Bohler-Uddeholm,BÖHLER S290 MICROCLEAN® High Speed Steel Rod/Bar

Bohler-Uddeholm BÖHLER S290 MICROCLEAN® High Speed Steel Rod Product Information -:- For detailed product information, please contact sales. -: Bohler-Uddeholm BÖHLER S290 MICROCLEAN® High Speed Steel Rod Synonyms -:- For detailed product information, please contact sales. -:

Bohler-Uddeholm BÖHLER S290 MICROCLEAN® High Speed Steel Product Information -:- For detailed product information, please contact sales. -: # **Böhler-Uddeholm BÖHLER S290 MICROCLEAN® High Speed Steel** ## **Product Overview** **BÖHLER S290 MICROCLEAN®** is a premium **cobalt-enhanced, tungsten-molybdenum powder metallurgy (PM) high-speed steel** manufactured using Böhler-Uddeholm's proprietary **MICROCLEAN®** technology. This advanced PM process produces an exceptionally homogeneous microstructure with ultra-fine, uniformly distributed carbides, eliminating the segregation limitations of conventional melting. S290 is engineered to deliver **outstanding red hardness, exceptional wear resistance, and superior grindability** in a balanced package, positioning it between standard high-speed steels and premium super high-speed steels for demanding machining applications requiring both high-temperature performance and manufacturing efficiency. --- ## **1. Key Characteristics & Advantages** * **Exceptional Microstructural Homogeneity:** MICROCLEAN® PM technology ensures perfect carbide distribution without segregation, providing isotropic properties and consistent performance in all directions. * **Superior Grindability:** Remarkably good grindability for its performance class - significantly better than conventional steels of comparable hardness and wear resistance, reducing manufacturing costs and enabling complex tool geometries. * **Excellent Red Hardness:** Cobalt-enhanced composition maintains cutting edge integrity at elevated temperatures (up to approximately 600°C/1110°F), suitable for high-speed and dry machining operations. * **High Wear Resistance:** Fine, uniformly distributed vanadium and tungsten carbides provide excellent resistance to abrasive wear. * **Good Toughness Balance:** The homogeneous microstructure delivers better toughness than conventionally produced steels at equivalent hardness levels. * **Enhanced Dimensional Stability:** Predictable heat treatment response with minimal distortion. * **Superior Surface Finish Capability:** The fine carbide structure enables excellent polishability for precision cutting edges. --- ## **2. Typical Chemical Composition (Weight %)** | Element | Carbon (C) | Tungsten (W) | Molybdenum (Mo) | Chromium (Cr) | Vanadium (V) | Cobalt (Co) | | :--- | :---: | :---: | :---: | :---: | :---: | :---: | | **Content** | **0.90 - 1.00** | **6.00 - 7.00** | **5.00 - 6.00** | **3.80 - 4.50** | **1.80 - 2.20** | **4.50 - 5.50** | **Alloying Rationale & PM Advantage:** * **Cobalt (5.0%):** Provides enhanced red hardness by raising the transformation temperature and slowing carbide coarsening at high temperatures. * **Vanadium (2.0%):** Forms hard vanadium carbides (VC) for wear resistance. In conventional steel, this level can cause grindability issues, but PM distribution maintains good grindability. * **Tungsten (6.5%) & Molybdenum (5.5%):** Balanced "6-5-2" type composition providing excellent secondary hardening and hot hardness characteristics. * **Carbon (0.95%):** Optimized to balance carbide formation with matrix properties. * **MICROCLEAN® Technology:** The gas atomization and hot isostatic pressing process creates: * No carbide networks or segregation * Carbide size typically <3μm (vs. 10-20μm in conventional steel) * Ultra-low oxygen content (<30 ppm) * Spherical, uniformly distributed carbides --- ## **3. Physical & Mechanical Properties** ### **Physical Properties:** * **Density:** ~8.15 g/cm³ * **Thermal Conductivity:** ~24 W/(m·K) at 20°C * **Modulus of Elasticity:** ~220 GPa * **Coefficient of Thermal Expansion:** ~11.2 x 10⁻⁶/K (20-400°C) ### **Heat Treatment & Mechanical Data:** * **Soft Annealed Hardness:** ~260 HBW * **Austenitizing Temperature:** 1190 - 1220°C (2175 - 2230°F) * **Quenching Medium:** Salt bath, vacuum/pressurized gas (2-5 bar), or oil. * **Tempering:** **Triple tempering recommended.