The mechanical properties define how the material behaves under load. ASTM A36 is specified primarily by its tensile strength, yield strength, and elongation.
Tensile Strength, Ultimate: 400 – 550 MPa (58,000 – 79,800 psi). This range represents the maximum stress the material can withstand while being stretched before necking and fracture. The variation can be due to processing variables and thickness.
Tensile Strength, Yield: Minimum 250 MPa (36,300 psi). This is the most critical design property, representing the stress at which the material begins to deform plastically (permanently). For plates and bars, this applies to thicknesses up to 200 mm.
Elongation at Break: Minimum 20% in 200 mm gauge length (or 23% in 50 mm). This measures ductility, indicating how much the material can stretch before breaking. Higher values mean better formability.
Modulus of Elasticity: 200 GPa (29,000 ksi). This is a measure of material stiffness, indicating its resistance to elastic deformation. It is constant for all steels.
Shear Modulus: 79.3 GPa (11,500 ksi). This measures resistance to shear deformation.
Poisson's Ratio: 0.260. This describes the ratio of lateral strain to axial strain under tension.
Note: Unlike some higher-grade structural steels (e.g., European S355J0), ASTM A36 does not have a mandated requirement for Charpy V-Notch impact toughness at low temperatures. It is intended for use in ambient temperature service.