ASTM A181 forgings API standard 650 mechanically-anchored flat-bottom tanks

Due to the volatility of oil products, the volatile consumption of oil products is inevitable in the storage process of large oil storage tanks such as API standard 650 mechanically-anchored flat-bottom tanks. The volatilization of oil causes economic losses and pollution to the environment. Especially in the open air environment, large-scale oil storage tanks in the petrochemical industry will continue to accumulate energy when exposed to the sun, causing their surface and interior to heat up rapidly, causing sun overheating, and accelerating the volatilization of oil. How to effectively reduce the volatile consumption of large oil storage tanks?

The API standard 650 mechanically-anchored flat-bottom 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.

Storage tanks API standard 650 mechanically-anchored flat-bottom tanks designed in accordance with the rules and guidelines of API 650 are called API 650 storage tanks. API 650 is a control rule for welded storage tanks that work normally in the normal pressure range.