JIS SK6 Water Hardening Tool Steel Wire

JIS SK6 Water Hardening Tool Steel Wire Product Information -:- For detailed product information, please contact sales. -: JIS SK6 Water Hardening Tool Steel Wire Synonyms -:- For detailed product information, please contact sales. -:

JIS SK6 Water Hardening Tool Steel Product Information -:- For detailed product information, please contact sales. -: ## Product Technical Datasheet: JIS SK6 Water-Hardening Tool Steel --- ### 1. Product Overview **JIS SK6** is a high-carbon, non-alloy water-hardening tool steel specified under Japanese Industrial Standard (JIS) G 4401. It is a member of the carbon tool steel series (SK1-SK7) with a **medium-high carbon content** (typically 0.70-0.80%), positioned between the very high-carbon SK5 and the medium-carbon SK7 grades. SK6 offers a balanced combination of **hardness, wear resistance, and toughness** within the water-hardening family, making it suitable for applications requiring good edge retention while maintaining better resistance to chipping and shock loading compared to higher-carbon SK grades. As a plain carbon steel, it achieves its properties through water or brine quenching, providing a cost-effective solution for various cold-work tooling applications. --- ### 2. International Standard Cross-Reference SK6 has direct equivalents in major international standards due to its standardized composition. | Standard System | Equivalent Grade | Key Similarity | |----------------|------------------|----------------| | **JIS (Japan)** | **SK6** | Defining Standard | | **ASTM (USA)** | W1-0.8C / W108 | Similar medium-high carbon water-hardening grade | | **DIN (Germany)** | C80W1 / 1.1620 | Comparable carbon content and application | | **BS (UK)** | BW1B (0.8C variant) | Water-hardening tool steel type | | **ISO** | TC80 | ISO designation for similar composition | | **GB (China)** | **T8(A)** | Nearly identical carbon content and properties | | **UNI (Italy)** | C80KU | Equivalent water-hardening grade | --- ### 3. Chemical Composition (JIS G 4401 Specification) The composition features a balanced carbon content with minimal alloying, characteristic of plain carbon tool steels. | Element | Carbon (C) | Silicon (Si) | Manganese (Mn) | Phosphorus (P) | Sulfur (S) | |---------|------------|--------------|----------------|----------------|------------| | **Content (%)** | 0.70 - 0.80 | ≤ 0.35 | ≤ 0.50 | ≤ 0.030 | ≤ 0.030 | **Key Characteristics:** - **Carbon Content:** At 0.70-0.80%, SK6 provides an optimal balance between hardness potential and toughness. This carbon range allows for good hardenability while maintaining better ductility than higher-carbon SK grades. - **Minimal Alloying:** The absence of significant alloying elements keeps material costs low but limits hardenability and hot hardness. --- ### 4. Physical & Mechanical Properties #### **Physical Properties:** - **Density:** 7.85 g/cm³ - **Melting Point:** ~1420-1460°C - **Thermal Conductivity:** 48-52 W/m·K (at 20°C) - **Coefficient of Thermal Expansion:** 11.5 × 10⁻⁶/°C (20-100°C) - **Modulus of Elasticity:** 200-210 GPa #### **Mechanical Properties (Typical):** - **Annealed Hardness:** 170-207 HB - **Hardened Hardness:** **60-63 HRC** (after water quenching and low-temperature tempering) - **Tensile Strength (Hardened):** 2000-2200 MPa - **Yield Strength:** 1800-2000 MPa - **Elongation (Annealed):** 10-15% - **Reduction of Area:** 30-40% - **Impact Toughness:** 10-15 J (higher than SK4/SK5 due to lower carbon content) #### **Hardenability Characteristics:** - **Critical Diameter (in water):** Approximately 8-12 mm - **Hardenability Depth:** Shallow to moderate; suitable for sections up to 10-15 mm thickness for full hardening - **Quenching Sensitivity:** High; requires rapid water or brine quenching for full hardness --- ### 5. Heat Treatment Specifications #### **Annealing:** - **Full Annealing:** Heat to 750-780°C, hold for 1-2 hours per inch of thickness, furnace cool to 500°C at ≤20°C/hour, then air cool - **Spheroidize Annealing:** Heat to 740-760°C, hold 2-4 hours, cool slowly to 680-700°C at 10-20°C/hour, hold 4-6 hours, then furnace cool to 500°C - **Resulting Hardness:** 170-207 HB (optimal for machining) #### **Hardening:** 1. **Preheating:** 650-700°C (essential to minimize thermal shock) 2. **Austenitizing Temperature:** 780-810°C 3. **Soaking Time:** 20-30 minutes per inch of thickness 4. **Quenching Medium:** Water, brine (5-10% NaCl), or caustic soda solution 5. **Quenching Method:** Vigorous agitation in quenching bath 6. **Critical Cooling Rate:** >100°C/second through the 700-550°C range #### **Tempering:** - **Immediate Tempering Required:** Temper immediately after quenching when part reaches 50-70°C - **Low-Temperature Tempering (Primary):** 150-200°C for 1-2 hours - **Medium-Temperature Tempering:** 250-300°C for applications requiring higher toughness (results in 55-60 HRC) - **Tempering Response:** Shows significant secondary hardening effect during low-temperature tempering --- ### 6. Product Applications #### **Primary Application Areas:** **1. Cutting Tools:** - Circular shear blades for metal and plastics - Paper cutting knives and slitter blades - Leather cutting knives - Hand saw blades (wood and metal) - Pruning shears and garden tool blades **2. Forming and Stamping Tools:** - Blanking and piercing punches for thin materials - Forming dies for non-ferrous metals - Bending and folding tools - Embossing tools **3. Hand Tools:** - Cold chisels - Screwdrivers (heavy-duty) - Scrapers and putty knives - Allen keys and wrenches (impact grade) **4. Wear Parts:** - Guide plates and wear strips - Bushings and bearings (low-speed applications) - Machine tool components subject to abrasion - Textile machinery parts **5. Special Applications:** - Springs requiring high elastic limit - Measuring tools (calipers, depth gauges) - Woodworking plane blades - Metalworking scrapers --- ### 7. Advantages & Limitations | Advantages | Limitations | |------------|-------------| | • **Cost-effective** compared to alloy tool steels
