Crucible Steel HALGRAPH® Tool Steel, AISI O6

Crucible Steel HALGRAPH® Tool Steel, AISI O6 Product Information -:- For detailed product information, please contact sales. -: Crucible Steel HALGRAPH® Tool Steel, AISI O6 Synonyms -:- For detailed product information, please contact sales. -:

Crucible Steel HALGRAPH® Tool Steel, AISI O6 Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: Crucible Steel HALGRAPH® (AISI O6) Tool Steel** Crucible Steel HALGRAPH® is a premium, oil-hardening, graphitic tool steel that conforms to the AISI O6 specification. It occupies a unique position in the tool steel spectrum, distinguished by its **exceptionally high silicon content and free graphite microstructure**. This composition grants HALGRAPH® **superior machinability in the annealed state—ranking among the best of all tool steels—along with good wear resistance, low distortion during heat treatment, and excellent resistance to galling and seizing**. It is specifically engineered for applications requiring intricate machining, good wear life, and reliable performance in forming and cutting operations. The "graphitic" characteristic is key to its performance. The high silicon content promotes the formation of fine, evenly distributed graphite particles within the steel matrix. These particles act as a built-in lubricant during both the machining of the tool itself and during the tool's service life, reducing friction and chip welding. HALGRAPH® is the material of choice for producing complex, precision tools where ease of manufacture and consistent performance are paramount. --- ## **1. Chemical Composition (Weight %)** The composition of O6 is defined by very high silicon and carbon, with balanced manganese and molybdenum. | **Element** | **Carbon (C)** | **Silicon (Si)** | **Manganese (Mn)** | **Molybdenum (Mo)** | **Sulfur (S)** | **Phosphorus (P)** | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | **Content** | 1.25 - 1.55 | **1.00 - 2.00** | 0.55 - 1.20 | 0.20 - 0.30 | 0.08 - 0.15 | ≤ 0.030 | | **Role** | Provides high hardness and wear resistance. Part of the carbon exists as free graphite, enhancing machinability and anti-galling properties. | **Primary modifier.** Promotes the formation of free graphite in the microstructure. Increases hardenability, strength, and resistance to softening. | Aids in deoxidation, contributes to hardenability, and helps control the graphite formation. | Enhances hardenability and increases strength, particularly in thicker sections. | Improves machinability by forming manganese sulfide inclusions. | Typically minimized; trace element. | *Note: Iron (Fe) constitutes the remainder. The combination of high carbon and silicon in a specific thermal history creates the unique graphitic structure.* --- ## **2. Physical & Mechanical Properties** *Typical properties after proper oil quenching and tempering to a working hardness of 57-61 HRC.* * **Density:** Slightly lower than most tool steels (~7.6-7.7 g/cm³) due to the presence of graphite. * **Modulus of Elasticity:** ~190-200 GPa, slightly lower due to the graphite phase. * **Thermal Conductivity:** Good; graphite aids in heat dissipation. * **Hardenability:** **Fair to Good (Oil-Hardening).** Suitable for through-hardening in moderate sections. Depth is less than some other oil-hardening grades due to its specific alloy design focused on graphite formation. * **Hardness (Typical Working Range):** **56 - 62 HRC.** Most commonly used at **58-60 HRC**. * **Wear Resistance:** **Good.** Provides reliable wear resistance for many cold work applications. The hard martensitic matrix resists abrasion, while the graphite reduces adhesive wear (galling). * **Machinability (Annealed):** **Exceptional.** HALGRAPH® is renowned as one of the most machinable tool steels. It can be machined at high speeds and feeds with excellent surface finish and long tool life, similar to free-machining steels like 12L14 but with the ability to be hardened. * **Resistance to Galling & Seizing:** **Excellent.** The free graphite particles act as a solid lubricant, making it ideal for forming tools and applications involving sliding contact against metals (especially aluminum and brass). * **Dimensional Stability:** **Very Good.** Exhibits low and predictable distortion during oil quenching, similar to other quality oil-hardening grades. * **Toughness:** **Moderate.** Adequate for most cold work applications but lower than tougher grades like S7 or A9. Not recommended for high-impact uses. --- ## **3. Heat Treatment** Heat treatment is straightforward but requires control to achieve the desired graphite structure and hardness. * **Annealing:** Furnace cool from 790-815°C (1450-1500°F) to develop the optimal soft, graphitic structure for machining. Annealed hardness: 183-229 HB. * **Stress Relieving:** 595-650°C (1100-1200°F), hold, then slow cool. * **Preheating:** Recommended at 650-700°C (1200-1290°F). * **Austenitizing:** **790-815°C (1450-1500°F).