API 650 unanchored liquid-storage tanks subject to a small internal pressure

Unqualified welding quality of API 650 unanchored liquid-storage tanks is prone to hidden dangers such as oil tank steel plate cracks and leakage. To avoid this situation as much as possible, it needs to be avoided when the oil storage tank is manufactured. Scientific and reasonable measures are adopted to control the welding quality when welding the API 650 unanchored liquid-storage tanks. How to reasonably control the welding process quality of oil storage tanks?

When API 650 storage tank is designed, when the design pressure is small F2 kPa, the impact of air pressure on the API 650 unanchored liquid-storage tanks tank wall thickness is not considered in the tank wall design.

Japan is a typical shipping first, and its raw materials are imported from Oceania, central and South America and other Asian countries. Most of the API 650 unanchored liquid-storage tanks steel produced is exported to China and other Asian countries, and a small amount is exported to America. Shipping is the main way of its API 650 unanchored liquid-storage tanks steel international transportation. According to the data, steel goods account for about 20% of the total sea freight in Japan. The domestic transportation of Japanese steel is mainly truck.

Any joints between the adjacent sections of API 620 oil storage tank stiffening rings, as shown in Figure Q-1, shall be made so that the required moment of inertia of the combined ring-shell section is provided. Weld joints between adjacent sections shall be made with full-thickness and full-penetration butt-welds. Stiffening-ring butt-welds may employ metal backing strips. Backing strips and the associated welding shall be made in a manner that provides a smooth contour in the rat hole and all other weld joint ends. All weld passes shall be started at the rat hole and other weld joint ends and shall be completed by moving away from these ends. Passes shall be overlapped away from edges to provide a smooth continuous weld.