AISI Type O7 Tool Steel Tube,Pipe

AISI Type O7 Tool Steel Tube Product Information -:- For detailed product information, please contact sales. -: AISI Type O7 Tool Steel Tube Synonyms -:- For detailed product information, please contact sales. -:

AISI Type O7 Tool Steel Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AISI Type O7 Tool Steel (UNS T31507)** ## **Overview** **AISI O7 (UNS T31507)** is a **tungsten-rich, oil-hardening cold work tool steel** renowned for its **superior abrasion resistance and edge-holding capability**. Often described as a **"file steel"** or **"shallow-hardening, high-wear" steel**, O7 occupies a unique niche by utilizing a high volume of hard, stable tungsten carbides to achieve exceptional wear resistance, comparable to some air-hardening grades, while maintaining the simpler heat treatment process of an oil-hardening steel. It is the premier choice within the O-series for applications where **maximum wear life is the primary concern**. ## **1. Chemical Composition (Nominal %)** O7's composition is dominated by tungsten and carbon to form abundant, hard carbides. | Element | Content (%) | Primary Function | |---------|------------|------------------| | **Carbon (C)** | 1.10 - 1.30 | **High carbon** to combine with tungsten, forming massive tungsten carbide (WC/W₂C) networks for extreme wear resistance. | | **Tungsten (W)** | 1.40 - 2.00 | **Key element.** Forms extremely hard, stable primary tungsten carbides that are the primary source of O7's abrasion resistance. | | **Manganese (Mn)** | 0.30 - 0.60 | Provides basic hardenability and counteracts sulfur. | | **Chromium (Cr)** | 0.30 - 0.60 | Contributes slightly to hardenability and wear resistance. | | **Silicon (Si)** | 0.30 (Max) | Deoxidizer. | | **Vanadium (V)** | 0.20 - 0.40 | Refines grain size and forms fine, secondary carbides that enhance toughness and wear. | | **Sulfur (S)** | ≤ 0.03 | Typically kept low. | | **Phosphorus (P)** | ≤ 0.03 | Typically kept low. | | **Iron (Fe)** | Balance | Base metal. | **Key Chemistry Note:** O7 is essentially a **simplified, oil-hardening analogue of the high-speed steel T1 (18-4-1)**, but with lower alloy content. The **high carbon and high tungsten** are designed to create a large volume of **undissolved, primary tungsten carbides** during heat treatment. These carbides, which are harder than vanadium carbides, are embedded in a hardened martensitic matrix, creating a highly wear-resistant composite structure. It has a **significantly higher alloy content than O1 or O2**, placing it closer to low-end high-speed steels in wear performance. ## **2. Physical & Mechanical Properties** | Property | Typical Value / Condition | |----------|--------------------------| | **Density** | ~8.1 g/cm³ | | **Melting Point** | ~1420°C (2590°F) | | **Thermal Conductivity** | Relatively low (~30 W/m·K) due to high carbide content. | | **Coefficient of Thermal Expansion** | ~11.5 × 10⁻⁶/K | | **Modulus of Elasticity** | ~210 GPa | | **Annealed Hardness** | 207-241 HB | | **As-Quenched Hardness** | ~64-66 HRC | | **Hardened & Tempered Hardness** | **59-63 HRC** (Typically optimized at 60-62 HRC for best wear/toughness balance). Can achieve up to ~64 HRC with low temper. | | **Tempering Temperature** | 150-260°C (300-500°F) for max hardness; 425-540°C (800-1000°F) for toughness. | | **Wear Resistance (Abrasion)** | **Excellent to Outstanding (for an oil-hardening steel).** Superior to all other O-series grades (O1, O2, O6). Comparable to air-hardening grades like A2. | | **Toughness** | **Low to Moderate.** The large, hard carbides act as stress raisers, reducing impact strength. Lower than O1 or A2 at similar hardness. | | **Hardenability** | **Shallow.** Despite its alloy content, it is still primarily an oil-hardening steel with limited depth of hardening (typically < 25mm / 1 inch fully hard). | | **Machinability (Annealed)** | **Poor.** The hard tungsten carbides are abrasive to cutting tools. Rated around 40-50% of O1. | | **Grindability** | **Difficult.** Tungsten carbides are hard and wear down grinding wheels quickly. | | **Dimensional Stability** | **Fair.