ASME SA588 Grade A (SA588GRA) Weathering Steel Plate
ASME SA588 Grade A (SA588GRA) Weathering Steel Plate: Full Data Sheet & Equivalents
In-depth material data for ASME SA588 Grade A (SA588GRA) weather-resistant structural steel plate: chemical composition, mechanical and physical properties, international equivalents, and application guidance.
Hot rolling, cold forming, welding, thermal cutting, machining
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ASME SA588 Grade A Weathering Steel Plate Introduction
ASME SA588 Grade A (SA588GRA) is a high-strength, low-alloy structural steel with enhanced atmospheric corrosion resistance, commonly known as weathering steel. It is governed by the ASME Boiler and Pressure Vessel Code Section II, Part A. The alloy is designed to form a stable, protective oxide layer when exposed to the atmosphere, eliminating the need for painting in many applications. Key elements such as chromium, copper, and nickel contribute to its superior corrosion resistance. This grade offers a minimum yield strength of 345 MPa (50 ksi) and is typically supplied in plate form for welded, bolted, or riveted structures. It exhibits excellent weldability and notch toughness, making it suitable for bridges, buildings, railcars, and transmission towers.
ASME SA588 Grade A Weathering Steel Plate Chemical Composition
The values below represent the heat analysis requirements per ASME SA588/SA588M for Grade A. All elements are intentionally added or residuals within the specified limits to achieve weathering characteristics.
- Copper, chromium, and nickel provide atmospheric corrosion resistance.
- Vanadium contributes to grain refinement and precipitation strengthening.
| Element | Content (%) | Remarks |
|---|---|---|
| Carbon (C) | ≤0.19 | |
| Manganese (Mn) | 0.80 – 1.25 | |
| Phosphorus (P) | ≤0.04 | |
| Sulfur (S) | ≤0.05 | |
| Silicon (Si) | 0.30 – 0.65 | |
| Nickel (Ni) | ≤0.40 | |
| Chromium (Cr) | 0.40 – 0.65 | |
| Copper (Cu) | 0.25 – 0.40 | |
| Vanadium (V) | 0.02 – 0.10 |
ASME SA588 Grade A Weathering Steel Plate Physical Properties
These physical properties are typical for ASME SA588 Grade A weathering steel and may vary slightly depending on processing history and exact composition. They are suitable for general engineering calculations.
- Density is equivalent to that of conventional carbon steels.
- Thermal expansion and conductivity closely follow those of low-alloy steels.
| Property | Typical Value | Unit | Condition |
|---|---|---|---|
| Density (ρ) | 7.85 | g/cm³ | 20 °C |
| Modulus of Elasticity (E) | 200 | GPa | 20 °C |
| Shear Modulus (G) | 77.2 | GPa | 20 °C |
| Poisson's Ratio (ν) | 0.3 | – | 20 °C |
| Thermal Expansion Coefficient (α), 20–100 °C | 11.7 | 10⁻⁶/°C | |
| Thermal Expansion Coefficient (α), 20–200 °C | 12.4 | 10⁻⁶/°C | |
| Thermal Conductivity (λ) | 44 | W/(m·K) | 20 °C |
| Specific Heat Capacity (c) | 460 | J/(kg·K) | 20 °C |
| Electrical Resistivity (ρ_e) | 0.15 | µΩ·m | 20 °C |
ASME SA588 Grade A Weathering Steel Plate Mechanical Properties
Tensile and bending properties are determined on test specimens taken from the product. Values apply to plates and bars up to 4 in. (100 mm) thickness.
- Elongation requirements depend on specimen gage length and product thickness.
- Bend test is performed cold using the specified ratio of mandrel diameter (D) to specimen thickness (T).
| Property | Required Value | Unit | Test Condition |
|---|---|---|---|
| Yield Strength (ReH) | ≥345 | MPa | Thickness ≤100 mm |
| Tensile Strength (Rm) | ≥485 | MPa | Thickness ≤100 mm |
| Elongation (A), 2 in. (50 mm) gage | ≥21 | % | Thickness ≤20 mm |
| Elongation (A), 8 in. (200 mm) gage | ≥18 | % | Thickness >20 mm |
| Bend test (cold), longitudinal | D = 1.5 T | – | Thickness ≤20 mm |
| Bend test (cold), longitudinal | D = 2.0 T | – | Thickness >20 – 25 mm |
| Bend test (cold), longitudinal | D = 2.5 T | – | Thickness >25 – 50 mm |
| Bend test (cold), longitudinal | D = 3.0 T | – | Thickness >50 – 100 mm |
ASME SA588 Grade A Weathering Steel Plate Fully Equivalent Materials – Direct Substitution Options
| Region | Standard | Grade | Remarks |
|---|---|---|---|
| USA | ASTM A588/A588M | Grade A | Chemically and mechanically identical to ASME SA588 Grade A. |
ASME SA588 Grade A Weathering Steel Plate Application Introduction
ASME SA588 Grade A is primarily used for load-bearing structures exposed to atmospheric corrosion. It achieves long-term durability through the formation of a protective patina.
- In many environments, it can be used without paint, reducing maintenance costs.
- It is suitable for welding with low-hydrogen procedures and matching weathering electrodes.
- Precautions should be taken in highly corrosive (marine/industrial) or continuously wet locations.
Product Applications: Weathering steel plates for structural fabrication, Hot-rolled coils and cut-to-length sheets, Welded H-beams and built-up sections, Prefabricated bridge modules, Transmission tower component kits
Processed into products: Bridge girders, diaphragms, and floor systems, Building frames, columns, and trusses, Railcar bodies, underframes, and hoppers, Intermodal shipping containers, Lattice transmission tower legs and bracing, Overhead sign supports and crash barriers
Application industries: Bridge Construction, Building and Infrastructure, Railway Vehicles and Freight Cars, Container Manufacturing, Power Transmission Towers, Highway Signage and Guardrails
ASME SA588 Grade A Weathering Steel Plate Similar Weathering Steel Grades
| Region | Standard | Grade | Remarks |
|---|---|---|---|
| Europe | EN 10025-5 | S355J2W | Comparable yield strength (355 MPa min); composition differs slightly; verify weldability and availability. |
| China | GB/T 4171 | Q355GNH | Similar strength and corrosion resistance; check specific chemical requirements for direct substitution. |
| Japan | JIS G3114 | SMA490AW | Weathering steel with min. 490 MPa tensile strength; chemical composition and impact properties may differ. |
Notes:
- Delivery condition is typically as-rolled; normalizing or stress relieving may be agreed at ordering.
- Charpy V-notch impact testing is not mandatory but can be specified as supplementary requirements (e.g., ASME SA20).
- When 'weathering' is desired, surface preparation and exposure must follow established practices for patina formation.
- For welded structures, use filler metals that produce a similar weathering weld deposit.
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