API Std 650 flat-bottom oil storage tanks maximum slenderness ratios

Heat-affected zone impact specimens shall be taken across the weld and as near the surface of the material as is practicable. The API Std 650 flat-bottom oil storage tanks material specimens shall be of sufficient length to locate the notch in the heat-affected zone after etching. The notch shall be cut approximately normal to the material surface to include as much heat-affected zone material as possible in the resulting fracture. Impact test specimens shall be cooled to the temperature stated in Q.22.

Structural features of API 650 double-layer oil tank: steel glass fiber reinforced plastic double-layer structure, special processing method is adopted between the API Std 650 flat-bottom oil storage tanks internal steel shell and glass fiber reinforced plastic layer, so that a gap of 0.1 mm is created between the internal and external layers. Even if the API 650 oil storage tank leaks, it can ensure that the contained dangerous substances only flow in the gap, and will not immediately overflow the external environment.

In order to prevent the deformation of the bottom of metal vertical API Std 650 flat-bottom oil storage tanks during welding, comprehensive control measures such as strict control of assembly geometry size, reasonable welding procedure, process control of welding deformation and rigid fixation are adopted during assembly welding. The specific methods are as follows:
1. Strictly control welding groove forming of API Std 650 flat-bottom oil storage tanks.
2. Strictly control the size of tank welding seam assembly.
3. Define the welding sequence of tank bottom plate.
4. Reasonable distribution of welders.