An Investigation on the Longitudinal Cracking of Electric Resistance Welded Steel Pipes

This study focuses on longitudinal cracks created within the weld seam of electric resistance welded steel pipes, after quenching and tempering processes. Results of the structural examinations conducted by utilizing optical microscope, energy-dispersive spectrometer equipped scanning electron microscope and X-ray diffractometer suggest that manganese silicate-type complex oxides gathered within the weld seam played crucial role in crack initiation and propagation by triggering de-bonding at the complex oxide/matrix interface and/or splitting of the complex oxides under thermal stresses generated during cooling.