AISI Type W1 Tool Steel

AISI Type W1 Tool Steel, water quenched at 775°C (1425°F), tempered 350°C (660°F) Product Information -:- For detailed product information, please contact sales. -: AISI Type W1 Tool Steel, water quenched at 775°C (1425°F), tempered 350°C (660°F) Synonyms -:- For detailed product information, please contact sales. -:

AISI Type W1 Tool Steel, water quenched at 775°C (1425°F), tempered 350°C (660°F) Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AISI Type W1 Water-Hardening Tool Steel (UNS T72301)** ## **Overview** **AISI W1 (UNS T72301)** is the quintessential **plain carbon, water-hardening tool steel**. Known for its simplicity, low cost, and ability to achieve a **very hard, sharp cutting edge**, W1 is one of the oldest and most fundamental tool steels. The specified heat treatment (water quenched from 775°C and tempered at 350°C) is a **classic regimen** designed to produce a tool with **high hardness and moderate toughness**, suitable for a wide range of hand tools and simple cutting applications. Its performance is highly dependent on precise heat treatment due to its shallow hardenability and severe quenching. ## **1. Chemical Composition (Nominal %)** W1 is defined by its carbon content; other elements are minimal. | Element | Content (%) | Primary Function | |---------|------------|------------------| | **Carbon (C)** | 0.70 - 1.50 | **The defining element.** Determines maximum achievable hardness. Common ranges are 0.8-1.0% C for general tools, up to 1.2% for files. Other elements are kept very low. | | **Manganese (Mn)** | 0.10 - 0.40 | Minimal; slightly increases hardenability. | | **Silicon (Si)** | 0.10 - 0.40 | Deoxidizer. | | **Chromium (Cr)** | ≤ 0.15 (Residual) | Typically not added. | | **Vanadium (V)** | ≤ 0.10 (Residual) | May be present in trace amounts for grain refinement in "V" variants (W1-9, W1-10). | | **Sulfur (S)** | ≤ 0.025 | Kept low. | | **Phosphorus (P)** | ≤ 0.025 | Kept low. | | **Iron (Fe)** | Balance | Base metal. | **Key Chemistry Note:** W1 is essentially a **high-carbon steel** with minimal alloying. The **carbon content is specified in tenths of a percent** (e.g., W1-8 is ~0.80% C, W1-10 is ~1.00% C). The **absence of significant alloying elements (Cr, Mo, W)** means it has **very shallow hardenability** and must be quenched rapidly in water or brine to achieve full hardness, which introduces high risk of distortion and cracking. ## **2. Physical & Mechanical Properties** *Properties after water quenching from 775°C and tempering at 350°C (for a typical ~1.0% C grade).* | Property | Typical Value / Condition | |----------|--------------------------| | **Density** | 7.84 g/cm³ (0.283 lb/in³) | | **Melting Point** | ~1480°C (2700°F) | | **Thermal Conductivity** | ~48 W/m·K (Good) | | **Coefficient of Thermal Expansion** | 12.5 × 10⁻⁶/K (20-100°C) | | **Modulus of Elasticity** | 210 GPa (30.5 × 10⁶ psi) | | **Hardness (Annealed)** | 183-212 HB | | **As-Quenched Hardness (Water)** | Up to **66-68 HRC** (for 1.0% C). | | **Hardness (Tempered @ 350°C)** | **~58-60 HRC** | | **Tensile Strength** | ~2000-2100 MPa (290-305 ksi) | | **Yield Strength (0.2%)** | ~1650-1750 MPa (239-254 ksi) | | **Impact Toughness** | **Moderate to Low** at this hardness. Tempering at 350°C avoids the 250°C embrittlement zone but results in a hard, somewhat brittle structure. | | **Wear Resistance** | **Good** (for a carbon steel), relies on high hardness rather than alloy carbides. | | **Hardenability** | **Very Shallow.** Effective full hardening only to a depth of a few millimeters. Core of thicker sections remains soft. | | **Machinability (Annealed)** | **Excellent.** | | **Grindability** | Good. | ## **3. International Standards & Cross-References** | Standard | Designation | |----------|------------| | **UNS** | T72301 | | **AISI (USA)** | W1 (ASTM A686) | | **ISO (International)** | **~C100W1** (ISO 4957: Tool steels) | | **DIN (Germany)** | **1.1545** (C105W1) | | **BS (UK)** | **BW1** | | **JIS (Japan)** | **SK1, SK2, SK3** (vary by carbon content) | | **GB (China)** | **T7, T8, T10, T12** (Chinese carbon tool steel series, vary by carbon) | | **Common Name** | **Water-Hardening Carbon Tool Steel, File Steel** | ## **4. Product Applications (Hardened to ~59 HRC)** This specific treatment yields a hard, durable edge suitable for many classic tools. **Primary Applications:** * **Hand Tools:** **Cold chisels**, **center punches**, **screwdrivers**, **hammers**. * **Cutting Tools:** **Knives**, **shear blades**, **woodworking tools** (chisels, plane blades). * **Measuring Tools:** **Calipers**, **gauges**, **surface plates**. * **Metal-Forming Tools:** **Simple punches and dies** for low-volume work. * **Files and Rasps** (typically higher carbon, ~1.2% C, hardened to >64 HRC with low temper). **Why This Specific Heat Treatment?