EC21 Product Catalogs - steel u channels i beam h beam angles sections http://www.ec21.com/ec-market/steel u channels i beam h beam angles sections.html Supply Varous Kinds of Medium-Sized Materialhttp://asyingyi07.en.ec21.com/Supply_Varous_Kinds_of_Medium--1770392_3308338.htmlI-beam: 20MnK 14.Mine support section: 16MnK; 20MnK 15.Mine flat steel: Q345A, B 16.U-beam: 30Mn 17.?-beam: 34SiMn 18.M20090622