What are the main points of the design American Standard flange bolt

　　Can calculate the bolt in the pre tightening condition and operation condition need minimum bolt area AA and AP, the calculation need bolt area am AA and AP to the larger value, the design of the actual configuration of the bolt area AB should be not less than am, and should be left a certain margin. The key point of the design of the bolt is to control the diameter of the center circle of the bolt as small as possible, and the choice of the specification and quantity of the bolt should be appropriate, the Db is too large or too small. American standard flange moment arm for the load to bolted to the center distance, pectinata of center bolt circle diameter size, directly affects the size of American standard flange moment, so try to tightening bolt circle diameter dB, on the flange design is very favorable. Bolt arrangement, according to GBl50 - 1998 "steel pressure vessel"