** Temperature range: 540 - 580°C (1005 - 1075°F). * **Achievable Hardness:** **65 - 68 HRC** * Typical operating hardness: **66-67 HRC** after triple tempering at 550-560°C. * **Hot Hardness (600°C):** ~58-60 HRC * **Transverse Rupture Strength:** ~3200 - 3500 MPa * **Impact Toughness:** 20-30% better than conventional steels of similar composition and hardness. * **Grindability Index:** 30-40% better than conventional M42 at equivalent hardness. --- ## **4. Primary Applications** S290 MICROCLEAN® is designed for high-performance cutting tools requiring an optimal balance of properties for difficult machining operations. * **High-Performance Cutting Tools:** * **End mills and drills** for machining stainless steels, high-temperature alloys, and hardened steels (45-55 HRC). * **Gear cutting tools** (hobs, shaper cutters) requiring complex profiles and good grindability. * **Thread mills and form tools** with intricate geometries. * **Broaches** for high-precision applications. * **High-Speed/Dry Machining Applications:** Where thermal stability is crucial for maintaining cutting edge geometry. * **Precision Cold Work Tooling:** * **Punches and dies** for cold forming of challenging materials. * **Precision blanking tools** requiring sharp edges and wear resistance. * **Wear Parts:** Components requiring high hardness and good toughness in demanding environments. --- ## **5. Relevant International Standards & Comparable Grades** S290 MICROCLEAN® is a proprietary PM grade with composition similar to enhanced M-class high-speed steels. | Standard | Grade / Designation | Similarity / Key Difference | | :--- | :--- | :--- | | **Proprietary (Böhler)** | **S290 MICROCLEAN®** | Reference PM cobalt HSS with optimized grindability. | | **AISI / ASTM** | **M42 Modified** | Similar cobalt level (~5% vs M42's 8%), with PM-enhanced properties. | | **ISO 4957** | **HS6-5-2-5** | Similar tungsten-molybdenum-vanadium-cobalt balance. | | **DIN / Werkstoff** | **~1.3245** | Similar cobalt HSS classification. | | **Other PM HSS** | **S690 MICROCLEAN®** | Different chemistry; S290 offers a specific balance of grindability and performance. | | **Conventional HSS** | **M35 (Co5%)** | Similar cobalt content, but S290 offers superior properties via PM technology. | **Performance Positioning:** S290 occupies the space between premium conventional HSS (like M35/M42) and ultra-high-performance PM super HSS (like S790/K294), offering an excellent price-to-performance ratio for demanding applications. --- ## **6. Processing & Fabrication Guidelines** * **Supply Form:** Round bars, square bars, and precision ground flats. * **Machining:** Machine in soft-annealed condition. Use sharp carbide tools with rigid setups. The PM structure provides consistent chip formation. * **Grinding:** **Excellent grindability for its performance level** - a key advantage. Use aluminum oxide or CBN wheels with adequate coolant. The fine carbide structure reduces wheel loading and enables finer finishes. * **EDM:** Suitable. Follow with stress-relieving temper (525-550°C) to address the transformed surface layer. * **Heat Treatment:** Requires controlled atmosphere or vacuum treatment. 1. **Preheating:** 800-850°C and 1050-1100°C stages recommended. 2. **Austenitizing:** Precise temperature control is essential. 3. **Quenching:** High-pressure gas quenching is ideal for complex tools. 4. **Tempering:** **Triple tempering** is standard practice. Cryogenic treatment (-196°C) between tempers enhances dimensional stability and final hardness. * **Surface Treatment:** Excellent substrate for advanced PVD coatings (TiAlN, AlCrN, AlTiN). The combination provides superior performance in dry and high-speed machining. --- ## **7. Conclusion** **BÖHLER S290 MICROCLEAN®** represents a sophisticated advancement in high-speed steel technology, leveraging powder metallurgy to overcome the traditional compromise between **high-temperature performance, wear resistance, and grindability**. It delivers the red hardness and wear characteristics needed for demanding machining applications while maintaining manufacturability often lost in conventional high-alloy steels. For tool manufacturers seeking to upgrade from standard M2/M35 steels or for those finding M42 too difficult to grind economically, S290 offers an optimal solution. Its balanced properties make it particularly valuable for manufacturing complex tool geometries where grindability directly impacts production costs and tool performance. By providing PM-enhanced properties with practical manufacturability, S290 MICROCLEAN® establishes itself as a high-value choice for precision cutting tools in today's challenging machining environments. -:- For detailed product information, please contact sales. -: Bohler-Uddeholm BÖHLER S290 MICROCLEAN® High Speed Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6905 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 S290 MICROCLEAN® High Speed Steel Properties -:- For detailed product information, please contact sales. -:

Applications of Bohler-Uddeholm BÖHLER S290 MICROCLEAN® High Speed Steel Rod -:- For detailed product information, please contact sales. -: Chemical Identifiers Bohler-Uddeholm BÖHLER S290 MICROCLEAN® High Speed Steel Rod -:- For detailed product information, please contact sales. -:

Packing of Bohler-Uddeholm BÖHLER S290 MICROCLEAN® 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 3376 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