AISI 50B40H Steel Capillary

AISI 50B40H Steel Capillary Product Information -:- For detailed product information, please contact sales. -: AISI 50B40H Steel Capillary Synonyms -:- For detailed product information, please contact sales. -:

AISI 50B40H Steel Product Information -:- For detailed product information, please contact sales. -: ## **Technical Specification: AISI 50B40H (UNS H50401) Steel - Boron-Treated, Hardenability-Guaranteed Medium Carbon Steel** ### **1. Product Overview** **AISI 50B40H** is a **medium-carbon, boron-treated alloy steel supplied with guaranteed hardenability characteristics**, denoted by the "H" suffix. This steel represents an optimized, cost-effective engineering material where a precise boron addition (typically 0.0005-0.003%) dramatically enhances hardenability without requiring expensive alloying elements like nickel and molybdenum. The "50" indicates a nominal carbon content of 0.48-0.53%, "B" signifies the intentional boron addition, and "40" represents the chromium content range. As an **H-steel**, 50B40H is produced to meet specific hardenability bands defined by end-quench (Jominy) testing, ensuring **predictable and consistent depth of hardening** across production batches. This makes it a **reliable, economical alternative** to more expensive guaranteed-hardenability steels like 4140H or 4340H for applications requiring good through-hardening in moderate sections. **Key Value Propositions:** - **Guaranteed Hardenability at Low Cost:** The combination of boron's hardenability multiplier effect and the H-grade certification ensures consistent hardening response with minimal alloy cost. - **Batch-to-Batch Consistency:** Each heat lot is tested to verify its Jominy curve falls within specified SAE hardenability bands, eliminating performance variations. - **Excellent Strength-to-Price Ratio:** Delivers mechanical properties comparable to more highly alloyed steels at significantly lower material cost. - **Manufacturing Reliability:** Predictable heat treatment response reduces scrap rates and improves quality control in high-volume production. --- ### **2. Standard Chemical Composition (Weight %)** The composition for 50B40H follows the same base ranges as 50B40 but is controlled to meet specific hardenability bands rather than fixed minima/maxima. | Element | AISI 50B40H Range (%) | Metallurgical Function | | :--- | :--- | :--- | | **Iron (Fe)** | Balance | Base Element | | **Carbon (C)** | 0.48 - 0.53 | Primary strength determinant; controlled to center hardenability band. | | **Manganese (Mn)** | 0.75 - 1.00 | **Primary hardenability adjuster**; range managed to tune Jominy curve. | | **Silicon (Si)** | 0.15 - 0.35 | Deoxidizer; solid solution strengthener. | | **Boron (B)** | 0.0005 - 0.003 | **Critical Hardenability Enhancer:** Segregates to austenite grain boundaries, providing disproportionate hardenability increase. | | **Chromium (Cr)** | 0.35 - 0.55 | Secondary hardenability element; improves wear resistance. | | **Sulfur (S)** | 0.040 max (often 0.020-0.035 for machinability) | Controlled for chip breaking in machining applications. | | **Phosphorus (P)** | 0.035 max | Kept low to maintain toughness. | **Critical Processing Note:** Boron must be in "active" form (solid solution) to be effective. Titanium or aluminum is often added in minute quantities (~0.02%) to protect boron by tying up nitrogen, preventing BN formation that would render boron ineffective. --- ### **3. Typical Mechanical & Physical Properties** *Properties after oil quenching from 845°C (1550°F) and tempering at 540°C (1000°F) for a 25mm diameter section:* | Property | Value / Range | Condition / Standard | | :--- | :--- | :--- | | **Hardness** | 28 - 34 HRC | Tempered condition | | **Tensile Strength** | 950 - 1100 MPa (138 - 160 ksi) | ASTM E8 | | **Yield Strength (0.2%)** | 800 - 950 MPa (116 - 138 ksi) | ASTM E8 | | **Elongation** | 16% - 22% | ASTM E8 | | **Reduction of Area** | 45% - 60% | ASTM E8 | | **Charpy V-Notch Impact** | 35 - 55 J (26 - 41 ft-lb) | ASTM A370 | | **Annealed Hardness** | 180 - 220 HB | Machining condition | | **Hardenability (Jominy)** | J₆ = 45-55 HRC; J₂₀ = 35-45 HRC | SAE J1268 typical band | | **Density** | 7.85 g/cm³ | - | | **Modulus of Elasticity** | 205 GPa (29.7 × 10⁶ psi) | - | --- ### **4. Hardenability Characteristics & Heat Treatment** **Guaranteed Hardenability:** - Governed by **SAE J1268** standard - Each heat lot supplied with a **Jominy Hardenability Test Certificate** - Hardenability band ensures consistent through-hardening in sections up to **~50mm (2 inches)** diameter with oil quenching **Optimal Heat Treatment:** 1. **Annealing:** 790-820°C (1450-1510°F), slow cool for machining 2. **Austenitizing:** 830-860°C (1525-1580°F) for quenching 3. **Quenching:** **Oil quench recommended** for sections >25mm 4. **Tempering:** 425-650°C (800-1200°F) depending on desired strength/toughness balance **Critical Consideration:** Boron's effectiveness is temperature-sensitive. Austenitizing above 900°C (1650°F) can cause boron to precipitate as borocarbides, reducing its hardenability effect. --- ### **5. Target Applications** 50B40H is specified for **high-volume, cost-sensitive components** requiring guaranteed heat treatment consistency: - **Automotive Mass Production:** - **Axle shafts** for