Crucible Steel Sheet,Plate,REX® M42 High Speed Steel Sheet,Plate, AISI M42

Crucible Steel Sheet/Plate REX® M42 High Speed Steel Sheet/Plate, AISI M42 Product Information -:- For detailed product information, please contact sales. -: Crucible Steel Sheet/Plate REX® M42 High Speed Steel Sheet/Plate, AISI M42 Synonyms -:- For detailed product information, please contact sales. -:

Crucible Steel REX® M42 High Speed Steel, AISI M42 Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: Crucible Steel REX® M42 (AISI M42) High Speed Steel** Crucible Steel REX® M42 is a premium, cobalt-bearing, super high-speed steel (HSS) that represents the pinnacle of conventional ingot-cast high-speed steel technology for extreme high-temperature applications. Conforming to the AISI M42 specification, it is engineered to deliver **exceptional hot hardness (red hardness), superior wear resistance, and excellent cutting performance** in the most demanding machining environments. The defining characteristic of M42 is its high cobalt content (approximately 8%), which dramatically strengthens the steel matrix at elevated temperatures, allowing cutting tools to maintain their hardness and cutting edge integrity at speeds and feeds that would cause other HSS grades to rapidly soften and fail. REX® M42 is specifically designed for machining **high-temperature alloys, superalloys, hardened steels, and other difficult-to-machine materials** where heat generation at the cutting edge is intense. While it shares a high vanadium content with grades like M4 for wear resistance, it is the synergistic effect of cobalt with molybdenum and tungsten that provides its outstanding high-temperature performance. It is the benchmark material for high-speed steel tools operating under severe thermal stress. --- ## **1. Chemical Composition (Weight %)** M42's chemistry is a high-carbon, high-cobalt, high-vanadium system designed for maximum hot hardness and wear resistance. | **Element** | **Carbon (C)** | **Cobalt (Co)** | **Molybdenum (Mo)** | **Tungsten (W)** | **Vanadium (V)** | **Chromium (Cr)** | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | **Content** | **1.05 - 1.15** | **7.75 - 8.75** | **9.00 - 10.00** | **1.15 - 1.85** | **0.95 - 1.35** | **3.50 - 4.25** | | **Role** | High carbon ensures high hardness and supports the formation of hard wear-resistant carbides. | **Key Differentiator.** Dramatically increases **hot hardness (red hardness)** by strengthening the ferrite matrix, resisting tempering effects at extreme cutting temperatures. | Primary agent for hardenability, hot hardness, and secondary hardening. The high content is central to M42's performance. | Contributes to hot hardness, wear resistance, and stabilizes the alloy structure. | Forms hard vanadium carbides (VC) for enhanced abrasion resistance at the cutting edge. | Provides deep hardenability and oxidation resistance. | *Note: Iron (Fe) constitutes the remainder. The high molybdenum and cobalt with controlled tungsten is a hallmark of this grade.* --- ## **2. Physical & Mechanical Properties** *Typical properties after optimal heat treatment to a working hardness of 66-70 HRC.* * **Density:** ~8.10 g/cm³ (0.293 lb/in³) * **Modulus of Elasticity:** ~215 GPa (31.2 x 10⁶ psi) * **Thermal Conductivity:** Moderate; cobalt improves heat transfer somewhat. * **Hot Hardness (Red Hardness):** **Exceptional.** Maintains a hardness above 64 HRC at temperatures exceeding **600°C (1110°F)**, significantly outperforming non-cobalt HSS grades like M2 or M7. This enables much higher cutting speeds in tough materials. * **Hardness (Typical Working Range):** **66 - 70 HRC.** One of the hardest commercially available HSS grades. Commonly applied at **67-69 HRC**. * **Abrasion Resistance:** **Excellent.** The combination of high carbon, vanadium, and ultra-high achievable hardness provides wear resistance superior to standard HSS and approaching that of some premium grades. * **Toughness:** **Moderate to Low.** This is the primary trade-off for its extreme hot hardness and wear resistance. M42 has lower impact toughness than M2, M7, or M4. It is more sensitive to chipping and requires rigid setups and optimal cutting geometries. * **Grindability:** **Difficult.** The high hardness and alloy content make grinding challenging. It requires sharp, friable aluminum oxide wheels or preferably CBN (Cubic Boron Nitride) abrasives. --- ## **3. Heat Treatment** Precision heat treatment is non-negotiable to achieve M42's legendary performance. Process control is critical. * **Annealing:** Heat to 870-900°C (1600-1650°F), slow cool. Annealed hardness: 260-300 HB. * **Stress Relieving:** 600-650°C (1110-1200°F), hold, then slow cool. * **Preheating:** **Mandatory.