API standard 650 self-anchored flat-bottom steel tanks bottom joints

The process parameters should be strictly controlled in sand blasting of API standard 650 self-anchored flat-bottom steel tanks. The working pressure of abrasive chamber is between 0.5 and 0.6a, and the outlet pressure of air compressor shall not be lower than 0.6 WPa. According to the test results, the distance between nozzle and workpiece shall be controlled at 80 - 200 mm and spraying angle of 30 ~ 75°is appropriate.

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 self-anchored flat-bottom steel tanks is highly desired and the thermal post-heat treatment is impractical.

Welding certification is regulated by Section 10 of the American Society of Mechanical Engineers (ASME). For both API standard 650 self-anchored flat-bottom steel tanks storage tank API 650, non-destructive inspection is required, but third-party inspection is not required.