Abstract: Carbon steel/low alloy steel-stainless steel composite plate ensures the mechanical properties (such as strength, toughness) and corrosion resistance required by pressure vessels, and its excellent economy is widely used in pressure vessels; Taking two companies whose main shell material is Q345R+S30403 (N10276) PTA crystallizer and natural gas glycol tower composite plate equipment as examples, the causes of corrosion and perforation during operation were analyzed, and the manufacturing, inspection and maintenance process and anti-corrosion control measures were optimized to further improve the quality of the equipment in the process of manufacture and inspection and maintenance.