国内外用于管道重要连接上的管法兰标准主要是欧洲DIN标准及美洲ASME B16.5、B16.47标准为代表两大体系。同一体系内各国的标准基本上是可以相互配用的，不同体系则不能互相配用。其中阀门用紧固件是压力管道系统的重要组成部分，法兰盘多使用螺栓类紧固件，而单头螺栓当拉紧力较大时，容易在螺杆和螺丝头连接处断裂，故不能用于中、高压法兰上。双头螺栓不仅可以用于中、高压法兰上，而且还便于从双面拧紧。
DThere are mainly two pipe flange standards used for important pipe connections at home and abroad: European DIN standards and American ASME B16.5 and B16.47 standards. The products in the same system standards can basically be matched with each other, but in different systems cannot be matched.Fasteners for valves are an important part of the pressure pipeline system. Bolt-type fasteners are mostly used for flange plates, When the tension is large, single-head bolts are easy to break at the connection of screw. So, they cannot be used on medium and high-pressure flanges. Double-end studs can not only be used on medium and high- pressure flanges, but also be easily tightened from both sides.
