SKS51M Air-Hardening Tool Steel Flange

1,We Manufacturing processes are primarily classified into four types: 1:Forging, 2:Casting, 3:Cutting, 4:Rolling. 2,We can manufacture in accordance with these standards. Standards: GB Series (Chinese Standards), JB Series (Machinery Standards), HG Series (Chemical Industry Standards), ASME B16.5 (American Standards), BS4504 (British Standards), DIN (German Standards), and JIS (Japanese Standards). Internationally, there are two primary systems of pipe flange standards: the European system, represented by the German DIN standards (including those of the former Soviet Union), and the American system, represented by the US ANSI pipe flange standards. Other common standards include: the Chinese Ministry of Machinery Industry standards (JB series), the Ministry of Chemical Industry standards (HG series), the Chinese National Standard *GB/T 9112–9124-2010 Steel Pipe Flanges*, as well as US standards (ASME B16.5), British standards (BS4504), German standards (DIN), Japanese standards (JIS), and marine standards (CBM), among others. The nominal pressure ratings for the PN series are designated by "PN" and comprise the following nine levels: PN2.5, PN6, PN10, PN16, PN25, PN40, PN63, PN100, and PN160. The nominal pressure ratings for the Class series are designated by "Class" and comprise the following six levels: Class150, Class300, Class600, Class900, Class1500, and Class2500. Flange Classification 1. **According to Chemical Industry Standards:** Flanges are classified as follows: Plate Flat Welding Flange (PL), Necked Flat Welding Flange (SO), Necked Butt Welding Flange (WN), Integral Flange (IF), Socket Welding Flange (SW), Threaded Flange (Th), Butt Welding Ring Loose Flange (PJ/SE), Blind Flange (BL), Flat Welding Ring Loose Flange (PJ/PJ), and Lined Blind Flange (BL(s)). 2. **According to Petrochemical (SH) Industry Standards:** Flanges are classified as follows: Threaded Flange (PL), Butt Welding Flange (WN), Flat Welding Flange (SO), Socket Welding Flange (SW), Loose Flange (LJ), and Blind Flange (no specific designation). 3. **According to Machinery (JB) Industry Standards:** Flanges are classified as follows: Integral Flange, Butt Welding Flange, Plate Flat Welding Flange, Butt Welding Ring Plate Loose Flange, Flat Welding Ring Plate Loose Flange, Lap Joint Ring Plate Loose Flange, and Blind Flange. 4. **According to Connection Method/Type:** Flanges are classified as follows: Plate Flat Welding Flange, Necked Flat Welding Flange, Necked Butt Welding Flange, Socket Welding Flange, Threaded Flange, Blind Flange, Necked Butt Welding Ring Loose Flange, Flat Welding Ring Loose Flange, Ring-Type Joint (RTJ) Flange and Blind Flange, Large-Diameter Plate Flange, Large-Diameter High-Neck Flange, Figure-8 Blind Plate, Butt Welding Ring Loose Flange, etc. 5. **According to the Component Being Connected:** Flanges can be classified into Vessel Flanges and Pipe Flanges. 6. **According to Structural Type:** Flanges include Integral Flanges, Threaded Flanges, Flat Welding Flanges, Butt Welding Flanges, Lap Joint (Loose/Swivel) Flanges, and Blind Flanges. A flange—also referred to as a flange plate or rim—is a component used to connect shafts to one another, or, more commonly, to join the ends of pipes. Flanges are also utilized at the inlet and outlet ports of equipment to facilitate connections between two devices—for instance, the flange on a speed reducer. A "flange connection" or "flanged joint" refers to a detachable joint assembly comprising three interconnected elements—a flange, a gasket, and bolts—that together form a sealed structural unit. In the context of piping systems, a "pipe flange" specifically denotes a flange used for plumbing within the installation; when applied to equipment, it refers to the inlet or outlet flange of that specific device. Flanges feature a series of holes through which bolts are inserted to securely fasten the two flanges together, while a gasket placed between the flanges ensures a leak-proof seal. Flanges are broadly categorized into three types: threaded (screw-in) flanges, welded flanges, and clamp-type flanges. Flanges are