Bohler-Uddeholm,BÖHLER S401(M1) High Speed Steel Rod/Bar

Bohler-Uddeholm BÖHLER S401(M1) High Speed Steel Rod Product Information -:- For detailed product information, please contact sales. -: Bohler-Uddeholm BÖHLER S401(M1) High Speed Steel Rod Synonyms -:- For detailed product information, please contact sales. -:

Bohler-Uddeholm BÖHLER S401(M1) High Speed Steel Product Information -:- For detailed product information, please contact sales. -: # **Böhler-Uddeholm BÖHLER S401 (M1) High Speed Steel** ## **Product Overview** **BÖHLER S401** is a high-performance **tungsten-molybdenum alloyed high-speed steel** conforming to the AISI M1 specification. Representing one of the foundational tungsten-molybdenum balance grades in the high-speed steel family, S401 is engineered to provide **excellent toughness, good wear resistance, and superior grindability**. This grade is particularly valued for applications requiring shock resistance and where ease of manufacturing is critical, serving as a reliable alternative to M2-type steels when maximum toughness and machinability are prioritized over extreme wear resistance. --- ## **1. Key Characteristics & Advantages** * **Exceptional Toughness:** Offers superior impact resistance and fracture toughness compared to higher-carbon, higher-vanadium high-speed steels like M2 and M4, making it ideal for tools subjected to intermittent cutting or shock loads. * **Excellent Grindability:** One of the most grindable high-speed steels, significantly easier to grind and resharpen than M2, M4, or cobalt-bearing grades, reducing manufacturing costs and lead times. * **Good Hot Hardness (Red Hardness):** Maintains adequate cutting edge integrity at elevated temperatures typical of high-speed machining operations. * **Good Wear Resistance:** Provides sufficient wear resistance for many general-purpose and semi-finishing applications. * **Superior Machinability in Annealed State:** Easier to machine than many other high-speed steels, facilitating complex tool fabrication. * **Good Through-Hardening Capability:** Can be uniformly hardened in substantial sections for consistent performance. * **Cost-Effective Manufacturing:** Lower grinding costs and longer grinding wheel life contribute to overall tool manufacturing economy. --- ## **2. Typical Chemical Composition (Weight %)** | Element | Carbon (C) | Tungsten (W) | Molybdenum (Mo) | Chromium (Cr) | Vanadium (V) | | :--- | :---: | :---: | :---: | :---: | :---: | | **Content** | **0.78 - 0.88** | **1.40 - 2.10** | **8.00 - 9.00** | **3.50 - 4.00** | **1.00 - 1.30** | **Alloying Rationale:** * **High Molybdenum (8.5%):** The primary alloying element, providing strong secondary hardening, good hardenability, and contributing significantly to hot hardness at a favorable cost. * **Moderate Tungsten (1.75%):** Works synergistically with molybdenum to enhance hot hardness and tempering resistance. * **Vanadium (1.15%):** Provides basic wear resistance through vanadium carbide formation while maintaining good grindability. * **Lower Carbon (0.83%):** Compared to M2 (~0.95%), this lower carbon content is key to S401's superior toughness and grindability, while still forming sufficient carbides for wear resistance. * **Chromium (3.75%):** Provides essential hardenability and contributes to overall wear characteristics. --- ## **3. Physical & Mechanical Properties** ### **Physical Properties:** * **Density:** ~8.10 g/cm³ * **Thermal Conductivity:** ~27 W/(m·K) at 20°C * **Modulus of Elasticity:** ~215 GPa * **Coefficient of Thermal Expansion:** ~11.5 x 10⁻⁶/K (20-400°C) ### **Heat Treatment & Mechanical Data:** * **Annealed Hardness:** ~230 HBW (max) * **Austenitizing Temperature:** 1190 - 1220°C (2175 - 2230°F) * **Quenching Medium:** Salt bath, vacuum/pressurized gas, or oil. * **Tempering:** **Double tempering is required.** Temperature range: 540 - 590°C (1005 - 1095°F). * **Achievable Hardness:** **63 - 65 HRC** * Typical operating hardness is **63-64 HRC** after tempering at 560-580°C, optimizing the toughness-hardness balance. * **Hot Hardness (600°C):** ~53-55 HRC * **Transverse Rupture Strength:** ~3500 - 3800 MPa (notably high due to toughness) * **Impact Toughness:** Excellent for a high-speed steel; typically 30-50% higher than M2 at equivalent hardness. --- ## **4. Primary Applications** BÖHLER S401 (M1) is ideally suited for tools where shock resistance and manufacturability are primary concerns. * **Cutting Tools Subject to Shock:** * **Broaches** and form tools requiring high fracture resistance. * **Thread cutting dies** and taps for tough materials. * **Milling cutters** for interrupted cuts. * **Drills** for applications with poor rigidity or hole misalignment. * **Tools Requiring Complex Grinding:** * **Gear hobs** with complex profiles. * **Form-relieved milling cutters.