API 650 unanchored liquid-storage tanks subsurface investigation and construction

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.

Supply covers for API 650 unanchored liquid-storage tanks connections specified with the service covers remaining in place following tests. For API 650 tank connections not specified to be supplied with service covers, the test covers may be removed after testing.

We supply 5800 tons A53 Gr B ERW pipes to Qatar for Qatar Integrated Railway Project - Green Line. This is the first Metro Line in Qatar, and it is located in Doha. We got the order by tender, launched by the Qatar Railways Company for designing, construction and completion of Green Line Project. Before putting order, a delegation from the API 650 unanchored liquid-storage tanks project side visited us and several other famous steel pipe mills in China for 15 days. Finally, we were chosen and finished the task exceeding their expectations.

Prefabrication requirements for API 650 unanchored liquid-storage tanks, large vertical storage tanks:
1. The machined surface of the edge of the steel plate should be smooth, and there should be no defects such as slag inclusion, delamination, cracks, etc., and the surface hardened layer produced by the flame cutting groove should be removed.
2. Dimension deviation after steel plate processing: the deviation of plate width is less than 1.5 mm, the deviation of plate length is less than 2 mm, and the difference between diagonals is less than 3 mm.

The 365 day service system is implemented, and the business, loading and delivery are handled as usual in holidays and festivals. Actively help users solve difficulties. When users encounter difficulties in handling business, they should actively coordinate with the external solution; if they need to solve the problems internally, they should solve them in a timely manner without prevarication and wrangling. In line with the API 650 unanchored liquid-storage tanks principle of "fairness, justice and timeliness", coordinate with relevant departments and deal with all kinds of objections in a timely manner.