螺纹钢中MnS夹杂物诱发的局部腐蚀行为

Localized Corrosion Behavior Induced by MnS Inclusions in HRB400E Rebar Steel

采用全自动夹杂物分析仪、浸泡实验和电子背散射衍射仪(EBSD)等手段研究了HRB400E螺纹钢中不同尺寸MnS夹杂物在Cl^(-)环境中诱发局部腐蚀行为。原位浸泡结果表明:MnS夹杂物尺寸越大,越容易诱发局部腐蚀行为。EBSD结果表明:尺寸大于40μm^(2)的夹杂物容易引发腐蚀,和周围有较多的小角度晶界和较高的位错密度有关。同时,团簇大尺寸夹杂物共同诱发局部腐蚀形成的蚀坑面积大于单一夹杂物诱发的蚀坑。

The effect of MnS inclusions with different sizes on the corrosion behavior of HRB400E rebar steel in 2%NaCl solution was investigated by means of automatic inclusion analyzer,immersion tests and Electron Backscattered Diffraction.The in-situ immersion test results showed that the localized corrosion was more easily induced by the relatively larger MnS inclusions than the smaller ones.The EBSD results suggested that corrosion was more likely initiated by inclusions with size above 40μm^(2),and this may be related to the presence of more low-angle grain boundaries and higher dislocation densities around them.Meanwhile,compared with the pit induced by a single inclusion,the width of pits initiated by clusters of large-size inclusions were greater.