ASTM A36 - Most Common Structural Steel

Mechanical Properties

Yield Strength: ~250 MPa (36 ksi)

Tensile Strength: 400-550 MPa (58-80 ksi)

Elongation: 20% minimum (in 200mm)

Material Type: Hot-Rolled Carbon Steel

Key Features

• Most widely used structural steel in North America
• Excellent weldability - No preheat required for most applications
• Good machinability - Easy to cut, drill, and form
• Low cost - Most economical structural steel grade
• Versatile - Suitable for a wide range of structural applications

Applications

• Structural beams, channels, and angles
• Building frames and supports
• Bridge components
• Base plates and mounting brackets
• General fabrication and construction
• Machinery frames and supports
• Towers and masts
• Gusset plates and bracing

Chemical Composition (Typical)

Carbon (C): ≤0.26%

Manganese (Mn): ≤1.03%

Phosphorus (P): ≤0.04%

Sulfur (S): ≤0.05%

Silicon (Si): 0.15-0.40%

Copper (Cu): ≥0.20% (when specified for corrosion resistance)

Advantages

• Industry standard - Widely available and well-understood
• Excellent weldability - Easy to join using common welding methods
• Good formability - Can be bent, punched, and sheared easily
• Cost-effective - Lower material cost than higher-strength grades
• Reliable performance - Proven track record in structural applications

Processing Characteristics

Cutting: Can be cut using all standard methods including oxy-fuel, plasma, and laser cutting.

Forming: Excellent formability. Can be cold-formed, bent, and rolled with standard equipment.

Welding: Excellent weldability with all common welding processes (SMAW, GMAW, FCAW, SAW). No preheat typically required for thicknesses under 25mm.

Machining: Good machinability. Standard carbon steel tooling suitable.

Available Forms

• Plates and sheets
• Structural shapes (I-beams, channels, angles)
• Bars (round, square, flat)
• Pipes and tubes

Comparison with Other Grades

vs. A572 Gr 50: A36 has lower strength but better formability and lower cost. A572 Gr 50 offers ~40% higher yield strength.

vs. S235 (EN): A36 and S235 are roughly equivalent grades with similar properties and applications.

Best for: General structural applications where moderate strength is sufficient and cost-effectiveness is important. Ideal for buildings, light bridges, and general fabrication.

Design Considerations

Temperature Range: Not recommended for service below -30°C without impact testing.

Corrosion Protection: Requires painting or galvanizing for outdoor applications.

Thickness Availability: Commonly available from 6mm to 200mm.