EFFECT OF CATHODIC PROTECTION ON FRACTURE BEHAVIOUR OF LOWALLOY STEELS IN SEAWATER

查看全文 作　　者：ZHENG Wenlong ZHU Xiying SU Limin Shanghai Research Institute of Materials,Shanghai,China ZHENG Wenlong,Senior Research Engineer,Shanghai Research Institute of Materials,99 Handan Road,Shanghai,China 出　　处：《Acta Metallurgica Sinica(English Letters)》索引1989年第2卷第1期,共6页 摘　　要：Fracture behaviour of low-alloy steels AIST4340,HY100,Welten60,AISIA537 and A131 inartificial seawater under static,cyclic loading and at cathodic protection potential has beeninvestigated by using the techniques of fracture mechanics, electrochemistry andelectronfractography.The results reveal that at hydrogen evolution potentials(cathodic pro-tection potential)the critical yield strength required for the occurrance of SCC decreasesfrom 985 at corrosion potential(E_c)to 872 MPa.The effect of cathodic protection on crackpropagation of corrosion fatigue(CF)is not simple,it is closely related to the yield strengthof steels and their SCC behaviour.For the steels with high yield strength,cathodic protectionpromotes(da/dN)_Ⅱ evidently,and reduces △K_th value.The(da/dN)-△K curves dis-play a plateau at the third stage of CF for steels with medium or low yield strength.It is men-tioned that the cathodic protection potential for oceaneering constructures should be control-led at top level of the protective range.It seems reasonable that the strength of steel foroceaneeing use might be increased by 200 or 300 MPa. 关 键 词：low-alloy steel cathodic protection stress CORROSION CRACKING CORROSION FATIGUE CRACK PROPAGATION rate