API standard 650 self-anchored flat-bottom steel tanks accessories

Inspection of low-pressure storage tank Butt-weldsComplete penetration and complete fusion is required (to the degree mandated by the acceptance criteria for examination method utilized) for welds joining tank wall plates to API standard 650 self-anchored flat-bottom steel tanks tank wall plates. Examination for quality of welds shall be made using either the radiographic method specified in API 620 standard 7.15.1 and applied in 7.17, or alternatively, by agreement between the Purchaser and the Manufacturer, using the ultrasonic method specified in 7.15.3.1. In addition to the radiographic or ultrasonic examination, these welds shall also be visually examined as specified in 7.15.5. Furthermore, the Purchaser’s inspector may visually inspect all butt-welds for cracks, arc strikes, excessive undercuts, surface porosity, incomplete fusion, and other defects.

API 650 storage tank stipulates that if the thickness of the lower wall panel obtained by calculating the anti-overturning moment is greater than the thickness of the API standard 650 self-anchored flat-bottom steel tanks hydrostatic pressure test (both do not include the corrosion allowance).

The manufacturing requirements of bottom plate of vertical metal tank, API standard 650 self-anchored flat-bottom steel tanks are as follows: 1. In order to compensate welding shrinkage, the layout diameter of tank bottom is 5-2mm than the design diameter; 2. The butt joint of edge plate of tank bottom shall be machined automatically or semi-automatically; 3. The distance between any two adjacent welding joints on the tank bottom plate and the distance between the butt joint of edge plate and the longitudinal weld of bottom ring wall plate shall not be greater than 200 mm.