Examination Of Mechanical Properties And Weld Zone Of X70 Pipe Steel After Welding

The demand for large diameter pipes in terms of their strength and toughness properties is increasing day by day. The quality and mechanical strength values of the steels used in new gas pipeline projects are gradually increasing. Today high strength steels are used instead of the steels with low yield values. In this study the micro-structure mechanical properties of the high strength X70 steel used in the Trans Anatolian Gas Pipeline Project TANAP were investigated before and after the welding process and the weld zone was examined. The submerger arc welding process has been employed for the weld process. While the mechanical properties were determined by tensile notched bend impact bend and hardness measurements the microstructures were examined by using optical microscope and scanning electron microscope SEM. The radiographic and ultrasonic methods were employed in the non-destructive test of the weld zone.