | **15-25 J** | 8-15 J | | **Maximum Service Temp** | **~680°C (1255°F)** | ~650°C (1200°F) | ~700°C (1290°F) | | **Primary Characteristic** | **Max Wear at High Temp** | Balanced Performance | **High Temp + Oxidation** | --- ## **Advantages & Considerations** ### **Advantages:** 1. **Exceptional Hot Hardness:** Outstanding resistance to softening at high temperatures due to extreme tungsten content. 2. **Superior High-Temperature Wear Resistance:** High carbon and vanadium content provides excellent abrasion resistance at elevated temperatures. 3. **Cobalt-Free Composition:** Advantageous when cobalt is undesirable due to cost, supply, or specific application requirements. 4. **Good High-Temperature Stability:** Maintains properties well during prolonged high-temperature exposure. ### **Considerations & Limitations:** 1. **Extremely Low Toughness:** Very brittle at all temperatures; requires meticulous handling and design. 2. **Very High Cost:** Extreme tungsten content makes it very expensive. 3. **Extremely Complex Heat Treatment:** Demands specialized equipment and expertise. 4. **Very Poor Thermal Conductivity:** Severe thermal gradients and stress concentrations. 5. **Near-Impossible Machinability:** Fabrication is exceptionally difficult and costly. 6. **Very Limited Availability:** Essentially special-order only with long lead times. 7. **Niche Application:** Only justifiable for specific extreme applications. --- ## **Special Metallurgical Characteristics** ### **Tungsten-Dominant Microstructure:** 1. **High Carbide Volume:** Extreme tungsten content creates very high volume fraction of tungsten carbides. 2. **Carbon Optimization:** Higher carbon than other tungsten H-grades increases carbide formation while maintaining some matrix integrity. 3. **Vanadium Enhancement:** Significant vanadium content provides additional wear resistance through VC carbides. ### **Absence of Cobalt Effects:** - **Pure Carbide Strengthening:** Relies exclusively on carbide strengthening rather than combined carbide-matrix strengthening. - **Different Tempering Response:** Exhibits different secondary hardening behavior compared to cobalt-containing grades. - **Matrix Characteristics:** Ferrite matrix has different high-temperature behavior without cobalt solid solution strengthening. --- ## **Processing Challenges** ### **Fabrication Considerations:** 1. **Consider Near-Net-Shape Forming:** Where possible, to minimize machining 2. **EDM Preferred:** For complex shapes, despite slow processing 3. **Specialized Grinding:** Required for final dimensions and surface finish 4. **Minimal Post-Heat-Treatment Machining:** Due to extreme hardness ### **Heat Treatment Criticalities:** 1. **Atmosphere Control:** Essential to prevent catastrophic decarburization 2. **Temperature Uniformity:** ±5°C control necessary during austenitizing 3. **Quenching Rate:** Must be rapid enough to achieve full hardness 4. **Tempering Precision:** Critical to develop optimal properties without overtempering --- ## **Economic & Practical Considerations** ### **Application Justification:** H26 might be considered when: 1. Maximum hot hardness is required without cobalt 2. High-temperature wear resistance is paramount 3. Alternative materials have failed 4. Budget allows for extreme material and processing costs 5. Application can accommodate very low toughness ### **Cost Analysis:** - **Material Cost:** 4-8× higher than H13 - **Fabrication Cost:** 3-6× higher due to machining difficulty - **Heat Treatment Cost:** 2-4× higher with specialized equipment - **Total Investment:** Often prohibitive for commercial applications --- ## **Modern Context & Alternatives** ### **Contemporary Alternatives:** 1. **Advanced Coatings:** PVD/CVD coatings on more economical substrates 2. **Powder Metallurgy Tool Steels:** For better toughness at high hardness 3. **Ceramic and Cermet Tooling:** For specific extreme conditions 4. **Modified Standard Grades:** Enhanced versions of H13, H21 with better balance of properties ### **H26's Diminishing Role:** In modern manufacturing, H26's applications have largely been superseded by: - **More manufacturable materials** with adequate performance - **Advanced surface engineering** techniques - **Improved process controls** that reduce tooling demands - **Alternative manufacturing approaches** that avoid extreme conditions --- ## **Conclusion** **AISI Type H26 Tungsten Hot Work Tool Steel (UNS T20826)** represents the **final evolution of traditional high-tungsten, non-cobalt hot work steels**, offering **extreme hot hardness and high-temperature wear resistance** through its remarkable tungsten content (17-19%) and optimized carbon level. As a material that **pushes traditional alloying to its practical limits**, H26 demonstrates both the **potential and the challenges** of extreme tungsten-based compositions. However, its **severe limitations in toughness, manufacturability, and cost** have rendered it largely obsolete for most practical applications. In today's manufacturing landscape, H26 serves more as a **metallurgical curiosity and historical benchmark** than as a viable production material for all but the most specialized, well-funded applications. The story of H26 illustrates an important principle in materials engineering: that **extreme performance in one area often comes at unacceptable costs in others**. While it remains a fascinating example of traditional metallurgical extremes, H26's practical relevance has been largely supplanted by more balanced, manufacturable alternatives and advanced surface engineering technologies. For materials historians and specialists, H26 represents an important chapter in the development of high-temperature tool steels. For practical engineers and manufacturers, it serves as a reminder to seek balanced solutions rather than pursuing single-property extremes at all costs. -:- For detailed product information, please contact sales. -: AISI Type H26 Tungsten Hot Work Tool Steel (UNS T20826) Specification Dimensions Size： Diameter 20-1000 mm Length <6699 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 H26 Tungsten Hot Work Tool Steel (UNS T20826) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Type H26 Tungsten Hot Work Tool Steel Flange (UNS T20826) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Type H26 Tungsten Hot Work Tool Steel Flange (UNS T20826) -:- For detailed product information, please contact sales. -:

Packing of AISI Type H26 Tungsten Hot Work Tool Steel Flange (UNS T20826) -:- 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 Flange 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 3170 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