What is the difference between ISMB, ISMC, HEB and IPE profiles?

These are all I-shaped steel profiles from different standards: ISMB (Indian Standard Medium Beam, IS 808) is the most common Indian wide-flange beam, with heights from 100 to 600 mm. ISMC (Indian Standard Medium Channel) is a C-shaped channel from the same Indian standard, used for secondary members, purlins and bracings. HEB (European wide flange, DIN/EN) has approximately square proportions (height ≈ flange width) and is used as a column. IPE (European I-section, EN) is a narrow I-beam optimized for bending (flange is ~50% of height), used as beams. For equivalent depth, HEB is ~40% heavier than IPE because of the wider flanges — use HEB for columns where axial compression governs, IPE for beams where bending governs.