A514 Grade B steel is a high-strength, quenched and tempered (Q&T) Alloy steel plate standardized under ASTM A514/A514M, primarily used in structural applications demanding exceptional strength, toughness, and weldability. Below is a detailed breakdown of its key characteristics:
1. Core Specifications
Standard: ASTM A514/A514M (latest version) .
Alternative Names: T-1 steel, A514GrB steel plate .
Material Number: 1.8974 (EN standard equivalent) .
2. Chemical Composition
Typical composition ranges (weight %):
| Element | Content (%) | Role |
|---|---|---|
| Carbon (C) | 0.12–0.21 | Enhances strength/hardness |
| Manganese (Mn) | 0.70–1.00 | Improves toughness and hardenability |
| Silicon (Si) | 0.20–0.35 | Increases strength and oxidation resistance |
| Chromium (Cr) | 0.40–0.65 | Boosts wear/corrosion resistance |
| Molybdenum (Mo) | 0.15–0.25 | Enhances high-temperature strength |
| Vanadium (V) | 0.03–0.08 | Refines grain structure, improves weldability |
| Boron (B) | 0.0005–0.005 | Increases hardenability |
| Phosphorus (P) & Sulfur (S) | ≤0.030 each | Minimized to reduce brittleness |
3. Mechanical Properties
Yield Strength: ≥690 MPa (100 ksi)
Tensile Strength: 760–895 MPa (110–130 ksi)
Elongation: ≥18% (in 50 mm)
Hardness: 235–293 HB (Brinell)
Impact Toughness: Excellent low-temperature performance (Charpy impact tested)
Z-Direction Performance: Certified for anti-lamellar tearing (Grades Z15-Z35)
4. Manufacturing & Delivery
Processing: Electric arc furnace smelting → LF/VOD refining → controlled rolling .
Heat Treatment: Supplied in quenched and tempered (Q&T) condition to ensure uniform microstructure .
Thickness Range: 3/16" to 1.25" (≈4.8–32 mm) .
5. Applications
Ideal for heavy-load structures requiring high strength-to-weight ratios:
Construction/Mining: Cranes, excavators, drilling rigs, bulldozers .
Marine/Energy: Offshore platforms, hydraulic supports, wind turbine components .
Transportation: Mining trucks, load-bearing trailers .
6. Comparison to Similar Steels
| Property | A514 Grade B | A572 Grade 50 |
|---|---|---|
| Yield Strength | 690 MPa | 345 MPa |
| Tensile Strength | 760–895 MPa | 450–550 MPa |
| Heat Treatment | Quenched & Tempered | As-rolled |
| Max Thickness | 32 mm | Typically <100 mm |
International Equivalents:
EN 10149-2: S700MC
SEW 092: QStE 690 TM
7. Critical Considerations
Welding: Requires preheating (100–150°C) and controlled procedures to avoid cracking .
Machining: Possible with conventional methods but demands robust tooling due to hardness .
Thickness Limitation: Max 32 mm for Grade B; thicker sections use Grades Q/E (up to 200 mm) .
Conclusion
A514 Grade B is a premium structural steel engineered for extreme conditions, combining high strength (690+ MPa yield), superior toughness, and weldability. Its rigorous manufacturing (Q&T treatment, vacuum refining) ensures reliability in critical infrastructure
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