invariably used in pairs; threaded flanges are suitable for low-pressure piping applications, whereas welded flanges are required for systems operating at pressures exceeding 4 kilograms per square centimeter. A sealing gasket is inserted between the two flange plates, which are then firmly secured using bolts. The thickness of a flange—as well as the specifications of the bolts used to fasten it—vary depending on the specific pressure rating required for the application. When connecting equipment such as water pumps or valves to piping systems, the corresponding connection points on these devices are often manufactured in the shape of a matching flange; this method of attachment is also referred to as a "flange connection." Generally, any connecting component that utilizes bolts to join and seal the perimeters of two flat surfaces—such as the joints in ventilation ducts—is termed a "flange"; such components may collectively be classified as "flange-type parts." However, since such a connection often constitutes merely a *portion* of a larger device—for instance, the interface between a flange and a water pump—it would be inappropriate to classify the entire water pump itself as a "flange-type part." Conversely, smaller components—such as valves—that feature such flanged interfaces may indeed be appropriately categorized as "flange-type parts." -:- For detailed product information, please contact sales. -: SKS51M Air-Hardening Tool Steel Flange Product Information -:- For detailed product information, please contact sales. -: SKS51M Air-Hardening Tool Steel Flange Synonyms -:- For detailed product information, please contact sales. -:

SKS51M Air-Hardening Tool Steel Product Information -:- For detailed product information, please contact sales. -: # **JIS SKS51M Air-Hardening Tool Steel** **International Standard:** JIS G4404 (Japan Industrial Standard) - Tool Steels --- ## **1. Overview** JIS SKS51M is an **improved-machinability, medium-alloy air-hardening cold work tool steel** that represents a specialized variant of traditional air-hardening steels. Characterized by its **excellent machinability in the annealed state combined with good dimensional stability during air quenching**, this steel is designed for complex tooling applications where extensive machining is required before heat treatment. The "M" suffix indicates enhanced machinability through controlled sulfur addition, making it particularly valuable for intricate molds, dies, and precision components requiring detailed machining operations. --- ## **2. Chemical Composition (Typical Weight %)** | Element | Content (%) | | :------ | :---------- | | C | 0.90–1.00 | | Si | 0.15–0.35 | | Mn | 0.80–1.10 | | Cr | 0.50–1.00 | | Mo | 0.15–0.30 | | V | 0.10–0.20 | | S | 0.06–0.12 | | P (max) | 0.030 | | Ca (optional) | 0.001–0.005 | **Balance:** Iron (Fe). **Key Characteristics:** SKS51M is essentially a **machinability-enhanced version of air-hardening tool steel** featuring: - **Controlled sulfur addition (0.06–0.12%)** to form manganese sulfide inclusions that act as internal chip breakers - **Balanced alloy content** for air hardenability with minimal distortion - **Medium carbon content** for good wear resistance after hardening - **Molybdenum and vanadium** for hardenability and grain refinement --- ## **3. Physical & Mechanical Properties** ### **Physical Properties** - **Density:** ~7.81 g/cm³ (slightly lower than non-free-machining grades) - **Thermal Conductivity:** ~36 W/m·K (at 20°C) - **Coefficient of Thermal Expansion:** ~11.5 ×10⁻⁶ /K (20–200°C) - **Specific Heat Capacity:** ~0.46 kJ/kg·K - **Modulus of Elasticity:** ~205 GPa (slightly anisotropic due to inclusions) - **Air-Hardenability:** Good – hardens fully in still air on moderate sections ### **Mechanical Properties (Heat-Treated)** - **Annealed Hardness:** 183–229 HB (excellent for machining) - **Hardened & Tempered Hardness:** **58–62 HRC** (typical working range) - **Tensile Strength:** ~1900–2200 MPa (at 60 HRC, longitudinal) - **Transverse Strength:** Reduced by 15–25% compared to longitudinal (due to sulfide stringers) - **Impact Toughness (Longitudinal):** Good – similar to standard air-hardening grades - **Impact Toughness (Transverse):** Reduced – typically 40–60% of longitudinal values - **Wear Resistance:** **Very Good** – Comparable to standard grades in service - **Dimensional Stability:** **Excellent** – Minimal distortion during air quenching - **Compressive Strength:** ~2500–2800 MPa ### **Machinability Characteristics** - **Machinability Rating:** 75–85% (compared to 100% for 1212 steel) - **Improvement over Standard:** 20–40% better machinability than non-free-machining air-hardening grades - **Chip Formation:** Short, broken chips – excellent for automated machining - **Surface Finish:** Good to excellent with proper parameters - **Tool Life:** Extended compared to standard air-hardening steels --- ## **4. Heat Treatment Specifications** ### **1. Annealing** - **Temperature:** 780–820°C - **Process:** Heat uniformly, hold for 2–3 hours, furnace cool slowly (≤ 20°C/h) to 550°C, then air cool - **Resulting Hardness:** 183–229 HB - **Spheroidize Annealing:** 790–810°C for 4–6 hours, slow cool to 600°C at 10°C/h ### **2. Stress Relieving** - **Temperature:** 600–650°C - **Hold Time:** 1–2 hours per 25mm thickness - **Purpose:** Critical after extensive machining operations ### **3. Hardening (Quenching)** - **Preheating:** Recommended for complex shapes - **First Preheat:** 500–550°C - **Second Preheat:** 750–800°C - **Austenitizing Temperature:** **850–900°C** (typically 870–880°C) - **Soaking Time:** 20–40 minutes per 25mm at temperature - **Quenching Medium:** **Air** (still air or forced air) - Oil quenching possible but not typically required - **Critical Cooling Rate:** Slow – air cooling sufficient for full hardening - **Hardening Depth:** Good – can through-harden sections up to 100mm ### **4. Tempering** - **Immediate Tempering Required:** Begin when tool reaches 50–80°C - **Temperature Range:** - **Low Temperature (150–250°C):** For maximum hardness (60–62 HRC) - **Medium Temperature (250–400°C):** For balanced properties (58–60 HRC) - **High Temperature (400–550°C):** For increased toughness (54–58 HRC) - **Hold Time:** 1–2 hours per 25mm, minimum 1.5 hours - **Cycles:** **Double tempering recommended** for dimensional stability - **Tempering Response:** Good secondary hardness development ### **5. Special Considerations:** - **Minimal Distortion:** Air quenching provides excellent dimensional control - **Low Residual Stress:** Compared to oil or water quenching - **Size Change:** Typically 0.02–0.05% growth during hardening - **Decarburization Protection:** Recommended during heating --- ## **5. Key Features & Advantages** 1. **Excellent Machinability:** Primary advantage – allows complex machining operations 2. **Superior Dimensional Stability:** Air quenching minimizes distortion 3. **Good Wear Resistance:** After hardening, provides excellent service performance 4. **Reduced Manufacturing Costs:** Faster machining, longer tool life during fabrication 5. **Complex Geometry Capability:** Can machine intricate details before hardening 6. **Good Toughness:** Maintains reasonable impact resistance 7. **Predictable Heat Treatment:** Reliable and consistent results 8. **Anisotropic Properties Managed:** When properly oriented in design **Limitations:** - **Directional Properties:** Reduced transverse strength and toughness - **Surface Finish Limitations:** For very high polish applications, inclusions may be visible - **Special Grinding Considerations:** May require adjusted parameters - **Not for Extreme Impact:** In transverse loading conditions --- ## **6. Typical Applications** SKS51M is specifically designed for **complex tooling requiring extensive machining** where dimensional stability and machinability are critical. ### **Mold & Die Applications:** - **Plastic Injection Molds:** Complex cavity inserts, cores, ejector pins - **Die Casting Dies:** For aluminum, zinc, magnesium alloys - **Powder Metal Compaction Dies:** Intricate shapes requiring precise machining - **Glass Mold Components:** For precision glassware production ### **Precision Tooling:** - **Gauges and Fixtures:** Complex inspection fixtures - **Jigs and Fixtures:** Precision