北京作为我国最大的供热城市, 其城市埋地热力管线土壤腐蚀研究具有非常重要的典型代表意义和实际工程应用价值。本工作研究了20钢在北京市4种不同类型土壤模拟溶液中的腐蚀行为以及在强腐蚀性桥梁下土壤中的电化学行为。结果表明, 20钢在北京市桥梁下土壤和城市主干道土壤中发生明显局部腐蚀, 而在城市公共绿地土壤和居民区土壤中腐蚀轻微, 以全面腐蚀为主; 在60天浸泡期内, 20钢在不同模拟溶液中的腐蚀速率大小依次为: 桥梁下土壤>城市主干道土壤>居民区土壤>城市公共绿地土壤。进一步对腐蚀性强的桥梁下土壤模拟溶液进行电化学测试发现, 桥梁下土壤的强腐蚀性对20钢并未一直持续, 随着反应的进行, 试样表面腐蚀产物的积累对基体起到了一定的保护作用, 最终使得腐蚀速率降低。

As the biggest heat-supply city in china, the soil corrosion of heat-supply pipelines buried in Beijing underground has an important significance as well as practical application value. The corrosion behaviors of 20 steel in four different types of simulated soil solution as well as the electrochemical behaviors in soils under the bridge were investigated. The results show that localized corrosion existed in soils under the bridge and city main roads. However, the corrosion behavior of 20 steel in the soils under urban grassland and residential areas was mainly general corrosion. After 60-days immersion, the ranking of corrosion rates of 20 steel in simulated soil solutions was in soil under the bridge > in soil under city main road > soils under residential areas in soil under urban grassland. The electrochemical measurements through the simulation solution of soils under the bridge showed that the corrosion of 20 steel didn't continue in the strong corrosive soil under the bridge since. the accumulation of corrosion products on the sample surface tesulted in a protective effect on the substrate and finally decreased the corrosion rates with the poogress of reactions.