AISI 50B40 Steel Sheet,Plate

AISI 50B40 Steel Sheet/Plate Product Information -:- For detailed product information, please contact sales. -: AISI 50B40 Steel Sheet/Plate Synonyms -:- For detailed product information, please contact sales. -:

AISI 50B40 Steel Product Information -:- For detailed product information, please contact sales. -: ## **Technical Specification: AISI 50B40 (UNS G50401) Steel - Boron-Treated Medium Carbon Steel** ### **1. Product Overview** AISI 50B40 is a **medium-carbon, boron-treated alloy steel** belonging to the family of **"B-Steels"** – cost-effective alloy steels where small boron additions (0.0005-0.003%) significantly enhance hardenability without the need for high levels of traditional alloying elements like chromium, nickel, and molybdenum. The "50" denotes a nominal carbon content of 0.48-0.53%, "B" indicates boron addition, and "40" represents the presence of key alloying elements. This steel offers **excellent hardenability-to-cost ratio**, making it an economical alternative to more expensive alloy steels like 4140 or 4340 for applications requiring good through-hardening in moderate to large sections. **Key Characteristics:** - **High Hardenability at Low Cost:** Boron multiplies the hardenability effect of other elements, allowing the use of simpler, less expensive chemistries to achieve deep hardening. - **Good Strength & Toughness Balance:** When properly quenched and tempered, it develops good tensile strength with adequate toughness. - **Machinability:** In the annealed or normalized condition, it offers fair to good machinability for a medium-carbon steel. - **Weldability:** Requires preheating and post-weld heat treatment due to medium carbon content and hardenability. --- ### **2. Standard Chemical Composition (Weight %)** | Element | Content (%) | Metallurgical Role | | :--- | :--- | :--- | | **Iron (Fe)** | Balance | Base Element | | **Carbon (C)** | 0.48 - 0.53 | Primary strengthening element; determines hardness potential. | | **Manganese (Mn)** | 0.75 - 1.00 | Increases strength and hardenability; deoxidizer. | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer; strengthens ferrite. | | **Boron (B)** | 0.0005 - 0.003 | **Critical:** Segregates to austenite grain boundaries, dramatically increasing hardenability. | | **Chromium (Cr)** | 0.35 - 0.55 | Enhances hardenability, wear resistance, and corrosion resistance. | | **Nickel (Ni)** | - | Typically not present (cost-saving feature). | | **Molybdenum (Mo)** | - | Typically not present (cost-saving feature). | | **Sulfur (S)** | ≤ 0.040 | Residual (improves machinability if slightly increased). | | **Phosphorus (P)** | ≤ 0.035 | Residual. | **Note:** The exact composition may vary slightly among producers. The key identifier is the intentional boron addition within the specified range. --- ### **3. Typical Mechanical & Physical Properties** *Properties after quenching and tempering (typical for 25mm round bar oil-quenched and tempered at 540°C/1000°F):* | Property | Value / Range | Condition / Notes | | :--- | :--- | :--- | | **Hardness (As-Q&T)** | 28 - 35 HRC | Depends on tempering temperature | | **Tensile Strength** | 900 - 1150 MPa (130 - 167 ksi) | ASTM E8 | | **Yield Strength (0.2%)** | 750 - 1000 MPa (109 - 145 ksi) | ASTM E8 | | **Elongation** | 15% - 20% | ASTM E8 | | **Reduction of Area** | 40% - 55% | ASTM E8 | | **Charpy Impact (V-Notch)** | 30 - 50 J (22 - 37 ft-lb) | ASTM A370 | | **Annealed Hardness** | 180 - 220 HB | Machining condition | | **Density** | 7.85 g/cm³ | - | | **Modulus of Elasticity** | 205 GPa (29.7 × 10⁶ psi) | - | | **End-Quench Hardenability** | Good (Jominy distance for 50 HRC: ~8-12 mm) | Boron effect evident | --- ### **4. Heat Treatment Response** - **Annealing:** Heat to 790-820°C (1450-1510°F), slow cool. Produces ferrite-pearlite structure (~200 HB) for machining. - **Normalizing:** Heat to 870-900°C (1600-1650°F), air cool. Refines grain structure. - **Quenching:** Austenitize at 830-860°C (1525-1580°F), oil quench. Boron enables through-hardening of sections up to ~75mm (3 inches) diameter. - **Tempering:** Typically tempered between 425-650°C (800-1200°F) to desired strength/toughness balance. **Important:** Boron's effectiveness depends on proper heat treatment. Overheating (>950°C) can cause boron to form compounds that reduce its effectiveness. --- ### **5. Primary Applications** 50B40 is used where good hardenability is needed at minimal cost: - **Automotive Components:** Axle shafts, crankshafts, torsion bars, steering components - **Agricultural Equipment:** Gears, shafts, plow beams, harrow parts - **General Machinery:** Bolts, studs, pins, rollers, spindles - **Hand Tools:** Wrenches, pry bars, hammer heads - **Construction Equipment:** Bucket pins, linkage components - **Forgings:** Medium-duty forgings requiring uniform properties --- ### **6. International Standards & Equivalents** | Country/Region | Standard | Equivalent Grade | Notes | | :--- | :--- | :--- | :--- | | **USA** | **AISI 50B40** / **SAE J404** | **UNS G50401** | Primary designation | | **USA** | **ASTM A29/A29M** | Grade 50B40 | Bar product standard | | **USA** | **SAE J770** | - | Hardenability bands for boron steels | | **International** | **ISO 683-1** | **Type 1.5517** | Designation for boron steels | | **Europe** | **EN 10083-3** | **38B3** (Similar concept) | Different carbon range | | **Japan** | **JIS G4106** | **S45CB** | Boron-treated carbon steel | | **Germany** | **DIN 17200** | **38B3** | Similar boron steel | | **China** | **GB/T 3077** | **40B** / **45B** | Similar boron steel series | **Key Distinction:** While 50B40 is a specific AISI/SAE grade, equivalent boron steels exist worldwide with varying carbon contents (e.g., 15B21, 10B22, 50B44). The "B" designation always indicates intentional boron addition for hardenability. --- ### **7. Comparison with Similar Grades** | Property | 50B40 | 4140 | 1045 | | :--- | :--- | :--- | :--- | | **Nominal Carbon** | 0.50% | 0.40% | 0.45% | | **Primary Alloying** | Cr + B | Cr, Mo | None | | **Hardenability** | **High** (Boron effect) | High | Low | | **Cost** | **Low-Medium** | Medium | **Low** | | **Typical Use** | Cost-effective hardened parts | High-performance parts | Shallow-hardening parts | **Advantages of 50B40:** - Lower cost than 4140/4340 - Good hardenability for section sizes up to 75mm - Adequate strength for many applications **Limitations:** - Not suitable for very high-toughness applications (lacks nickel) - Limited high-temperature properties (lacks molybdenum) - Requires careful heat treatment to maximize boron effect --- ### **8. Processing Recommendations** 1. **Machining:** Perform in annealed condition; use positive rake tools, moderate speeds/feeds 2. **Welding:** Preheat to 150-200°C (300-400°F); use low-hydrogen electrodes; post-weld heat treat immediately 3. **Forging:** Heat to 1150-1200°C (2100-2200°F); finish above 850°C (1560°F); slow cool after forging 4. **Quality Control:** Verify boron content through chemical analysis; conduct hardenability tests (Jominy) for critical applications **Procurement Note:** When ordering 50B40, specify if hardenability testing is required. For critical applications, request Jominy hardenability curves to ensure consistency. -:- For detailed product information, please contact sales. -: AISI 50B40 Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6268 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 50B40 Steel Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 50B40 Steel Sheet,Plate -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 50B40 Steel Sheet,Plate -:- For detailed product information, please contact sales. -:

Packing of AISI 50B40 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 2739 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