machining fixtures - **Forming Tools:** With intricate profiles - **Patterns and Models:** For prototyping and production ### **Stamping & Forming Tools:** - **Progressive Dies:** Complex multi-station dies - **Fine Blanking Dies:** Precision blanking applications - **Lamination Dies:** For electrical motor components - **Embossing Dies:** Detailed surface patterns ### **Specialized Components:** - **Machine Tool Components:** Complex gears, cams, guides - **Wear Parts:** With intricate cooling channels or features - **Aerospace Tooling:** Jigs and fixtures for composite parts - **Medical Device Tooling:** Precision molds for medical components ### **Application Guidelines:** - **Best for:** Complex shapes requiring extensive milling, drilling, EDM - **Ideal for:** Production tooling where manufacturing efficiency matters - **Suitable for:** Components with primary stresses aligned with rolling direction - **Avoid for:** Applications with significant multi-directional impact loading --- ## **7. International Standard Equivalents** | Standard | Grade Designation | Notes | | :--------------- | :------------------ | :----------------------------------------- | | **JIS** | SKS51M | Original specification (JIS G4404) | | **AISI/SAE (USA)**| A6 Free-Machining | Similar free-machining air-hardening grade | | **Proprietary** | Various "Improved Machining" grades | From specialty steel producers | | **Custom** | Modified A-series with S | Engineered for specific applications | | **DIN (Germany)** | Special treated grades | With machinability enhancement | **Note:** The "M" designation for improved machinability is consistent across JIS standards, though exact compositions may vary between producers. --- ## **8. Machining & Fabrication Guidelines** ### **Machining (In Annealed State):** - **Exceptional Machinability for Air-Hardening Steel:** 25–40% better than standard grades - **Cutting Speeds:** 25–40 m/min with HSS, 80–120 m/min with carbide - **Feeds:** Can use more aggressive feeds than non-free-machining grades - **Tool Materials:** Carbide recommended for production, HSS suitable - **Chip Control:** Excellent – produces short, manageable chips - **Coolant:** Use for best surface finish and tool life ### **Optimal Machining Parameters:** - **Turning:** 70–100 m/min with HSS, 150–200 m/min with carbide - **Milling:** 35–50 m/min with HSS, 100–150 m/min with carbide - **Drilling:** 20–35 m/min with HSS, 50–80 m/min with carbide - **Tapping:** Excellent performance – reduced tap breakage ### **Grinding:** - **Good Grindability:** Requires attention to wheel selection - **Wheel Selection:** Softer grade wheels (I–K hardness) recommended - **Coolant:** Essential to prevent wheel loading - **Surface Finish:** Can achieve good finishes with proper technique ### **Electrical Discharge Machining (EDM):** - **Excellent for EDM:** Performs very well in both sinking and wire EDM - **Material Removal Rate:** Similar to standard grades - **Surface Finish:** Good with proper finishing passes - **Post-EDM:** Temper at 150–200°C to relieve white layer stresses ### **Welding:** - **Not Generally Recommended:** Sulfur content increases hot cracking risk - **If Necessary:** Use specialized low-hydrogen procedures with high preheat (350–450°C) - **Post-Weld:** Full annealing and re-hardening recommended - **Practical Approach:** Avoid welding – use mechanical fastening or design as one piece ### **Orientation Considerations:** - **Critical Design Factor:** Align primary stress direction with rolling direction - **Material Specification:** Clearly indicate orientation requirements - **Machining Strategy:** Plan operations to minimize transverse stresses - **Quality Control:** Verify orientation during incoming inspection --- ## **9. Surface Treatment** ### **1. Nitriding:** - **Highly Effective:** Improves surface hardness and wear resistance - **Process:** Plasma or gas nitriding at 480–520°C - **Case Depth:** 0.1–0.2 mm typical - **Surface Hardness:** 800–1000 HV - **Benefits:** Extends tool life without affecting core properties ### **2. PVD Coatings:** - **Excellent Results:** TiN, TiCN, TiAlN coatings adhere