AISI Type T4 Tungsten High Speed Tool Steel Sheet,Plate (UNS T12004)

AISI Type T4 Tungsten High Speed Tool Steel Sheet/Plate (UNS T12004) Product Information -:- For detailed product information, please contact sales. -: AISI Type T4 Tungsten High Speed Tool Steel Sheet/Plate (UNS T12004) Synonyms -:- For detailed product information, please contact sales. -:

AISI Type T4 Tungsten High Speed Tool Steel (UNS T12004) Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AISI Type T4 Tungsten High-Speed Tool Steel (UNS T12004)** ## **Overview** **AISI T4 (UNS T12004)** is a **cobalt-enriched, tungsten-based high-speed steel (HSS)** designed to deliver **superior red-hardness and hot wear resistance**. As a direct evolution from the classic T1, T4 incorporates a **significant cobalt addition (4.25-5.00%)** to dramatically enhance its ability to maintain hardness and cutting edge integrity at elevated temperatures. It represents the entry point into the family of **cobalt-bearing super high-speed steels** within the T-series, offering a balanced performance upgrade for machining tough and high-temperature alloys where standard HSS grades like T1 or M2 begin to soften. ## **1. Chemical Composition (Nominal %)** T4 builds upon the T1 foundation with a strategic cobalt alloying. | Element | Content (%) | Primary Function | |---------|------------|------------------| | **Carbon (C)** | 0.70 - 0.80 | Provides matrix hardness and supports carbide formation. Slightly higher than T1 to balance the composition. | | **Tungsten (W)** | 17.50 - 19.00 | **Primary element.** Forms stable tungsten carbides, providing the fundamental red-hardness and hot strength. | | **Chromium (Cr)** | 3.75 - 4.50 | Ensures hardenability and provides oxidation resistance. | | **Vanadium (V)** | 0.80 - 1.20 | Forms hard vanadium carbides for wear resistance; content is similar to T1. | | **Cobalt (Co)** | **4.25 - 5.00** | **Key differentiating element.** Does not form carbides but dissolves in the matrix, dramatically increasing red-hardness, tempering resistance, and hot hardness through solid solution strengthening. | | **Molybdenum (Mo)** | ≤ 0.50 (Residual) | Not a primary alloying element. | | **Iron (Fe)** | Balance | Base metal. | **Key Chemistry Note:** T4's composition is essentially **"T1 + 4.5% Co"**. The **cobalt addition is its defining characteristic**. Cobalt raises the transformation temperatures and strengthens the ferrite matrix, allowing the tool to retain its hardness much more effectively when the cutting edge becomes hot during high-speed or heavy-duty machining. This comes at a slight cost to toughness and a significant increase in material cost due to the strategic nature of cobalt. The wear resistance is driven by the same tungsten and vanadium carbides as T1, but they are now supported by a thermally more stable matrix. ## **2. Physical & Mechanical Properties** | Property | Typical Value / Condition | |----------|--------------------------| | **Density** | ~8.75 g/cm³ (High, due to W and Co) | | **Melting Point** | ~1420°C (2590°F) | | **Thermal Conductivity** | Low (~24 W/m·K) | | **Coefficient of Thermal Expansion** | ~10.6 × 10⁻⁶/K (20-600°C) | | **Modulus of Elasticity** | ~215 GPa (31.2 × 10⁶ psi) | | **Annealed Hardness** | 241-285 HB | | **Hardened & Tempered Hardness** | **64-66 HRC** (Can achieve and maintain high hardness). | | **Red Hardness** | **Excellent to Outstanding.** Significantly better than T1. Maintains usable hardness well above **600°C (1110°F)**, suitable for high-speed machining of difficult materials. | | **Abrasion Resistance** | **Very Good.** Comparable to T1; relies on the tungsten-vanadium carbide network. | | **Toughness** | **Moderate.** Slightly lower than cobalt-free T1 due to the cobalt-strengthened matrix, which can be more brittle. Requires stable cutting conditions. | | **Tempering Temperature** | 540-600°C (1000-1110°F), **triple tempering is essential**. | | **Grindability** | **Poor** (~30-35% relative to M2). Difficult due to hard carbides; cobalt can increase work hardening during grinding. | ## **3. International Standards & Cross-References** | Standard | Designation | |----------|------------| | **UNS** | T12004 | | **AISI/ASTM (USA)** | T4 (ASTM A600) | | **ISO (International)** | **HS 18-1-1-5** (ISO 4957: Tool steels) | | **DIN (Germany)** | **1.3255** | | **JIS (Japan)** | **SKH4** | | **GB (China)** | **W18Cr4VCo5** (The "Co5" denotes the cobalt content) | | **Common Name** | **5% Cobalt Tungsten High-Speed Steel** | ## **4. Product Applications** T4 is selected for applications that generate high cutting temperatures, where thermal softening is the primary limit on tool life for standard HSS. **Primary Applications:** * **High-Speed Machining of Difficult Materials:** * **Heat-resistant alloys** (some stainless steels, high-temperature alloys). * **High-strength and high-hardness steels.