原油船货油舱用耐蚀钢及焊接接头腐蚀性能研究

Study on the Corrosion Performance of Corrosion Resistanct Steel and Weld Joint for Cargo Oil Tanks of Crude Oil Tankers

根据国际海事组织《油船货油舱耐蚀钢认可试验程序》,对新开发的SGNS-A32级货油舱用耐蚀钢及其焊接接头进行浸泡腐蚀试验,并辅以金相分析、电化学试验等研究手段,探讨了成分、组织等对耐蚀钢腐蚀行为的影响。结果表明,耐蚀钢板和焊接接头的力学性能和腐蚀性能均满足国际海事组织标准要求,钢板浸泡均匀腐蚀速率0.3mm/a,焊接接头焊缝与母材间腐蚀深度小于12μm;耐蚀钢板组织为铁素体+珠光体组织,焊缝组织为铁素体+贝氏体,热影响区组织为贝氏体;母材的自腐蚀电位较正,其次是焊缝,热影响区的自腐蚀电位最负。

Corrosion tests in immersion were carried out for the late-model SGNS-A32 corrosion resisitant steel and weld joint for cargo oil tank according to the <Test procedures for qualification for corrosion resistance steel for cargo tank in iol tankers > by the International Maritime Organization(IMO),the metallography and electrochemistry were also used to discuss the effect of chemical composition and microstructure on the corrosion resistance.The experimental results show that the mechanical properties and corrosion resistance of ship plate and weld joint all meet the requirements of IMO,the general corrosion rate of ship plate was 0.3 mm/a,and the depth between weld joint and base matal under the corrosion was less than 12 μm;The microstructure of base metal is ferrite and pearlite,weld joint is ferrite and bainite,and heat-affected zone is bainite;The corrosion potential of base metal was positive than the weld joint,and the heat-affected zone was more negative than the others.