passenger vehicles and light trucks - **Torsion bars** and **stabilizer bars** - **Steering linkage components** (pitman arms, idler arms) - **Driveshaft components** - **Agricultural & Off-Highway Equipment:** - **PTO shafts** - **Implement pins** and **bushings** - **Gear blanks** for transmission applications - **Fastener Industry:** - **High-strength bolts** (Grade 8.8 equivalent and above) - **Studs** and **pins** requiring consistent hardening - **General Machinery:** - **Hydraulic cylinder rods** - **Machine tool components** (levers, handles) - **Spindles** and **arbors** for moderate-duty applications --- ### **6. International Standards & Equivalents** | Standard System | Designation | Equivalent / Note | | :--- | :--- | :--- | | **USA (Primary)** | **AISI 50B40H** / **SAE J404** | **UNS H50401** | | **USA (Product)** | **ASTM A304** | Standard for bars with hardenability requirements | | **USA (Testing)** | **SAE J1268** | Hardenability band specification | | **ISO** | **ISO 683-1** | **Type 1.5517** with hardenability requirements | | **Europe** | **EN 10083-3** | Similar: **38B3 + H** (different carbon range) | | **Japan** | **JIS G4106** | **S45CB-H** (Boron-treated with hardenability) | | **Germany** | **DIN 17200** | **38B3 + H** | | **China** | **GB/T 5216** | **40BH** / **45BH** (Similar boron H-steels) | **Important Distinction:** While 50B40H has exact AISI/SAE specifications, international equivalents may have slightly different carbon ranges (e.g., 0.38-0.43%C for 38B3 vs. 0.48-0.53%C for 50B40H). The "H" suffix is universally recognized for hardenability-guaranteed steels. --- ### **7. Comparison with Other H-Steels** | Grade | Typical Cost Index | Hardenability Index | Max Hard Section | Key Applications | | :--- | :--- | :--- | :--- | :--- | | **50B40H** | **1.0** (Baseline) | High | ~50mm | Cost-sensitive automotive, agricultural | | **4140H** | 1.3 - 1.5 | Very High | ~75mm | General machinery, higher-duty components | | **4340H** | 2.0 - 2.5 | Excellent | ~100mm | Aerospace, high-performance applications | | **1045H** | 0.8 - 0.9 | Low-Moderate | ~25mm | Light-duty, shallow-hardening parts | **Advantages of 50B40H:** - **Best cost-to-hardenability ratio** among alloy H-steels - Suitable for **automated, high-volume heat treatment** lines - **Reduced alloy surcharge** compared to Mo- and Ni-containing grades - **Adequate properties** for majority of medium-duty applications **Limitations:** - **Not for severe impact** or high-toughness applications (lacks nickel) - **Limited high-temperature** stability (lacks molybdenum) - **Requires proper processing** to maintain boron effectiveness --- ### **8. Procurement & Quality Assurance** **Essential Purchase Specification:** 1. **Material Designation:** AISI 50B40H per ASTM A304 2. **Hardenability Requirement:** "To meet SAE J1268 H-band for 50B40H" 3. **Condition:** As-rolled, annealed, or normalized as required for machining 4. **Special Requirements:** Boron protection (Ti/Al addition) if specified **Mandatory Certification:** - **Mill Test Report** with full chemical analysis - **Jominy Hardenability Test Certificate** showing actual test data and compliance with SAE bands - **Mechanical property reports** if supplied heat-treated **Quality Notes:** - Verify **active boron content** through hardenability testing rather than chemical analysis alone - For critical applications, specify **grain size requirements** (ASTM 5 or finer recommended) - Consider **inclusion control** (ASTM E45) for fatigue-critical components --- ### **9. Processing Guidelines** **Machining:** - Best machined in **annealed condition** (180-220 HB) - Use **positive rake angles**, moderate speeds (60-100 m/min for turning) - **Sulfur content** can be optimized for improved machinability (0.020-0.035%) **Welding:** - **Preheat required:** 150-200°C (300-400°F) - Use **low-hydrogen electrodes** exclusively - **Post-weld heat treat immediately** (temper at 595-650°C / 1100-1200°F) - Not recommended for highly restrained welds or critical welded structures **Heat Treatment:** - **Protect from decarburization** during austenitizing - **Quench delay** should be minimized (<5 seconds) - **Temper immediately** after quenching to prevent cracking - For optimal toughness, **temper above 540°C (1000°F)** **Economic Justification:** 50B40H typically provides **20-35% cost savings** over 4140H for equivalent hardenability in sections up to 50mm diameter, making it the **preferred choice for high-volume, cost-driven applications** where guaranteed consistency is required but premium alloy properties are unnecessary. -:- For detailed product information, please contact sales. -: AISI 50B40H Steel Specification Dimensions Size： Diameter 20-1000 mm Length <6269 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 50B40H Steel Properties -:- For detailed product information, please contact sales. -:

Applications of AISI 50B40H Steel Capillary -:- For detailed product information, please contact sales. -: Chemical Identifiers AISI 50B40H Steel Capillary -:- For detailed product information, please contact sales. -:

Packing of AISI 50B40H Steel Capillary -:- 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 Capillary 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 2740 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