JIS SKH4 Tungsten High-Speed-Tool Steel

JIS SKH4 Tungsten High-Speed-Tool Steel Product Information -:- For detailed product information, please contact sales. -: JIS SKH4 Tungsten High-Speed-Tool Steel Synonyms -:- For detailed product information, please contact sales. -:

JIS SKH4 Tungsten High-Speed-Tool Steel Product Information -:- For detailed product information, please contact sales. -: # JIS SKH4 Tungsten High-Speed Tool Steel ## Overview JIS SKH4 is a **high-cobalt, tungsten-based high-speed steel** classified under the T-series in the JIS G4403 standard. Characterized by its **exceptional red hardness and superior high-temperature strength**, it is specifically engineered for the most demanding cutting applications. The significant cobalt content (9-10%) enhances its ability to retain hardness and cutting performance at elevated temperatures, making it ideal for machining superalloys, hardened steels, and other difficult-to-cut materials under severe operating conditions. --- ## Chemical Composition (Typical Weight %) | Element | Content (%) | |---------|-------------| | C | 0.75–0.85 | | Si | 0.20–0.40 | | Mn | 0.20–0.40 | | Cr | 4.00–4.50 | | W | 18.00–20.00 | | V | 1.00–1.50 | | Mo | 0.50–1.00 | | Co | 9.00–10.00 | | P (max) | 0.030 | | S (max) | 0.030 | **Balance:** Iron (Fe). --- ## Physical & Mechanical Properties ### Physical Properties - **Density:** 8.4 – 8.6 g/cm³ - **Melting Point:** ~1410°C - **Thermal Conductivity:** 22 – 24 W/m·K (at 20°C) - **Coefficient of Thermal Expansion:** 10.2 – 11.0 ×10⁻⁶/K (20–500°C) - **Specific Heat Capacity:** 0.46 kJ/kg·K - **Elastic Modulus:** 200 – 210 GPa ### Mechanical Properties (Heat-Treated) - **Annealed Hardness:** ≤ 285 HB - **Hardened & Tempered Hardness:** 65 – 68 HRC - **Red Hardness:** Excellent; maintains hardness up to 630–650°C - **Transverse Rupture Strength:** 2400 – 2800 MPa - **Compressive Strength:** 3200 – 3700 MPa - **Toughness:** Moderate (typical of high-cobalt HSS) --- ## Heat Treatment Specifications ### 1. Annealing - **Temperature:** 830 – 880°C - **Process:** Heat uniformly, hold for 2–4 hours, then furnace cool slowly (10–20°C/h) to 600°C, followed by air cooling. - **Resulting Hardness:** ≤ 285 HB ### 2. Stress Relieving - **Temperature:** 600 – 650°C (after rough machining) - **Purpose:** Minimize distortion during final hardening. ### 3. Hardening (Quenching) - **Preheating:** Critical due to high alloy content. - First Preheat: 450 – 550°C - Second Preheat: 800 – 850°C - **Austenitizing Temperature:** **1270 – 1300°C** - **Soaking Time:** 2 – 4 minutes per 25mm section (shorter for salt bath). - **Quenching Medium:** Oil, air, or salt bath. ### 4. Tempering - **Temperature Range:** 540 – 600°C - **Cycle:** **Triple tempering** is strongly recommended. - **Process:** Temper immediately after quenching. Heat to tempering temperature, hold for 1–2 hours, air cool to room temperature. Repeat 2 more times. - **Peak Hardness:** Typically achieved after tempering at 560 – 580°C. --- ## Key Features & Advantages 1. **Superior Red Hardness:** The high cobalt content enables outstanding retention of hardness and cutting edge integrity at very high temperatures (650°C+), surpassing most conventional HSS grades. 2. **Exceptional High-Temperature Strength:** Resists deformation and softening during high-speed, heavy-cut machining operations. 3. **Good Wear Resistance:** Provided by a hard matrix and stable vanadium/tungsten carbides. 4. **Optimized for Severe Service:** Designed for continuous cutting of the toughest materials where heat generation is extreme. **Trade-off:** The high hardness and cobalt content come with **reduced toughness** compared to lower-alloy HSS grades, making it less suitable for highly interrupted cuts or high-impact applications. --- ## Typical Applications SKH4 is reserved for the most challenging machining tasks where extreme heat is the primary limiting factor. ### Primary Cutting Applications: - **Cutting Superalloys:** Nickel-based (Inconel, Hastelloy) and cobalt-based superalloys in the aerospace and power generation industries. - **Machining High-Hardness Steels:** Tools for turning, milling, and drilling hardened tool steels, die steels, and high-strength alloy steels (>45 HRC). - **High-Speed Heavy-Duty