A709 Steel Plate: High-Performance Structural Steel for Bridge Construction
Overview:
A709 steel plate is a specialized grade primarily used in the manufacture of bridges and other heavy-duty structural applications. This steel is available in both standard and high-performance grades, ensuring it can meet the diverse needs of engineers and construction professionals. Available grades include 36, 50, 50W, and high-performance grades HPS 50W and HPS 70W. These grades are certified to meet ASTM and AASHTO specifications, making them ideal for bridge construction projects requiring high-strength materials.
A709 Steel Plate Material Properties
The following table outlines the material properties of A709 steel grades as per ASTM and AASHTO specifications:
| Grade | Yield Point (ksi) | Tensile Strength (ksi) | Min. 8” Elongation (%) |
|---|---|---|---|
| 36 | 36 | 58-80 | 20 |
| 50 | 50 | 65 | 18 |
| 50W | 50 | 70 | 18 |
| HPS 50W | 50 | 70 | 18 |
| HPS 70W | 70 | 85-110 | 19 at 2″ elongation |
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Grade 36: Offers moderate yield and tensile strength, ideal for general structural applications.
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Grade 50: Provides enhanced strength and is commonly used for more demanding structural requirements.
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Grade 50W: Adds weathering resistance, making it suitable for exposure to outdoor environments.
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HPS 50W: A high-performance version of 50W with additional toughness, designed for high-stress and low-temperature environments.
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HPS 70W: Offers the highest strength, typically used in heavy-duty applications with extreme stress or exposure conditions.
Chemical Composition of A709 Steel Plate
The chemical composition of A709 steel grades varies slightly based on the specific grade. Below is a breakdown of the key elements:
| Element | Grade 36 | Grade 50 | Grade 50W | HPS 50W & HPS 70W |
|---|---|---|---|---|
| Carbon (C) | 0.25-0.27% | 0.23% max | 0.19-0.20% max | 0.11% max |
| Manganese (Mn) | 0.85-1.35% | 0.80-1.35% | 0.75-1.35% | 1.10-1.50% |
| Phosphorus (P) | 0.030-0.040% | 0.030% max | 0.030% max | 0.020% max |
| Sulfur (S) | 0.030-0.050% | 0.030% max | 0.030% max | 0.006% max |
| Silicon (Si) | 0.40% max | 0.15-0.40% | 0.30-0.65% | 0.30-0.50% |
| Nickel (Ni) | — | — | 0.40% max | 0.25-0.40% |
| Chromium (Cr) | — | — | 0.40-0.65% | 0.45-0.70% |
| Copper (Cu) | 0.20% min | 0.25-0.40% | 0.25-0.40% | 0.25-0.40% |
| Vanadium (V) | — | 0.01-0.15% | 0.02-0.10% | 0.04-0.08% |
| Columbium (Cb) | — | 0.005-0.05% | — | — |
| Molybdenum (Mo) | — | — | — | 0.02-0.08% |
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Grade 36: Lower carbon content with moderate manganese and phosphorus for general structural use.
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Grade 50: Enhanced with vanadium for improved toughness, with a well-balanced composition for high-strength requirements.
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Grade 50W: Contains nickel and chromium for additional weathering resistance, making it ideal for outdoor use.
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HPS 50W & HPS 70W: Both grades are highly alloyed with additional elements like molybdenum and vanadium for improved performance in harsh conditions.
Available Sizes of A709 Steel Plate
Leeco® Steel offers A709 steel plates in various sizes, with special sizes available upon request.
| Grade | Thickness | Width | Length |
|---|---|---|---|
| 36 | 3/16″ – 4″ | 48″ – 120″ | Up to 480″ |
| 50 | 3/16″ – 4″ | 48″ – 120″ | Up to 480″ |
| 50W | 3/16″ – 4″ | 48″ – 120″ | Up to 480″ |
| HPS 50W | 3/16″ – 4″ | 48″ – 120″ | Up to 480″ |
| HPS 70W | 3/16″ – 4″ | 48″ – 120″ | Up to 480″ |
Comparative Analysis of A709 Grades
| Feature | Grade 36 | Grade 50 | Grade 50W | HPS 50W | HPS 70W |
|---|---|---|---|---|---|
| Yield Strength | 36 ksi | 50 ksi | 50 ksi | 50 ksi | 70 ksi |
| Tensile Strength | 58-80 ksi | 65 ksi | 70 ksi | 70 ksi | 85-110 ksi |
| Elongation | 20% | 18% | 18% | 18% | 19% at 2” |
| Weather Resistance | Moderate | Moderate | High | High | Very High |
| Strength | Moderate | High | High | Very High | Very High |
| Best Use | General structures | Heavy-duty use | Outdoor structures | Extreme conditions | Heavy-duty & cold weather |