** * **Specialty cutting tools** with intricate geometries. * **Cold Work Applications:** * **Punches** for cold heading and forming where chipping is a concern. * **Blankng dies** for non-abrasive materials requiring tough tooling. * **Woodworking Tools:** High-performance planer knives and cutterheads. --- ## **5. Relevant International Standards & Comparable Grades** BÖHLER S401 is the Böhler-Uddeholm designation for AISI M1 high-speed steel. | Standard | Grade / Designation | Country/Region | Note | | :--- | :--- | :--- | :--- | | **AISI / ASTM A600** | **M1** | USA | Direct equivalent. | | **ISO 4957** | **HS1-8-1** | International | Corresponding ISO designation (approx. 1%W, 8%Mo, 1%V). | | **DIN / Werkstoff** | **~1.3345** | Germany/EU | Often specified by chemical composition rather than a standard number. | | **JIS G4403** | **SKH53** | Japan | The Japanese M1 equivalent. | | **Performance Comparison** | **vs. M2** | N/A | S401 (M1) has lower C and V than M2, resulting in better toughness and grindability but lower wear resistance. | | **Performance Comparison** | **vs. M7** | N/A | S401 has lower C and V than S400 (M7), making it tougher and easier to grind, with slightly lower wear resistance. | --- ## **6. Processing & Fabrication Guidelines** * **Supply Form:** Round bars, square bars, flat stock, and tool blanks. * **Machining:** **Excellent machinability for a high-speed steel** in the annealed condition. Produces relatively short chips and is kinder to cutting tools than higher-alloy grades. * **Grinding:** **Outstanding grindability.** Considered one of the easiest high-speed steels to grind. This allows for faster material removal, finer finishes, and extended grinding wheel life. Use standard aluminum oxide wheels. * **EDM:** Performs well. A stress-relieving temper (~550°C) post-EDM is recommended for precision tools. * **Heat Treatment:** Requires standard high-speed steel heat treatment practices in a controlled atmosphere. 1. **Preheating:** 800-850°C and 1050-1100°C. 2. **Austenitizing:** Controlled temperature is key to achieving optimal hardness without grain growth. 3. **Quenching:** Oil, salt, or gas quenching are all suitable. 4. **Tempering:** **Double temper immediately.** A third temper enhances dimensional stability. * **Surface Treatment:** Can be coated with standard PVD coatings (TiN, TiCN) to improve performance, though its primary advantages are bulk properties. --- ## **7. Conclusion** **BÖHLER S401 (M1)** occupies a vital niche as the **high-toughness, high-grindability workhorse** of the high-speed steel family. It excels in applications where tool failure due to chipping or breakage is a greater risk than gradual wear, and where complex tool geometries make grindability a critical economic factor. While it may not offer the ultimate in wear resistance or hot hardness, its balanced properties make it an exceptionally reliable and manufacturable choice. For toolmakers producing intricate tools, for applications involving intermittent cutting or shock, or when grinding costs are a significant portion of tool manufacturing, S401 provides an optimal, cost-effective solution that maximizes tool reliability and manufacturing efficiency. It remains a fundamental and highly valued grade for practical, demanding industrial tooling. -:- For detailed product information, please contact sales. -: Bohler-Uddeholm BÖHLER S401(M1) High Speed Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6903 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. -: Bohler-Uddeholm BÖHLER S401(M1) High Speed Steel Properties -:- For detailed product information, please contact sales. -:

Applications of Bohler-Uddeholm BÖHLER S401(M1) High Speed Steel Rod -:- For detailed product information, please contact sales. -: Chemical Identifiers Bohler-Uddeholm BÖHLER S401(M1) High Speed Steel Rod -:- For detailed product information, please contact sales. -:

Packing of Bohler-Uddeholm BÖHLER S401(M1) High Speed Steel Rod -:- 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 3374 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