ASTM A529 Structural Steel Plate

What is ASTM A529 Steel?

ASTM A529 is a specification for structural steel plates that are typically used in construction applications. It covers high-strength carbon manganese steel shapes, plates, and bars of structural quality for use in riveted, bolted, or welded construction. The steel plates under ASTM A529 are available in different grades, including Grade 50 and Grade 55.

Material Composition

Balance (=>97.69%)<=1.35%<=0.27%=>0.20%<=0.050%<=0.040%<=0.40% max
Chemical Composition Table

Manufacturing Process

Thermomechanically controlled processing leads to fine grain structure for enhanced strength. Plate is produced via hot/cold rolling while bar undergoes forging or rolling.

Mechanical Properties

PropertyGrade 50 [345] ImperialGrade 50 [345] MetricGrade 55 [380] ImperialGrade 55 [380] Metric
Tensile Strength, min70* ksi485 MPa70 ksi485 MPa
Tensile Strength, max100 ksi690 MPa100 ksi690 MPa
Yield Strength, min50 ksi345 MPa55 ksi380 MPa
Elongation in 8 in. (200 mm), % (min)18181717
Elongation in 2 in. (50 mm), % (min)21212020
Density7.85 g/cm³ or 0.284 lb/in³7.85 g/cm³ or 0.284 lb/in³7.85 g/cm³ or 0.284 lb/in³7.85 g/cm³ or 0.284 lb/in³
Mechanical and Physical Properties Table
ASTM A529 Structural Steel Plate
ASTM A529 Structural Steel Plate


Offshore structures, shipbuilding, pressure vessels etc. allow efficient designs during fabrication. Forming/welding are easier than higher strength variants.

Available Grades

The Grade 50 steel is the most common grade specified under ASTM A529. It has a minimum yield strength of 50,000 psi (345 MPa) and a minimum tensile strength of 70,000-100,000 psi (485-690 MPa). Grade 50 steel is often used in general construction and structural applications, such as buildings, bridges, and machinery.

Grade 55 steel, on the other hand, has a higher yield strength of 55,000 psi (380 MPa) and a minimum tensile strength of 70,000-100,000 psi (485-690 MPa). It offers improved strength compared to Grade 50 steel and is also commonly used in construction applications.

Both Grade 50 and Grade 55 steel plates are weldable and can be used in structural applications where welding or bolting is required. They have good formability and are typically supplied in the as-rolled condition.Higher grades up to Grade 100 (Grade 690) are also available with increasing yield strengths.

A529 Steel Equivalent

ASTM A529 steel does not have a direct equivalent in other international standards. However, there are similar steel grades in other standards that can be considered as alternatives.

One common alternative is ASTM A572 Grade 50 steel. ASTM A572 Grade 50 is a high-strength, low-alloy structural steel that is similar in composition to ASTM A529 Grade 50 steel. Another alternative is EN 10025-2 S355JR steel. EN 10025-2 is a European standard for hot-rolled structural steel. S355JR is a non-alloy structural steel grade that is widely used in Europe and has similar mechanical properties to ASTM A529 Grade 50 steel.

It’s important to note that while these alternatives have similar mechanical properties to ASTM A529 Grade 50 steel, there may be some differences in chemical composition and other specifications.

Inspection and Testing

Mill test reports include chemical analysis and mechanical properties as per ASTM A529. 100% ultrasonic testing of plate/bar for defects or laminations.

Handling and Storage

Proper support and packing during transport. Sheltered storage on level ground to prevent damage, corrosion during fabrication/erection.

Please contact us for any other information required on A529 steel applications and availability. We would be glad to assist.

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