JIS SKH51 Molybdenum High Speed Tool Steel Wire

JIS SKH51 Molybdenum High Speed Tool Steel Wire Product Information -:- For detailed product information, please contact sales. -: JIS SKH51 Molybdenum High Speed Tool Steel Wire Synonyms -:- For detailed product information, please contact sales. -:

JIS SKH51 Molybdenum High Speed Tool Steel Product Information -:- For detailed product information, please contact sales. -: # **JIS SKH51 Molybdenum High-Speed Tool Steel** **International Standard:** JIS G4403 (Japan Industrial Standard) - High-Speed Tool Steels --- ## **1. Overview** JIS SKH51 is a **molybdenum-tungsten-vanadium high-speed steel** belonging to the molybdenum-based "M-series" of high-speed steels. It represents the **Japanese industry-standard equivalent to the globally prevalent AISI M2 grade**. Characterized by an **excellent balance of wear resistance, toughness, and red hardness at a competitive cost**, SKH51 is arguably the most widely used general-purpose high-speed steel worldwide. It is versatile, reliable, and performs superbly in a vast range of cutting and cold-work applications. --- ## **2. Chemical Composition (Typical Weight %)** | Element | Content (%) | | :------ | :---------- | | C | 0.78–0.88 | | Si | 0.20–0.45 | | Mn | 0.15–0.40 | | Cr | 3.80–4.50 | | Mo | 4.70–5.20 | | W | 5.90–6.70 | | V | 1.70–2.10 | | Co | ≤ 0.50 | | P (max) | 0.030 | | S (max) | 0.030 | **Balance:** Iron (Fe). **Note:** The modern SKH51 often features a carbon content at the higher end of the range ("high-carbon M2") to better match the vanadium content, optimizing wear resistance. --- ## **3. Physical & Mechanical Properties** ### **Physical Properties** - **Density:** ~8.16 g/cm³ - **Thermal Conductivity:** ~23 W/m·K (at 20°C) - **Coefficient of Thermal Expansion:** ~11.5 ×10⁻⁶ /K (20–500°C) - **Specific Heat Capacity:** 0.46 kJ/kg·K ### **Mechanical Properties (Heat-Treated)** - **Annealed Hardness:** ≤ 262 HB - **Typical Hardened & Tempered Hardness:** 63–65 HRC - **Achievable Hardness (Optimized):** Up to 66–67 HRC - **Red Hardness:** Maintains cutting edge up to ~600°C - **Transverse Rupture Strength:** ~3,500 MPa - **Toughness:** **Good** – superior to most tungsten-based (T-series) HSS grades of similar hardness. --- ## **4. Heat Treatment Specifications** ### **1. Annealing** - **Temperature:** 850–900°C - **Process:** Heat uniformly, hold for 2–4 hours, then furnace cool slowly (10–20°C/h) to about 600°C, followed by air cooling. - **Resulting Hardness:** ≤ 262 HB ### **2. Hardening (Quenching)** - **Preheating:** **Essential** to prevent thermal shock and distortion. - **First Preheat:** 400–500°C - **Second Preheat:** 800–850°C - **Austenitizing (Hardening) Temperature:** **1190–1220°C** - **Soaking Time:** 2–4 minutes per 25mm of thickness (shorter in salt baths). - **Quenching Medium:** Oil, air (for simple shapes), or salt bath. ### **3. Tempering** - **Critical Step:** **Must be tempered immediately** after quenching to room temperature (50–80°C). - **Temperature Range:** 540–580°C - **Cycle:** **Double or triple tempering is mandatory.** Each cycle: heat to temperature, hold for 1–2 hours, air cool to room temperature. - **Typical Process:** Temper at 550–570°C twice. A third temper improves dimensional stability. - **Hardness Development:** Achieves peak secondary hardness after tempering. --- ## **5. Key Features & Advantages** 1. **Superior Balance of Properties:** Offers an optimal blend of wear resistance (from high vanadium), toughness (from molybdenum), and red hardness. 2. **Excellent Wear Resistance:** The combination of high carbon and 2% vanadium forms numerous hard MC-type carbides, providing excellent abrasion resistance. 3. **Better Toughness than T-Series Grades:** Generally exhibits higher resistance to chipping and fracture compared to equivalent tungsten-based grades like SKH2/SKH9. 4. **Good Grindability:** Although vanadium carbides are hard, its balanced composition allows for satisfactory grindability with proper wheels. 5. **Cost-Effectiveness:** More economical to produce than high-cobalt or high-tungsten grades, offering outstanding value for performance. 