Investigation of Residual Stresses within a Friction Welded Steel Pipeline by the Contour and X-ray Diffraction Methods

Residual stresses (RS) in pipes welded by a fully automated friction welding process, called FRIEX, are investigated using the contour method (CM) and X-ray diffraction (XRD). Samples were produced self-developed equipment, which is based on interaction between consumable intermediate rotary ring two stationary pipe sections, varying loading rate applied during of API 5L B with an X65 ring. Mechanical metallurgical properties locally analyzed through metallography microflat tensile tests. RS measured XRD CM showed comparable values; zones found HAZ compressive its adjacent areas. Tensile approximately half local yield strength components also found, mostly internal surface, their values decrease increasing loads. Microflat tests increase TMAZ HAZ, clear influence rates.