Bethlehem Steel ASTM A678 Grade D, steel

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

Bethlehem Steel ASTM A678 Grade D 3/16 to 3 in. thick, steel plate Product Information -:- For detailed product information, please contact sales. -: ## **Product Datasheet: Bethlehem Steel ASTM A678 Grade D Steel Plate** **Product Overview** Bethlehem Steel ASTM A678 Grade D is a high-strength, quenched and tempered (Q&T) structural steel plate representing the highest standard grade within the ASTM A678 specification. Engineered for the most demanding applications requiring maximum strength-to-weight ratio alongside superior toughness, this plate undergoes a rigorous thermal process of austenitizing, quenching, and tempering to achieve a fine-grained tempered martensitic microstructure. It delivers a guaranteed 80 ksi minimum yield strength and excellent resistance to brittle fracture, making it a critical material for heavily loaded structures and components operating in severe environments. This plate is available in a broad thickness range from **3/16 inch (4.8 mm) to 3 inches (76.2 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 is manufactured to meet all requirements for **Grade D** as defined in ASTM A678. The standard allows for adjusted mechanical properties based on thickness, with specific requirements for plates over 1.5 inches. * **Essential Supplementary Requirements:** For critical applications, the following ASTM A6 supplementary requirements are typically invoked: * **S1. Charpy V-Notch Impact Testing:** Mandatory for most structural uses, specified at designated temperatures (e.g., -50°F / -46°C). For plates over 1.5 in., testing is conducted at the quarter-thickness location. * **S4. Ultrasonic Examination:** Required for plates over specific thicknesses (often >1 in.) to ensure internal soundness per ASTM A578/A578M. * **S5. Maximum Carbon Equivalent:** Crucial for controlling weldability, especially in thick sections. * **S8. Maximum Tensile Strength:** May be specified to prevent over-strength and ensure uniformity in fabrication. * **Industry & Global Recognition:** Recognized by AISC for use in high-strength applications and often cross-referenced in specifications requiring high performance similar to European S690Q or similar Q&T grades. **Chemical Composition (Weight % - ASTM A678 Grade D Requirements & Typical Ranges)** Chemistry is carefully balanced to achieve high hardenability for thick sections while maintaining good weldability and toughness. Ranges vary significantly with thickness. | Element | ASTM A678 Grade D Requirement (Max) | Typical Aim (Thin Plate, e.g., <0.75") | Typical Aim (Heavy Plate, e.g., >1.5") | | :--- | :--- | :--- | :--- | | **Carbon (C)** | 0.27% | 0.18 - 0.22% | 0.16 - 0.20% | | **Manganese (Mn)** | 1.60% | 1.20 - 1.50% | 1.35 - 1.60% | | **Phosphorus (P)** | 0.035% | ≤ 0.020% | ≤ 0.012% | | **Sulfur (S)** | 0.05% | ≤ 0.010% | ≤ 0.005% | | **Silicon (Si)** | 0.15 - 0.50% | 0.20 - 0.35% | 0.20 - 0.35% | | **Copper (Cu)** | 0.20% Min (when specified) | 0.20 - 0.40% | 0.25 - 0.45% | | **Nickel (Ni)** | -- | 0.25 - 0.50% | 0.60 - 1.00% | | **Chromium (Cr)** | -- | 0.40 - 0.65% | 0.50 - 0.80% | | **Molybdenum (Mo)** | -- | 0.15 - 0.25% | 0.20 - 0.35% | | **Vanadium (V)** | 0.10% Max (if added) | 0.03 - 0.07% | 0.04 - 0.08% | | **Boron (B)** | -- | Trace (0.0005-0.002%) | 0.0015 - 0.003% | | **Carbon Equivalent (C.E. IIW)** | -- | 0.50 - 0.58 | 0.58 - 0.68 | **Physical & Mechanical Properties (ASTM A678 Grade D Requirements)** *Properties vary by thickness; values shown are for general reference. Plates over 1.5 in. have adjusted requirements.* | Property | Requirement for Grade D (General) | Typical Performance (Thickness Dependent) | | :--- | :--- | :--- | | **Yield Strength (Min)** | 80 ksi (550 MPa) | Thinner: 85 - 95 ksi (586 - 655 MPa)
Heavier: 80 - 88 ksi (550 - 607 MPa) | | **Tensile Strength** | 95 - 115 ksi (655 - 795 MPa) | Thinner: 100 - 110 ksi (690 - 759 MPa)
