How to distinguish I-beams from H-beams?

Differences between I-beams HW, HM, HN and H-sections: The flanges of I-beams have a varying thickness, being thicker near the web and thinner on the outside; whereas the flanges of H-sections have a constant thickness. HW, HM, and HN are general terms for H-sections, with H-sections being welded together, while HW, HM, and HN are produced by hot rolling. In the case of HW, the height of the H-section is roughly equal to its flange width; it is mainly used as steel core columns in reinforced concrete frame structures, also known as rigid steel columns, and is primarily utilized for columns in steel structures. For HM, the ratio of the height to the flange width is approximately 1.33–1.75; it is mainly used in steel structures as columns in steel frames, as well as as frame beams in structures subjected to dynamic loads, such as equipment platforms. HN has a ratio of height to flange width of 2 or more; it is mainly used for beams. The applications of I-beams are similar to those of HN-sections. 1. Whether they are regular or lightweight, I-beams have relatively high and narrow cross-sectional dimensions, resulting in significant differences in the inertial moments of their two main axes. Therefore, they can generally only be used in components that are subjected to bending within the plane of their web, or they can be used to form lattice-type structural elements. It is not suitable for axially compressed members or those that also experience bending perpendicular to the web plane, which limits its range of applications significantly. 　 　　2. H-shaped steel belongs to the category of high-efficiency and economical cross-sectional profiles (others include cold-formed thin-walled steel profiles and profiled steel sheets, etc.). Due to their rational cross-sectional shape, they enable steel to achieve higher efficiency and improve its load-bearing capacity. Unlike ordinary I-beams, the flanges of H-beams are widened, and their inner and outer surfaces are usually parallel, which facilitates connection using high-strength bolts and other components. Its dimensions form a reasonable range with a full selection of models, facilitating design and selection. 　 　　3. The flanges of H-beams have uniform thickness; they can have a rolled cross-section or a composite cross-section formed by welding three plates together. I-beams all have rolled cross-sections, and due to poor manufacturing processes, there is a 1:10 slope on the inner edge of the flanges. The rolling of H-shaped steel differs from that of ordinary I-beams, which use only a set of horizontal rollers. Due to its wider flanges and lack of slope (or very slight slope), an additional set of vertical rollers is required for rolling as well; therefore, its rolling process and equipment are more complex than those of ordinary rolling mills. The maximum height of rolled H-beams that can be produced domestically is 800 mm; beyond this, only welded composite sections are possible. 　　China’s national standard for hot-rolled H-beams (GB/T11263-1998) classifies H-beams into three categories: narrow flange, wide flange, and steel piles, with codesHZ, HK, and HU respectively. Wide-flange H-beams are suitable for beams or compression-bending members, whereas wide-flange H-beams and H-beam piles are suitable for axially compressed members or compression-bending members. Compared to H-beams, under the same weight condition, w, ix, and iy are all inferior to those of H-beams

I learned something new. I used to think that I-beams and H-beams were the same thing; next time I see them, I’ll take a closer look at them. For building platforms and supports, I always thought that H-beams were used

It’s in the hardware manual; you can understand it as soon as you look at it at the steel market

H-beams are also available in hot-rolled form, and no difference can be seen from the web. Looking at the flanges, the flanges of H-beams are flat, while those of I-beams are generally sloped. In other words, the cross-section of H-shaped steel is very regular; aside from the curved sections at the edges, all other lines are parallel to each other.

The teacher upstairs answered based on theory; if one wants to see it at a glance, it’s best to look at the cross-section. The cross-section of H-beams is regular, with all its planes being perpendicular or parallel to each other, whereas the cross-section of I-beams has slopes. That’s more or less what happened.