API standard 650 storage tanks fittings

Preheat Treatment
Many 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 storage tanks is highly desired and the thermal post-heat treatment is impractical.

Before the start of erection, inspect each API 650 tank foundation to ensure that it is level and acceptable to receive Work. Remove temporary erection attachments welded to the interior or exterior of the API standard 650 storage tanks shell or to the bottom by arc gouging, and grind weld area smooth.

The establishment of a correct method for evaluating the life of API standard 650 storage tanks requires the preparation of criteria related to the strength and cracks of API standard 650 storage tanks, mechanical damage mechanisms, corrosion mechanisms, and mathematical models of fatigue crack growth, etc., which are compiled into computer programs. In the process of programming the program, it is required to select the operating parameters, plates, reinforcement accessories, metal properties, corrosion levels, mechanical damage defects and other data of the oil storage tank under various conditions.