Crucible Steel Sheet,Plate,CPM® Rex® 20® (HS) High Speed Steel Sheet,Plate

Crucible Steel Sheet/Plate CPM® Rex® 20® (HS) High Speed Steel Sheet/Plate Product Information -:- For detailed product information, please contact sales. -: Crucible Steel Sheet/Plate CPM® Rex® 20® (HS) High Speed Steel Sheet/Plate Synonyms -:- For detailed product information, please contact sales. -:

Crucible Steel CPM® Rex® 20® (HS) High Speed Steel Product Information -:- For detailed product information, please contact sales. -: # **Technical Datasheet: Crucible Steel CPM® Rex® 20® (HS) High Speed Steel** --- ## **1. Product Overview** **Crucible CPM® Rex® 20®** is an ultra-premium, **powder metallurgy (PM), cobalt-bearing high-speed steel (HSS)** developed to deliver **exceptional hot hardness and cutting performance** under the most demanding high-temperature, high-speed machining conditions. The "Rex® 20®" designation signifies a specialized, high-cobalt variant designed to maximize **red-hardness**—the ability to retain hardness and cutting edge integrity at elevated temperatures. Manufactured via Crucible's proprietary CPM process, it features a highly refined, uniform microstructure free from the segregation and large carbides of conventional wrought cobalt HSS grades. This steel is engineered for **extreme productivity applications** where high cutting speeds and feeds generate substantial heat, causing standard HSS grades to soften and fail rapidly. It excels in machining heat-resistant superalloys, hardened steels, and other tough materials where thermal loading is the primary challenge. --- ## **2. Key International Standards & Designations** | Country/System | Standard Designation | Equivalent/Closest Specification | | :--- | :--- | :--- | | **USA (Crucible)** | **CPM® Rex® 20®** | Proprietary PM Cobalt HSS | | **USA (AISI/SAE)** | **- -** | Similar in spirit to M41/M42, but proprietary | | **USA (ASTM)** | **ASTM A600** | Custom PM Grade | | **ISO** | **ISO 4957:2018** | **HS7-6-3-10 / 1.3249** (Approximate) | | **Europe (EN)** | **EN ISO 4957** | **1.3249** (S 7-6-3-10) | | **Germany (DIN/W-Nr.)** | **1.3249** | S 7-6-3-10 | | **Japan (JIS)** | **- -** | Proprietary composition | | **Common Industry Names** | Super Cobalt HSS, High-Redness Steel | - | **Note:** CPM Rex 20 is a proprietary alloy. Its closest conventional analogues are **AISI M41** or **M42**, but its PM structure and optimized chemistry provide significantly enhanced performance, consistency, and grindability. --- ## **3. Chemical Composition (Typical %)** The composition is balanced with high cobalt and carbon to maximize hot hardness and tempering resistance, while maintaining adequate wear resistance and toughness. | Element | Weight % (Typical) | Metallurgical Function & Rationale | | :--- | :--- | :--- | | **Carbon (C)** | 1.30 - 1.45 | High carbon ensures a hard martensitic matrix and supports the formation of hard carbides. Critical for achieving high base hardness (≥67 HRC). | | **Tungsten (W)** | 6.00 - 7.00 | Primary contributor to **hot hardness (red-hardness)** through solid solution strengthening. Forms stable tungsten carbides. | | **Molybdenum (Mo)** | 3.00 - 4.00 | Enhances hardenability, refines grain structure, and contributes to secondary hardening. More efficient than tungsten on a weight basis. | | **Chromium (Cr)** | 3.50 - 4.50 | Provides hardenability and wear/corrosion resistance. Forms chromium carbides (M₇C₃). | | **Vanadium (V)** | 1.50 - 2.50 | Forms hard vanadium carbides (MC type) for wear resistance and grain refinement. Level is balanced to provide wear without excessively harming grindability. | | **Cobalt (Co)** | **8.00 - 10.00** | **The defining element.