What is the ISO standard for structural I-beams?

ISO 657-2 specifies dimensions, mechanical properties, and testing for structural I-beams worldwide. It harmonizes regional standards, defining common grades like ISO 235 (235 MPa yield) and ISO 355 (355 MPa yield). The standard includes both metric (100-600mm depth) and imperial sizes, facilitating international trade. ISO 657-2 requires tensile strength 1.25× yield strength (e.g., 310 MPa minimum for ISO 235) and elongation ≥20%. It also defines surface quality (no cracks, scale) and allows manufacturers to use either hot-rolling or controlled cooling processes, provided properties are met. This global benchmark simplifies procurement for multinational construction projects.