AISI 51B60 Steel, annealed

AISI 51B60 Steel, annealed, 25 mm (1 in.) round Product Information -:- For detailed product information, please contact sales. -: AISI 51B60 Steel, annealed, 25 mm (1 in.) round Synonyms -:- For detailed product information, please contact sales. -:

AISI 51B60 Steel, annealed, 25 mm (1 in.) round Product Information -:- For detailed product information, please contact sales. -: # **AISI 51B60 Steel, Annealed, 25 mm (1 inch) Round Bar - Technical Data Sheet** ## **1. Product Overview** **AISI 51B60 annealed 25 mm (1 inch) round bar** is a **boron-treated, high-carbon chromium alloy steel** supplied in a fully softened condition to optimize machinability and formability. The "B" in the designation indicates boron addition (typically 0.0005-0.003%), which significantly enhances hardenability without the need for higher levels of expensive alloying elements. This 25mm diameter product combines the high strength potential of 5160 chemistry with the cost-effective hardenability boost of boron, making it an economical choice for applications requiring deep hardening characteristics. The annealed condition provides excellent machinability for complex component manufacturing, while the boron addition ensures superior through-hardening capability during subsequent heat treatment. The 25mm diameter represents an optimal size for uniform annealing response and predictable property gradients after hardening. --- ## **2. Chemical Composition (SAE J404/J412)** | Element | Composition Range (%) | Metallurgical Function in 25mm Annealed Bar | |---------|----------------------|---------------------------------------------| | **Carbon (C)** | 0.56 - 0.64 | Provides high strength and hardness potential; primary strengthening element | | **Manganese (Mn)** | 0.75 - 1.00 | Enhances hardenability and strength; improves response to boron addition | | **Phosphorus (P)** | ≤ 0.035 | Impurity; minimized for improved toughness | | **Sulfur (S)** | 0.040 - 0.070 | Intentionally added for improved machinability (free-machining characteristic) | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer; strengthens ferrite matrix | | **Chromium (Cr)** | 0.70 - 0.90 | Improves hardenability and wear resistance | | **Boron (B)** | 0.0005 - 0.003 | **Key element**; dramatically increases hardenability at minimal addition | | **Iron (Fe)** | Balance | Base metal | **Key Boron Characteristics:** - **Hardenability multiplier:** ~3× effectiveness compared to chromium - **Optimal range:** 0.001-0.002% for maximum benefit - **Protection required:** Titanium or aluminum often added to protect boron from nitrogen - **Economic advantage:** Cost-effective alternative to higher alloy steels **Product Specifications:** - **SAE/AISI:** 51B60 - **Form:** Round bar, annealed condition - **Diameter:** 25.0 mm ±0.5 mm (1.00 inch ±0.020 inch) - **Condition:** Fully Annealed (typically 179-229 HB) - **Length:** Standard 3m, 6m; cut lengths available --- ## **3. Physical & Mechanical Properties (As-Annealed, 25mm Round)** ### **Typical As-Annealed Properties:** - **Hardness:** 179-229 HB (85-97 HRB) - **Tensile Strength:** 585-795 MPa (85-115 ksi) - **Yield Strength (0.2% offset):** 345-550 MPa (50-80 ksi) - **Elongation (in 50mm/2"):** 18-25% - **Reduction of Area:** 40-55% - **Modulus of Elasticity:** 205 GPa (29,700 ksi) - **Shear Modulus:** 80 GPa (11,600 ksi) ### **Machinability Characteristics (25mm Round):** - **Machinability Rating:** 55-65% (relative to 1212 steel = 100%) - **Improved machinability** due to sulfur addition (free-machining) - **Optimal Cutting Parameters:** - Turning: 50-70 m/min (165-230 SFM) with carbide - Feed: 0.20-0.40 mm/rev (0.008-0.016 in/rev) - Tool life: Good with proper coolant - **Chip Formation:** Short-breaking chips due to sulfur content - **Surface Finish:** 1.6-3.2 μm Ra (63-125 μin) achievable ### **Physical Properties:** - **Weight per meter:** 3.85 kg/m (2.59 lb/ft) - **Cross-sectional Area:** 490.9 mm² (0.761 in²) - **Density:** 7.85 g/cm³ (0.284 lb/in³) - **Thermal Conductivity:** 42.0 W/m·K at 100°C - **Coefficient of Thermal Expansion:** 12.3 μm/m·°C (20-100°C) - **Specific Heat:** 460 J/kg·K at 20°C ### **Boron-Enhanced Hardenability (After Heat Treatment):** - **Ideal Critical Diameter (D₁) in oil:** ~90-105 mm (vs. ~80-95 mm for 5160) - **Maximum hardness in 25mm round:** 58-63 HRC (as-quenched) - **Hardness gradient:** Reduced compared to non-boron grades - **Through-hardening capability:** Excellent for 25mm section --- ## **4. Annealing Process & Metallurgical Structure** ### **Standard Annealing Parameters:** - **Temperature:** 790-820°C (1450-1510°F) - **Soak Time:** 1.5-2 hours at temperature - **Cooling Rate:** Furnace cool to 600°C at 20-30°C/hour - **Atmosphere:** Protective to minimize decarburization - **Decarburization Control:** ≤0.25mm typical ### **Microstructural Characteristics:** - **Primary Structure:** Pearlite with proeutectoid ferrite - **Sulfide Inclusions:** MnS particles from sulfur addition (improve machinability) - **Boron Distribution:** Concentrated at prior austenite grain boundaries - **Grain Size:** ASTM 5-7 - **Carbide Distribution:** Uniform with possible partial spheroidization ### **Effect of Boron on Annealed Structure:** 1. **Grain boundary segregation** of boron atoms 2. **Reduced transformation temperatures** during annealing 3. **Modified carbide precipitation** behavior 4. **Improved hardenability retention** after annealing --- ## **5. Manufacturing & Processing** ### **Recommended Machining Parameters:** | Operation | Speed (m/min) | Feed (mm/rev) | Depth of Cut (mm) | Notes | |-----------|---------------|---------------|-------------------|-------| | **Turning** | 50-70 | 0.20-0.40 | 1.0-5.0 | Excellent chip control | | **Drilling** | 25-40 | 0.15-0.30 | Full diameter | Good hole quality | | **Milling** | 40-60 | 0.10-0.25/tooth | 2.0-4.0 | Free-machining benefits | | **Tapping** | 10-20 | Pitch determined | Full depth | Reduced tap wear | ### **Forming & Fabrication:** - **Cold Bending:** Minimum radius = 2× diameter (50mm) - **Hot Forging:** Good at 1050-850°C - **Cold Heading:** Suitable with proper die design - **Thread Rolling:** Excellent due to free-machining characteristics ### **Subsequent Heat Treatment:** - **Austenitizing:** 830-850°C (1525-1560°F) - **Quenching:** Oil (excellent for 25mm diameter) - **Tempering:** 400-600°C for most applications - **Boron Advantage:** More uniform hardness in 25mm section --- ## **6. Product Applications** ### **Cost-Effective High-Strength Components:** - **Axle shafts** for automotive and agricultural equipment - **Hydraulic piston rods** and cylinder components - **Shafts** for industrial machinery - **Gear blanks** requiring deep hardening - **Fastener stock** for high-strength bolts ### **Agricultural & Off-Road Equipment:** - **Implement shafts** and drive components - **Pivot pins** and bushings - **Tillage tool components** - **Sprockets** and chain drives ### **General Manufacturing:** - **Machine tool components** - **Material handling parts** - **Construction equipment components** - **Mining equipment wear parts** ### **Why Choose 51B60 25mm Annealed:** 1. **Cost savings** vs. higher alloy steels 2. **Excellent machinability** for production efficiency 3. **Good hardenability** for 25mm sections 4. **Wide availability** in standard sizes 5. **Predictable heat treatment response** --- ## **7. International Standards & Equivalents** ### **Primary Standards:** | Standard | Designation | Specification | |----------|-------------|---------------| | **SAE/AISI** | **51B60** | SAE J404, J412 | | **ASTM** | **A29/A29M** | Steel Bars, Carbon and Alloy | ### **Global Equivalents:** - **Europe:** Similar to boron-treated spring steels - **Japan:** Equivalent to boron-modified SCr materials - **China:** Similar to boron-containing spring steels ### **Boron Steel Standards:** - **SAE J404:** Includes boron steel specifications - **ASTM A304:** Covers boron-treated alloy steels --- ## **8. Quality Control** ### **Standard Testing:** - **Chemical Analysis:** Including boron content verification - **Hardness Testing:** Brinell or Rockwell B - **Microstructure:** Grain size and inclusion assessment - **Hardenability:** Optional Jominy testing ### **Boron-Specific Considerations:** - **Boron analysis** critical for performance - **Protection elements** (Ti, Al) should be verified - **Sulfide inclusion control** for transverse properties --- ## **9. Technical Advantages** ### **Advantages:** ✅ **Cost-effective hardenability** through boron addition ✅ **Excellent machinability** from sulfur content ✅ **Good through-hardening** for 25mm sections ✅ **Reduced alloy cost** vs. conventional alloy steels ✅ **Predictable heat treatment response** ### **Limitations:** ⚠️ **Reduced transverse properties** due to sulfides ⚠️ **Boron sensitivity** to overheating ⚠️ **Welding difficulties** ⚠️ **Not for highest toughness applications** --- ## **10. Economic Considerations** | Factor | Impact | Notes | |--------|--------|-------| | **Material Cost** | Lower than 5160 | Boron reduces need for other alloys | | **Machining Cost** | Lower | Free-machining characteristics | | **Heat Treatment** | Standard | Similar to 5160 but more consistent | | **Tooling Cost** | Lower | Improved machinability | | **Overall Cost** | **15-25% savings** vs. conventional alloy steels | --- ## **11. Comparison with 5160** | Property | 51B60 | Standard 5160 | |----------|-------|---------------| | **Hardenability** | Higher (boron-enhanced) | Good | | **Machinability** | Better (sulfur-added) | Standard | | **Transverse Properties** | Lower | Better | | **Cost** | Lower | Higher | | **Weldability** | Poorer | Poor | | **Applications** | Cost-sensitive, high-volume | Critical, high-performance | --- **Technical Significance:** AISI 51B60 represents an optimized, cost-effective alternative to conventional alloy steels for applications requiring good hardenability without premium alloy costs. The 25mm annealed round bar form provides excellent manufacturability for a wide range of components, while the boron addition ensures adequate hardening response for most industrial applications. **Revision:** 1.0 **Date:** October 2023 **Disclaimer:** This technical data is for informational purposes. Boron steels require careful heat treatment control to realize their full potential. Always consult with material suppliers for application-specific recommendations. Transverse properties may be reduced compared to non-sulfur grades; design accordingly. -:- For detailed product information, please contact sales. -: AISI 51B60 Steel, annealed, 25 mm (1 in.) round Specification Dimensions Size： Diameter 20-1000 mm Length <4131 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 51B60 Steel, annealed, 25 mm (1 in.) round Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 51B60 Steel, annealed, 25 mm (1 in.) round -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 51B60 Steel, annealed, 25 mm (1 in.) round -:- For detailed product information, please contact sales. -:

Packing of AISI 51B60 Steel, annealed, 25 mm (1 in.) round -:- 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 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 602 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