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For thick plates, some specific requirements are as follows: 01 Carbon steel and low-alloy steel plates with a thickness of 12 mm or more (excluding the plates of multi-layer pressure vessels) used to manufacture the main pressure-bearing components of pressure vessels shall be subject to ultrasonic testing on a sheet-by-sheet basis in accordance with NB/T 47013.3-2015; the acceptable quality grade must be at least Grade II. This applies to cases involving media that pose an extreme or high level of hazard； (2) For use in wet H2S corrosion environments ； (3) Design pressure ≥ 10 MPa ； 02 Shell sections with a thickness greater than 36 mm made of Q245R and Q345R should be used in the normalized state. 03 Other compressed components with a thickness greater than 50 mm (flanges, tube sheets, flat covers, etc.) made of Q245R and Q345R should be used in the normalized state. 04 Steel plates with a shell thickness greater than 60 mm shall undergo tensile testing and V-notch impact testing after each heat treatment. 05 For quenched and tempered steel plates with a thickness greater than 36 mm, and normalized or normalized and tempered steel plates with a thickness greater than 80 mm, an additional impact test at 1/2T can be carried out. 06 For steel plates with a thickness greater than 36 mm and an Rm value of ≥540 MPa, a drop hammer test may be conducted; the test is carried out in accordance with GB/T6803 using P-2 type specimens. The acceptance criteria regarding the temperature at which no plastic transformation occurs are specified in the design documents. 07 For shell assemblies with a thickness greater than 100 mm made of steel plates and their welded joints, stricter requirements for impact testing shall be specified; the following methods may be adopted: (1) The impact test temperature shall be based on MDMT, with the impact energy requirement increased ； (Frequently used) (2) The impact test temperature is below MDMT, and the impact energy value remains unchanged ； 08 The thickness of the reinforcement ring is less than or equal to 1.5 times the thickness of the shell. 09 When the nominal thickness of the shell is greater than 38 mm, a reinforcement ring structure shall not be used. 10 Flanges made of carbon steel or low-alloy steel with a cross-sectional thickness greater than 50 mm shall be normalized. 11 Cold-formed compressed components made of carbon steel or low-alloy steel, with a thickness greater than 16 mm before forming or a reduction in thickness of more than 10% after forming; if the deformation rate exceeds the values specified in Table 4 for p330, heat treatment should be carried out after forming to restore the material’s properties. 12 For quenched and tempered steel plates with a thickness greater than 36 mm, or normalized or normalized and tempered steel plates with a thickness greater than 50 mm, an additional impact test at 1/2T can be carried out.