weld inspection weld defect. defective welded butt seam of the pipeline and branch du50

arc branch butt construction corrosion danger defect defective design drawings du50 edges electric energy gas gasoline heat height heights industry inspection kerosene life many metal metalwork oil petrochemical pipeline pipelines plant pore precautions preparation process project pumping risk safety seam slag specialist steel technological tee treatment weld welded welder welding welds work working