AISI Type W2 Tool Steel

AISI Type W2 Tool Steel, water quenched at 775°C (1425°F), and tempered Product Information -:- For detailed product information, please contact sales. -: AISI Type W2 Tool Steel, water quenched at 775°C (1425°F), and tempered Synonyms -:- For detailed product information, please contact sales. -:

AISI Type W2 Tool Steel, water quenched at 775°C (1425°F), and tempered Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AISI Type W2 Water-Hardening Tool Steel (UNS T72302)** ## **Overview** **AISI W2 (UNS T72302)** is a **vanadium-modified, plain carbon water-hardening tool steel**. It is a direct evolution of the basic W1 grade, distinguished by the **intentional addition of vanadium (0.15-0.35%)**. This small but critical addition refines the grain structure during heat treatment, resulting in a **finer, tougher martensitic microstructure** compared to W1. The specified heat treatment of water quenching from 775°C (1425°F) followed by tempering is a classic regimen designed to leverage W2's ability to achieve a **very hard, yet slightly less brittle, cutting edge** than W1, making it a preferred choice for premium hand tools and cutting implements where edge integrity is paramount. ## **1. Chemical Composition (Nominal %)** W2 enhances W1 with vanadium for grain refinement. | Element | Content (%) | Primary Function | |---------|------------|------------------| | **Carbon (C)** | 0.85 - 1.50 | **Primary element.** Determines maximum hardness. Common grades: W2-9 (~0.90% C), W2-10 (~1.00% C). | | **Vanadium (V)** | **0.15 - 0.35** | **Key differentiator.** Acts as a potent grain refiner by forming stable vanadium carbides that pin austenite grain boundaries during heating, resulting in a finer final martensite and improved toughness. | | **Manganese (Mn)** | 0.10 - 0.40 | Minimal effect on hardenability. | | **Silicon (Si)** | 0.10 - 0.40 | Deoxidizer. | | **Chromium (Cr)** | ≤ 0.15 (Residual) | Not intentionally added. | | **Sulfur (S)** | ≤ 0.025 | Impurity, kept low. | | **Phosphorus (P)** | ≤ 0.025 | Impurity, kept low. | | **Iron (Fe)** | Balance | Base metal. | **Key Chemistry Note:** W2 is essentially **"W1 + V"**. The **vanadium content, even at these low levels (0.15-0.35%), is transformative**. It inhibits austenite grain growth during the austenitizing stage, leading to a much finer prior austenite grain size. Upon quenching, this produces a finer, more uniform martensitic structure, which directly translates to **better toughness and less susceptibility to quench cracking** at equivalent hardness levels compared to W1. It retains the very high hardenability limitation of a plain carbon steel. ## **2. Physical & Mechanical Properties** *Properties after water quenching from 775°C and tempering (tempering temperature determines final hardness).* | Property | Typical Value / Condition | |----------|--------------------------| | **Density** | ~7.84 g/cm³ | | **Melting Point** | ~1475°C (2690°F) | | **Thermal Conductivity** | ~48 W/m·K | | **Coefficient of Thermal Expansion** | 12.5 × 10⁻⁶/K (20-100°C) | | **Modulus of Elasticity** | 210 GPa (30.5 × 10⁶ psi) | | **Annealed Hardness** | 183-212 HB | | **As-Quenched Hardness (Water)** | Up to **65-67 HRC** (for 1.0% C). | | **Hardness (After Tempering)** | **Variable: 55-64 HRC.** Depends on tempering temperature (see table below). | | **Tensile Strength (at ~60 HRC)** | ~1950-2050 MPa (283-297 ksi) | | **Impact Toughness** | **Moderate, but superior to W1 at the same hardness** due to finer grain structure. | | **Wear Resistance** | **Good.** Slightly better than W1 due to fine vanadium carbides. | | **Hardenability** | **Very Shallow.** Identical to W1; effective depth only a few millimeters. | | **Machinability (Annealed)** | **Excellent.** | | **Grindability** | Good. | ## **3. Tempering Response & Final Hardness** *The "and tempered" specification requires definition. Here are common outcomes:* | Tempering Temperature | Approx. Final Hardness (for ~1.0% C) | Resulting Property Emphasis | |------------------------|--------------------------------------|-----------------------------| | **150°C (300°F)** | 64-65 HRC | Maximum hardness, high stress, lowest toughness. | | **200°C (390°F)** | 62-63 HRC | High hardness for cutting tools, some stress relief. | | **315°C (600°F)** | 58-60 HRC | **Good balance for many tools** (chisels, punches). Relieves most quenching stress. | | **425°C (800°F)** | 54-56 HRC | Higher toughness, lower hardness for impact tools. | **Important:** For plain carbon steels like W2, the **tempered martensite embrittlement (TME) zone is approximately 250-350°C (480-660°F)**. Tempering within this range should generally be avoided or followed by rapid cooling to