** Cobalt **does not form carbides**. It increases the matrix's **tempering resistance and hot hardness** by raising the dissolution temperature of other alloying elements' carbides during heating. This is the key to its red-hardness. | | **Silicon (Si), Manganese (Mn)** | < 0.50 | Standard deoxidizers and strengtheners. | **Key Microstructural Advantages of CPM Process:** - **Eliminates Cobalt Segregation:** In wrought cobalt steels, cobalt can segregate, causing soft spots. The PM process ensures perfect homogeneity. - **Refined Carbide Structure:** Fine, uniformly dispersed carbides improve toughness, grindability, and cutting edge stability compared to wrought equivalents like M42. - **Predictable Performance:** Isotropic properties ensure consistent behavior in all directions for complex tools like drills and end mills. --- ## **4. Physical & Mechanical Properties** ### **4.1 Standard Heat Treatment** * **Annealing:** Heat to 850-880°C (1560-1615°F), slow cool. Annealed hardness: **~260-280 HB**. * **Preheating:** **Mandatory.** Double preheat at 650°C (1200°F) and 850°C (1560°F) to prevent cracking. * **Austenitizing:** **1190-1220°C (2175-2230°F).** High temperature required to put sufficient carbon and alloys into solution. **Precise control (±5°C) is critical.** Vacuum or salt bath furnace required. * **Quenching:** **Oil, salt bath, or high-pressure gas quench.** * **Tempering:** **Triple or quadruple tempering is mandatory.** Temper at **540-570°C (1000-1060°F)** for 2+ hours each. **Cryogenic treatment** between quenching and first temper is highly recommended to maximize transformation of retained austenite. * **Expected Hardness:** **67-69 HRC** (can reach up to 70 HRC with optimal treatment). ### **4.2 Mechanical Properties (Hardened & Triple Tempered)** | Property | Value / Rating (Typical) | Performance Context | | :--- | :--- | :--- | | **Hardness** | **67 - 69 HRC** | **Extremely high** base hardness, enabling very sharp, durable cutting edges. | | **Hot Hardness (Red-Hardness)** | **Exceptional** | **Primary advantage.** Retains ~62-64 HRC at 600°C (1112°F), significantly outperforming non-cobalt HSS. | | **Abrasive Wear Resistance** | **Very Good** | Good due to high hardness and vanadium carbides, though not its *primary* feature (that is hot hardness). | | **Transverse Rupture Strength (TRS)** | **2,800 - 3,400 MPa** | Moderate for HSS. Cobalt increases hardness but can reduce toughness. The PM structure helps optimize this balance. | | **Impact Toughness** | **Fair** | Lower than M2/M4 types due to high cobalt and carbon. Requires robust tool geometries. | | **Grindability** | **Fair to Good (for Cobalt HSS)** | **Significantly better than wrought cobalt HSS** (e.g., M42) due to fine, uniform carbides. CBN grinding is most effective. | | **Tempering/Softening Resistance** | **Outstanding** | The high cobalt content provides exceptional resistance to overtempering during use or during multiple regrinds. | ### **4.3 Physical Properties (Approximate)** * Density: ~8.30 g/cm³ * Thermal Conductivity: ~25 W/m·K (Slightly higher than standard HSS due to Co) * Coefficient of Thermal Expansion: 11.5 x 10⁻⁶/K * Modulus of Elasticity: 220-225 GPa --- ## **5. Typical Product Applications** CPM Rex 20 is specified for **high-speed, high-feed, and dry machining operations** where heat generation is intense and tool softening is the failure mode. * **High-Performance Cutting Tools:** * **Drills & End Mills:** For **dry or high-speed machining of heat-resistant superalloys (Inconel, Hastelloy, Waspaloy), titanium alloys, and hardened steels (45-55 HRC).** * **Gear Hobs & Shaper Cutters:** For high-speed gear production, especially in tough materials. * **Broaches & Reamers:** For precision holes in high-temperature alloys. * **Inserts & Tool Bits:** For turning applications where high cutting speeds are used. * **Specialized Wear Parts:** Requiring high hardness and thermal stability in non-impact, elevated-temperature environments. --- ## **6. Processing & Manufacturing Guidelines** * **Machinability (Annealed):** **Very Poor.** The combination of high hardness in the annealed state and hard carbides makes machining difficult. Requires **CBN or premium carbide tooling**, low speeds, and high rigidity. * **Grindability:** **Fair to Good.