AISI Type D4 High Carbon, High Chromium Cold Work Tool Steel Wire (UNS T30404)

AISI Type D4 High Carbon, High Chromium Cold Work Tool Steel Wire (UNS T30404) Product Information -:- For detailed product information, please contact sales. -: AISI Type D4 High Carbon, High Chromium Cold Work Tool Steel Wire (UNS T30404) Synonyms -:- For detailed product information, please contact sales. -:

AISI Type D4 High Carbon, High Chromium Cold Work Tool Steel (UNS T30404) Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: AISI Type D4 High Carbon, High Chromium Cold Work Tool Steel (UNS T30404)** ## **Overview** **AISI Type D4 (UNS T30404)** is a **premium-grade, high-carbon, high-chromium, air-hardening cold work tool steel** that represents an advanced evolution within the D-series family. Positioned between the widely used D2 and the ultra-high carbon D3, D4 offers a sophisticated balance of **exceptional wear resistance, good dimensional stability, and improved microstructural control**. Its optimized composition is designed to provide superior performance in severe abrasive environments while maintaining better toughness and grindability than D3, making it a preferred choice for demanding precision tooling applications where both wear resistance and tool integrity are critical. --- ## **Chemical Composition (Typical Weight %)** D4 features a carefully calibrated high-carbon, high-chromium composition with strategic vanadium addition. | Element | Content (%) | Role in Microstructure & Properties | | :--- | :--- | :--- | | **Carbon (C)** | 2.05 - 2.40 | **Very high carbon content.** Forms a substantial volume of hard carbides with chromium and vanadium, providing the foundation for extreme wear resistance. Higher than D2 but typically with better control than D3. | | **Chromium (Cr)** | 11.00 - 13.00 | Provides excellent air-hardening capability, forms primary chromium carbides (M₇C₃), and enhances corrosion/oxidation resistance. | | **Molybdenum (Mo)** | 0.70 - 1.20 | Enhances hardenability, promotes secondary hardening during tempering, refines grain structure, and improves toughness. | | **Vanadium (V)** | **0.50 - 1.10** | **Critical addition.** Forms ultra-hard vanadium carbides (VC/V₄C₃) that significantly boost abrasion resistance, refine grain size, and improve toughness through microstructural control. | | **Silicon (Si)** | 0.10 - 0.60 | Deoxidizer and strengthens the matrix. | | **Manganese (Mn)** | 0.20 - 0.60 | Aids hardenability. | | **Sulfur (S)** | ≤ 0.03 | - | | **Phosphorus (P)** | ≤ 0.03 | - | | **Iron (Fe)** | **Balance** | - | **Key Distinction:** D4 combines the **high carbon approach of D3** with the **balanced alloying philosophy of D2**, typically including consistent vanadium content. This results in a carbide structure that is both voluminous and refined, offering excellent wear resistance with better structural integrity than D3. --- ## **Physical & Mechanical Properties** *Properties are for material in the hardened and tempered condition (typical working hardness 58-62 HRC).* | Property | Typical Value / Description | | :--- | :--- | | **Density** | ~7.75 g/cm³ (0.280 lb/in³) | | **Hardness (Annealed)** | 230 - 255 HB | | **Hardness (Hardened & Tempered)** | **58 - 64 HRC** (Typically operated at 60-62 HRC) | | **Wear Resistance** | **Exceptional.** Generally superior to D2 and comparable to D3 in abrasion resistance, but with a more refined carbide distribution that may offer better performance in certain applications. | | **Toughness** | **Fair to Good (for its wear class).** Better than D3 at equivalent hardness due to more controlled carbide size and distribution, but lower than D2. | | **Dimensional Stability** | **Excellent.** As an air-hardening steel, it exhibits minimal distortion during heat treatment (<0.0003 in/in), superior to oil-hardening grades like D3. | | **Machinability (Annealed)** | **Poor** (~30% of 1% carbon steel). Difficult due to high carbide content; requires carbide tooling. | | **Grindability** | **Very Poor.** Challenging due to hard vanadium carbides, but often considered better than D3 due to more consistent microstructure. | | **Thermal Conductivity** | Low (~22 W/m·K) | | **Coefficient of Thermal Expansion** | ~10.3 × 10⁻⁶/°C (20-100°C) | | **Deep Hardenability** | **Excellent.** Fully air-hardens in sections up to 150mm (6") or more. | --- ## **Heat Treatment Guidelines** D4 requires careful heat treatment to optimize its high-performance microstructure. | Process | Parameters | | :--- | :--- | | **Annealing** | Heat to 870-900°C (1600-1650°F), slow furnace cool at ≤15°C/hour to 480°C (900°F), then air cool. Result: 230-255 HB. | | **Stress Relieving** | 650-675°C (1200-1250°F) for 2+ hours, slow cool. | | **Preheating** | **Critical:** Double preheat at 550-650°C (1025-1200°F) and 800-850°C (1475-1560°F). | | **Austenitizing** | 970-1020°C (1780-1870°F). Higher temperatures increase carbide dissolution and hardness but reduce toughness. 980-1000°C is typical. | | **Quenching** | **Air quench** in still or forced air. High-pressure gas quenching recommended for complex shapes. | | **Tempering** | **Multiple tempers mandatory.** Temper immediately at 480-540°C (900-1000°F) for 2+ hours each cycle. Double or triple tempering is standard. For high hardness (60-62 HRC): temper at 200-250°C (390-480°F). | --- ## **Product Applications** D4 is engineered for the most demanding wear applications where precision, stability, and longevity are paramount. ### **Primary Applications:** 1. **Precision Blanking and Forming Dies:** For long production runs on highly abrasive materials (fiberglass composites, prepainted metals, abrasive laminates). 2. **Powder Compaction Tooling:** Dies and punches for pressing hard metal powders, ceramics, and tungsten carbide where extreme die wear occurs. 