Crucible Steel Sheet,Plate,REX® AAA Tungsten Type High Speed Steel Sheet,Plate, AISI T4

Crucible Steel Sheet/Plate REX® AAA Tungsten Type High Speed Steel Sheet/Plate, AISI T4 Product Information -:- For detailed product information, please contact sales. -: Crucible Steel Sheet/Plate REX® AAA Tungsten Type High Speed Steel Sheet/Plate, AISI T4 Synonyms -:- For detailed product information, please contact sales. -:

Crucible Steel REX® AAA Tungsten Type High Speed Steel, AISI T4 Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: Crucible Steel REX® AAA (AISI T4) Tungsten-Type High Speed Steel** Crucible Steel REX® AAA is a premium, high-tungsten, high-cobalt, high-speed steel (HSS) conforming to the classic AISI T4 specification. Representing the pinnacle of traditional tungsten-based high-speed steel technology, it is engineered for applications demanding **exceptional hot hardness (red hardness), maximum wear resistance, and the ability to maintain a cutting edge under the most extreme thermal and abrasive conditions**. The "AAA" designation signifies Crucible's highest quality classification for this alloy, reflecting superior metallurgical control and consistency. As a tungsten-type steel (T-series), REX® AAA relies on a high volume of tungsten carbides within a cobalt-strengthened matrix to achieve its performance. It is specifically designed for **heavy-duty machining of high-temperature alloys, superalloys, hardened steels, and highly abrasive materials** where heat generation at the tool-workpiece interface is intense. This grade is the benchmark for tools that must retain hardness and resist deformation at temperatures where molybdenum-based M-series steels begin to soften significantly. It is a specialist material for the most severe cutting applications. --- ## **1. Chemical Composition (Weight %)** The chemistry of T4 is defined by very high tungsten and cobalt, with substantial carbon and vanadium. | **Element** | **Tungsten (W)** | **Cobalt (Co)** | **Chromium (Cr)** | **Vanadium (V)** | **Carbon (C)** | **Molybdenum (Mo)** | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | **Content** | **17.50 - 19.00** | **4.50 - 5.50** | **4.00 - 4.75** | **0.80 - 1.20** | **0.70 - 0.80** | ≤ 1.00 | | **Role** | **Primary alloy.** Provides exceptional **hot hardness (red hardness)** and wear resistance through solid solution strengthening and the formation of stable, hard tungsten carbides. | **Key performance enhancer.** Dramatically increases hot hardness by strengthening the ferrite matrix, allowing the tool to maintain its edge at extreme cutting temperatures. | Ensures deep hardenability and provides oxidation resistance at high temperatures. | Forms hard vanadium carbides (VC) to enhance abrasion resistance at the cutting edge and refine grain structure. | Provides the necessary carbon for carbide formation and matrix hardness. Optimized to balance hardness and toughness in this high-alloy system. | May be present in small amounts; can enhance hardenability and tempering resistance. | *Note: Iron (Fe) constitutes the remainder. The high tungsten-to-cobalt ratio is characteristic of the T4 grade.* --- ## **2. Physical & Mechanical Properties** *Typical properties after optimal heat treatment to a working hardness of 64-67 HRC.* * **Density:** ~8.70 g/cm³ (0.314 lb/in³) – **Very high**, due to the high tungsten content. * **Modulus of Elasticity:** ~215 GPa (31.2 x 10⁶ psi) * **Thermal Conductivity:** Lower than molybdenum-based HSS; tungsten carbides impede heat flow. * **Hot Hardness (Red Hardness):** **Exceptional.** Maintains hardness above 62 HRC at temperatures exceeding **650°C (1200°F)**, outperforming most M-series HSS. This is its defining property. * **Hardness (Typical Working Range):** **64 - 67 HRC.** Commonly applied at **65-66 HRC**. * **Abrasion Resistance:** **Excellent.** The combination of massive tungsten carbide content and high achievable hardness provides outstanding resistance to wear, especially under high-temperature conditions. * **Toughness:** **Low.** This is the primary trade-off. T4 has **very low impact toughness** and is highly sensitive to chipping and shock loading. It requires extremely rigid setups, optimal cutting geometry, and uninterrupted cuts. * **Compressive Strength:** Extremely high, making it excellent for tools under high compressive loads. * **Grindability:** **Very Difficult.** The high volume of extremely hard and wear-resistant tungsten carbides makes grinding a slow and specialized process. Requires the use of diamond or CBN (Cubic Boron Nitride) abrasives. --- ## **3. Heat Treatment** Heat treatment is complex and demands the highest level of precision and control due to the high alloy content and risk of decarburization. * **Annealing:** Heat to 870-900°C (1600-1650°F), slow cool at ≤15°C/hr to 600°C. Annealed hardness: 260-310 HB. * **Stress Relieving:** 600-650°C (1110-1200°F), hold, then slow cool. * **Preheating:** **Absolutely Mandatory.** Thorough double preheat: First at 540-650°C (1000-1200°F), then at 815-870°C (1500-1600°F) with complete soaking. * **Austenitizing:** **1260-1290°C (2300-2355°F).** **Extreme caution required.