JIS SKD6 Hot Work Tool Steel Sheet,Plate

JIS SKD6 Hot Work Tool Steel Sheet/Plate Product Information -:- For detailed product information, please contact sales. -: JIS SKD6 Hot Work Tool Steel Sheet/Plate Synonyms -:- For detailed product information, please contact sales. -:

JIS SKD6 Hot Work Tool Steel Product Information -:- For detailed product information, please contact sales. -: ### **Product Technical Datasheet: JIS SKD6 Hot Work Tool Steel** --- #### **1. Product Overview** **JIS SKD6** is a **medium-carbon, chromium-molybdenum-vanadium hot work tool steel** specified under Japanese Industrial Standard (JIS) G 4404. It represents an **intermediate-grade hot work steel** within the 5% chromium family, positioned between the tungsten-rich SKD5 and the modern, balanced SKD61. SKD6 is designed to offer a **good combination of hot hardness, thermal fatigue resistance, and toughness** for a wide range of hot forming applications. With a moderate alloy content focused on chromium, molybdenum, and vanadium, it provides reliable performance at elevated temperatures (typically up to **500-600°C**) while maintaining better processability than higher-alloy grades. It serves as a versatile and cost-effective choice for many general hot work tooling needs. --- #### **2. International Standard Cross-Reference** SKD6 has well-established equivalents in major international standards, often classified as a general-purpose chromium hot work steel. | Standard System | Equivalent / Similar Grade | Note | | :--- | :--- | :--- | | **JIS G 4404 (Japan)** | **SKD6** | Defining Standard | | **AISI (USA)** | **H12** | The primary direct equivalent. | | **DIN (Germany)** | **1.2606 / X37CrMoV5-1** | Very similar composition, often grouped with H11 types. | | **BS (UK)** | **BH12** | Chromium hot work steel type. | | **ISO** | **~35CrMoV5** | ISO chemical designation. | | **GB (China)** | **4Cr5MoSiV1** | China's equivalent, though this designation is often used for H13. **Note:** The exact Chinese equivalent for H12 is less standardized. | *Note: There is often close relation and some overlap in specifications between H11 (SKD4), H12 (SKD6), and H13 (SKD61). SKD6/H12 typically has slightly higher vanadium than H11, and lower carbon/vanadium than H13.* --- #### **3. Chemical Composition (Typical, weight % per JIS G 4404)** The composition is based on a balanced 5% chromium system with strategic additions of molybdenum and vanadium. | Element | Carbon (C) | Silicon (Si) | Manganese (Mn) | Chromium (Cr) | Molybdenum (Mo) | Vanadium (V) | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | **Content (%)** | 0.32 - 0.42 | 0.80 - 1.20 | 0.20 - 0.50 | 4.50 - 5.50 | 1.00 - 1.50 | 0.80 - 1.20 | **Function of Key Alloying Elements:** * **Chromium (4.50-5.50%):** Provides **oxidation resistance**, improves hardenability, and contributes to hot strength through carbide formation. * **Molybdenum (1.00-1.50%):** Enhances **high-temperature strength and hardness (red-hardness)**, improves hardenability, and reduces temper embrittlement. It is a key element for balancing hot strength and toughness. * **Vanadium (0.80-1.20%):** **Higher than SKD4 (H11).** Forms fine, stable vanadium carbides that significantly improve **wear resistance, hot hardness, and grain refinement**. This gives SKD6 better abrasion resistance than H11. * **Silicon (0.80-1.20%):** Improves oxidation resistance and provides solid solution strengthening. --- #### **4. Physical & Mechanical Properties** * **Density:** ~7.80 g/cm³. * **Thermal Conductivity:** **Moderate** (~28-32 W/m·K at 20°C). Better than tungsten-type steels (like SKD5) but generally lower than optimized modern H13 variants. * **Thermal Expansion Coefficient:** ~11.5 x 10⁻⁶ /K (20-550°C). * **Specific Heat Capacity:** ~460 J/kg·K. * **Machinability (Annealed State):** **Fair.** Comparable to other 5% Cr steels; machinable with proper techniques but more challenging than low-alloy steels. * **Hardenability:** **Excellent (Air-Hardening).** Capable of through-hardening very large sections with minimal distortion. * **Key High-Temperature Properties:** * **Red Hardness:** Good. Can maintain a hardness of **~45-48 HRC at 550°C** after proper tempering. * **Tempering Resistance:** **Very Good.** Exhibits a strong **secondary hardening** response in the range of **500-580°C**. * **Thermal Fatigue Resistance:** **Good.** Offers a better balance between hot strength and thermal conductivity than SKD5, leading to improved resistance to heat-checking in cyclic applications. * **Typical Working Hardness:** **46-50 HRC** (after tempering at 560-600°C for hot work). Can be tempered to lower temperatures for higher hardness (e.g., 50-54 HRC) for applications requiring more wear resistance. --- #### **5. Heat Treatment Guidelines** * **Forging:** Heat slowly to **1100-1150°C**. Forge between **1050-900°C**. Cool slowly in furnace or insulating material. * **Annealing:** Heat to **840-880°C**, hold, then furnace cool very slowly to 600°C, then air cool. Target hardness: ≤ 229 HB. * **Stress Relieving (after rough machining):** **650-750°C**, slow cool. * **Hardening:** 1. **Preheating:** **Critical.