AISI Type T6 Tungsten High Speed Tool Steel Rod/Bar (UNS T12006)

AISI Type T6 Tungsten High Speed Tool Steel Rod (UNS T12006) Product Information -:- For detailed product information, please contact sales. -: AISI Type T6 Tungsten High Speed Tool Steel Rod (UNS T12006) Synonyms -:- For detailed product information, please contact sales. -:

AISI Type T6 Tungsten High Speed Tool Steel (UNS T12006) Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AISI Type T6 Tungsten High-Speed Tool Steel (UNS T12006)** ## **Overview** **AISI T6 (UNS T12006)** is a **very high-cobalt, tungsten-based super high-speed steel (HSS)** designed to deliver **maximum red-hardness** among the conventional T-series grades. Building upon the T5 formulation, T6 features an even **higher cobalt content (11.0-13.0%)**, pushing the limits of solid solution strengthening to achieve exceptional resistance to thermal softening. It represents the extreme end of the traditional cobalt-enriched tungsten HSS spectrum, engineered for the most severe high-speed machining applications where the cutting edge is subjected to sustained, extreme temperatures that would rapidly degrade lower-alloy grades. ## **1. Chemical Composition (Nominal %)** T6's composition is focused on maximizing hot hardness through ultra-high cobalt. | Element | Content (%) | Primary Function | |---------|------------|------------------| | **Carbon (C)** | 0.75 - 0.85 | Provides matrix hardness; balanced to support the carbide structure without excessive brittleness. | | **Tungsten (W)** | 18.00 - 20.00 | **Primary element.** Forms a dense network of stable tungsten carbides, providing the foundational red-hardness and hot strength. Slightly higher than T5. | | **Chromium (Cr)** | 4.00 - 4.75 | Ensures hardenability and provides oxidation resistance. | | **Vanadium (V)** | 1.50 - 2.00 | Forms hard vanadium carbides for wear resistance; content maintained to balance the high cobalt. | | **Cobalt (Co)** | **11.00 - 13.00** | **Defining and dominant element.** Ultra-high cobalt content provides the highest level of solid solution strengthening, dramatically elevating the steel's hot hardness, tempering resistance, and ability to maintain an edge at extreme temperatures. | | **Molybdenum (Mo)** | ≤ 0.50 (Residual) | Not a primary alloying element. | | **Iron (Fe)** | Balance | Base metal. | **Key Chemistry Note:** T6 is characterized by its **ultra-high cobalt content**, the highest among the standard AISI T-series (T1-T15). This composition represents a philosophy of **maximizing matrix-based hot hardness** through cobalt, supported by the classic tungsten-vanadium carbide system for wear resistance. The **very high tungsten (up to 20%)** works synergistically with cobalt. While effective for red-hardness, this high alloy content comes at a significant cost to toughness, ductility, and grindability. ## **2. Physical & Mechanical Properties** | Property | Typical Value / Condition | |----------|--------------------------| | **Density** | ~8.85 g/cm³ (Very high due to W and high Co) | | **Melting Point** | ~1410°C (2570°F) | | **Thermal Conductivity** | Low (~22 W/m·K) | | **Coefficient of Thermal Expansion** | ~10.4 × 10⁻⁶/K (20-600°C) | | **Modulus of Elasticity** | ~215 GPa (31.2 × 10⁶ psi) | | **Annealed Hardness** | 269-321 HB | | **Hardened & Tempered Hardness** | **65-67 HRC** (Capable of achieving and maintaining very high hardness). | | **Red Hardness** | **Exceptional.** The highest among the standard T1-T15 series. Maintains cutting edge hardness effectively at temperatures approaching **650°C (1200°F)** or above, under optimal conditions. | | **Abrasion Resistance** | **Very Good.** Provided by the tungsten and vanadium carbide network. However, its supreme property is hot hardness, not necessarily room-temperature abrasion resistance. | | **Toughness** | **Low.** The extremely high cobalt content results in a very strong but brittle matrix. T6 is highly susceptible to chipping and catastrophic fracture under shock or uneven loading. Requires impeccably stable machining conditions. | | **Tempering Temperature** | 540-600°C (1000-1110°F), **multiple tempering (3-4 times) is absolutely critical**. | | **Grindability** | **Extremely Poor** (~20-25% relative to M2). One of the most difficult steels to grind due to hard carbides and a work-hardening cobalt matrix. | ## **3. International Standards & Cross-References** | Standard | Designation | |----------|------------| | **UNS** | T12006 | | **AISI/ASTM (USA)** | T6 (ASTM A600) | | **ISO (International)** | **HS 20-1-2-12** (ISO 4957: Tool steels) | | **DIN (Germany)** | **1.3267** | | **JIS (Japan)** | **SKH4B** (or similar very high-cobalt variant) | | **GB (China)** | **W18Cr4VCo12** (Reflecting the ~12% cobalt content) | | **Common Name** | **12% Cobalt Tungsten Super High-Speed Steel** | ## **4. Product Applications** T6 is reserved for the most extreme, high-temperature machining applications where thermal softening is the absolute limiting factor and all other HSS grades fail. **Primary Applications:** * **Ultra-High-Speed Machining of Exotic Alloys:** * **Nickel-based and cobalt-based superalloys** (Inconel, Hastelloy, Waspaloy) under aggressive, high-speed parameters. * **High-speed turning and milling of hardened tool steels** and high-strength alloys. * **Specialized Single-Point Cutting Tools:** * **Lathe tools and planer tools** for maximum speed and feed on the most difficult materials in continuous cutting operations. * **Tools for Machining Abrasive Materials at High Speeds** where heat buildup is intense. * **Certain Hot Work Applications** where extreme hot hardness is required, though dedicated hot-work steels (H-series) are often preferred for their toughness. **Application Rationale:** T6 is a **specialist's steel for a specific problem: extreme thermal softening.