埋地热力管道Q235钢盐碱土腐蚀的现场试验研究

摘要

The technology of buried heat pipelines has been used more and more because of the demand for the urban construction,environmental protection and energy conservation.Therefore,much attention should be payed to the problem of soil corrosion urgently.In this study,the corrosion behaviors of a typical heat pepeline steel,i.e.Q235 steel were investigated in saline soil containing high concentrations of Cl-at 80 ℃.The results showed that,within 6 months,the corrosion products on the surface of Q235 steel became thickened continually.However,the average corrosion rate first increased and then decreased with the time,the maximum value reached 0.47 mm/a.The corrosion products of Q235 steel reached about 1500 μm after 6 months of the field tests.And the outer layer was composed mainly of Fe3O4,Fe2O3 and SiO2,the inner layer was consisted mostly of Fe3O4.It is suggested that the influence of high temperature,high concentration of Cl-and water brought by the seasonal freezing and thawing resulted in the acceleration of corrosion of the heat pipeline steel buried in saline soil.%采用现场埋片试验方法,研究了典型热力管道材料Q235钢在80℃含有高浓度Cl-的盐碱土中的腐蚀行为。结果表明,在6个月的埋片周期内,随着时间的延长,Q235钢试样表层腐蚀产物不断增厚,而平均腐蚀速率呈先升高后降低的趋势,且最大平均腐蚀速率为0.47mm/a;现场埋片6个月的Q235钢试样表面附着大约1500μm厚的腐蚀产物,外层腐蚀产物主要含有Fe3O4、Fe2O3以及SiO2;内层腐蚀产物主要含有Fe3O4。作者分析认为,埋地热力管线钢在盐碱土中受高温、高Cl-浓度以及季节性冻融带来水分的影响呈现出加速腐蚀状态。