Experiments and evaluation on residual strength of X52 steel pipe with various internal defects

The strength of the natural gas transmission pipe is reduced due to sag deformation and corrosion defects. However, there are rare experiment data quantitatively describe effect defect’s size position on strength. This paper designed seven groups steel pipes with various defects perform hydrostatic bursting experiments, research effects pipe. experimental sample selected as X52 material. Three types were set up: concave combinational defects, one defect, two rupture size, strain around perimeters before after experiments measured, finally yielding strain-pressure curve each Comparisons results show that defect depth dominant factor affecting Moreover, DNV-RP-F101 code tends yield less distance beyond which will not affect other. ASME B31G also give a lower residual in comparison PCORRC criterion, formula has higher accuracy for pipes. average relative deviation between calculated corroded 14.87%.