A537 class 2 plates API Std 650 carbon steel tank

Crack treatment of API Std 650 carbon steel tank weld area: find out the crack tip with ray or ultrasonic flaw detection, drill cut-off holes at both ends of the crack with the cut-off method, the hole depth is slightly greater than the crack depth, or groove (crack stop groove) is made by angle grinder at both ends of the crack, shovel and grind the whole crack, and grind it into a suitable groove; use radiographic inspection and dye detection to verify that the crack has been completely excavated, and finally repair welding.

In this project a cylindrical tank 75 ft in diameter is designed for an internal pressure of 0.5 lbf/in.2 gauge in the vapor space. The plate material is ASTM A131 Grade B steel for thicknesses of 1/2 in. and less.
The top course of the butt-welded cylindrical sidewall is 1/4 in. thick. The tank API Std 650 carbon steel tank roof is a conical shape with a 2:12 slope and a 1/4 in. thickness with single full-fillet welded lap joints. The maximum design liquid level is 6 in. below the plane of juncture of the roof and sidewall.

The vent pipe mouth should be 4m or more above the ground. The nominal diameter of the API Std 650 carbon steel tank API 650 petroleum storage tank vent pipe should be no less than 50mm and a flame arrestor should be installed.