** * **Quenching at 775°C:** This is a **relatively low austenitizing temperature** for a tool steel. It is chosen to: 1. Minimize austenite grain growth, promoting a finer, tougher martensite. 2. Reduce thermal stress and distortion. 3. Be appropriate for the plain carbon composition; higher temperatures offer little benefit and increase risks. * **Water Quench:** Necessary due to the lack of alloying elements. It provides the rapid cooling required to form hard martensite, but is severe and risky. * **Tempering at 350°C (660°F):** This temperature is chosen to: 1. **Relieve the extreme internal stresses** from the water quench, preventing spontaneous cracking. 2. Achieve a **useful working hardness of ~59 HRC**. 3. **Avoid the tempered martensite embrittlement (TME) zone**, which for plain carbon steels is typically between **~250-350°C (480-660°F)**. Tempering at 350°C is at the upper edge of or just past this zone, providing a safer toughness condition than tempering at, for example, 300°C. ## **5. Specified Heat Treatment Process** 1. **Preheating (Highly Recommended):** Heat slowly to **650-700°C (1200-1290°F)** to minimize thermal shock. 2. **Austenitizing:** Heat uniformly to **770-780°C (1420-1435°F)**. Soak for **10-15 minutes per inch** of thinnest cross-section. Avoid overheating. 3. **Quenching (The Critical Step):** * Quench **immediately and vigorously in agitated water or brine (5-10% NaCl)**. * For complex shapes, an **interrupted quench** is often used: quench in water until the part is just below 400°C (when the sizzling sound stops), then immediately transfer to oil or air to cool slowly. This reduces cracking risk. * Cool to hand-warm. 4. **Tempering:** * **Temper immediately** (within 30-60 minutes). * Heat to **350°C (662°F)** and hold for **1-2 hours per inch** of thickness. * **Double tempering** is strongly advised for stress relief. * Cool in air. ## **6. Key Advantages & Limitations** **Advantages:** * **Lowest Cost** tool steel. * **Can achieve the highest possible hardness** (up to 67-68 HRC) of any tool steel due to high carbon and lack of retained austenite. * **Excellent machinability and grindability** in annealed state. * **Simple heat treatment** in principle (but requires skill in practice). **Limitations:** * **Very Low Hardenability:** Only surface hardens; thick sections have a soft core. * **High Distortion & Cracking Risk:** Severe water quench causes uneven stresses. * **Poor Toughness at High Hardness:** More brittle than alloy tool steels at similar hardness. * **Low Wear & Hot Hardness:** Lacks alloy carbides; edge dulls quickly on abrasive materials and softens at low temperatures (~200°C / 400°F). * **Decarburizes Easily** during heat treatment. --- **Disclaimer:** The water quench of W1 is a high-risk operation, especially for tools with sharp corners, holes, or variable sections. The success of this treatment depends heavily on the skill of the heat treater. For tools requiring better depth of hardening, less distortion, or improved toughness, **oil-hardening grades like O1 or air-hardening grades like A2** are strongly recommended. The specified tempering at 350°C is appropriate to mitigate quench stresses, but for maximum toughness, a higher temper (e.g., 425°C) yielding lower hardness (~55 HRC) may be preferable. Always consider the specific tool geometry and service requirements. -:- For detailed product information, please contact sales. -: AISI Type W1 Tool Steel, water quenched at 775°C (1425°F), tempered 350°C (660°F) Specification Dimensions Size： Diameter 20-1000 mm Length <6775 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 W1 Tool Steel, water quenched at 775°C (1425°F), tempered 350°C (660°F) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Type W1 Tool Steel, water quenched at 775°C (1425°F), tempered 350°C (660°F) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Type W1 Tool Steel, water quenched at 775°C (1425°F), tempered 350°C (660°F) -:- For detailed product information, please contact sales. -:

Packing of AISI Type W1 Tool Steel, water quenched at 775°C (1425°F), tempered 350°C (660°F) -:- 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 3246 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