API Std 650 open-top tanks hydrostatic testing requirements

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 Std 650 open-top tanks is highly desired and the thermal post-heat treatment is impractical.According to API standard 650, the stairs used for API 650 petroleum storage tanks or thermal insulation tanks should be double longitudinal beams supported by a minimum of ribs. If the gap between the API Std 650 open-top tanks tank shell and the stringer of the API 650 petroleum storage tank exceeds 200mm, handrails should be provided on both sides of the stairs. Unless otherwise specified, according to API Std 650 open-top tanks ASTM A123, the following accessories shall be hot-dip galvanized. The damaged zinc coating should be repaired with zinc alloy.We supply 5800 tons A53 Gr B ERW pipes to Qatar for Qatar Integrated Railway Project - Green Line. This is the first Metro Line in Qatar, and it is located in Doha. We got the order by tender, launched by the Qatar Railways Company for designing, construction and completion of Green Line Project. Before putting order, a delegation from the API Std 650 open-top tanks project side visited us and several other famous steel pipe mills in China for 15 days. Finally, we were chosen and finished the task exceeding their expectations.The bottom plate of the vertical API Std 650 open-top tanks directly contacts with the foundation soil, which is suitable for the flexible foundation, and its settlement characteristics are quite different from that of the rigid foundation. For the settlement calculation of the foundation of a vertical API Std 650 open-top tanks, the one-way compression layered sum method can be used. The calculation method is to divide the foundation soil into several layers of compression within the calculation depth of the foundation settlement, and then find the sum. The calculation method of the compression amount of each layer is the same as the calculation method of the compression amount under the condition of no lateral deformation.Our company will accept the product quality objection registration record, pass it to the API Std 650 open-top tanks production unit and relevant departments, and timely coordinate the supervision of product API Std 650 open-top tanks quality objection. Our company coordinates the relevant department personnel to the customer unit to carry on the investigation, the processing.