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The minimum thickness requirements specified in GB150 take into account the effects of typical forming, alignment, and welding methods during container manufacturing on the product’s shape, in order to meet the thickness requirements of the respective manufacturing processes and to ensure compliance with the requirements regarding the cylindrical shape, geometric dimensions, and tolerances of the container shell. For small-diameter cylinders (such as those below DN1500), it also meets the stiffness requirements during manufacturing, transportation, and installation ； For cylinders with larger diameters, in order to save steel, no minimum thickness requirement for stiffness is specified; in such cases, necessary support measures must be taken during manufacturing, transportation, and installation depending on the specific conditions, to ensure the required stiffness and prevent unacceptable deformation. The specific requirements for the minimum thickness of the shell after processing, excluding the corrosion allowance, are as follows: 1) For containers made of carbon steel or low-alloy steel, it shall be not less than 3 mm ； 2) For high-alloy steel containers, it should generally be not less than 2 mm ； Here, “general” refers to special containers in certain industries; based on successful usage experiences, the wall thickness of pressure vessels made of high-alloy steel can be less than 2 mm. The standards also specify minimum thicknesses required to ensure stiffness; for example: 1) the method for determining the minimum thickness of heads as specified in GB150.3 ； 2) GB151 specifies the minimum thickness of heat exchanger shells ； 3) Based on the method of connection between the tube sheet and the heat exchange tubes, the application scenario of the heat exchanger (properties of the fluid), and whether the tube sheet is a composite type, GB151 specifies the principles for determining the minimum thickness of the tube sheet. That is, in the design process, designers must not only consider the strength calculations related to the tube sheet but also adhere to the minimum thickness requirements specified by the standards.