** **CBN wheels are strongly recommended** for all finishing operations. The fine PM structure makes grinding more efficient and consistent than with wrought cobalt steels. Use ample coolant. * **EDM Machining:** Excellent and commonly used for complex shapes. Provides good accuracy and surface finish. A post-EDM low-temperature stress relief is advised. * **Surface Treatments/Coatings:** An excellent substrate for advanced **PVD coatings (AlTiN, AlCrN)**. The extreme base hardness and thermal stability allow these coatings to perform optimally under high heat. --- ## **7. Comparative Performance & Selection Notes** | Criterion | **CPM Rex 20** | **CPM M4** | **Wrought M42** | **Cemented Carbide** | | :--- | :--- | :--- | :--- | :--- | | **Hot Hardness (600°C)** | **Best (HSS)** | Excellent | Very Good | **Superior** | | **Room Temp Hardness** | **67-69 HRC** | 64-66 HRC | 66-68 HRC | 88-92 HRA | | **Wear Resistance** | Very Good | **Excellent** | Good | **Best** | | **Toughness** | Fair | **Good** | Poor | **Very Poor** | | **Optimal Cutting Speed** | **High (HSS)** | Moderate-High | High | **Very High** | | **Key Strength** | **Heat Resistance in Cutting** | **Abrasion Resistance** | Hot Hardness (but brittle) | **Speed & Wear** | **When to Choose CPM Rex 20:** 1. **High cutting speeds and feeds** generate excessive heat, causing other HSS tools to soften and fail rapidly. 2. Machining **high-temperature alloys (Ni/Co-based superalloys)** is the primary application. 3. **Dry machining or minimal coolant** strategies are employed, leading to high tool-tip temperatures. 4. You need the **maximum possible hot hardness from a HSS** to bridge the gap between standard HSS and carbide. **Limitations:** - **Lower toughness** than M2/M4 HSS; requires careful tool design. - **High cost** due to cobalt content and PM processing. - **Complex heat treatment** requires precise furnace capability. --- ## **8. Conclusion** **Crucible CPM® Rex® 20® represents the pinnacle of hot hardness in high-speed steel technology.** It is a specialist material engineered for one primary mission: to **maintain a sharp, hard cutting edge under the intense thermal loads of modern, aggressive machining.** Its value is unlocked in applications where heat, not pure abrasion, is the tool killer. By leveraging the synergy of **high cobalt content and the refined microstructure of powder metallurgy**, Rex 20 delivers: - **Unmatched red-hardness** for a steel, allowing higher cutting parameters. - **Superior consistency and grindability** compared to traditional cobalt HSS. - **Extended tool life in high-temperature machining** environments. For manufacturers pushing the boundaries of speed and productivity on the toughest aerospace, power generation, and die & mold materials, **CPM Rex 20 provides a critical performance bridge, offering the thermal resilience needed to maximize machine output where standard HSS fails and where carbide may be too brittle or costly to implement.** It is the definitive choice for high-heat, high-speed HSS machining. --- -:- For detailed product information, please contact sales. -: Crucible Steel CPM® Rex® 20® (HS) High Speed Steel Specification Dimensions Size： Diameter 20-1000 mm Length <5233 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 CPM® Rex® 20® (HS) High Speed Steel Properties -:- For detailed product information, please contact sales. -:

Applications of Crucible Steel Sheet,Plate CPM® Rex® 20® (HS) High Speed Steel Sheet,Plate -:- For detailed product information, please contact sales. -: Chemical Identifiers Crucible Steel Sheet,Plate CPM® Rex® 20® (HS) High Speed Steel Sheet,Plate -:- For detailed product information, please contact sales. -:

Packing of Crucible Steel Sheet/Plate CPM® Rex® 20® (HS) High Speed Steel Sheet/Plate -:- 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 1704 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