In urea production,tubes are exposed to corrosive media such as high-temperature and high-pressure ammonia,carbon dioxide,and urea solution,making them susceptible to corrosion,particularly intergranular corrosion,To address this,it is essential to select appropriate stainless steel materials like 316L Mod and 310MoLN,which are designed for urea service,Surface treatments such as acid pickling and passivation can enhance corrosion resistance by forming a dense chromium oxide layer,