接地网材料在我国典型土壤环境下的腐蚀研究

发布时间：2018-07-07 09:26

本文选题：土壤腐蚀 + 热镀锌钢　；参考：《机械科学研究总院》2016年硕士论文

【摘要】：对于电网系统,接地网主要承担着泄流的任务,对电力系统的保护有巨大作用。在综合考虑接地网材料的导电、导热、易加工、易施工、经济等特性的条件下,我国接地网材料一般选用Q235碳钢,其缺点是碳钢在土壤中的耐蚀性很差。为了达到接地网对泄流的要求,在电阻率高的土壤中会添加化学降阻剂,化学降阻剂中的Cl~-、SO_4~(2-)又会增加碳钢的腐蚀。为了保障接地网的正常运行,必须频繁地对接地网进行开挖检查、更换,且此过程工程量大、难度也较高,不仅影响接地网的正常运行,还会带来大量的人力物力财力的消耗。对接地网材料在土壤中的腐蚀行为研究对接地网的选材、维护周期确定有重大意义。本文讨论了碳钢、镀锌钢、渗锌钢在天津大港、江西鹰潭、青海格尔木、新疆克拉玛依四个土壤站的腐蚀行为。碳钢、镀锌钢、渗锌钢经过2年的实地埋片试验。对大港滨海盐土、鹰潭酸性红壤、格尔木盐渍土和克拉玛依棕漠土的主要理化性质进行了分析比较；结合土壤理化性质和腐蚀速率得出各个站点影响土壤腐蚀性的关键因素。采用XRD物相结构检测来分析锈层的主要成分以及大致含量的变化,并通过与土壤理化性质的对比推断出土壤化学性质与腐蚀产物成分变化与转化的关系。电化学测试分析锈层对腐蚀介质的阻挡能力。研究结果表明：结合四个土壤站的理化性质和1年的腐蚀速率,并参考相关标准,大港滨海盐土鹰潭酸性红壤、克拉玛依棕漠土和格尔木盐渍土的腐蚀等级分别是重、中、轻和极轻。大港和鹰潭站碳钢主要以全面腐蚀为主；克拉玛依和格尔木站的碳钢主要以麻坑腐蚀为主。试验室对带锈试样的电化学测试结果说明,碳钢在四个站点的自腐蚀电位随时间呈下降趋势,说明碳钢耐蚀性在降低。综合碳钢在各个站点的腐蚀情况和土壤的理化性质,得出各个站点影响腐蚀的主要因素：影响大港滨海盐土腐蚀性的主要因素是含水率和C1-含量；影响鹰潭酸性红壤腐蚀性的主要因素是含水率和pH值；影响格尔木盐渍土腐蚀性的主要因素是土壤的透气性、孔隙率、氧含量和pH值；影响克拉玛依站棕漠土的腐蚀性的主要因素是土壤的含水率。镀锌钢和渗锌钢的腐蚀速率明显低于碳钢,所以镀锌、渗锌能显著提升碳钢在土壤中的耐蚀性。渗锌钢在大港滨海盐土、格尔木盐渍土、克拉玛依棕漠土等碱性土壤中的耐蚀性明显优于镀锌钢；鹰潭酸性红壤中,镀锌钢与渗锌钢的腐蚀速率差异不大,其耐蚀性也不相上下。土壤的化学性质如Cl~-和SO_4~(2-)的含量是决定镀锌钢和渗锌钢腐蚀产物成分和相对含量的因素。四个站点镀锌钢和渗锌钢的腐蚀产物中,大港、格尔木、克拉玛依三个碱性土壤站中,腐蚀产物主要以碱性氯化锌和氯代碱式硫酸锌钠为主。氯离子含量的提升,腐蚀产物中碱性氯化锌(Zn_5(OH)_8Cl_2·H_2O)的相对含量也有明显提升,由此说明氯离子会促进Zn_5(OH)_8Cl_2·H_2O的转化或生成。鹰潭站的酸性红壤中,镀锌钢和渗锌钢的各个周期主要腐蚀产物均为Zn_5(CO_3)_2(OH)_6,其原因主要是鹰潭站的Cl~-和SO_4~(2-)的含量都非常小,无法形成氯代碱式硫酸锌钠或碱性氯化钠。
[Abstract]:For the power grid system, the grounding grid is mainly responsible for the discharge task and has a great effect on the protection of the power system. In the condition of the comprehensive consideration of the electrical conductivity, heat conduction, easy processing, easy construction, economic and other characteristics of the grounding grid material, the Q235 carbon steel is generally used in the ground network materials in our country, and its disadvantage is that the corrosion resistance of carbon steel in the soil is very poor. In the ground network, chemical drag agents will be added to the soil with high resistivity. Cl~- and SO_4~ (2-) in chemical drag reducer will increase the corrosion of carbon steel. In order to ensure the normal operation of grounding grid, it must be frequently excavated to check and replace the ground network, and the process is large and difficult, which not only affects the grounding grid. Normal operation will bring a lot of manpower and material resources. The corrosion behavior of the docking ground network materials in the soil is of great significance to the selection of the ground network and the maintenance period. The corrosion of carbon steel, galvanized steel and zinc steel in Tianjin Dagang, Yingtan, Jiangxi, Qinghai Golmud and Karamay Xinjiang Karamay is discussed in this paper. Behavior. Carbon steel, galvanized steel, and zinc permeable steel after 2 years of field burial test. The main physical and chemical properties of Dagang coastal saline soil, Yingtan acid red soil, Golmud saline soil and Karamay brown desert soil were analyzed and compared. The key factors affecting soil corrosion by the physical and chemical properties and corrosion rate of soil were obtained. The XRD material was used. The relationship between the chemical properties of the soil and the change of the corrosion product composition