3. **Thread Rolling and Cold Forming Dies:** For hard or abrasive materials requiring exceptional wear life. 4. **Slitter Knives and Rotary Cutters:** In paper, plastic, and composite cutting industries where edge retention is critical. 5. **Cold Extrusion Tools:** For forming abrasive materials. 6. **Precision Gauges and Wear Parts:** Requiring dimensional stability under severe abrasive conditions. 7. **Plastic Injection Molds:** For highly abrasive filled plastics (glass-filled, mineral-filled polymers). ### **Industry Usage:** - **Advanced Composites Manufacturing** - **Powder Metallurgy** - **Precision Metal Stamping** - **Cutting Tool Industry** - **High-Performance Plastics Molding** --- ## **International Standards & Cross-Reference** AISI D4 is recognized in several international systems, though less common than D2 or D3. | Standard | Designation | Equivalent / Similar Grade | | :--- | :--- | :--- | | **AISI/SAE (USA)** | **Type D4** | - | | **UNS (USA)** | **T30404** | - | | **ASTM (USA)** | A681 | Grade D4 | | **Europe (EN)** | **~1.2436** | X210CrW12 (Similar high-C, high-Cr steel) | | **Germany (DIN)** | **~1.2436** | X210CrW12 | | **Japan (JIS)** | **~SKD2** | - | | **Sweden (SS)** | **~2310** | - | **Note:** True, chemically identical equivalents to AISI D4 are less common than for D2 or D3. The European 1.2436 is a close approximation, and many suppliers treat D4 as a specialized or premium version of high-carbon, high-chromium tool steels. --- ## **Technical Comparison Within D-Series** | Property | **D4 (UNS T30404)** | **D2 (T30402)** | **D3 (T30403)** | | :--- | :--- | :--- | :--- | | **Carbon Content** | **2.05-2.40%** (Highest) | 1.40-1.60% | 2.00-2.35% | | **Primary Hardening** | **Air** | **Air** | **Oil** | | **Typical Carbide Volume** | **Highest** | High | Very High | | **Wear Resistance** | **Exceptional (Best in class)** | Excellent | Exceptional | | **Toughness** | Fair (Better than D3) | **Good (Best)** | Poor | | **Dimensional Stability** | **Excellent (Air)** | **Excellent (Air)** | Good (Oil) | | **Grindability** | Very Poor | Poor | **Very Poor to Extremely Poor** | | **Primary Advantage** | **Max wear + Air hardening** | Best balance | Max wear in simple shapes | --- ## **Advantages & Considerations** ### **Advantages:** 1. **Superior Wear Resistance:** Offers some of the highest abrasion resistance available in standard air-hardening tool steels. 2. **Excellent Dimensional Stability:** Air-hardening provides minimal distortion for precision tooling. 3. **Better Microstructural Control:** Typically has a more refined carbide structure than D3, potentially offering better performance under high stress. 4. **Good Deep Hardenability:** Suitable for large, thick sections without the distortion risks of oil quenching. 5. **Corrosion Resistance:** High chromium content provides better corrosion resistance than many tool steels. ### **Considerations:** 1. **Low Toughness:** Still relatively brittle compared to lower-carbon steels; not suitable for impact applications. 2. **Very Poor Machinability & Grindability:** High fabrication costs and requires specialized machining/grinding techniques. 3. **Complex Heat Treatment:** Requires precise temperature control and multiple tempering cycles. 4. **Higher Cost:** Typically more expensive than D2 and often D3 due to its specialized nature. 5. **Limited Availability:** Less commonly stocked than D2; may require special ordering. --- ## **Special Processing Notes** ### **Machining:** - Use **carbide or CBN tools** exclusively - Maintain heavy, constant feeds to fracture chips - Use high-pressure coolant to manage heat - Avoid interrupted cuts when possible ### **Grinding:** - **Diamond or CBN wheels are strongly recommended** - Use light infeeds (0.0125-0.025mm/pass) - Maintain consistent traverse rates - Flood coolant is essential to prevent thermal damage ### **EDM:** - Can be EDM machined but requires post-EDM tempering (180-200°C for 2+ hours) to relieve white layer stresses --- ## **Conclusion** **AISI Type D4 High Carbon, High Chromium Cold Work Tool Steel (UNS T30404)** represents the **pinnacle of wear-resistant, air-hardening tool steel technology** within the standard D-series classification. It combines the **extreme carbon content of D3** with the **processing advantages and microstructural refinement of D2**, creating a material optimized for applications where **maximum abrasion resistance must coexist with the dimensional precision of air hardening**. While its toughness limitations and fabrication challenges restrict it to specialized applications, D4 delivers **unparalleled service life in severe abrasive environments** for precision tooling. For engineers and toolmakers facing wear problems that exceed D2's capabilities but require the stability and precision of air-hardening processing, D4 offers a sophisticated, high-performance solution that bridges the gap between extreme wear resistance and practical toolmaking considerations. -:- For detailed product information, please contact sales. -: AISI Type D4 High Carbon, High Chromium Cold Work Tool Steel (UNS T30404) Specification Dimensions Size： Diameter 20-1000 mm Length <6679 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 D4 High Carbon, High Chromium Cold Work Tool Steel (UNS T30404) Properties -:- For detailed product information, please contact sales. -:

Applications of AISI Type D4 High Carbon, High Chromium Cold Work Tool Steel Wire (UNS T30404) -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI Type D4 High Carbon, High Chromium Cold Work Tool Steel Wire (UNS T30404) -:- For detailed product information, please contact sales. -:

Packing of AISI Type D4 High Carbon, High Chromium Cold Work Tool Steel Wire (UNS T30404) -:- 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 3150 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