API standard 650 cylindrical tanks welding symbols

Weld inspection of API standard 650 cylindrical tanks, vertical oil tank wall plate: In the welding inspection process of oil tank wall plate, attention should be paid to the defects of thick wall plate, such as incomplete penetration, incomplete root fusion and cracks. If there is a root incomplete penetration defect, it is necessary to open the weld joint with carbon arc air gouging and grinding machine grinding, or even weld through, and then weld again after the defect is removed.

Any joints between the adjacent sections of API 620 oil storage tank stiffening rings, as shown in Figure Q-1, shall be made so that the required moment of inertia of the combined ring-shell section is provided. Weld joints between adjacent sections shall be made with full-thickness and full-penetration butt-welds. Stiffening-ring butt-welds may employ metal backing strips. Backing strips and the associated welding shall be made in a manner that provides a smooth contour in the rat hole and all other weld joint ends. All weld passes shall be started at the rat hole and other weld joint ends and shall be completed by moving away from these ends. Passes shall be overlapped away from edges to provide a smooth continuous weld.

Test welds of each API 650 tank nozzle and manway reinforcing pad (or each section of multiple piece pad) using dry air and apply a soap solution test in the presence of Purchaser's Inspector before hydro testing the API standard 650 cylindrical tanks tank. Tap one inch NPT test hole in each pad or section.