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H-beams can be manufactured either by welding or rolling. In the case of welded H-beams, steel strips of appropriate thickness and width are cut and then welded together using a continuous welding unit to form the flange and web. However, this method has several drawbacks, such as high material consumption, inconsistent product quality, and limited size options. As a result, most H-beams today are produced using the rolling method.
In modern steel production, H-beams are typically rolled using universal rolling mills. During the process, the web is formed between the upper and lower horizontal rolls, while the flanges are shaped simultaneously between the side of the horizontal roll and the vertical roll. However, since the universal rolling mill alone cannot press down the flange edge, an additional edger stand is usually placed after the universal stand. This device, known as an edge rolling machine, is used to control the flange width and flatten the edges.
In practice, the rolling operation often involves multiple stands working in groups. The billet is passed back and forth through these stands several times (as shown in Figure 2a), or it moves through a series of universal stands followed by one or two edger stands. Each pass reduces the cross-section gradually until the desired shape and dimensions are achieved. Due to friction between the horizontal roll and the flange during rolling, the roll surfaces experience significant wear. To ensure the rolls can be restored to their original shape after heavy use, the sides of the upper and lower horizontal rolls in the roughing mill, along with the corresponding vertical rolls, are angled between 3° and 8°.
To correct any angular deviation in the final flange, a finishing universal mill—also called a universal finishing mill—is installed. In this mill, the horizontal roll’s side is perpendicular to its axis or slightly inclined, typically no more than 20 minutes, and the vertical roll is cylindrical (as illustrated in Figure 2d).
Rolling H-beams on a universal rolling mill offers several advantages. It allows for more uniform section extension and minimizes the speed difference between the inner and outer surfaces of the flange, which helps reduce internal stress and surface defects. By adjusting the reduction amount of the horizontal and vertical rolls, H-beams of various specifications can be produced. The design of the universal rolling mill's rolls is simple, durable, and cost-effective, significantly reducing roll consumption. The major benefit of this method is that, within the same dimension series, only the thickness of the web and flange changes, while other dimensions remain constant. This means that a single set of universal passes can produce a wide range of H-beam sizes, offering great flexibility and convenience for users.
In cases where a universal rolling mill is not available, sometimes a vertical roll frame is added to a standard two-high rolling mill to create a universal pass for H-beam production. However, this method results in lower dimensional accuracy, difficulty in forming a precise right angle between the flange and the web, higher costs, and smaller size capabilities. Rolling H-beams for columns using this method is particularly challenging, which limits its application and user base.