U-shaped steel, Mining Support Steel, 25U, Material 20Mnk, Baori Steel Custom Industrial AccessoriesU-shaped steel (full name: Hot-rolled U-shaped steel for mine tunnel support)U-shaped steel is a type of steel with a cross-section resembling the English letter "U," sometimes taking the shape of the Japanese letter "ひ" as well.The new standard, issued in 2008, became a national recommended standard effective April 1, 2009.GB/T 4697-2008U-channel steel bracketKey Features: High pressure-bearing capacity, long support duration, easy installation, and resistance to deformation.Main Applications: Primarily used for mine tunneling, secondary support of mine tunnels, and support for mountain tunneling, etc.As the main type of steel used for manufacturing retractable metal supports for tunnels, U-shaped steel is widely adopted both domestically and internationally.Due to varying understandings of the performance and requirements of U-shaped steel, the cross-sectional shapes, geometric parameters, and materials of U-shaped steel in different countries are not uniform.Our domestically produced U-shaped steel models mainly include 18U, 25U, 29U, and 36U. The first two are from the 1960s and are waist-located; the latter two are from the 1980s and are ear-located. The U18, due to its low load-bearing capacity, is now rarely produced.