** More prone to distortion and size change than O1/O2 due to higher alloy content and carbide volume. | ## **3. International Standards & Cross-References** O7 is a well-defined but less common grade. | Standard | Designation | Notes | |----------|------------|-------| | **UNS** | T31507 | | | **AISI/ASTM (USA)** | O7 (ASTM A681) | | | **ISO (International)** | No direct equivalent. Closest is a high-carbon, high-tungsten oil-hardening type. | | | **DIN (Germany)** | **~1.2514** (100V1) - Not a perfect match, but similar high-carbon, carbide-forming philosophy. | | | **BS (UK)** | **BO7** | | | **JIS (Japan)** | No direct equivalent. | | | **GB (China)** | No direct equivalent. | | | **Common Names** | **"File Steel," "Tungsten Oil-Hardening Steel"** | | ## **4. Product Applications** O7 is selected for tools where **extreme wear resistance is paramount** and the simpler, lower-cost oil-hardening process is preferred over air-hardening, or where its specific carbide structure offers an advantage. **Primary Applications:** * **Severe Abrasive Wear Tools:** * **File blades** and **rasps** (a classic application). * **Woodworking tools:** Planer blades, chipper knives, and router bits for processed woods and composites. * **Cutting knives** for abrasive materials: fiber-reinforced rubber, hard plastics, paper, and cardboard. * **Metal Cutting & Forming:** * **Cold drawing dies** and **mandrels** for wire and tube. * **Shear blades** and **slitter knives** for sheet metal, especially stainless steels. * **Burnishing tools** and **broaches** for finishing operations. * **Wear Parts:** * **Guides**, **wear plates**, and **liners** in machinery handling abrasive materials. * **Punches** and **dies** for abrasive non-metallic materials. **Applications to Avoid:** * Tools subject to heavy shock or impact (low toughness). * Very large cross-sections (limited hardenability). * Applications requiring intricate machining (poor machinability). * Tools requiring minimal distortion during heat treatment (fair stability). ## **5. Heat Treatment Guidelines** Heat treatment is critical to develop O7's wear-resistant carbide structure without causing excessive distortion or cracking. * **Forging:** Forge at **1040-1095°C (1900-2000°F)**. Finish above **925°C (1700°F)**. Cool very slowly in lime or furnace. * **Annealing:** Heat to **790-815°C (1450-1500°F)**, hold, furnace cool slowly (≤15°C/hr) to **480°C (900°F)**, then air cool. Annealed hardness: 207-241 HB. * **Hardening:** 1. **Preheat Thoroughly:** **650-700°C (1200-1290°F)** is essential to prevent cracking. 2. **Austenitize:** **790-820°C (1455-1510°F).** Soak for 20-30 min per inch. **Temperature control is critical.** Higher temperatures dissolve more carbides, increasing hardness but also distortion and cracking risk. 3. **Quench:** Quench **immediately in fast, well-agitated oil** at 40-60°C. Cool to hand-warm. * **Tempering:** **Temper immediately.** For wear tools, temper at **150-200°C (300-400°F)** to achieve 62-64 HRC. For a better toughness balance, temper at **425-480°C (800-900°F)** to achieve 58-60 HRC. **Double tempering is strongly recommended.** ## **6. Comparative Position** O7 offers a unique trade-off: * **vs. O1/O2:** Far superior wear resistance, but worse machinability, toughness, and dimensional stability. * **vs. A2 (Air-Hardening):** Similar wear resistance in many applications, but O7 has lower toughness, more distortion, and shallower hardenability. However, O7 can be heat treated with simpler equipment (oil quench vs. air). * **vs. D2 (High-Carbon, High-Chromium):** Lower wear resistance and much lower hardenability than D2, but simpler to heat treat and often less prone to chipping in very hard conditions due to a different carbide type. --- **Disclaimer:** AISI O7 is a specialized, high-wear oil-hardening steel. Its successful use requires accepting its limitations in machinability, toughness, and hardenability to gain its exceptional wear life. Precise heat treatment is crucial. Always consult the supplier's technical data and consider prototyping for critical applications. The high carbide content makes it sensitive to grinding burns; use light passes and sharp wheels. -:- For detailed product information, please contact sales. -: AISI Type O7 Tool Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6744 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. -: AISI Type O7 Tool Steel Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Type O7 Tool Steel Tube -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Type O7 Tool Steel Tube -:- For detailed product information, please contact sales. -:

Packing of AISI Type O7 Tool Steel Tube -:- 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 Tube 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 3215 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