** A common temperature is **800°C (1475°F)**. **Soaking time is critical**—too short prevents proper austenitization; too long can dissolve excessive graphite, reducing its beneficial effects. Typical soak is 20-30 minutes per inch of thickness. * **Quenching:** **Oil quench** in warm, agitated oil (40-60°C / 100-140°F). * **Tempering:** **Mandatory.** Temper immediately after quenching. * **Typical Tempering Range:** **150-315°C (300-600°F).** * For a hardness of 58-60 HRC, temper at **175-230°C (350-450°F)** for 1-2 hours. * **Avoid tempering between 260-370°C (500-700°F)** due to risk of embrittlement and loss of beneficial graphite effects. * A double temper is often beneficial. --- ## **4. Key Applications** HALGRAPH® (O6) is uniquely suited for applications that benefit from its machinability and anti-galling properties. * **Intricate Forming and Drawing Dies:** Especially for non-ferrous metals like aluminum, brass, and copper, where galling is a common problem. * **Knurls, Thread Rolls, and Form Rolls:** Tools for cold forming where smooth, non-seizing operation is critical. * **Plastic Injection Molds and Cores:** For molding abrasive or sticky plastics, where the graphite helps with part release. * **Master Hubs, Patterns, and Model Tools:** Where complex shapes must be easily machined and then hardened for durability. * **Gears, Cams, and Wear Plates:** In mechanisms with sliding contact where lubrication is difficult. * **General Purpose Tooling Requiring Complex Machining:** Punches, dies, and fixtures that are too intricate to be economically made from less machinable steels. --- ## **5. International Standards & Cross-References** Crucible HALGRAPH® is the brand name for Crucible's AISI O6 grade. * **AISI/SAE:** **O6** * **UNS:** T31506 * **European (EN):** No direct equivalent. The closest in concept might be a graphitic steel like **1.2210** but compositions differ significantly. * **Japanese (JIS):** No direct JIS equivalent. * **Common Trade Names:** Graphitic Tool Steel O6, Oil-Hardening Graphitic Steel. --- ## **6. Advantages & Limitations** **Advantages:** * **Unsurpassed Machinability:** Allows for fast, low-cost fabrication of complex tooling with excellent finishes. * **Excellent Anti-Galling Properties:** The graphite provides built-in lubrication, reducing friction and part sticking. * **Good Wear Resistance:** Suitable for a wide range of industrial applications. * **Low Distortion:** Predictable behavior during heat treatment. * **Good Surface Finish:** Both in the machined and in-service condition. **Limitations:** * **Limited Hardenability Depth:** Not for very large sections. * **Moderate Toughness:** Not suitable for high-shock applications. * **Heat Treatment Sensitivity:** Requires precise control of austenitizing time/temperature to preserve graphite benefits. * **Not Stainless:** Will rust if not protected. * **Lower Hot Hardness:** Not for elevated temperature service. --- ## **7. Summary** **Crucible Steel HALGRAPH® (AISI O6) is a specialized, problem-solving tool steel that excels where ease of manufacturing and friction reduction are critical design parameters.** Its unique graphitic microstructure makes it the ultimate choice for machining intricate tools that also require good wear resistance and anti-galling characteristics. For toolmakers facing the challenge of producing complex forming dies for aluminum or intricate plastic molds, HALGRAPH® provides a practical path: machine it easily like a low-carbon steel, then harden it to perform like a durable tool steel. It is the intelligent choice for applications where the cost and difficulty of machining are primary concerns, without sacrificing the functional performance of the finished tool. -:- For detailed product information, please contact sales. -: Crucible Steel HALGRAPH® Tool Steel, AISI O6 Specification Dimensions Size： Diameter 20-1000 mm Length <6980 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 HALGRAPH® Tool Steel, AISI O6 Properties -:- For detailed product information, please contact sales. -:

Applications of Crucible Steel HALGRAPH® Tool Steel, AISI O6 -:- For detailed product information, please contact sales. -: Chemical Identifiers Crucible Steel HALGRAPH® Tool Steel, AISI O6 -:- For detailed product information, please contact sales. -:

Packing of Crucible Steel HALGRAPH® Tool Steel, AISI O6 -:- 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 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 3451 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