The mechanical properties define how the H-beam performs under load. For ASTM A36 shapes, including H-beams, the key requirements are:
| Property | Requirement | Significance for H-Beams |
|---|---|---|
| Tensile Strength, Ultimate | 400 - 550 MPa (58,000 - 79,800 psi) | The maximum stress the beam can withstand before fracture. The range accommodates normal production variations. |
| Tensile Strength, Yield (Minimum) | 250 MPa (36,300 psi) | The most critical design property. The stress at which the beam begins to deform plastically (permanently). Structural design ensures stresses remain below this point. |
| Elongation in 200 mm (8 in.) | 20% minimum | A measure of ductility. A higher percentage means the steel can undergo significant deformation before fracturing, which is a key safety factor. |
| Modulus of Elasticity | 200,000 MPa (29,000,000 psi) | A constant for all steel, measuring stiffness (resistance to elastic deformation). It determines how much a beam will deflect under load before yielding. |
It is important to note that these are minimum values for material up to a certain thickness (e.g., 8 inches/200 mm for shapes). Yield strength can decrease slightly in thicker sections due to slower cooling rates during rolling.