Floating roofs 6 m (20 ft) in diameter API 650 welded storage tanks

X-ray inspection is mainly applicable to the internal inspection of pressure bearing parts and materials of metal oil tanks such as API 650 welded storage tanks. It can clearly find the blocky defects inside the welded joints. However, the cost and resource consumption of radiographic testing are large. Magnetic particle testing can effectively detect the surface and near surface defects of API 650 welded storage tanks etc. metal oil tanks, but magnetic particle testing can not effectively identify the internal defects of oil tanks.

Impact Tests for High Alloys
Impact tests are not required for the high-alloy (austenitic stainless steel) API 650 welded storage tanks base materials, nickel alloy based materials, aluminum base materials, and weld deposited for the nonferrous (aluminum) materials. Impact tests are not required for austenitic stainless steel welds deposited by all the welding processes for services of –200°F and above. Austenitic stainless steel welds deposited for service below –200°F by all welding processes shall be impact tested in accordance with Q.6.2 except that the required impact values shall be 75% of the values as given in Q.2.2.2, Item c.

The inner layer of API 650 tank is the same as that of single layer tank. It is made of high-quality steel plate in strict accordance with the standard of "steel welded atmospheric pressure vessel". The thickness of API 650 welded storage tanks steel plate reaches the standard and the service life is longer.