minimize embrittlement. ## **4. International Standards & Cross-References** | Standard | Designation | Notes | |----------|------------|-------| | **UNS** | T72302 | | | **AISI/ASTM (USA)** | W2 (ASTM A686) | | | **ISO (International)** | **~C105W2** (ISO 4957) | Reflects carbon and vanadium content. | | **DIN (Germany)** | **1.1645** (Similar steel with vanadium) | | | **BS (UK)** | **BW2** | | | **JIS (Japan)** | **SK1~SK4 with V** (No direct equivalent; vanadium versions exist). | | | **GB (China)** | **T8A, T10A, T12A** (The "A" denotes higher quality, often with V) | | | **Common Name** | **Vanadium Water-Hardening Steel** | | ## **5. Product Applications** W2 is favored for tools requiring a keen, durable edge where the slight premium over W1 is justified by better performance. **Primary Applications (After Full HT):** * **Premium Hand Tools:** **Files, rasps, cold chisels, center punches, engraving tools.** The finer grain improves edge stability and reduces chipping. * **Woodworking Tools:** **High-quality plane blades, chisels, carving tools, drawknives.** Can take and hold a sharper edge than W1. * **Metal Cutting Tools:** **Lathe tools for soft metals, knives, shear blades.** * **Punches and Dies:** For simpler, low-volume forming operations. * **Springs** for tools and instruments. ## **6. Specified Heat Treatment Process** 1. **Preheating (Highly Recommended):** Heat to **650-700°C (1200-1290°F)**. 2. **Austenitizing:** Heat uniformly to **770-780°C (1420-1435°F)**. The **775°C (1425°F)** target is ideal. Soak for **10-15 min/inch**. The vanadium helps maintain a fine grain even at this temperature. 3. **Quenching:** Quench **immediately and vigorously in agitated water or brine.** For complex shapes, use an **interrupted quench**: quench in water until ~400°C (sizzling stops), then transfer to oil. 4. **Tempering (Must be Specified):** * **Temper immediately** (within 30-60 minutes). * Choose tempering temperature based on desired final hardness (see Section 3). **315°C (600°F)** is a common target for a balanced tool (~59 HRC). * Hold for **1-2 hours per inch**. * **Double tempering** is strongly advised for best stress relief and stability. ## **7. Advantages over W1 and Limitations** **Advantages over W1:** * **Finer Grain Structure:** Leads to better toughness and edge strength. * **Reduced Tendency to Crack** during quenching. * **Ability to withstand slightly higher austenitizing temperatures** without grain coarsening. * **Marginally better wear resistance.** **Shared Limitations with W1:** * **Very Shallow Hardenability.** * **Severe Quenching Required** with high distortion/cracking risk. * **Poor Toughness** compared to alloy tool steels. * **Very Low Hot Hardness.** * **Decarburizes easily.** **Conclusion:** AISI W2 represents a **refined version of the classic water-hardening tool steel**. The addition of vanadium provides a clear, if modest, improvement in grain control and toughness, making it the **grade of choice among water-hardening steels for quality cutting edges**. However, it still carries all the fundamental limitations of the water-hardening process. For most modern applications requiring reliable performance and dimensional stability, **oil-hardening (O1) or air-hardening (A2, A8) steels are superior choices.** --- **Disclaimer:** The heat treatment of W2, particularly the water quench, remains a high-skill operation with significant risk of failure. The final properties are **entirely dependent on the unspecified tempering temperature**. Always specify the complete heat treatment cycle, including tempering temperature and time. For tools where consistent performance and minimal distortion are critical, moving to an oil- or air-hardening grade is strongly recommended. The information provided assumes proper execution of the heat treatment process; results may vary based on section size, furnace conditions, and quenching technique. -:- For detailed product information, please contact sales. -: AISI Type W2 Tool Steel, water quenched at 775°C (1425°F), and tempered Specification Dimensions Size： Diameter 20-1000 mm Length <6777 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 W2 Tool Steel, water quenched at 775°C (1425°F), and tempered Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Type W2 Tool Steel, water quenched at 775°C (1425°F), and tempered -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Type W2 Tool Steel, water quenched at 775°C (1425°F), and tempered -:- For detailed product information, please contact sales. -:

Packing of AISI Type W2 Tool Steel, water quenched at 775°C (1425°F), and tempered -:- 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 3248 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