** Preheat at **550-650°C** and again at **800-850°C**. 2. **Austenitizing:** **1000-1040°C.** The vanadium content requires adequate temperature/time for solutioning. Soak time: 20-30 minutes per inch. 3. **Quench:** Cool in **still or forced air (air-hardening)**. High-pressure gas quenching or oil quenching (for specific geometries) are alternatives. * **Tempering:** * **Must be performed immediately** after quenching. * **Double tempering is mandatory.** For hot work applications, temper in the range of **540-600°C**, for 2+ hours each cycle. This utilizes the secondary hardening peak for optimal high-temperature performance. * The higher vanadium content compared to H11 gives SKD6 a slightly higher peak secondary hardness. --- #### **6. Product Applications** SKD6 is a versatile hot work steel suitable for various applications requiring a balance of heat resistance, wear resistance, and toughness. * **Hot Forging Dies:** **Dies, inserts, and punches** for forging hammers and presses, particularly for **steel and titanium alloys**. It is a traditional choice for many forging applications. * **Hot Extrusion Tools:** **Mandrels, dies, and liners** for extruding **aluminum and copper alloys**. * **Die Casting:** **Cores, pins, and cavity inserts** for **aluminum and magnesium die-casting**, especially for smaller or less severe applications. (Often superseded by SKD61/H13 for high-volume casting). * **Hot Punching and Shearing Tools:** For cutting hot metal. * **Plastic Molds:** For high-temperature engineering plastics and hot-runner system components. * **General Purpose Hot Work Tools:** A reliable all-rounder for various press tools and fixtures operating at elevated temperatures. --- #### **7. Advantages & Limitations** | Advantages | Limitations | | :--- | :--- | | • **Good balance of hot hardness, wear resistance, and toughness.**
• **Excellent hardenability and dimensional stability** (air-hardening).
• **Better wear resistance than H11/SKD4** due to higher vanadium content.
• **Good resistance to thermal softening** (temper resistance).
• **Versatile** for a wide range of hot work applications. | • **Thermal fatigue resistance is generally considered inferior to SKD61/H13**, which has a more optimized balance of alloying for this property.
• **Lower high-temperature strength** compared to tungsten-rich grades like SKD5/H21.
• **Has been largely superseded in popularity by SKD61/H13** for many die-casting and forging applications due to H13's superior all-around performance.
• **Can be prone to heat checking in severe, high-cycle applications.** | --- #### **8. Selection Guidance: SKD6 vs. SKD61 (H12 vs. H13)** * **Choose SKD6 (H12) when:** The application requires a **proven, general-purpose hot work steel** with **good wear resistance and hot hardness**, for processes like **hot forging or extrusion** where thermal cycling is not extremely severe. It may also be chosen for **cost or availability** reasons in certain markets. * **Choose SKD61 (H13) when:** The application involves **severe thermal cycling** (e.g., aluminum die-casting) or where **maximum resistance to heat checking and optimized toughness** are the top priorities. **H13 is the modern industry standard** for most demanding hot work applications. * **Positioning:** SKD6/H12 occupies a middle ground. It is more wear-resistant than H11 and tougher than H21, but for most new tool designs where thermal fatigue is a concern, H13 is the preferred upgrade. **Conclusion:** JIS SKD6 (AISI H12) is a **robust and well-balanced chromium hot work tool steel** that has served as a reliable workhorse for decades. Its balanced alloying provides a **solid combination of properties** suitable for a broad spectrum of hot forming operations, particularly in forging and extrusion. While its prominence has been eclipsed in many fields by the more thermally efficient SKD61/H13, SKD6 remains a **perfectly viable and competent material** for numerous applications. It represents a **classic, high-performance choice** for tooling designers who require a steel with proven reliability for moderate-severity hot work, where its balanced characteristics provide excellent service life and value. -:- For detailed product information, please contact sales. -: JIS SKD6 Hot Work Tool Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6803 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. -: JIS SKD6 Hot Work Tool Steel Properties -:- For detailed product information, please contact sales. -:

Applications of JIS SKD6 Hot Work Tool Steel Sheet,Plate -:- For detailed product information, please contact sales. -: Chemical Identifiers JIS SKD6 Hot Work Tool Steel Sheet,Plate -:- For detailed product information, please contact sales. -:

Packing of JIS SKD6 Hot Work Tool Steel Sheet/Plate -:- 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 Sheet/Plate 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 3274 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