Tools:** Drills, end mills, and inserts for machining cast iron and abrasive materials at very high speeds. - **Broaches and Gear Hobs:** For precision finishing of hardened components. ### Specialized Tooling: - **Aerospace Manufacturing:** Critical cutting tools for engine components and structural parts. - **Automotive Racing & High-Performance:** Tools for machining hardened racing components. - **Die & Mold Industry:** Cutting tools for machining hardened mold inserts (e.g., for die-casting or plastic injection). --- ## International Standard Equivalents | Standard | Grade Designation | Notes / Comparability | |-----------------|------------------------|-------------------------------------------| | **JIS** | SKH4 | Original specification (JIS G4403) | | **ISO** | HS18-1-1-10 | Closest ISO designation | | **DIN (Germany)**| 1.3267 / S18-1-2-10 | German equivalent | | **AISI/SAE (USA)**| T5 | Direct equivalent (T5: W18Cr4VCo10) | | **UNS** | T12005 | Unified Numbering System | | **GB (China)** | W18Cr4VCo10 | Nearly identical composition | | **AFNOR (France)**| Z80WKCV18-10-01 | French standard | --- ## Machining & Fabrication Guidelines ### Machining (In Annealed State): - **Difficulty:** More difficult than standard HSS due to high alloy content. - **Tooling:** Use carbide tools for productivity. - **Parameters:** Use moderate speeds and feeds with ample coolant. ### Grinding: - **Critical Process:** Essential for finishing hardened tools. - **Wheel Recommendation:** Use soft-grade aluminum oxide or Cubic Boron Nitride (CBN) wheels. - **Practice:** Employ low-stress grinding techniques with generous coolant to prevent thermal cracking (grinding burns). ### Welding: - **Not Recommended** for tool fabrication due to extreme crack sensitivity. - **Repair:** If absolutely necessary, requires specialized procedures with high preheat (500°C+) and controlled post-weld cooling/annealing. --- ## Surface Treatment Options 1. **Nitriding (Gas or Plasma):** * **Benefit:** Significantly increases surface hardness (up to 1200 HV) and wear resistance. * **Caution:** Must be performed at temperatures **below the final tempering temperature** (typically 480-520°C) to avoid core softening. 2. **PVD Coatings (TiN, TiAlN, AlCrN):** * **Benefit:** Provides a hard, lubricious surface layer that reduces friction, improves chip flow, and further enhances wear and crater resistance. * **Application:** Applied as a final step after polishing and cleaning. --- ## Summary JIS SKH4 is a **premium, high-cobalt tungsten high-speed steel** designed for peak performance in extreme thermal conditions. Its defining characteristic is its **unmatched red hardness**, achieved through a high tungsten content supplemented with 9-10% cobalt. This makes it the material of choice for: * **Continuous high-speed machining** of materials that generate intense heat at the cutting edge. * **Machining modern superalloys and hardened steels** that are impractical with lower-grade HSS. **Selection Consideration:** SKH4 represents a strategic choice where **heat resistance is the paramount requirement**, even at the expense of some toughness and at a higher material cost. It fills the critical performance gap between conventional HSS (like SKH2/SKH51) and even more advanced materials like carbide or powder metallurgy steels. For applications demanding the ultimate in high-speed steel high-temperature capability, SKH4 (and its international equivalents like AISI T5) remains a benchmark material. -:- For detailed product information, please contact sales. -: JIS SKH4 Tungsten High-Speed-Tool Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6810 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. -: JIS SKH4 Tungsten High-Speed-Tool Steel Properties -:- For detailed product information, please contact sales. -:

Applications of JIS SKH4 Tungsten High-Speed-Tool Steel -:- For detailed product information, please contact sales. -: Chemical Identifiers JIS SKH4 Tungsten High-Speed-Tool Steel -:- For detailed product information, please contact sales. -:

Packing of JIS SKH4 Tungsten High-Speed-Tool Steel -:- 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 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 3281 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