CSA G40.21 grade 350W plates API 650 mixed material tanks

Allowable compressive stresses shall be in accordance with 5.5.4 except that for aluminum alloy plate the allowable compressive stresses shall be reduced by the ratio of the modulus of compressive elasticity to 29,000 for values of (t – c)/R less than 0.0175 and by the ratio of the minimum yield strength for the aluminum alloy in question to 30,000 for values of (t – c)/R equal to or greater than 0.0175 (see 5.5.2 for definitions). In all other equations in this standard API 650 mixed material tanks where yield strength or modulus of elasticity is used, such as Equations 27 and 28, similar corrections shall be made for aluminum alloys.

Selection of nominal diameter D of API 650 storage tank. In the design calculation of API 650 storage tank, the bottom plate thickness is the net plate thickness, that is, the actual thickness minus the corrosion allowance. In the design and calculation of API 650 mixed material tanks wall thickness in hydrostatic test, the thickness of bottom plate is the total thickness of steel plate.

Requirements for prefabrication of the top of large vertical API 650 mixed material tanks: The prefabrication of the tank top shall be prefabricated in blocks according to the drawings. Pay attention to the spacing of the welds after installation when setting out the material. Reinforcing ribs should be formed and inspected with an arc-shaped template. When a single top plate needs to be spliced, butt joints should be used. The forming of a single top plate should be welded between the reinforcing ribs and the top plate on the mould. After forming, check with an arc-shaped sample plate, and the gap should not be greater than 10 mm.