U steel support Mainly characteristic: bear big pressure, support time is long, easy installation and not easy to deform etc. Mainly application: mainly used in mine tunnel, second support of mine tunnel, and the support of mountain tunnel. It is used as the main profile steel of the compressible metal support of tunnel, U-shaped steel is widely used at domestic and overseas. However, the cognition of the performance and requirement of U-shaped steel are not consistent, therefore, the section shape, geometry and material of u beam are different. The model of u beam produced in China mainly includes 18U, 25U, 29U and 36U. The first two is the sixties product, belong to the waist position. The latter two is the eighties product, belong to the ear position. In GB/T 4697-2008, the model of 40U is added in addition to the above four models.