Overview:
The AASHTO M270 steel plate is a high-strength structural steel designed specifically for vehicle bridge construction. It is certified to meet the American Association of State Highway and Transportation Officials (AASHTO) M270 specifications, ensuring high durability and reliability in transportation infrastructure projects. AASHTO M270 is available in two grades: 50 and 50W, each providing different mechanical properties suitable for various environmental conditions.
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Grade 50 is known for its excellent strength and is commonly used in bridge applications.
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Grade 50W offers enhanced weathering properties, making it ideal for outdoor exposure where corrosion resistance is critical.
Available Sizes of AASHTO M270 Steel Plate
Leeco® Steel stocks AASHTO M270 plates in various sizes, with the option for special orders based on specific project requirements.
| Grade | Thickness | Width | Length |
|---|---|---|---|
| M270 50 & 50W | 3/16″ – 4″ | 48″ – 120″ | Up to 480″ |
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Plates with thicknesses ranging from 3/16″ to 4″.
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Widths ranging from 48″ to 120″.
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Lengths can be up to 480″, with other custom sizes available.
Material Properties
The material properties of AASHTO M270 steel plate, including yield point, tensile strength, and elongation, are detailed in the table below. These properties are essential for ensuring the material meets the required strength and durability for bridge construction.
| Grade | Yield Point (ksi) | Tensile Strength (ksi) | Min. 8” Elongation (%) |
|---|---|---|---|
| 50 | 50 | 65 | 18 |
| 50W | 50 | 70 | 18 |
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Grade 50: Offers strong performance for general bridge construction, with a yield point of 50 ksi and a tensile strength of 65 ksi.
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Grade 50W: Designed for environments exposed to harsh weather, offering improved tensile strength (70 ksi) and the same yield strength (50 ksi).
Chemical Composition
The chemical composition of AASHTO M270 plates is based on ASTM A709 specifications, ensuring the material’s quality and reliability for structural applications. Below is an outline of the key elements:
| Element | Grade 50 | Grade 50W |
|---|---|---|
| Carbon (C) | 0.23% max | 0.19% max |
| Manganese (Mn) | 0.80-1.35% | 0.75-1.35% |
| Phosphorus (P) | 0.030% max | 0.030% max |
| Sulfur (S) | 0.030% max | 0.030% max |
| Silicon (Si) | 0.15-0.40% | 0.30-0.65% |
| Nickel (Ni) | 0.40% max | 0.50% max |
| Chromium (Cr) | 0.40-0.65% | 0.40-0.70% |
| Copper (Cu) | 0.25-0.40% | 0.25-0.40% |
| Vanadium (V) | 0.01-0.15% | 0.02-0.10% |
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Grade 50: Offers moderate carbon and manganese content, ideal for most bridge construction needs.
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Grade 50W: Features a higher silicon content and additional nickel for better weathering resistance, making it suitable for exposure to the elements.
Comparison: AASHTO M270 Grade 50 vs Grade 50W
| Feature | Grade 50 | Grade 50W |
|---|---|---|
| Yield Strength | 50 ksi | 50 ksi |
| Tensile Strength | 65 ksi | 70 ksi |
| Weather Resistance | Moderate | High (weathering) |
| Best Use | General bridge use | Bridge use in harsh weather |
| Elongation | 18% | 18% |
| Nickel Content | 0.40% max | 0.50% max |