Bethlehem Steel ASTM A678 Grade B, steel

Bethlehem Steel ASTM A678 Grade B 3/16 to 1-1/2 in. thick, steel plate Product Information -:- For detailed product information, please contact sales. -: Bethlehem Steel ASTM A678 Grade B 3/16 to 1-1/2 in. thick, steel plate Synonyms -:- For detailed product information, please contact sales. -:

Bethlehem Steel ASTM A678 Grade B 3/16 to 1-1/2 in. thick, steel plate Product Information -:- For detailed product information, please contact sales. -: ## **Product Datasheet: Bethlehem Steel ASTM A678 Grade B Steel Plate** **Product Overview** Bethlehem Steel ASTM A678 Grade B is a high-performance, quenched and tempered (Q&T) structural steel plate offering enhanced strength and excellent toughness. Produced through a precise thermal cycle of austenitizing, rapid quenching, and tempering, this plate achieves a fine-grained tempered martensitic or bainitic microstructure, delivering superior mechanical properties compared to as-rolled or normalized steels. As the intermediate strength grade within the ASTM A678 specification, Grade B provides an optimal balance for applications requiring a significant strength increase over mild steel while maintaining critical fracture resistance. This plate is available in thicknesses ranging from **3/16 inch (4.8 mm) to 1-1/2 inches (38.1 mm)**. **Key International Standards** * **Primary Standard:** **ASTM A678 / A678M** - Standard Specification for Quenched-and-Tempered Carbon and High-Strength Low-Alloy Structural Steel Plate. * **Governing Specification:** This product fully conforms to all chemical, mechanical, and heat treatment requirements for **Grade B** as defined in ASTM A678. * **Supplementary Requirements:** Commonly ordered with ASTM A6 supplementary requirements, such as **S1 (Charpy V-Notch Impact Testing)** for verification of toughness at specified temperatures, and **S5 (Maximum Carbon Equivalent)** to ensure weldability. * **Global Recognition:** The ASTM A678 specification is widely recognized and accepted in international engineering and construction projects. **Chemical Composition (Weight % - ASTM A678 Grade B Requirements & Typical Range)** The composition is engineered for good hardenability to achieve the required strength through thickness, while maintaining lean alloying for weldability and cost-effectiveness. | Element | ASTM A678 Grade B Requirement (Max, unless noted) | Typical Bethlehem Steel Production Range | | :--- | :--- | :--- | | **Carbon (C)** | 0.23% | 0.19 - 0.22% | | **Manganese (Mn)** | 1.50% | 1.10 - 1.40% | | **Phosphorus (P)** | 0.035% | ≤ 0.020% | | **Sulfur (S)** | 0.05% | ≤ 0.010% | | **Silicon (Si)** | 0.15 - 0.50% | 0.20 - 0.35% | | **Copper (Cu)** | 0.20% Min (when specified) | 0.20 - 0.40% (for atmospheric corrosion resistance) | | **Nickel (Ni)** | -- | May be added (~0.25-0.50%) for enhanced low-temperature toughness | | **Chromium (Cr)** | -- | May be added (~0.20-0.40%) for hardenability | | **Molybdenum (Mo)** | -- | May be added (~0.08-0.15%) for hardenability and tempering resistance | | **Vanadium (V)** | 0.10% Max (if added) | May be added (~0.03-0.08%) for grain refinement | | **Carbon Equivalent (C.E. IIW)** | Not specified in standard | Typically 0.45 - 0.52 | **Physical & Mechanical Properties (ASTM A678 Grade B Requirements)** | Property | Requirement for Grade B | Typical Performance / Notes | | :--- | :--- | :--- | | **Yield Strength (Min)** | 60 ksi (415 MPa) | Typically 65 - 75 ksi (448 - 517 MPa) | | **Tensile Strength** | 80 - 100 ksi (550 - 690 MPa) | Typically 85 - 95 ksi (586 - 655 MPa) | | **Elongation in 2" (Min)** | 20% (for plates ≤ 3/4") | Often 22-26% | | **Elongation in 8" (Min)** | 16% (for plates ≤ 3/4") | -- | | **Modulus of Elasticity** | ~29,000 ksi (200 GPa) | ~29,000 ksi (200 GPa) | | **Density** | 0.284 lb/in³ (7.85 g/cm³) | 0.284 lb/in³ (7.85 g/cm³) | | **Charpy V-Notch Toughness (Typical)** | Can be specified per A6 S1 | Excellent; often achieves 30-50 ft-lb (41-68 J) at -50°F (-46°C) or lower, depending on chemistry and tempering. | | **Key Feature** | **Optimized Q&T Performance:** Provides a robust combination of 60 ksi minimum yield strength and outstanding notch toughness, making it resistant to crack initiation and propagation under dynamic or impact loads. | **Product Applications** The superior strength-toughness combination of ASTM A678 Grade B makes it ideal for critical structures and components subjected to severe service conditions. * **Bridge Construction:** Fracture-critical members, girders, and connections in highly loaded or long-span bridges, particularly in cold climates. * **Building & Heavy Construction:** Columns, beams, and base plates in high-rise buildings, seismic-resistant structures, and industrial facilities with dynamic loads. * **Mining & Heavy Equipment:** Critical weldments in excavator booms, shovel dippers, crusher frames, and other components exposed to shock loading and abrasion. * **Material Handling:** Crane runway girders, trolley beams, and components for heavy-duty stacker/reclaimers. * **Pressure Vessel & Penstock Construction:** For applications requiring certified impact properties and higher strength than standard carbon steel plate. * **Military & Defense:** Armor vehicle structural components and other applications demanding high strength with guaranteed toughness. **Advantages & Fabrication Notes** * **Exceptional Toughness:** The quenched and tempered microstructure provides industry-leading resistance to brittle fracture, which is its primary advantage over as-rolled HSLA plates of similar strength. * **Good Weldability with Precautions:** Weldability is good for its strength class due to controlled carbon content. However, **strict adherence to low-hydrogen welding procedures** (SMAW, GMAW, FCAW with suitable filler metals), proper preheat (often 200-300°F / 93-149°C), and interpass temperature control are **mandatory** to prevent hydrogen-induced cracking and preserve HAZ toughness. * **Uniform Through-Thickness Properties:** The Q&T process minimizes the strength gradient from surface to center, providing more predictable performance in thick sections. * **Formability:** Can be cold formed, but requires larger bend radii than lower-strength steels. Hot forming is not recommended without subsequent full re-quenching and tempering. * **Heat Treatment Verification:** Material is supplied with full heat treatment (quench and temper) certification, ensuring consistent properties. **Disclaimer:** This datasheet describes the historical product from **Bethlehem Steel Corporation** meeting **ASTM A678 Grade B**. For current projects, specify **ASTM A678 Grade B** along with required supplementary requirements (e.g., impact test temperature). Source material from modern steel producers who can provide current Mill Test Certificates that include heat treatment records, certified mechanical properties, and Charpy impact test reports. Always consult the producer's latest welding and fabrication guidelines prior to processing. -:- For detailed product information, please contact sales. -: Bethlehem Steel ASTM A678 Grade B 3/16 to 1-1/2 in. thick, steel plate Specification Dimensions Size： Diameter 20-1000 mm Length <4663 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. -: Bethlehem Steel ASTM A678 Grade B 3/16 to 1-1/2 in. thick, steel plate Properties -:- For detailed product information, please contact sales. -:

Applications of Bethlehem Steel ASTM A678 Grade B 3/16 to 1-1/2 in. thick, steel plate -:- For detailed product information, please contact sales. -: Chemical Identifiers Bethlehem Steel ASTM A678 Grade B 3/16 to 1-1/2 in. thick, steel plate -:- For detailed product information, please contact sales. -:

Packing of Bethlehem Steel ASTM A678 Grade B 3/16 to 1-1/2 in. thick, steel 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 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 1134 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