安徽省电网接地材料Q235钢的土壤腐蚀特性及规律性研究

Soil Corrosion Characteristics of Q235 Steel Grounding Material Used in Power Grid in Anhui Province

针对安徽省内代表性变电站站点土壤自然环境埋藏1a期的Q235钢试样,分析试样表面腐蚀层的形貌及组成,探讨其土壤腐蚀机理;采用失重法获取不同站点Q235钢试样1a期土壤腐蚀速率;最后,采用Spearman相关性分析方法,开展主要土壤理化性质对该试样1a期土壤腐蚀影响规律研究。结果表明,Q235钢试样土壤腐蚀产物主要为Fe_(3)O_(4)、Fe_(2)O_(3)、γ-FeOOH和α-FeOOH,但不同站点腐蚀产物的相对量存在差异。部分站点土壤中含有较高的S2-,形成FeS腐蚀产物,说明土壤微生物生理活动也影响Q235钢的腐蚀。安徽省内代表性站点Q235钢试样的平均土壤腐蚀速率为0.053 mm/a,大多数处于“中”腐蚀等级,腐蚀速率较高的站点主要集中于沿江地区与工业污染区。基于Spearman相关性分析,Q235试样1a期土壤腐蚀速率与安徽省土壤质地及土壤理化性质指标相关性大小的排序为:pH值>土壤质地>土壤电阻>含盐量>含水量>氧化-还原电位>Cl-浓度。

Q235 steel samples were buried for one year in soils of test sites in 100 substations,which distributed at different areas in Anhui province presenting various typical soils of peculiar characteristics and meteorological conditions.Afterwards,the corrosion rates and corrosion products of the test samples were assessed via mass loss measurement,SEM,EDS and XRD.The results showed the rust scales formed on the samples were composed mainly of Fe_(3)O_(4),Fe_(2)O_(3),γ-FeOOH and α-FeOOH,but their relative amount varied by different soil test sites.The S2-content in the soils of some soil test sites is high enough to generate FeS as the corrosion product of the samples.It indicates that the physiological activities of microorganisms have an effect on the soil corrosion behavior of the Q235 steel.In general,according to the test results from several typical soil test sites of Anhui province,Q235 steel samples present an average soil corrosion rate of 0.053 mm/a,and their corrosion grades are mostly“moderate”.The soil test sites where the samples have a high corrosion rate are mainly located in the areas along the Changjiang River and/or the industrial pollution areas.In terms of the Spearman correlation analysis,the correlation degree sequence of the index of soil texture and soil physicochemical properties affecting the one year soil corrosion behavior of the Q235 steel is:pH value>soil texture>soil resistance>salt content>water content>redox potential>Cl-concentration.