Crucible Steel Wire,CPM® REX® 121 HS High Speed Steel Wire

Crucible Steel Wire CPM® REX® 121 HS High Speed Steel Wire Product Information -:- For detailed product information, please contact sales. -: Crucible Steel Wire CPM® REX® 121 HS High Speed Steel Wire Synonyms -:- For detailed product information, please contact sales. -:

Crucible Steel CPM® REX® 121 HS High Speed Steel Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: Crucible CPM® REX® 121 (HS) High Speed Steel** Crucible CPM® REX® 121 (HS) represents the absolute pinnacle of particle metallurgy (PM) high-speed steel technology, engineered to deliver **unprecedented hot hardness (red hardness) and extreme wear resistance** for the most severe machining challenges on the planet. It is not merely an incremental improvement but a breakthrough alloy designed to operate where all other high-speed steels fail—particularly in the ultra-high-speed machining of advanced aerospace superalloys, hardened tool steels, and other extremely abrasive and high-temperature materials. Manufactured via Crucible's proprietary CPM process, REX 121 achieves a chemistry impossible with conventional ingot metallurgy: an ultra-high carbon, high vanadium, high cobalt, and high tungsten system. This creates an enormous volume of ultra-hard vanadium and tungsten carbides within a cobalt-strengthened matrix. The "HS" designation underscores its optimization for **High-Speed** machining under extreme thermal duress. This material defines the outer limit of cutting tool material performance, offering a unique combination of **hardness exceeding 70 HRC, exceptional red hardness, and abrasion resistance rivaling cemented carbides**, while retaining the manufacturability and toughness of steel. --- ## **1. Chemical Composition (Weight %)** The composition of REX 121 is extreme, pushing the boundaries of alloying element solubility in steel. | **Element** | **Carbon (C)** | **Tungsten (W)** | **Vanadium (V)** | **Cobalt (Co)** | **Chromium (Cr)** | **Molybdenum (Mo)** | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | **Content** | **3.40** | **10.00** | **9.50** | **9.50** | **4.00** | **5.25** | | **Role** | **Extremely High.** Essential for forming the massive volume of complex carbides (MC, M₆C) that provide the foundation for its legendary hardness and wear resistance. Near the solubility limit for steel. | Major contributor to hot hardness and wear resistance; forms hard, stable tungsten-rich carbides. | **Dominant wear element.** The 9.5% content creates an extraordinary volume of ultra-hard vanadium carbides (VC), providing peerless abrasion resistance. | **Critical matrix strengthener.** The high cobalt content (9.5%) provides exceptional hot hardness by dramatically increasing the matrix's resistance to tempering at extreme temperatures. | Provides necessary hardenability and oxidation resistance. The level is balanced to support the other elements without forming excessive chromium carbides. | Enhances hardenability, refines the matrix, and contributes to hot hardness and tempering resistance. Works synergistically with tungsten. | *Note: Iron (Fe) constitutes the remainder. This composition results in one of the highest carbide volumes of any commercial steel.* --- ## **2. Physical & Mechanical Properties** *Typical properties after optimal and highly specialized heat treatment. Its performance is defined by extremes.* * **Density:** ~8.1 - 8.2 g/cm³ * **Modulus of Elasticity:** ~215 GPa (31.2 x 10⁶ psi) * **Thermal Conductivity:** Low, due to the very high volume of carbide phases obstructing heat flow. * **Hot Hardness (Red Hardness):** **Exceptional.** Capable of maintaining a hardness above 66 HRC at temperatures exceeding **650°C (1200°F)**, a benchmark that surpasses virtually all other high-speed steels. * **Hardness (Typical Working Range):** **67 - 72+ HRC.** It is one of the few commercial steels capable of reliably achieving and maintaining **70-72 HRC**. This is a defining characteristic. * **Abrasion Resistance:** **Unrivaled among high-speed steels.** Its wear resistance is in a class of its own, significantly exceeding that of CPM 10V/15V and approaching some grades of cemented carbide. This is due to the colossal volume of ultra-hard carbides. * **Toughness:** **Low.** This is the primary and critical trade-off. At its working hardness, REX 121 has **very low impact toughness**. It is brittle and highly sensitive to notches, shock, and interrupted cuts. It must be used in extremely rigid setups with optimal geometry and continuous cutting conditions. * **Compressive Strength:** Extremely high, suitable for very high-pressure cutting. * **Grindability (Hardened):** **Extremely Difficult.** The extreme hardness and carbide volume make grinding a major challenge. **Diamond abrasives are absolutely mandatory**; grinding is slow and requires expertise. --- ## **3. Heat Treatment** Heat treatment is complex, critical, and requires the highest level of precision and equipment. * **Annealing:** Heat to 900-925°C (1650-1700°F), slow cool. Annealed hardness: 300-350 HB. * **Preheating:** **Absolutely Critical.** Use a thorough **double or triple preheat**: e.g., 540°C (1000°F), 815°C (1500°F), and 950°C (1740°F) to minimize thermal shock. * **Austenitizing:** **1150-1180°C (2100-2155°F).