** This very high temperature is necessary to put the tungsten and carbon into solution. Must be performed in a controlled atmosphere or vacuum furnace to prevent severe decarburization. A typical target is **1275°C (2325°F)**. * **Quenching:** **Oil quench** (for complex shapes) or **air quench** (for simple shapes). Due to the high hardening temperature, oil quenching is common but increases distortion risk. Salt bath quenching is another historical method. * **Tempering:** **Mandatory Multiple Tempers.** Temper immediately after quenching. **Minimum of three tempers**, each for 2+ hours, is essential. * **Typical tempering range: 540-570°C (1005-1060°F).** A strong secondary hardening response occurs. * **Sub-Zero Treatment:** **Highly recommended, often essential.** Deep cryogenic treatment (-100°C / -148°F or below) between quenching and first temper is crucial to transform retained austenite and achieve maximum hardness and stability. --- ## **4. Key Applications** REX® AAA (T4) is reserved for the most severe, specialized machining operations where its hot hardness is the critical enabling property. * **Machining High-Temperature Superalloys:** Turning tools, boring bars, and form tools for nickel-based and cobalt-based superalloys (e.g., Inconel, Waspaloy, Hastelloy) in aerospace and gas turbine component manufacturing. * **Heavy-Duty Machining of High-Hardness Steels:** Tools for roughing and semi-finishing hardened alloy steels and tool steels. * **High-Speed Machining of Abrasive Cast Irons:** For automotive and heavy equipment components. * **Precision Cutting Tools for Demanding Production:** Where other HSS grades fail due to thermal softening. * **Specialty Forming and Cutting Tools:** For non-ferrous metals like titanium under high-speed conditions. --- ## **5. International Standards & Cross-References** Crucible REX® AAA conforms to the AISI T4 specification, representing a top-tier quality level. * **AISI/SAE:** **T4** * **UNS:** T12004 * **European (EN):** No direct, widely-used equivalent. Falls into the category of high-tungsten, high-cobalt high-speed steels. * **Japanese (JIS):** **SKH3** or **SKH4** are similar high-tungsten, high-cobalt grades. * **ISO:** HS18-1-2-5 (approximate classification reflecting 18%W, 1%V, 2%Cr, 5%Co). * **Common Trade Names:** T4 HSS, Tungsten-Cobalt HSS. --- ## **6. Advantages & Limitations** **Advantages:** * **Unrivaled Hot Hardness (Red Hardness):** The benchmark for high-temperature cutting edge retention among traditional HSS grades. * **Exceptional Wear Resistance at Temperature:** Maintains its abrasion resistance under extreme thermal loads. * **High Compressive Strength:** Withstands heavy cutting forces without deforming. * **Superior Quality (AAA):** Ensures consistency and reliability in performance. **Limitations:** * **Very Low Toughness:** Extremely brittle; highly susceptible to chipping and catastrophic failure with any shock or interruption. * **Extremely Difficult to Grind:** High manufacturing and resharpening costs. * **Complex and Critical Heat Treatment:** Requires very high, precisely controlled austenitizing temperatures with atmosphere protection. High risk of decarburization and distortion. * **Very High Cost:** Due to high tungsten and cobalt content. * **High Density:** Results in heavier tools. * **Niche Application:** Its use is only justified in specific, extreme thermal conditions where its unique properties are fully utilized. --- ## **7. Summary** **Crucible Steel REX® AAA (AISI T4) is the ultimate expression of traditional tungsten-based high-speed steel technology, engineered for a single, critical purpose: to cut the toughest, hottest materials when all other HSS grades fail.** It is not a general-purpose steel but a specialized thermal shield for the cutting edge. Its successful application demands respect for its brittleness, expertise in its complex heat treatment, and a machining environment that minimizes shock. For aerospace, power generation, and specialized heavy industries facing the challenge of machining high-temperature superalloys, T4 remains a historic and powerful tool material that defines the outer limits of HSS capability. It is the specialist's choice for the most thermally punishing cuts imaginable. -:- For detailed product information, please contact sales. -: Crucible Steel REX® AAA Tungsten Type High Speed Steel, AISI T4 Specification Dimensions Size： Diameter 20-1000 mm Length <6988 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. -: Crucible Steel REX® AAA Tungsten Type High Speed Steel, AISI T4 Properties -:- For detailed product information, please contact sales. -:

Applications of Crucible Steel Sheet,Plate REX® AAA Tungsten Type High Speed Steel Sheet,Plate, AISI T4 -:- For detailed product information, please contact sales. -: Chemical Identifiers Crucible Steel Sheet,Plate REX® AAA Tungsten Type High Speed Steel Sheet,Plate, AISI T4 -:- For detailed product information, please contact sales. -:

Packing of Crucible Steel Sheet/Plate REX® AAA Tungsten Type High Speed Steel Sheet/Plate, AISI T4 -:- 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 3459 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