The foundations for API Std 650 mixed material tanks

API 650 Tanks in which liquid fluids are stored and designed to withstand atmospheric pressure operation, less than 18 kPa, or internal pressures not exceeding the weight of the API Std 650 mixed material tanks roof, with temperatures no higher than 93, 3 C are included in the scope of this design code.

Inspection of weld and micro crack of API Std 650 mixed material tanks: the inner and outer surface of API Std 650 mixed material tanks, weld and heat affected zone shall be observed by naked eyes first. 100% ultrasonic testing or 100% penetrant testing are carried out for butt welds of API Std 650 mixed material tanks. For the defects found by 100% magnetic particle inspection, dye detection, 100% ultrasonic inspection or 100% penetrant inspection, the radiographic inspection shall be used again to ensure the accuracy of the test results.

In this project, an elemental area of API 620 oil storage tank wall is constructed of ASTM A516 Grade 55 steel plate subjected to a meridional unit force, T1, of 2620 lbf/in. tension and a latitudinal unit force, T2, of 2880 lbf/in. compression. The meridional radius of curvature, R1, is 132 in., and the length of the normal from the surface to the axis of revolution, R2, is 409 in. The joints in the wall are spot-radiographed, double-welded butt joints, and no corrosion allowance is required.
The problem in this example is to graphically find the minimum thickness of tank wall required for the given conditions (see API 620 tank standard 5.10.3.3).
Solution: As determined from Table 5-1, the maximum, allowable tensile stress value, Sts, for ASTM A516 Grade 55 steel plate in simple tension is 16,500 lbf/in.2. Since the compressive stress is latitudinal, the governing value of R for this situation is R1, or 132 in.

The business department is mainly responsible for communicating with customers, from the manufacturing of steel plates, steel pipes and other products, knowing customers' needs and processing conditions, etc. within the time agreed with customers, the delivery time is short, the price is the most competitive, and the service is the best. Their responsibilities are to deal with customer consultation, solve customer problems, update production plans, and instruct the logistics department to deliver products to customers.

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