** * **Malleable and abrasive cast irons.** * **Heavy-Duty Cutting Tools:** * **Single-point turning and planing tools** for severe, high-speed cuts. * **End mills, drills, and reamers** for tough materials in production environments. * **Gear hobs and broaches** for long production runs where tool temperature rises. * **Tools for Interrupted Cuts** on hard materials, where the cutting edge is subjected to thermal cycling. **Application Rationale:** T4 is chosen over T1 or M2 when the cutting operation consistently pushes the tool into the temperature range where those grades begin to lose hardness rapidly. Its cobalt content "buys" additional speed or feed rate before thermal softening occurs. It is often compared to **M35 (Co5%)**, which offers similar red-hardness benefits but with the grindability and toughness advantages of the molybdenum-based series. ## **5. Processing & Heat Treatment Guidelines** Heat treatment of T4 is similar to T1 but requires careful control to fully realize the cobalt's benefits. * **Forging:** Heat slowly to **1100-1150°C (2010-2100°F)**. Do not forge below **950°C (1740°F)**. Cool very slowly. * **Annealing:** Heat to **850-870°C (1565-1600°F)**, hold, then furnace cool slowly to **500°C (930°F)**. * **Hardening (Austenitizing):** 1. **Preheating is critical:** Use two stages (e.g., 550-650°C then 800-850°C). 2. **Austenitize:** **1270-1290°C (2320-2355°F).** The high temperature is still required to dissolve tungsten carbides. Cobalt does not lower this requirement. 3. **Quench:** In salt bath, oil, or vacuum/gas. * **Tempering:** * **Temper immediately.** * Temper at **550-570°C (1020-1060°F)** for 2+ hours per cycle. * **Triple tempering is mandatory.** Cobalt promotes secondary hardening, and multiple tempers ensure maximum hardness and dimensional stability. ## **6. Comparative Position & Modern Context** * **vs. T1:** T4 provides **significantly better red-hardness and hot wear performance**, allowing for higher productivity on difficult materials. It is a direct performance upgrade. * **vs. M35 (Co5%):** These are **functional equivalents** in terms of red-hardness enhancement. M35 generally offers **better grindability, toughness, and more consistent carbide distribution** due to its molybdenum base, making it the more common choice in modern industry. * **vs. Higher-Cobalt Grades (T5, T6, M42):** T4 has lower cobalt content, so its maximum red-hardness is less than these grades. It represents a middle tier of performance. **Conclusion:** AISI T4 is a well-defined, capable cobalt-bearing tungsten HSS that successfully addresses the thermal softening limitations of the original T-series. While its use has declined in favor of more manufacturable molybdenum-cobalt grades like M35 and M42, it remains a standardized grade with a clear performance niche. It is a reliable choice for applications demanding the specific high-temperature performance profile of a tungsten-cobalt HSS, particularly in contexts where this traditional composition is specified or trusted. --- **Disclaimer:** T4 is a premium material requiring precise high-temperature heat treatment and presents grinding challenges. Its performance and economic justification depend heavily on the specific machining application generating sufficient heat to leverage its cobalt advantage. For general-purpose HSS needs, M2 or M35 are typically more cost-effective. Always consult the material producer's specific heat treatment guidelines and consider application testing. -:- For detailed product information, please contact sales. -: AISI Type T4 Tungsten High Speed Tool Steel (UNS T12004) Specification Dimensions Size： Diameter 20-1000 mm Length <6769 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 T4 Tungsten High Speed Tool Steel (UNS T12004) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Type T4 Tungsten High Speed Tool Steel Sheet,Plate (UNS T12004) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Type T4 Tungsten High Speed Tool Steel Sheet,Plate (UNS T12004) -:- For detailed product information, please contact sales. -:

Packing of AISI Type T4 Tungsten High Speed Tool Steel Sheet/Plate (UNS T12004) -:- 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 3240 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