and transformation was deduced from the comparison of the soil physical and chemical properties between the main components of the rust layer and the change of the rough content. The results showed that the physicochemical properties of the four soil stations were combined with the electrochemical test. The corrosion rate of quality and 1 years, and referring to the relevant standards, the corrosion grades of Yingtan acid red soil, Karamay brown desert soil and Golmud saline soil in Dagang coastal saline soil are heavy, medium, light and extremely light respectively. The main carbon steel in Dagang and Yingtan Railway Station is mainly based on Comprehensive corrosion; the main carbon steel in Karamay and Golmud Railway Station is mainly by jute pit corrosion. The results of electrochemical testing of rust specimens show that the self corrosion potential of carbon steel at four sites decreases with time, indicating that corrosion resistance of carbon steel is reduced. The corrosion of comprehensive carbon steel at various sites and the physical and chemical properties of soil are the main factors affecting corrosion at various sites: the main factors affecting the corrosivity of the coastal saline soil in Dagang Water content and C1- content are the main factors affecting the corrosion of acid red soil in Yingtan. The main factors affecting the corrosion of Golmud saline soil are soil permeability, porosity, oxygen content and pH value, and the main factors affecting the corrosion of the brown desert soil in Karamay station are the soil moisture content, galvanized steel and infiltration. The corrosion rate of zinc steel is obviously lower than that of carbon steel, so galvanizing and zinc permeation can significantly improve corrosion resistance of carbon steel in soil. The corrosion resistance of zinc permeable steel in the alkaline soil of Dagang coastal saline soil, Golmud saline soil and Karamay brown desert soil is obviously superior to that of galvanized steel; in Yingtan acid red soil, the corrosion rate of galvanized steel and zinc permeable steel is not different. The chemical properties of soil, such as Cl~- and SO_4~ (2-), are factors determining the components and relative content of corrosion products of galvanized and zinedic steel. The corrosion products of four sites of galvanized steel and zinc permeable steel, in Dagang, Golmud and Karamay, are mainly alkaline zinc chloride and alkaline zinc chloride. The relative content of the alkaline zinc chloride (Zn_5 (OH) _8Cl_2. H_2O) in the corrosion products also improved obviously, which indicates that the chloride ion will promote the transformation or formation of Zn_5 (OH) _8Cl_2. H_2O. In the acid red soil of Yingtan Railway Station, the main corrosion products of the galvanized and zinc permeable steel are all the main corrosion products in the acid red soil of Yingtan Railway Station. The main reason of Zn_5 (CO_3) _2 (OH) _6 is that the content of Cl~- and SO_4~ (2-) in Yingtan Railway Station is very small, so it is impossible to form zinc chloride sodium sulfate or alkaline sodium chloride.
【学位授予单位】：机械科学研究总院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TG172.4;TM862

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