API standard 650 self anchored flatbottom tanks gauge float wells
Prefabricating API standard 650 self anchored flatbottom tanks components before construction can improve construction efficiency, save time and cost, and is currently a common method for the construction of large vertical storage tanks. The main prefabricated components of a large vertical API standard 650 self anchored flatbottom tanks include the tank body, the storage tank wall, the top of the storage tank, the bottom of the storage tank, and the accessories of the storage tank. The prefabrication of the components should follow a reasonable workflow, and carry out appropriate heat treatment and testing, so as to improve manufacturing accuracy.
Preheat TreatmentMany laboratory tests have shown preheat treatment of carbon steel to 300°F-400°F to be the equivalent of the post-heat treatment at no less than 1100°F insofar as the physical properties of the weldment are concerned.40,41 Some tests have indicated a slight advantage of the post-heat treatment. Most of the tests have been made on plates 3/4 in. - 1 in. thick; results must be viewed with caution if preheating is applied appreciably beyond this thickness range. However, for all practical purposes, improvement resulting from preheating is sufficiently well established so that preheat should be considered for field fabrication of API 620 crude oil tank plates over 3/4-in. thick whenever toughness of the tank API standard 650 self anchored flatbottom tanks is highly desired and the thermal post-heat treatment is impractical.
Upon completion of API standard 650 self anchored flatbottom tanks construction, provide Purchase with a Vendor's Certification that the tank conforms to the requirements of API 650 and to the additional requirements as specified.