Flange bolts classification: 1, hex flange type: hex head has two kinds, one kind is flat brain, another kind is concave brain. 2, the surface color category: according to different requirements, the surface has plating JunLu, color of white, yellow, another never rust dacro. 3, flange categories: according to the use of flange bolts, plate size nods different demands are each are not identical, otherwise flat-bottomed and take the points, take tooth gear up skidproof. 4, according to the stress of the connection way, there are common and articulation hole use. Articulation hole using flange bolts to and pore size to cooperate, used in by transverse force. In order to meet the needs of after installation lock, have stem with a hole, these holes can make bolt vibrated when not loose. Some flange bolts not threads of strength to do fine, that thin rod flange bolts. The flange bolts to be become force coupling. Steel structure has special high strength bolts. The head will do some bigger. Dimensions also has change.