JIS SKD5 Hot Work Tool Steel Tube,Pipe

JIS SKD5 Hot Work Tool Steel Tube Product Information -:- For detailed product information, please contact sales. -: JIS SKD5 Hot Work Tool Steel Tube Synonyms -:- For detailed product information, please contact sales. -:

JIS SKD5 Hot Work Tool Steel Product Information -:- For detailed product information, please contact sales. -: ### **Product Technical Datasheet: JIS SKD5 Hot Work Tool Steel** --- #### **1. Product Overview** **JIS SKD5** is a **high-tungsten, chromium hot work tool steel** specified under the Japanese Industrial Standard (JIS) G 4404. It represents a classic, high-performance alloy within the 5% chromium hot-work steel family, distinguished by its **exceptionally high tungsten content** (typically 5-6%). This composition is engineered to deliver outstanding **red-hardness (hot hardness) and tempering resistance at elevated temperatures**, making it particularly suitable for applications involving high thermal loads and moderate impact. SKD5 is renowned for its ability to maintain cutting edges and dimensional stability under severe thermal cycling, though its high alloy content also introduces challenges in toughness and thermal conductivity compared to modern molybdenum-rich grades. --- #### **2. International Standard Cross-Reference** SKD5 is a specialized grade with close equivalents in other major standards, often classified under the tungsten-chromium hot-work steel category. | Standard System | Equivalent / Similar Grade | Note | | :--- | :--- | :--- | | **JIS G 4404 (Japan)** | **SKD5** | Defining Standard | | **AISI (USA)** | **H21** | The primary direct equivalent. | | **DIN (Germany)** | **1.2581 / X30WCrV9-3** | Similar high-tungsten hot work steel. | | **BS (UK)** | **BH21** | Tungsten-chromium hot work type. | | **ISO** | **~30WCrV9** | ISO chemical designation. | | **GB (China)** | **3Cr2W8V** | China's classic equivalent, widely used historically. | --- #### **3. Chemical Composition (Typical, weight % per JIS G 4404)** The hallmark of SKD5 is its high tungsten and carbon content, balanced with chromium and vanadium. | Element | Carbon (C) | Silicon (Si) | Manganese (Mn) | Chromium (Cr) | Tungsten (W) | Vanadium (V) | | :--- | :--- | :--- | :--- | :--- | :--- | :--- | | **Content (%)** | 0.30 - 0.40 | ≤ 0.40 | ≤ 0.40 | 2.00 - 3.00 | 5.00 - 6.00 | 0.30 - 0.50 | **Function of Key Alloying Elements:** * **Tungsten (5.00-6.00%):** The defining element. Provides exceptional **solid solution strengthening at high temperatures**, resulting in superior **red-hardness and resistance to deformation under load**. It also contributes to secondary hardening and wear resistance. * **Chromium (2.00-3.00%):** Enhances hardenability, provides moderate oxidation resistance, and contributes to the formation of stable carbides. * **Vanadium (0.30-0.50%):** Forms fine, hard vanadium carbides that refine grain size, improve wear resistance, and enhance hot hardness. * **Carbon (0.30-0.40%):** Balances carbide formation with matrix toughness. Lower than in cold work steels to prioritize hot toughness. --- #### **4. Physical & Mechanical Properties** * **Density:** ~8.10 g/cm³ (higher than standard steels due to high tungsten content). * **Thermal Conductivity:** **Low** (~25-28 W/m·K at 20°C). This is a critical limitation, as poor heat dissipation accelerates heat-checking (thermal fatigue cracking). * **Thermal Expansion Coefficient:** ~12.0 x 10⁻⁶ /K (20-600°C). * **Specific Heat Capacity:** ~460 J/kg·K. * **Machinability (Annealed State):** **Fair to Poor.** The high alloy content, particularly tungsten, makes it tougher and more abrasive to machine than lower-alloy hot work steels. * **Hardenability:** **Very Good (Air-Hardening).** Capable of through-hardening large sections. * **Key High-Temperature Properties:** * **Red Hardness:** **Excellent.** Can maintain a hardness of **~45 HRC at 600°C** and useful hardness up to ~650°C, outperforming many other hot work steels at these extreme temperatures. * **Tempering Resistance:** **Outstanding.** Exhibits a pronounced secondary hardening peak around **550-600°C**, allowing it to be tempered to high hardness levels for high-temperature service. * **Thermal Fatigue Resistance:** **Moderate to Poor.** Its **low thermal conductivity** is a major drawback, causing high thermal gradients and stresses that lead to heat checking in rapid thermal cycling applications. * **Typical Working Hardness:** **48-52 HRC** (after high-temperature tempering, e.g., 600-620°C). Can be tempered to higher hardness (up to ~55 HRC) for applications requiring more wear resistance. --- #### **5. Heat Treatment Guidelines** * **Forging:** Heat slowly to **1150-1200°C**. Forge carefully between **1100-900°C**. Cool very slowly in furnace or insulating material. * **Annealing:** Heat to **850-880°C**, hold, then furnace cool very slowly to 500°C, then air cool. Target hardness: ≤ 229 HB. * **Stress Relieving (after rough machining):** **700-750°C**, slow cool. * **Hardening:** 1. **Preheating:** **Essential.