Hot-rolled Hexagonal Steel and Octagonal Steel Sizing, Shapes, Weights, and Tolerances (abstract) GB 705–89
Hot-rolled hexagonal and octagonal steel are steel products that are manufactured with the help of hot rolling, which is used to shape the metal into shape and size. Hexagonal and octagonal steel are commonly used in steel building construction, machinery, and other mechanical components, to name a few. While the steel can also be used for other applications, the main application for this type of metal is for structures.
Hot rolling is a process of forming metal into shape, using thermal energy and high temperatures. During this process, high temperatures allow the metal to be workable, where it can be rolled, stretched, bent, and cut into a variety of shapes. In the making of hexagonal and octagonal steel, the billets are heated to very high temperatures, then forced through a series of rollers until the desired shape and size is achieved. This process then allows the metal to be cut into pieces according to the customers specifications.
The sizing, shapes, and tolerances of hot-rolled hexagonal and octagonal steel are set by the Chinese standard GB 705–89. This standard details the specifications for the hexagonal and octagonal steel, including permissible deviations from the exact dimensions, shapes, and sizes. Additionally, the standard outlines the allowable variation in the weights for hexagonal and octagonal steel, as well as the strength that is required for proper sizing and shape formation.
The exact tolerances allowed for the manufacture of hexagonal and octagonal steel are quite specific and for this reason, the standard also outlines rules for guidance on the machining of these products. For instance, the range of tolerances established for each shape must be taken into consideration when machining techniques such as grinding, turning, and drilling are employed. In addition, the standard also provides guidance on the appropriate hardness of each shape, and the maximum weight the steel can bear.
Finally, the standard requires that the finished product be fully marked with the date of manufacture, the steel type, and other relevant information. This marking is done on each individual piece of hexagonal and octagonal steel. As long as the hot-rolled hexagonal and octagonal steel conforms to the detailed specifications outlined in the GB 705–89, it can be used for a variety of purposes in a variety of different applications.
