A516 Gr 55 plates API Std 650 low-alloy steel tanks

Welders participating in the construction of API Std 650 low-alloy steel tanks must pass the examination and perform welding within the validity period of the qualified items. Special operators such as on-site maintenance electricians, cranes, and shelf workers must hold job certificates. All oil pipelines need to use arc welding for bottoming and electric welding to ensure the welding quality. Oil tanks and process pipelines must be tested for non-destructive flaws in accordance with the flaw detection ratios and methods required by the design and acceptance specifications. The flaw detectors must be certified.

For all API 620 crude oil tank other materials, the impact test temperature shall be at least 30°F colder than the design metal temperature. Alternately, materials impact tested at the design metal temperature or lower with Charpy impact test energy value of 25 ft-lb (average), 20 ft-lb (minimum) are acceptable for design metal temperatures above –40°F. API Std 650 low-alloy steel tanks materials with an energy value of 30 ft-lb (average), 25 ft-lb (minimum) are acceptable for design metal temperatures of –40°F or lower.

Under the action of the earthquake, API 650 storage tank is mainly damaged by the phenomenon of the lower part of the API Std 650 low-alloy steel tanks tank wall. Therefore, the key point of seismic calculation is to prevent the tank wall from buckling under axial pressure.