The flange of I-beam is thick on the web with variable cross-section and thin on the outside, while the flange of H-beam is equal cross-section.
HW is basically equal to H-shaped steel height and flange width; it is mainly used for steel core columns, also known as stiff steel columns, in reinforced concrete frame columns; in steel structures, it is mainly used for columns.
HM is H-shaped steel with a height-to-flange width ratio of 1.33 to 1.75. It is mainly used in steel structures: steel frame columns are used as frame beams in frame structures under dynamic loads.
HN is H-shaped steel with a ratio of height to flange width greater than or equal to 2, which is mainly used for beams; the use of I-beam is equivalent to that of HN-shaped steel.
1. Whether the I-beam is ordinary or light, because the cross-section dimensions are relatively high and narrow, the moment of inertia of the two main sleeves of the cross-section is quite different, so it can only be directly used for members bending in the plane of its web or to form lattice-loaded members. It is not suitable for axial compression members or members that are perpendicular to the plane of the web and bent, which makes it very limited in the scope of application.
2. H-section steel belongs to economic cutting profile. Because of the reasonable section shape, they can make the steel more efficient and improve the cutting capacity. Different from the ordinary I-shape, the flange of h-beam is widened, and the inner and outer surfaces are usually parallel, so that it is easy to connect with other components with high strength. Its size constitutes a reasonable series and has a full range of models, which is convenient for design and selection.
3. The flanges of h-beam are all of equal thickness, with rolling cross-section and combined cross-section composed of three plates welded. The I-beams are all rolled cross-sections, and there is a 1:10 slope on the inside of the flange due to poor production process. The rolling of H-beam is different from that of ordinary I-beam with only one set of horizontal rolls. because of its wide flange and no slope, it is necessary to add a set of vertical rolls to roll at the same time, so its rolling process and equipment are more complex than ordinary rolling mills. The height of large rolled h-beam that can be produced in China is 800mm, which exceeds the combined section of welding.
According to the national standard of hot rolled H-beam in China, h-beam is divided into three categories: narrow flange, wide flange and steel pile, whose codes are hz, hk and hu respectively. Narrow flange h-section steel is suitable for beams or compression-bending members, while wide flange h-section steel and h-section steel piles are suitable for axial compression members or compression-bending members. Compared with H-beam, w, ix and iy are not as good as h-beam under the same weight.
