API 650 flat-bottom oil storage tanks toughness procedure of plates

The main types of metal storage tanks are vertical dome roof tank, vertical external floating roof tank, vertical inner floating roof tank, spherical oil tank and horizontal oil storage tank. API 650 flat-bottom oil storage tanks is vertical tank. The capacity of vertical dome roof oil storage tank is generally less than 10000 cubic meters. The wall plate adopts sleeve type fillet weld, and it is usually installed by inverted or forward installation method during construction.

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 650 flat-bottom oil storage 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.

Floating roofs shall comply with API standard 650, Appendix C (Attachment 01) or with the API 650 flat-bottom oil storage tanks requirements as layed (laid )down in the national Chinese specifications SH3046-92 and GBJ128-90.