Regarding the issue of local thinning in containers
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The local thinning amount of the vessel is not specified in either GB150 or JB 4732. Appendix 32 in Volume 8, Book 1 of ASME provides a permissible provision. But it is for internal-pressure vessels. European standards also have corresponding regulations on this; aside from differences in details compared to American standards, they do not specify that it is a pressure vessel. I wonder if anyone else has encountered a similar problem? Why does the American standard specify only internal pressure? In my personal understanding, external pressures should not be subject to this restriction. That is, the requirement for external pressure should be lower than that for internal pressure. The European standards are more stringent in this regard than the American standards. I would appreciate some advice from experts in this field. It’s best to explain it from the perspective of the principles of force.
Is the poster referring to corrosion-induced thinning during the manufacturing process or during use? For the manufacturing stage, meeting the minimum wall thickness requirement is sufficient, while equipment in use must comply with the regulations for regular inspection of pressure vessels. The section on safety status rating specifies what types of pitting are permitted, taking both depth and area into account
In the manufacturing process, is it acceptable if the entire thickness is the minimum thickness instead of the thickness specified in the drawings?