ASTM A588 Weathering Steel Plate

What is ASTM A588 Plate?

ASTM A588 steel plate is specifically designed to withstand atmospheric corrosion, also known as weathering steel. It exhibits enhanced corrosion resistance compared to ordinary carbon steel due to the formation of a protective oxide layer on the steel surface when exposed to the elements. This oxide layer, known as a patina, helps to protect the steel from further corrosion.

ASTM A588 is a specification for high-strength low-alloy (HSLA) structural steel plate that is commonly used in structural applications such as bridges, buildings, and construction equipment. The specification covers high-strength, low-alloy structural steel shapes, plates, and bars for welded, riveted, or bolted construction with atmospheric corrosion resistance.

Composition and Manufacturing

The ASTM A588 specification includes several grades, namely Grade A, Grade B, Grade K, and Grade C. Each grade has different mechanical properties and chemical compositions, allowing for different applications and environmental conditions. The most commonly used grade is ASTM A588 Grade A, which has a minimum yield strength of 50,000 psi (345 MPa) and a minimum tensile strength of 70,000-85,000 psi (485-590 MPa). It is produced via continuous casting and rolling into plates and sheets.

ElementGrade AElementGrade BElementGrade K
chemical composition table

Mechanism of Weathering

When exposed to oxygen and moisture, a microscopically thin oxide layer forms on the steel surface which protects the base metal. This patina blends the structure into the surroundings.

ASTM A588 Weathering Steel Plate
ASTM A588 Weathering Steel Plate

Mechanical Properties

The minimum yield strength is 50 ksi. Higher tensile strength of 65-85 ksi and good toughness allows usage in bridges, infrastructure for over 50 years under all weather conditions.


Bridges, buildings, canopies, walls, fences where maintenance of painted surfaces is not feasible in the long run. Cost savings over the lifetime of the structure.

Forms and Sizes

ASTM A588 steel plate is typically supplied in the normalized or quenched and tempered condition. It is available in various thicknesses and widths to suit different construction needs. The plate can be further processed through cutting, bending, welding, and other fabrication methods to meet specific project requirements. Available as plates, angles and other structural sections as per project requirements.

Sustainable Solution

The use of ASTM A588 steel plate can provide cost-effective solutions in structural applications where exposure to atmospheric conditions, such as rain, humidity, and corrosive environments, is a concern. It offers durability, long service life, and aesthetic appeal due to its weathering properties. Eliminates need for re-painting over multi-decade lifespan. Reduces use of paint, thinner and maintenance cost. Environment friendly through zero VOCs release into the atmosphere.

I hope this covers all the essential details about weathering steel as per the ASTM A588 specification. Please let me know if any other information is required.

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