Shear Fracture Arrestability of Controlled Rolled Steel X70 Line Pipe by Full-Scale Burst Test

Abstract

The High Strength Line Pipe Research Committee organized by the Iron and Steel Institute of Japan has conducted five full-scale burst tests on line pipe of 48 in. o.d. × 0.720 in. w.t. (wall thickness) and grade X70 under pressure of 80 percent SMYS with air: 1) to study the influence of separation on the arrestability of shear fracture, and 2) to obtain the material criterion for arresting the propagating shear fracture. Test pipes of Charpy V notch energy from 80 to 290J with different amount of separation, were produced from both controlled rolled steels and quenched and tempered steels. These research projects clarified that the separation of material itself did not influence the crack propagation behavior and its arrestability. Furthermore, the material criterion for arresting the shear fracture was analyzed by the pressure-velocity relationship counterbalancing the crack velocity curve and gas decompression curve.