well - **Benefits:** Further enhance wear resistance and reduce friction - **Application:** After final polishing and cleaning ### **3. Polishing:** - **Good Polishability:** Can achieve excellent surface finishes - **Consideration:** Sulfide inclusions may be visible at very high polish levels - **Technique:** Standard polishing procedures apply ### **4. Texturing:** - **Excellent for:** Mold surfaces requiring texture (leather, wood grain, etc.) - **Methods:** Chemical etching, laser texturing, EDM texturing - **Benefits:** Good surface consistency for texture replication --- ## **10. Performance Comparison** ### **Compared to Standard Air-Hardening Grades:** | Property | SKS51M (Free-Machining) | Standard Air-Hardening | Oil-Hardening (O1) | |-----------------------|-------------------------|------------------------|--------------------| | **Machinability** | **Excellent** | Fair to Good | Excellent | | **Dimensional Stability**| **Excellent** | Excellent | Good | | **Distortion** | Minimal | Minimal | Low | | **Wear Resistance** | Very Good | Very Good | Good | | **Toughness (Longitudinal)** | Good | Good | Very Good | | **Toughness (Transverse)** | Reduced | Isotropic | Isotropic | | **Grindability** | Good | Good | Excellent | | **Manufacturing Cost**| **Lower** | Higher | Lowest | ### **Economic Comparison:** | Factor | SKS51M Advantage | Standard Grade | |-----------------------|-------------------------|------------------------| | **Machining Time** | 25–40% reduction | Baseline | | **Tooling Cost** | 20–35% reduction | Baseline | | **Scrap Rate** | Lower for complex parts | Higher | | **Setup Time** | Reduced | Standard | | **Overall Manufacturing Cost** | 20–30% lower | Baseline | --- ## **11. Design & Manufacturing Considerations** ### **Material Orientation Strategy:** - **Design Priority:** Align primary tensile stresses with rolling direction - **Critical Components:** Specify orientation on drawings - **Stock Selection:** Purchase material with orientation in mind - **Worst-Case Loading:** Analyze transverse loading scenarios ### **Section Size Capability:** - **Air Hardening Advantage:** Can harden thick sections uniformly - **Optimal Range:** 10–150 mm sections - **Large Components:** Excellent for large mold bases and die sets - **Thin Sections:** Good dimensional control ### **Stress Concentration Management:** - **More Sensitive:** To notches in transverse direction - **Design Rule:** Use larger radii than with isotropic materials - **Minimum Radius:** 1.0–1.5 mm recommended - **Critical Areas:** Avoid placing stress raisers in transverse loading zones ### **Heat Treatment Planning:** - **Minimal Fixturing:** Usually not required due to air hardening - **Size Change Prediction:** More predictable than oil or water quenching - **Post-Hardening Machining:** Usually minimal due to dimensional stability - **Finishing Allowance:** 0.05–0.15 mm per side typically sufficient --- ## **12. Quality Control & Inspection** ### **Material Certification:** - **Chemistry Verification:** Particularly sulfur content - **Machinability Tests:** Optional but valuable for critical applications - **Ultrasonic Testing:** Note that sulfide stringers will appear (normal) ### **Heat Treatment Validation:** - **Hardness Testing:** Multiple locations and orientations - **Dimensional Verification:** Check for minimal distortion - **Microstructure:** Properly tempered martensite ### **Non-Destructive Testing:** - **Understand Limitations:** Know what sulfide indications look like - **Establish Baselines:** For normal material characteristics - **Critical Applications:** May require more extensive testing ### **Orientation Verification:** - **Marking Systems:** Maintain orientation throughout manufacturing - **Final Inspection:** Verify critical orientation before heat treatment - **Documentation:** Record orientation in quality records --- ## **13. Summary & Selection Guidelines** JIS SKS51M represents a **strategic optimization of air-hardening tool steel** for applications where complex machining and dimensional stability are paramount. ### **Select SKS51M When:** 1. **Complex tool geometries** require