** Thorough double preheat: First at 540-650°C (1000-1200°F), then at 815-870°C (1500-1600°F). * **Austenitizing:** **1170-1205°C (2140-2200°F).** A common and critical range is **1185-1195°C (2165-2185°F)**. Temperature must be precisely controlled. * **Quenching:** **Air quench** or, preferably, **controlled gas/pressure quenching** for best dimensional stability. Oil quenching is not recommended for complex tools. * **Tempering:** **Mandatory Multiple Tempers.** Temper immediately after quenching. **Minimum of three tempers**, each for 2 hours, is standard. **Typical tempering range: 540-560°C (1005-1040°F).** Exhibits a very strong secondary hardening response. Hardness typically peaks after the second temper. * **Sub-Zero Treatment:** **Highly recommended** (-80°C to -100°C / -112°F to -148°F) between quenching and first temper to transform retained austenite, ensuring maximum hardness and dimensional stability. --- ## **4. Key Applications** REX® M42 is reserved for the most challenging high-speed, high-temperature machining operations. * **Machining High-Temperature Alloys (Superalloys):** End mills, drills, and reamers for nickel-based (Inconel, Hastelloy) and cobalt-based alloys in aerospace and power generation. * **Hard Machining:** Cutting tools for machining pre-hardened steels (45-55 HRC) and hardened tool steels. * **High-Speed Gear Production:** Premium gear hobs for cutting high-strength materials. * **Precision Boring and Milling:** Tools for high-precision, high-speed finishing operations where thermal stability is critical. * **Demanding General Machining:** For abrasive cast irons and high-strength alloy steels where extended tool life at high speeds is required. --- ## **5. International Standards & Cross-References** Crucible REX® M42 conforms to the AISI M42 specification. * **AISI/SAE:** **M42** * **UNS:** T11342 * **European (EN):** **HS 2-9-1-8** (This designation reflects high cobalt content; a common material number is **1.3247**). * **Japanese (JIS):** **SKH59** (High-cobalt, high-speed steel). * **ISO:** HS2-9-1-8 * **Common Trade Names:** M42 HSS, Cobalt HSS, Super High-Speed Steel. --- ## **6. Advantages & Limitations** **Advantages:** * **Unmatched Hot Hardness among Standard HSS:** Enables the highest practical cutting speeds in tough materials. * **High Hardness and Wear Resistance:** Provides long tool life in severe conditions. * **Excellent Cutting Performance in Hard/Abvasive Materials:** The benchmark for difficult-to-machine alloys. * **Well-Established Grade:** A proven, reliable solution with decades of successful use. **Limitations:** * **Lower Toughness:** Prone to chipping if not used correctly; requires optimal tool geometry and rigid setups. * **High Cost:** Significant cobalt and molybdenum content make it one of the most expensive standard HSS grades. * **Difficult to Grind:** Increases tool maintenance time and cost. * **Heat Treatment Sensitivity:** Requires precise and controlled thermal processing. * **Not a General-Purpose Steel:** Its capabilities are wasted on less demanding materials; M2 or M7 are more cost-effective for general use. --- ## **7. Summary** **Crucible Steel REX® M42 is the definitive super high-speed steel for conquering extreme machining challenges.** It is the material of choice when cutting forces generate intense heat that would degrade lesser tools. By investing in M42, manufacturers gain the capability to machine aerospace superalloys, hardened dies, and other premium materials at productive speeds, reducing total machining time and cost per part despite the higher initial tool cost. For applications where pushing the boundaries of speed and material hardness is necessary, M42 provides the thermal armor and cutting edge integrity that makes the impossible, possible. It is not merely a tool steel; it is a productivity multiplier for the most demanding sectors of precision manufacturing. -:- For detailed product information, please contact sales. -: Crucible Steel REX® M42 High Speed Steel, AISI M42 Specification Dimensions Size： Diameter 20-1000 mm Length <6987 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. -: Crucible Steel REX® M42 High Speed Steel, AISI M42 Properties -:- For detailed product information, please contact sales. -:

Applications of Crucible Steel Sheet,Plate REX® M42 High Speed Steel Sheet,Plate, AISI M42 -:- For detailed product information, please contact sales. -: Chemical Identifiers Crucible Steel Sheet,Plate REX® M42 High Speed Steel Sheet,Plate, AISI M42 -:- For detailed product information, please contact sales. -:

Packing of Crucible Steel Sheet/Plate REX® M42 High Speed Steel Sheet/Plate, AISI M42 -:- 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 3458 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