Heavier: 95 - 105 ksi (655 - 724 MPa) | | **Elongation in 2" (Min)** | 16% (for plates ≤ 3/4") | Typically meets or exceeds; decreases slightly with thickness. | | **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** | As specified per S1. Common: 20-30 ft-lb @ -50°F. | Excellent for its strength class; achieved through precise Q&T. Heavy plate toughness is tested at the T/4 location. | | **Key Feature** | **Pinnacle of Standardized Q&T Plate:** Offers the highest strength level standardized in ASTM A678, combined with the toughness, fatigue resistance, and uniform properties inherent to the quenched and tempered condition. | **Product Applications** ASTM A678 Grade D is specified for primary load-bearing components in critical structures and machinery where material failure is not an option. * **Advanced Civil Structures:** Fracture-critical bridge members (tension ties, box girders), seismic dampers, and nodes in offshore wind jacket foundations. * **Heavy Mining & Material Handling:** Main frames, booms, and dippers for giant electric mining shovels, draglines, and stacker/reclaimers. * **Power Generation:** Spherical valve housings, turbine runner supports in hydropower, and critical thick-section components in advanced nuclear facilities. * **Defense & Aerospace:** Armor vehicle structural members, launch platform components, and other high-integrity military applications. * **Specialized Transportation:** High-stress components in heavy-haul rail and marine equipment. **Advantages & Fabrication Notes** * **Optimum Strength-Toughness Balance:** Provides an unmatched combination of 80 ksi yield strength and high fracture toughness, enabling lighter, more efficient designs for extreme conditions. * **Demanding Fabrication Protocols:** Requires the highest level of fabrication control: * **Welding:** Strict low-hydrogen procedures with preheat (300-400°F+), often using temper-bead techniques or PWHT. Filler metal selection is critical (high toughness, matching/undermatching). * **Thermal Cutting:** Plasma or laser cutting preferred; flame cutting requires preheat and controlled cooling to prevent HAZ cracking. * **Forming:** Cold forming is limited; hot forming requires subsequent re-austentizing, quenching, and tempering. * **Through-Thickness Consistency:** The Q&T process ensures uniform properties, minimizing the strength drop-off at the center of thick plates—a key advantage over normalized or TMCP steels at this strength level. * **Full Metallurgical Traceability:** Supplied with comprehensive documentation including heat treatment charts, mechanical test reports from appropriate locations (surface, T/4), and impact test data. **Disclaimer:** This datasheet describes the historical capabilities of **Bethlehem Steel Corporation** for producing ASTM A678 Grade D across a wide thickness range. Modern production of this grade, especially in thicknesses above 2 inches, is a specialized capability of select global mills. Current procurement requires detailed specifications addressing hardenability verification (e.g., Jominy tests for heavy plate), strict chemistry limits, and explicit fabrication guidelines. Engagement with the steel producer's technical team during the design and specification phase is essential. All welding procedures must be rigorously qualified on representative thicknesses. -:- For detailed product information, please contact sales. -: Bethlehem Steel ASTM A678 Grade D 3/16 to 3 in. thick, steel plate Specification Dimensions Size： Diameter 20-1000 mm Length <4668 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 D 3/16 to 3 in. thick, steel plate Properties -:- For detailed product information, please contact sales. -:

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

Packing of Bethlehem Steel ASTM A678 Grade D 3/16 to 3 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 1139 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