碳钢、低合金钢16年大气暴露腐蚀研究

SIXTEEN-YEAR ATMOSPHERIC CORROSION EXPOSURE STUDY OF STEELS

获得了 17种钢在我国 7个试验点的 16年大气暴露腐蚀试验数据 ,试验点的环境包括了亚热带、温带、工业性、海洋性 ,干燥环境及湿热环境等各种典型环境 .钢的大气腐蚀的发展遵循幂函数规律 :D =Atn;其中D为腐蚀深度 (mm) ,t为暴露时间 (年 ) ,A、n为常数 .短期暴露所显示的大气腐蚀规律与长期暴露所显示的不同 ,可靠的大气腐蚀参数只能来自长期暴露 .对碳钢和低合金钢 ,危害最大的污染是SO2 及氯离子 .SO2 在开始一、二年危害作用很突出 ,但在以后作用明显下降 .对非耐候钢 ,湿热条件对长期腐蚀的影响非常大 ,如果加上污染 ,会造成特别高的腐蚀 .

Sixteen-year atmospheric exposures of 17 steels at 7 sites were made.Power function D=Atn can describe the corrosion process quite well.The pattern of corrosion development in the early stage is different from that in the long-term exposure.It is not proper to determine corrosivity of an environment by means of one-year exposure result,a method stipulated by ISO-9226.It is also not correct to predict the long-term corrosion results by short-term exposure.The major damaging pollution factors are sulphur dioxide and chloride ion.The effect of sulphur dioxide is serious in the early exposure years.It is no longer so in the later years.Environment factor of humid hot is much more important in long run.In addition of chloride ion pollution,an extradinary high corrosion can be resulted in mild steels.