extensive machining operations 2. **Dimensional stability** during heat treatment is critical 3. **Manufacturing efficiency** and reduced machining time are priorities 4. **Air-hardening characteristics** are required for minimal distortion 5. **Production tooling** with significant machining content 6. **Prototype development** requires quick turnaround of complex shapes 7. **Cost reduction** in tool manufacturing is important ### **Optimal Application Scenarios:** - **Complex injection molds** with intricate cores and cavities - **Precision stamping dies** with detailed features - **Multi-cavity mold sets** requiring extensive machining - **Prototype tooling** where design may change frequently - **Educational and training tools** where machinability is valued - **Replacement parts** for existing air-hardening tools ### **Avoid SKS51M When:** 1. **Multi-directional impact loading** is significant 2. **Maximum transverse properties** are critical 3. **Mirror polishing** is required (inclusions may be visible) 4. **Welding or extensive repair** is anticipated 5. **Material orientation** cannot be controlled in design/manufacturing 6. **Simple shapes** make machinability advantages less valuable ### **Economic Justification:** - **Rule of Thumb:** Consider when machining accounts for >40% of total tool cost - **Break-even Analysis:** Compare material premium vs. machining savings - **Total Cost Calculation:** Include all manufacturing steps, not just material cost - **Production Volume:** Higher volumes increase economic benefits ### **Implementation Strategy:** 1. **Start with Medium-Complexity Tools:** Gain experience 2. **Document Orientation Requirements:** From design through manufacturing 3. **Optimize Machining Parameters:** Take full advantage of improved machinability 4. **Monitor Tool Performance:** In service compared to standard grades 5. **Expand Application:** To more complex tools as experience grows ### **Industry Applications:** SKS51M is particularly valued in: - **Plastic injection mold making** - **Die casting tool and die shops** - **Precision stamping die manufacturers** - **Prototype and development facilities** - **Educational institutions** teaching tool and die making ### **Final Recommendation:** JIS SKS51M offers a **practical engineering solution** that optimizes the total manufacturing process for complex air-hardened tooling. By accepting some directional property limitations in exchange for dramatically improved manufacturability, it provides **real economic benefits for appropriate applications**. For tool designers and manufacturers facing challenges with machining complex tools from conventional air-hardening steels, SKS51M provides a **validated solution that balances performance with producibility**. Its use should be considered within a **total cost framework**, recognizing that sometimes paying more for material can result in lower total costs through manufacturing efficiencies. When applied with proper attention to **orientation, design, and service conditions**, SKS51M can deliver **exceptional value through reduced manufacturing time and costs** while maintaining excellent performance for demanding cold work tooling applications. It represents a **smart choice for modern tool manufacturing** where complexity and precision requirements continue to increase while cost pressures remain intense. -:- For detailed product information, please contact sales. -: SKS51M Air-Hardening Tool Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6828 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. -: SKS51M Air-Hardening Tool Steel Properties -:- For detailed product information, please contact sales. -:

Applications of SKS51M Air-Hardening Tool Steel Flange -:- For detailed product information, please contact sales. -: Chemical Identifiers SKS51M Air-Hardening Tool Steel Flange -:- For detailed product information, please contact sales. -:

Packing of SKS51M Air-Hardening Tool Steel Flange -:- 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 Flange 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 3299 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