** **Extreme precision required.** A typical target is **1165-1175°C (2130-2145°F)**. Temperature control within ±5°C is crucial. Higher temperatures dissolve more carbides but drastically increase brittleness and retained austenite. * **Quenching:** **High-pressure gas quenching** in a vacuum furnace is **mandatory** for dimensional control and to avoid cracking. Air quenching is not recommended for complex tools. * **Tempering:** **Complex and Mandatory.** Requires **multiple (4-5 or more) tempering cycles**, each for 2 hours. * **Typical tempering range: 540-560°C (1005-1040°F).** A very strong secondary hardening response occurs. * **Sub-Zero Treatment:** **Essential.** Multiple deep cryogenic treatments (e.g., -100°C / -148°F) interspersed between tempering cycles are often necessary to fully transform the high levels of retained austenite and achieve maximum hardness (>70 HRC) and stability. --- ## **4. Key Applications** REX 121 is reserved for the most extreme, high-value machining applications where its unique properties are indispensable. * **Ultra-High-Speed Machining of Superalloys:** Finishing end mills, ball-nose cutters, and drills for aerospace components made from nickel-based (Inconel 718, Rene alloys) and cobalt-based superalloys. * **Hard Machining / High-Speed Die & Mold Finishing:** Tools for machining hardened tool and die steels (55-65 HRC) where extreme wear resistance and edge sharpness are required. * **Machining Highly Abrasive Composites:** Carbon fiber reinforced polymers (CFRP), metal matrix composites (MMCs), and ceramic-filled materials. * **Precision Boring and Reaming** of high-temperature alloy components. * **Specialty Cutting Tools** where maximizing tool life in continuous, high-temperature, abrasive cutting is the sole economic driver. --- ## **5. International Standards & Cross-References** CPM REX 121 is a proprietary, ultra-high-performance grade with no direct international standard equivalents. * **AISI/SAE:** No equivalent. It is a "beyond classification" PM super high-speed steel. * **UNS:** No standard designation. * **European (EN) / ISO / JIS:** No direct equivalents. * **Common Trade Names/Comparisons:** Often referred to simply as **REX 121**. It is the benchmark for ultimate wear resistance and hardness in PM HSS. The closest competitor analogues are other ultra-high-performance PM grades like **Böhler S790** or similar "maximum performance" steels designed for similar niche applications. --- ## **6. Advantages & Limitations** **Advantages:** * **Unmatched Combination of Hardness & Hot Hardness:** Can achieve >70 HRC while maintaining exceptional red hardness. * **Peerless Wear Resistance among HSS:** Provides tool life that can rival or exceed carbide in specific abrasive applications. * **CPM Microstructure Benefits:** Offers the only way to make this chemistry usable, providing the toughness and grindability it has, which would be non-existent in an ingot-cast version. * **Ultimate Performance for Specific Cuts:** Solves machining problems that no other steel can. **Limitations:** * **Very Low Toughness:** **Extremely brittle.** Application failure due to chipping or fracture is the primary risk. * **Extremely High Cost:** Very expensive due to extreme alloy content (V, Co, W) and complex PM/heat treatment. * **Exceptionally Difficult to Heat Treat and Grind:** Requires world-class furnace and grinding capabilities. * **Highly Specialized and Demanding Application:** Its use is only justified in a very narrow, extreme performance window. Incorrect application leads to catastrophic and expensive failure. --- ## **7. Summary** **Crucible CPM® REX® 121 (HS) is not just a tool steel; it is a cutting-edge material system engineered for the absolute limit of metallic cutting tool performance.** It represents the pinnacle of what is possible when particle metallurgy is used to transcend the chemical limits of conventional steelmaking. Its successful application is a testament to advanced engineering, requiring perfect harmony between material, heat treatment, tool design, and machining process. For the aerospace, defense, and precision mold industries facing the challenge of machining the world's toughest materials at productive speeds, REX 121 offers a capability that borders on the revolutionary. It is the definitive choice when the mission is to push the boundaries of speed, hardness, and wear resistance, accepting no compromise except for the inherent brittleness that comes with such extreme properties. -:- For detailed product information, please contact sales. -: Crucible Steel CPM® REX® 121 HS High Speed Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6991 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® 121 HS High Speed Steel Properties -:- For detailed product information, please contact sales. -:

Applications of Crucible Steel Wire CPM® REX® 121 HS High Speed Steel Wire -:- For detailed product information, please contact sales. -: Chemical Identifiers Crucible Steel Wire CPM® REX® 121 HS High Speed Steel Wire -:- For detailed product information, please contact sales. -:

Packing of Crucible Steel Wire CPM® REX® 121 HS High Speed 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 3462 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