API 650 insulated tanks reinforcement and welding

Deformation of the welding seam of the API 650 insulated tanks is a common quality problem during the actual use of the API 650 insulated tanks, which easily causes the tank body to leak and affects the safety of the oil storage tank. The welding seam deformation of the API 650 insulated tanks is mainly caused by the lack of reserved welding seam gap and irregular operation. The oil storage tank has not reserved the corresponding weld gap, resulting in deeper root removal during the front welding activity. The heat output of the weld will increase under the influence of a long time, and the deformation of the weld will gradually become serious.

The API 650 insulated tanks stiffener ring and backing strip (if used) are primary components, and they shall comply with the requirements of API 620 storage steel tank Q.2.1. The stiffener rings may be fabricated from plate using an intermittent weld on alternating sides between the web and the flange.
Except for aluminum or stainless steel tanks, all fillet welds shall consist of a minimum of two passes. The ends of the fillet welds shall be 2 in. from the rat hole (see Figure Q-1), and these welds shall be deposited by starting 2 in. from the rat hole and welding away from the rat hole. An acceptable alternative to the detail that includes stopping fillet welds 2 in. short of the rat hole would be to weld continuously through the rat hole from one side of the stiffener to the opposite side. All craters in fillet welds shall be repaired by back welding.

Determination of API 650 oil tank container: The total volume should be determined according to factors such as transportation mode and API 650 insulated tanks fuel supply cycle. For train and ship transportation, the maximum consumption is not less than 20-30 days; the maximum consumption for automobile transportation is not less than 5-10 days.