A Study on the Sensitivity to Pressure Reversal fracture with ERW Variables in Hot coil API-X70

열연 API-X70 강재의 ERW 조건에 따른 피로파괴 감수성 고찰

A pressure reversal is where ERW pipes fail at an applied pressure lower than one experienced previously. The susceptibility to pressure reversals of ERW joints has been investigated by varying heat input in the range of 230-268㎾ power and seam annealing temperature of 850-970$^{\circ}C$. The application of repeated loading to notched three point bend specimens was used in this study. There was no occurrence of reversals in all the condition investigated. Furthermore, the bond line ductility is found to be satisfactory. These results can be explained by the fact that a bond line free from defects is successfully obtained from a wide range of ERW conditions.