• **Capable of high hardness** (60-63 HRC) after proper heat treatment
• **Good wear resistance** in non-shock applications
• **Better toughness** than higher-carbon SK grades (SK3-SK5)
• **Simple heat treatment** requiring only basic equipment
• **Good machinability** in annealed condition
• **Excellent sharpness potential** for cutting edges | • **Poor hardenability** – limited to thin sections (<15 mm)
• **High distortion and cracking risk** during water quenching
• **Low toughness at full hardness** compared to alloy steels
• **No hot hardness** – properties degrade rapidly above 200°C
• **Dimensional instability** during heat treatment
• **Susceptible to decarburization** during heat treatment
• **Limited fatigue resistance** in cyclic loading applications | --- ### 8. Processing Recommendations #### **Machining:** - **Annealed State:** Machine using standard high-speed steel tools - **Cutting Speeds:** 20-30 m/min for turning, 15-25 m/min for milling - **Feed Rates:** Moderate to light feeds recommended - **Coolant:** Use soluble oil or chemical coolants to prevent work hardening #### **Grinding:** - Use aluminum oxide or silicon carbide wheels - Employ light cuts with good coolant flow - Avoid overheating to prevent grinding cracks #### **Welding:** - **Not recommended** for hardened components - If necessary, preheat to 300-400°C and use low-hydrogen electrodes - Post-weld heat treatment required for stress relief --- ### 9. Quality Considerations #### **Microstructure Requirements:** - **Annealed:** Spheroidized carbide structure (100% spheroidization desired) - **Hardened:** Fine martensite with minimal retained austenite (<5%) - **Grain Size:** ASTM 8 or finer for optimal toughness #### **Common Defects to Avoid:** - **Quench Cracks:** Due to rapid cooling and part geometry - **Soft Spots:** From inadequate quenching agitation or scale formation - **Excessive Distortion:** Particularly in long, thin sections - **Decarburization:** From improper atmosphere control during heat treatment --- ### 10. Selection Guidelines **Choose SK6 when:** - Application requires hardness 60-63 HRC - Part cross-section is less than 15 mm - Tool operates at room temperature with moderate impact - Cost is a primary consideration - Tool geometry is relatively simple **Consider alternatives when:** - Section thickness exceeds 15 mm → Use **oil-hardening grades (SKS series)** - Complex geometry with risk of distortion → Use **air-hardening steels (SKD series)** - High impact resistance required → Use **shock-resisting grades (SKS4, S7)** - Elevated temperature operation → Use **high-speed steels (SKH series)** - Maximum wear resistance needed → Use **high-carbon, high-chromium steels (SKD11, D2)** --- ### 11. Comparative Analysis with Other SK Grades | Property | SK6 | SK5 | SK7 | SK4 | |----------|-----|-----|-----|-----| | **Carbon Content** | 0.70-0.80% | 0.80-0.90% | 0.60-0.70% | 0.90-1.00% | | **Typical Hardness** | 60-63 HRC | 62-65 HRC | 58-61 HRC | 63-66 HRC | | **Toughness** | Good | Fair | Very Good | Poor | | **Wear Resistance** | Very Good | Excellent | Good | Excellent | | **Distortion Risk** | High | Very High | Medium-High | Very High | | **Primary Use** | Balanced tools | High hardness tools | Tough tools | Maximum hardness tools | --- ### Conclusion JIS SK6 represents an **optimal balance point** in the carbon tool steel spectrum, offering a favorable compromise between hardness, toughness, and cost. Its 0.70-0.80% carbon content makes it **versatile for a wide range of general-purpose tooling applications** where both cutting ability and some shock resistance are required. While it shares the limitations of all water-hardening steels—particularly shallow hardenability and high distortion risk—its balanced properties make it a **popular choice for many industrial cutting, forming, and wear applications**. Successful implementation requires **careful attention to heat treatment practices**, particularly regarding quenching techniques and tempering schedules. For applications where its limitations become significant, progression to oil-hardening or alloy tool steels is recommended. When properly applied within its design parameters, SK6 provides **excellent performance and value** for a broad category of tooling needs. **Typical Industry Applications:** - Tool and die making for thin materials - General machinery maintenance tools - Cutlery and blade manufacturing - Textile and paper industry cutting tools - Automotive repair tools and fixtures -:- For detailed product information, please contact sales. -: JIS SK6 Water Hardening Tool Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6794 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 SK6 Water Hardening Tool Steel Properties -:- For detailed product information, please contact sales. -:

Applications of JIS SK6 Water Hardening Tool Steel Wire -:- For detailed product information, please contact sales. -: Chemical Identifiers JIS SK6 Water Hardening Tool Steel Wire -:- For detailed product information, please contact sales. -:

Packing of JIS SK6 Water Hardening Tool Steel Wire -:- 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 3265 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