Research On The Assembly Procedure Of Gasketed Flange Joint Of Metal-to-metal Contact Type

It’s very common to use bolted flange joints in nuclear power and petrochemical industries and petrochemical industrics.But it would lead to serious accident because of joints leakage, and one main reason of the leakage is the result of the poor regulation of its installation process.This paper mainly research for bolt tightening procedure of flange joint with MMC gasket, combining ASME PCC-1legacy and JIS B2251tightening pattern to find out ways to modify and simplify the tightening sequence. Taking an example of the PN5.0and DN300flange, two ways of more optimal measures tightening sequence are proposed. The first method is two round of four corner bolts respectively70%and110%of the target preload tightened before3times of100%target preload of whole bolts sequentially.The second method is to firstly preload four corner bolts of70%target load, followed3times of100%target preload for entire bolts.Using the finite element method ANSYS to simulate ASMEPCC-1legacy methods, ASME PCC-1alternative pattern3#simplified scheme, as well as two proposed ways. Comparative analysis of the distribution of bolt preload for each mode after the tightening method showed that even with the fewer rounds can make bolt preload force distribution uniformity and achieve the target preload.Flange bolts experiments using strain gauges to monitor the whole process of bolt pre-tighten, the experimental results also proved the correctness of finite element analysis.