6. **Versatility:** Can be used for both cutting tools and high-wear cold-work applications. --- ## **6. Typical Applications** SKH51 is the **workhorse of the high-speed steel family**, used in countless industrial tools. ### **Cutting Tools (Primary Application):** - **Drills:** Twist drills, step drills, core drills. - **End Mills:** All types – square end, ball nose, corner radius. - **Milling Cutters:** Face mills, slotting cutters, side-and-face cutters. - **Gear Cutting Tools:** Hobs, shaper cutters, shaving cutters. - **Broaches:** Internal and surface broaches. - **Taps & Dies:** High-performance threading tools. - **Saw Blades:** Metal-cutting band saw and hole saw blades. ### **Forming & Wear Parts:** - **Cold Work Tooling:** Punches, dies, forming rolls, and shear blades for blanking and forming. - **Machine Parts:** Guide pins, wear plates, and bearings requiring high wear resistance. ### **Industries Served:** - General machining & metalworking - Automotive component manufacturing - Aerospace subcontracting - Die & mold making - Tool & die shops --- ## **7. International Standard Equivalents** | Standard | Grade Designation | Notes | | :--------------- | :---------------- | :----------------------------------------- | | **JIS** | SKH51 | Original specification (JIS G4403) | | **AISI/SAE (USA)**| M2 | **Direct Equivalent** (Regular & High-Carbon) | | **DIN (Germany)** | 1.3343 / HS6-5-2 | European standard equivalent | | **ISO** | HS6-5-2 | International designation | | **GB (China)** | W6Mo5Cr4V2 | Nearly identical composition | | **UNS** | T11302 | Unified Numbering System | | **AFNOR (France)**| Z85WDCV 06-05-04-02 | French standard | --- ## **8. Machining & Fabrication Guidelines** ### **Machining (In Annealed State):** - Use carbide tools for best productivity. - Its annealed hardness requires moderate cutting forces; use positive rake angles. ### **Grinding:** - **Wheel Choice:** Use aluminum oxide (Al₂O₃) or ceramic-aluminum oxide (SG) wheels. Cubic Boron Nitride (CBN) is highly efficient for large volumes. - **Practice:** Use sharp wheels, light cuts, and **ample coolant** to avoid thermal damage (grinding burns) which can cause cracking. ### **Electrical Discharge Machining (EDM):** - Can be readily machined by EDM in the hardened state. - **Post-EDM Requirement:** The white, re-cast layer must be removed by polishing or a low-temperature stress relief/stabilization treatment to prevent premature tool failure. ### **Welding:** - Generally not recommended for tool fabrication. - Repair welding is possible but requires specialized procedures, including high preheat (450-500°C), matching filler rods, and immediate post-weld tempering. --- ## **9. Surface Treatment** SKH51 is an **excellent substrate for surface treatments**, which greatly enhance performance. 1. **Nitriding (Gas, Liquid, Plasma):** * Creates a hard, wear-resistant surface layer. * **Crucial:** Perform at temperatures **below the final tempering temperature** (typically 480–520°C). 2. **Physical Vapor Deposition (PVD) Coatings:** * **Standard coatings:** TiN (gold), TiCN (blue-gray), TiAlN (violet-black). * **Advanced coatings:** AlCrN, TiSiN. * **Benefits:** Reduce friction, increase hardness, improve lubricity, and significantly extend tool life (often by 200–500%). --- ## **10. Summary** JIS SKH51 (AISI M2) is the **quintessential and most balanced high-speed steel grade** available. Its dominance in the global market is a testament to its **unmatched versatility and outstanding price-to-performance ratio**. It is the **default choice** for the majority of high-speed steel cutting tools and high-wear components where a balance of wear resistance and toughness is required. For applications demanding higher red hardness, grades like SKH55 (M35 – cobalt-added) or SKH10 (Tungsten-based) might be selected, while for extreme wear resistance, higher vanadium grades like SKH53 (M3:2) are used. However, SKH51 remains the central benchmark against which other high-speed steels are measured. **In short, for robust, reliable, and high-performance general-purpose tooling, SKH51 is the industry-proven standard.** -:- For detailed product information, please contact sales. -: JIS SKH51 Molybdenum High Speed Tool Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6811 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 SKH51 Molybdenum High Speed Tool Steel Properties -:- For detailed product information, please contact sales. -:

Applications of JIS SKH51 Molybdenum High Speed Tool Steel Wire -:- For detailed product information, please contact sales. -: Chemical Identifiers JIS SKH51 Molybdenum High Speed Tool Steel Wire -:- For detailed product information, please contact sales. -:

Packing of JIS SKH51 Molybdenum High Speed Tool Steel Wire -:- 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 Wire 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 3282 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