石化设备常见的应力腐蚀开裂原因及防护措施

Cause analysis on stress corrosion cracking of petrochemical equipment and protective measures

石化设备应力腐蚀开裂会造成突发性事故,且在各项腐蚀破坏中占比高,需引起设计和使用单位的重视。通过对引起应力腐蚀开裂的外加载荷、残余应力和腐蚀产物;氯化物-阳极溶解、硫化物-氢脆、浓热碱-碱脆、氮化物-硝脆和高温高压水等影响因素进行分析讨论,来全面了解应力腐蚀开裂。阴极保护、缓蚀剂和防腐涂层等防护技术可以抑制应力腐蚀开裂;从材料选择、制造安装工艺、使用维护、腐蚀在线监测等方面也能达到预防和降低应力腐蚀开裂的目的。

Stress corrosion cracking of petrochemical equipment will cause unpredictable hazards.It accounts for quite a high proportion of all corrosion damages,which require the highest attention in design and use.Comprehensive understanding of stress corrosion cracking was learnt through analysis of environmental factors affecting stress corrosion:applied load,residual stress and corrosion products;chloride-anodic dissolution,sulfide-hydrogen embrittlement,concentrated hot alkali-alkali embrittlement,nitride-nitrate embrittlement,high temperature and high pressure water.Protective measures were adopted such as cathodic protection,corrosion inhibitor,anti-corrosion coating.The purpose of preventing and reducing corrosion was achieved by making improvements on material selection,manufacturing and installation process,use and maintenance,on-line monitoring.