** Preheat at **550-650°C** and again at **800-850°C**. 2. **Austenitizing:** **1080-1130°C.** The high tungsten requires a high temperature for adequate solutioning. Soak time: 20-30 minutes per inch. **Caution:** High temperature risks grain growth. 3. **Quench:** Cool in **still or forced air (air-hardening)**. Oil quenching can be used for complex shapes or to maximize hardness but increases distortion and cracking risk. * **Tempering:** * **Must be performed immediately** after quenching. * **Double or triple tempering is mandatory.** The standard tempering range for hot work is **560-620°C**, for 2+ hours each cycle, to achieve peak secondary hardness and stability. * For applications requiring maximum wear resistance over extreme hot hardness, a lower temper (e.g., 500-550°C) can be used. --- #### **6. Product Applications** SKD5 is suited for hot work applications where extreme temperature resistance is more critical than resistance to severe thermal shock. * **Hot Extrusion Dies:** **Mandrels, dies, liners, and dummy blocks** for extruding **brass, copper alloys, and steel**, where die temperatures are very high and wear is a primary concern. * **Hot Forging Dies:** **Inserts and dies** for forging high-temperature alloys or under conditions where die temperatures exceed the optimal range for H13-type steels. * **Die Casting Cores & Inserts:** For **copper-based alloy die casting** (e.g., brass), where the molten metal temperature is exceptionally high (900-1100°C). * **Hot Punching & Piercing Tools:** For heavy sections or high-temperature materials. * **Glass Mold Tools:** For forming glass at high temperatures. * **High-Temperature Structural Components:** Such as **hot work rolls** in certain rolling mill applications. --- #### **7. Advantages & Limitations** | Advantages | Limitations | | :--- | :--- | | • **Exceptional red-hardness and hot strength** at temperatures above 600°C.
• **Superior resistance to deformation and softening** under sustained thermal load.
• **Excellent tempering resistance** due to strong secondary hardening.
• **Good wear resistance** at high temperatures.
• **Good oxidation resistance** due to chromium content. | • **Poor thermal fatigue resistance (heat checking)** due to **low thermal conductivity**, making it unsuitable for rapid thermal cycling (e.g., aluminum die-casting).
• **Lower toughness and impact resistance** at room and moderate temperatures compared to molybdenum-based grades like SKD61/H13.
• **High density and cost** due to high tungsten content.
• **More difficult to machine and grind.**
• **Sensitive to overheating** during austenitizing, leading to grain growth and brittleness. | --- #### **8. Selection Guidance: SKD5 vs. SKD61 (H21 vs. H13)** * **Choose SKD5 (H21/3Cr2W8V) when:** The primary failure mode is **die softening or deformation under very high, sustained thermal load** (e.g., brass extrusion, hot forging of steel), and **thermal cycling is relatively slow**. It is the material for **extreme temperature** applications. * **Choose SKD61 (H13) when:** The application involves **severe, rapid thermal cycling** (e.g., aluminum die-casting, hot forging of aluminum), where **resistance to heat checking and overall toughness** are paramount. H13 offers a much better balance for most modern hot work processes. * **General Trend:** SKD61/H13 has become the dominant hot work steel due to its superior balance of properties. SKD5 remains a **specialist grade** for niche, high-temperature applications where its unique red-hardness is indispensable. **Conclusion:** JIS SKD5 (AISI H21) is a **classic, high-performance tungsten hot work steel** that excels in environments of **extreme and sustained heat**. Its unparalleled ability to retain hardness and resist deformation at temperatures where other steels soften makes it irreplaceable for specific demanding applications. However, its inherent drawbacks—particularly poor thermal conductivity and lower toughness—limit its use in processes involving rapid temperature changes. For tooling designers, SKD5 represents a **powerful but specialized tool** best deployed where its exceptional high-temperature strength can be fully utilized without being undermined by thermal shock. In the modern landscape, it is often the right answer for the most thermally severe applications, but not the most common one. -:- For detailed product information, please contact sales. -: JIS SKD5 Hot Work Tool Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6802 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 SKD5 Hot Work Tool Steel Properties -:- For detailed product information, please contact sales. -:

Applications of JIS SKD5 Hot Work Tool Steel Tube -:- For detailed product information, please contact sales. -: Chemical Identifiers JIS SKD5 Hot Work Tool Steel Tube -:- For detailed product information, please contact sales. -:

Packing of JIS SKD5 Hot Work 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 3273 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