** It is not a general-purpose grade. Its use is justified only when cutting speeds and feeds generate temperatures that cause the cutting edge of T5 or M42 to lose hardness rapidly, and when the workpiece material or operation does not impose significant mechanical shock on the tool. ## **5. Processing & Heat Treatment Guidelines** Heat treatment of T6 is demanding and requires the highest level of control. * **Forging:** Exercise extreme caution. Heat slowly to **1090-1130°C (1995-2070°F)**. **Do not forge below 960°C (1760°F)**. Cool extremely slowly in an insulating medium or furnace. * **Annealing:** Heat to **870-900°C (1600-1650°F)**, hold, then furnace cool very slowly (≤10°C/hour to 500°C). * **Hardening (Austenitizing):** 1. **Preheating is mandatory:** Use two, or even three, stages (e.g., 500°C, 800°C, 850°C). 2. **Austenitize:** **1270-1290°C (2320-2355°F).** Precise temperature control within a narrow range is vital to prevent grain growth or under-austenitizing. 3. **Quench:** Best performed in a **vacuum furnace with high-pressure gas (N₂/Ar) quenching** or a salt bath. Oil quenching is possible for simple shapes but increases distortion risk. * **Tempering:** * **Temper immediately** upon reaching 40-50°C. * Temper at **540-560°C (1005-1040°F)** for 2+ hours per cycle. * **Triple or quadruple tempering is required.** The high alloy content creates significant retained austenite. * **Cryogenic treatment** between tempers is highly recommended to maximize transformation, hardness, and dimensional stability. ## **6. Comparative Position & Modern Context** * **vs. T5:** T6 provides a **step-change increase in red-hardness** due to its much higher cobalt, but with a **further reduction in toughness**. * **vs. M42 (Co8%):** While M42 has less cobalt, its molybdenum-based structure and more balanced composition often result in **more reliable overall performance and vastly better grindability**. T6's higher cobalt may give it a theoretical hot hardness advantage in very specific, controlled conditions. * **Modern Relevance:** The use of T6 has **declined significantly**. Its extreme brittleness, poor grindability, and very high cost are major drawbacks. For most ultra-high-performance applications, the industry has shifted towards: 1. **Advanced powder metallurgy (PM) HSS grades** (e.g., S390, ASP 2060), which offer better combinations of hardness, toughness, and wear resistance. 2. **Advanced coatings (AlTiN, AlCrN)** on tougher substrate steels like M42 or S7, which provide surface hardness and thermal barriers. 3. **Solid carbide or ceramic inserts** for the most severe applications. **Conclusion:** AISI T6 is a **historical high-performance material** that represents the logical extreme of cobalt alloying in traditional tungsten HSS. It serves as a metallurgical benchmark for maximum red-hardness but is largely obsolete for practical tooling due to its severe limitations in toughness, manufacturability, and cost-effectiveness compared to modern alternatives. Its study remains valuable for understanding the trade-offs in tool steel design. --- **Disclaimer:** AISI T6 is an extremely challenging material to process and apply successfully. Its use should only be contemplated by specialists with extensive experience in heat treating and grinding high-alloy tool steels, and only after all other high-performance options (M42, PM HSS, coated carbides) have been thoroughly evaluated and found wanting for a very specific thermal limitation. The economic and technical risks associated with T6 are very high. Always follow the steel producer's exact specifications and validate performance with rigorous application testing. -:- For detailed product information, please contact sales. -: AISI Type T6 Tungsten High Speed Tool Steel (UNS T12006) Specification Dimensions Size： Diameter 20-1000 mm Length <6771 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 T6 Tungsten High Speed Tool Steel (UNS T12006) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Type T6 Tungsten High Speed Tool Steel Rod (UNS T12006) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Type T6 Tungsten High Speed Tool Steel Rod (UNS T12006) -:- For detailed product information, please contact sales. -:

Packing of AISI Type T6 Tungsten High Speed Tool Steel Rod (UNS T12006) -:- 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 Rod 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 3242 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